7Baggers

NiSource Inc
(NYSE:NI) 

NI stock logo

NiSource Inc., an energy holding company, operates as a regulated natural gas and electric utility company in the United States. The company operates through two segments, Gas Distribution Operations and Electric Operations. It provides natural gas services and transportation for residential, commer...

Founded: 1912
Full Time Employees: 8,363
Sector: Utilities
Industry: Utilities-Regulated Gas

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Quarterly
Annual
    Unit: USD2026-03-31 2025-12-31 2025-09-30 2025-06-30 2025-03-31 2024-12-31 2024-09-30 2024-06-30 2024-03-31 2023-12-31 2023-09-30 2023-06-30 2023-03-31 2022-12-31 2022-09-30 2022-06-30 2022-03-31 2021-12-31 2021-09-30 2021-06-30 2021-03-31 2020-12-31 2020-09-30 2020-06-30 2020-03-31 2019-12-31 2019-09-30 2019-06-30 2019-03-31 2018-12-31 2018-09-30 2018-06-30 2018-03-31 2017-12-31 2017-09-30 2017-06-30 2017-03-31 2016-12-31 2016-09-30 2016-06-30 2016-03-31 2015-12-31 2015-09-30 2015-06-30 2015-03-31 2014-12-31 2014-09-30 2014-06-30 2014-03-31 2013-12-31 2013-09-30 2013-06-30 2013-03-31 2012-12-31 2012-09-30 2011-12-31 2011-09-30 2011-06-30 2011-03-31 2010-12-31 2010-09-30 2010-06-30 2010-03-31 2009-12-31 2009-09-30 2009-06-30 2009-03-31 2008-12-31 2008-09-30 2008-06-30 2008-03-31 2007-12-31 2007-09-30 2007-06-30 2007-03-31 2006-12-31 2006-09-30 2006-06-30 2006-03-31 2005-12-31 2005-09-30 2005-06-30 2005-03-31 2004-12-31 
                                                                                        
      operating revenues
                                                                                        
      customer revenues
    2,322,300,000 1,886,600,000 1,240,200,000 1,246,500,000 2,149,500,000 1,539,700,000 1,046,100,000 1,054,100,000 1,643,000,000 1,381,900,000 1,002,600,000 1,067,200,000 1,896,100,000 1,683,600,000 1,058,200,000 1,156,500,000 1,840,300,000 1,353,600,000 918,800,000 952,400,000 1,506,500,000 1,153,100,000 861,500,000 932,700,000 1,525,900,000 1,358,700,000 891,000,000 969,200,000 1,834,500,000 1,436,000,000 855,800,000 982,100,000 1,717,200,000                                                    
      other revenues
    40,800,000 16,300,000 32,900,000 36,500,000 33,700,000 48,100,000 30,200,000 30,600,000 63,300,000 40,100,000 24,800,000 22,800,000 69,900,000 21,000,000 31,300,000 26,700,000 33,000,000 55,000,000 40,600,000 33,600,000 39,100,000 57,900,000 41,000,000 30,000,000 79,600,000 38,500,000 40,500,000 41,200,000 35,300,000 25,700,000 39,200,000 24,900,000 33,600,000        38,700,000                                            
      total operating revenues
    2,363,100,000 1,902,900,000 1,273,100,000 1,283,000,000 2,183,200,000 1,587,800,000 1,076,300,000 1,084,700,000 1,706,300,000 1,422,000,000 1,027,400,000 1,090,000,000 1,966,000,000 1,704,600,000 1,089,500,000 1,183,200,000 1,873,300,000 1,408,600,000 959,400,000 986,000,000 1,545,600,000 1,211,000,000 902,500,000 962,700,000 1,605,500,000 1,397,200,000 931,500,000 1,010,400,000 1,869,800,000 1,461,700,000 895,000,000 1,007,000,000 1,750,800,000                                                    
      operating expenses
                                                                                        
      cost of energy
    669,200,000 481,500,000 193,600,000 261,800,000 647,500,000 376,600,000 165,900,000 164,700,000 425,000,000 335,000,000 181,300,000 251,900,000 765,100,000 689,300,000 330,800,000 383,700,000 706,700,000 478,900,000 208,300,000 228,300,000 476,800,000                                                                
      operation and maintenance
    489,200,000 485,100,000 401,100,000 396,200,000 427,800,000 421,700,000 357,400,000 357,700,000 378,400,000 393,000,000 341,200,000 369,500,000 391,200,000 365,300,000 347,900,000 381,900,000 394,300,000 380,600,000 351,100,000 362,800,000 361,500,000 408,300,000 379,900,000 353,100,000 444,600,000 359,200,000 393,900,000 49,200,000 552,400,000 804,400,000 780,800,000 365,200,000 402,500,000 427,400,000 383,300,000 391,100,000 410,500,000 424,800,000 336,600,000 337,600,000 165,000,000 349,200,000 311,100,000 561,000,000 574,100,000 572,500,000 529,500,000 533,100,000 501,200,000 498,300,000 468,900,000 452,900,000 455,400,000 440,200,000 422,900,000 480,400,000 407,100,000 402,500,000 432,500,000 457,100,000 382,100,000 377,100,000 439,400,000 455,600,000 356,900,000 363,700,000 478,300,000 387,000,000 313,100,000 345,200,000 410,700,000 418,800,000 320,600,000 342,900,000 385,900,000 400,300,000 309,800,000 307,000,000 372,900,000 346,300,000 326,500,000 317,900,000 337,600,000  
      depreciation and amortization
    288,300,000 315,400,000 306,900,000 286,700,000 258,600,000 278,100,000 269,500,000 253,500,000 242,100,000 257,300,000 210,900,000 233,100,000 206,900,000 216,200,000 203,200,000 208,700,000 192,700,000 188,200,000 188,900,000 186,300,000 185,000,000 183,500,000 180,600,000 177,500,000 184,300,000 182,200,000 182,200,000 177,900,000 175,100,000 161,800,000 148,500,000 144,600,000 144,700,000 141,800,000 143,000,000 142,200,000 143,300,000 141,100,000 136,300,000 136,900,000 32,500,000 133,400,000 132,500,000 167,400,000 157,500,000 154,700,000 153,000,000 149,100,000 148,700,000 145,900,000 144,500,000 143,300,000 143,600,000 141,800,000 126,000,000 129,900,000 134,900,000 134,500,000 138,900,000 141,800,000 153,100,000 151,600,000 149,800,000 148,900,000 148,700,000 148,200,000 143,800,000 142,900,000 141,000,000 147,700,000 135,600,000 139,800,000 142,200,000 138,200,000 139,000,000 137,800,000 136,500,000 138,100,000 136,900,000 137,600,000 136,100,000 136,400,000 135,100,000  
      loss on impairment of assets
       400,000 300,000 3,200,000  2,900,000                                                                             
      other taxes
    97,200,000 105,700,000 74,600,000 74,200,000 89,600,000 89,600,000 65,700,000 67,300,000 77,400,000 70,700,000 61,200,000 66,900,000 71,800,000 67,200,000 51,200,000 65,600,000 84,300,000 75,700,000 65,100,000 66,500,000 81,000,000 74,900,000 70,200,000 68,200,000 85,900,000 74,900,000 67,900,000 66,400,000 87,600,000 71,500,000 58,900,000 65,500,000 78,900,000 67,500,000 57,500,000 56,200,000 76,000,000 66,200,000 56,600,000 50,200,000 19,200,000 58,900,000 53,700,000 79,100,000 102,400,000 77,800,000 68,000,000 73,400,000 101,100,000 78,900,000 64,300,000 70,900,000 86,800,000 72,400,000 62,400,000 74,700,000 59,200,000 67,800,000 93,000,000 74,000,000 62,000,000 64,500,000 86,900,000 75,500,000 53,700,000 52,600,000 103,400,000 82,400,000 58,200,000 63,300,000 103,600,000 80,000,000 56,400,000 65,000,000 101,600,000 76,800,000 49,100,000 60,600,000 103,000,000 86,200,000 51,900,000 60,100,000 103,100,000  
      total operating expenses
    1,543,900,000 1,387,400,000 975,600,000 1,020,100,000 1,423,800,000 1,171,000,000 858,000,000 847,700,000 1,122,900,000 1,059,400,000 794,400,000 921,100,000 1,435,000,000 1,339,100,000 932,800,000 1,039,900,000 1,273,000,000 1,124,200,000 812,300,000 843,800,000 1,112,400,000 992,900,000 809,700,000 871,000,000 1,457,300,000 1,435,200,000 840,500,000 546,900,000 1,495,600,000 1,540,100,000 1,210,900,000 888,600,000 1,350,200,000 2,161,000,000 583,800,000 589,400,000 629,800,000 631,500,000 529,400,000 524,500,000 211,400,000 541,900,000 498,400,000 799,000,000 829,000,000 792,800,000 747,600,000 754,900,000 735,300,000 715,800,000 667,900,000 666,900,000 685,600,000 654,400,000 610,600,000 700,700,000 601,600,000 604,800,000 665,100,000 673,700,000 598,300,000 593,200,000 676,200,000 696,800,000 563,700,000 564,500,000 723,500,000 622,700,000 511,900,000 555,300,000 648,400,000 639,600,000 519,800,000 552,400,000 629,400,000 614,200,000 495,100,000 509,900,000 612,600,000 571,900,000 514,500,000 535,300,000 575,300,000  
      operating income
    819,200,000 515,500,000 297,500,000 262,900,000 759,400,000 416,800,000 218,300,000 237,000,000 583,400,000 362,600,000 233,000,000 168,900,000 531,000,000 365,500,000 156,700,000 143,300,000 600,300,000 284,400,000 147,100,000 142,200,000 433,200,000 218,100,000 92,800,000 91,700,000 148,200,000 -38,000,000 91,000,000 463,500,000 374,200,000 -78,400,000 -315,900,000 118,400,000 400,600,000 270,000,000 99,600,000 124,500,000 416,500,000 224,900,000 113,700,000 138,200,000  219,500,000 109,700,000 165,100,000 530,100,000 351,300,000 157,800,000 219,600,000 533,700,000 344,100,000 176,400,000 193,500,000 428,100,000 297,500,000 137,200,000 195,100,000 147,500,000 163,300,000 399,200,000 255,400,000 123,300,000 139,200,000 403,200,000 249,900,000 99,600,000 103,900,000 348,300,000 298,700,000 107,900,000 116,600,000 394,800,000 241,100,000 112,900,000 143,300,000 434,600,000 244,400,000 136,400,000 131,600,000 368,500,000 302,500,000 93,200,000 119,400,000 437,700,000  
      yoy
    7.87% 23.68% 36.28% 10.93% 30.17% 14.95% -6.31% 40.32% 9.87% -0.79% 48.69% 17.86% -11.54% 28.52% 6.53% 0.77% 38.57% 30.40% 58.51% 55.07% 192.31% -673.95% 1.98% -80.22% -60.40% -51.53% -128.81% 291.47% -6.59% -129.04% -417.17% -4.90% -3.82% 20.05% -12.40% -9.91%  2.46% 3.65% -16.29%  -37.52% -30.48% -24.82% -0.67% 2.09% -10.54% 13.49% 24.67% 15.66% 28.57% -0.82% 190.24% 82.18% -65.63% -23.61% 19.63% 17.31% -0.99% 2.20% 23.80% 33.97% 15.76% -16.34% -7.69% -10.89% -11.78% 23.89% -4.43% -18.63% -9.16% -1.35% -17.23% 8.89% 17.94% -19.21% 46.35% 10.22% -15.81%      
      qoq
    58.91% 73.28% 13.16% -65.38% 82.20% 90.93% -7.89% -59.38% 60.89% 55.62% 37.95% -68.19% 45.28% 133.25% 9.35% -76.13% 111.08% 93.34% 3.45% -67.17% 98.62% 135.02% 1.20% -38.12% -490.00% -141.76% -80.37% 23.86% -577.30% -75.18% -366.81% -70.44% 48.37% 171.08% -20.00% -70.11% 85.19% 97.80% -17.73%   100.09% -33.56% -68.85% 50.90% 122.62% -28.14% -58.85% 55.10% 95.07% -8.84% -54.80% 43.90% 116.84% -29.68% 32.27% -9.68% -59.09% 56.30% 107.14% -11.42% -65.48% 61.34% 150.90% -4.14% -70.17% 16.61% 176.83% -7.46% -70.47% 63.75% 113.55% -21.21% -67.03% 77.82% 79.18% 3.65% -64.29% 21.82% 224.57% -21.94% -72.72%   
      operating margin %
    Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% -Infinity% Infinity% Infinity% Infinity% -Infinity% -Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% 0% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity%  
      other income
                                                                                        
      interest expense
    -191,600,000 -187,300,000 -179,800,000 -139,100,000 -132,800,000 -137,000,000 -134,600,000 -129,300,000 -116,300,000 -141,000,000 -129,200,000 -110,500,000 -108,900,000 -101,800,000 -91,600,000 -84,500,000 -83,700,000 -87,600,000 -84,400,000 -84,500,000 -84,600,000 -85,600,000 -95,200,000 -97,000,000 -92,900,000 -93,300,000 -95,900,000 -94,100,000 -95,600,000 -88,100,000 -83,400,000 -88,700,000 -93,100,000 -92,400,000 -87,900,000 -87,700,000 -85,200,000 -88,000,000 -85,000,000 -86,000,000 -18,200,000 -94,300,000 -94,900,000 -117,100,000 -111,000,000 -115,800,000 -109,600,000 -109,100,000 -109,100,000 -110,500,000 -103,700,000 -102,000,000 -98,600,000 -103,900,000 -107,900,000 -96,900,000 -95,700,000 -94,400,000 -89,800,000 -97,500,000 -97,600,000 -98,400,000 -98,700,000 -98,600,000 -104,800,000 -105,300,000 -90,500,000 -100,700,000 -100,200,000 -87,400,000 -91,800,000 -103,200,000 -100,800,000 -98,100,000 -98,600,000 -102,500,000 -96,200,000 -93,300,000 -95,800,000 -108,200,000 -107,100,000 -101,700,000 -104,000,000  
      other
    14,400,000 3,900,000 9,900,000 500,000 5,800,000 13,100,000 29,200,000 13,000,000 9,200,000 6,100,000 -1,600,000 2,000,000 1,500,000 22,200,000 10,100,000 9,000,000 10,900,000 3,600,000 14,300,000 12,400,000 10,500,000 12,200,000 8,000,000 6,500,000 5,400,000 -5,500,000 1,300,000 -300,000 -700,000 1,100,000 -1,700,000 12,800,000 31,300,000 1,700,000 200,000 700,000 1,800,000 3,700,000 3,500,000 4,100,000 3,600,000 7,300,000 7,800,000 60,100,000 46,300,000 57,100,000 77,300,000 116,700,000 77,000,000 61,600,000 61,400,000 68,000,000 56,300,000 24,400,000 50,900,000 83,400,000 54,000,000 71,400,000 110,100,000 96,000,000 142,700,000 112,000,000 328,900,000 840,600,000 24,600,000 14,100,000 310,300,000 283,600,000 268,300,000 292,900,000 371,000,000 280,800,000 197,500,000 246,200,000 320,700,000 252,700,000 183,500,000 184,200,000 348,300,000 381,700,000 222,900,000 202,000,000 243,500,000  
      total other deductions
    -177,200,000 -183,400,000 -169,900,000 -138,600,000 -127,000,000 -123,900,000 -105,400,000 -116,300,000 -107,100,000 -134,900,000 -130,800,000 -108,500,000 -107,400,000 -79,600,000 -81,500,000 -75,500,000 -72,800,000 -84,000,000 -70,100,000 -72,100,000 -74,100,000 -73,500,000 -330,600,000 -90,500,000 -87,500,000 -98,800,000 -94,600,000 -94,400,000 -96,300,000 -87,000,000 -118,100,000 -88,400,000 -61,800,000 -105,000,000 -83,100,000 -195,400,000 -84,000,000 -84,600,000 -81,500,000 -92,100,000  -88,500,000 -89,100,000 -207,800,000 -103,900,000 -114,700,000 -100,400,000 -101,600,000 -104,600,000 -108,400,000 -99,000,000 -88,700,000 -94,500,000 -107,500,000 -105,700,000 -163,600,000 -94,100,000 -93,800,000 -86,500,000 -197,700,000 -95,500,000 -95,800,000                       
      income before income taxes
    642,000,000 332,100,000 127,600,000 124,300,000 632,400,000 292,900,000 112,900,000 120,700,000 476,300,000 227,700,000 102,200,000 60,400,000 423,600,000 285,900,000 75,200,000 67,800,000 527,500,000 200,400,000 77,000,000 70,100,000 359,100,000 144,600,000 -237,800,000 1,200,000 60,700,000 -136,800,000 -3,600,000 369,100,000 277,900,000 -165,400,000 -434,000,000 30,000,000 338,800,000                                                    
      income taxes
    85,800,000 53,700,000 20,600,000 23,800,000 105,700,000 48,600,000 15,900,000 17,600,000 76,000,000 35,800,000 3,800,000 14,100,000 85,800,000 44,700,000 11,700,000 12,000,000 96,200,000 27,200,000 14,800,000 13,200,000 62,600,000 56,800,000 -64,900,000 5,900,000 -14,900,000 2,500,000 -10,200,000 72,200,000 59,000,000 -153,700,000 -94,500,000 5,500,000 62,700,000 217,400,000 2,500,000 -26,600,000 121,200,000 51,500,000 8,500,000 17,400,000 46,400,000 66,600,000 5,800,000 -15,300,000 150,900,000 82,300,000 25,900,000 39,500,000 162,700,000 82,700,000 27,900,000 32,700,000 118,200,000 63,400,000 11,500,000    107,900,000   15,400,000 109,800,000 55,300,000 6,800,000 6,100,000 97,500,000 68,000,000 -4,100,000 9,500,000 112,100,000 27,700,000 3,700,000 16,600,000 124,100,000 49,100,000 13,500,000 13,400,000 96,500,000 19,500,000 -5,800,000 12,300,000 123,400,000  
      net income
    556,200,000 278,400,000 107,000,000 100,500,000 526,700,000 244,300,000 97,000,000 103,100,000 400,300,000 191,900,000 98,400,000 46,300,000 337,800,000 241,200,000 63,500,000 55,800,000 431,300,000 173,200,000 62,200,000 56,900,000 296,500,000 87,800,000 -172,900,000 -4,700,000 75,600,000 -139,300,000 6,600,000 296,900,000 218,900,000 -11,700,000 -339,500,000 24,500,000 276,100,000 -52,400,000 14,000,000 -44,400,000 211,300,000 88,800,000 27,200,000 28,600,000  59,400,000 -4,900,000 -27,700,000 275,300,000 154,200,000 31,400,000 78,200,000 266,200,000 151,800,000 48,100,000 71,700,000 260,500,000 134,000,000 19,300,000 20,300,000 34,700,000 38,900,000 205,200,000 33,400,000 33,200,000 28,100,000 197,300,000 89,500,000 -15,400,000 -4,800,000 148,400,000 162,000,000 20,000,000 -202,300,000 99,300,000 67,000,000 11,000,000 26,700,000 216,700,000 62,500,000 25,800,000 21,000,000 172,900,000 68,000,000 -6,800,000 39,000,000 206,300,000  
      yoy
    5.60% 13.96% 10.31% -2.52% 31.58% 27.31% -1.42% 122.68% 18.50% -20.44% 54.96% -17.03% -21.68% 39.26% 2.09% -1.93% 45.46% 97.27% -135.97% -1310.64% 292.20% -163.03% -2719.70% -101.58% -65.46% 1090.60% -101.94% 1111.84% -20.72% -77.67% -2525.00% -155.18% 30.67% -159.01% -48.53% -255.24%  49.49% -655.10% -203.25%  -61.48% -115.61% -135.42% 3.42% 1.58% -34.72% 9.07% 2.19% 13.28% 149.22% 253.20% 650.72% 244.47% -90.59% -39.22% 4.52% 38.43% 4.00% -62.68% -315.58% -685.42% 32.95% -44.75% -177.00% -97.63% 49.45% 141.79% 81.82% -857.68% -54.18% 7.20% -57.36% 27.14% 25.33% -8.09% -479.41% -46.15% -16.19%      
      qoq
    99.78% 160.19% 6.47% -80.92% 115.60% 151.86% -5.92% -74.24% 108.60% 95.02% 112.53% -86.29% 40.05% 279.84% 13.80% -87.06% 149.02% 178.46% 9.31% -80.81% 237.70% -150.78% 3578.72% -106.22% -154.27% -2210.61% -97.78% 35.63% -1970.94% -96.55% -1485.71% -91.13% -626.91% -474.29% -131.53% -121.01% 137.95% 226.47% -4.90%   -1312.24% -82.31% -110.06% 78.53% 391.08% -59.85% -70.62% 75.36% 215.59% -32.91% -72.48% 94.40% 594.30% -4.93% -41.50% -10.80% -81.04% 514.37% 0.60% 18.15% -85.76% 120.45% -681.17% 220.83% -103.23% -8.40% 710.00% -109.89% -303.73% 48.21% 509.09% -58.80% -87.68% 246.72% 142.25% 22.86% -87.85% 154.26% -1100.00% -117.44% -81.10%   
      net income margin %
    Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% -Infinity% -Infinity% Infinity% -Infinity% Infinity% Infinity% Infinity% -Infinity% -Infinity% Infinity% Infinity% -Infinity% Infinity% -Infinity% Infinity% Infinity% Infinity% Infinity% 0% Infinity% -Infinity% -Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% -Infinity% -Infinity% Infinity% Infinity% Infinity% -Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% -Infinity% Infinity% Infinity%  
      net income attributable to noncontrolling interest
    49,100,000 20,600,000 12,300,000 -1,700,000 51,900,000 20,400,000 11,300,000 17,300,000 35,300,000 -45,500,000 13,300,000  4,800,000    4,500,000    1,000,000                                                                
      net income attributable to nisource
    507,100,000 257,800,000 94,700,000 102,200,000 474,800,000 223,900,000 85,700,000 85,800,000 365,000,000 237,400,000 85,100,000 58,800,000 333,000,000 244,500,000 65,800,000 67,000,000 426,800,000 165,900,000 63,200,000 60,300,000 295,500,000                 88,800,000 27,200,000 28,600,000  59,400,000 -4,900,000 -36,400,000 268,400,000                                        
      preferred dividends redemption premium
    3,600,000                                                                                    
      net income available to common shareholders
    510,700,000 257,800,000 94,700,000 102,200,000 474,800,000 223,900,000 85,700,000 85,800,000 344,300,000 225,600,000 77,000,000 39,900,000 319,200,000 230,800,000 52,000,000 53,200,000 413,000,000 152,200,000 49,400,000 46,500,000 281,700,000 70,700,000 -186,700,000 -18,500,000 61,800,000 -153,000,000 -7,200,000 283,100,000 205,100,000 -19,800,000 -345,100,000 23,200,000                                                     
      earnings per share
                                                                                        
      basic earnings per share
    1.06 0.54 0.2 0.22 1.01 0.48 0.19 0.19 0.77 0.54 0.19 0.1 0.77 0.56 0.13 0.13 1.02 0.39 0.13 0.12 0.72 0.18 -0.49 -0.05 0.16 -0.41 -0.02 0.76 0.55 -0.05 -0.95 0.07 0.82 -0.16 0.04 -0.14 0.65 0.27 0.08 0.09  0.18 -0.02 -0.11 0.85 0.49 0.1 0.25 0.85 0.48 0.16 0.23 0.84 0.44 0.06 0.07 0.12 0.14 0.73 0.12 0.12 0.1 0.71 0.32 -0.05 -0.02 0.54 0.59 0.08 -0.74 0.36 0.24 0.04 0.1 0.79 0.23 0.1 0.08 0.63 0.25 -0.03 0.15 0.76  
      diluted earnings per share
    1.06 0.53 0.2 0.22 0.48 0.19 0.19 0.77 0.5 0.17 0.09 0.71 0.52 0.12 0.12 0.94 0.36 0.12 0.11 0.72 0.18 -0.49 -0.05 0.16 -0.41 -0.02 0.75 0.55 -0.05 -0.95 0.07 0.81 -0.16 0.04 -0.14 0.65 0.27 0.08 0.09  0.19 -0.02 -0.11 0.85 0.48 0.1 0.25 0.85 0.48 0.16 0.23 0.83 0.44 0.06 0.06 0.12 0.14 0.72 0.11 0.12 0.1 0.71 0.32 -0.05 -0.02 0.54 0.59 0.07 -0.73 0.36 0.24 0.04 0.1 0.79 0.22 0.1 0.08 0.63 0.25 -0.03 0.14 0.76  
      basic average common shares outstanding
    479 1.8 472.1 471 470.4 4.8 451.9 448.5 447.9 2.9 413.5 413.3 412.8 0.8 406.5 406.4 406 0.7 393.2 393 392.7 0.8 383.8 383.5 383.1 0.8 374.1 373.9 373.4 4.4 363.9 354.2 338 2.7 331.1 325.1 323.7 0.4 322.3 321.7  0.3 318.1 317.5 316.6 0.2 315.4 315 314.2 0.3 312.8 312.2 311.1 290.3 0.3 280.8 280.2 279.3 0.3 278.1 277.6 276.9 0.3 275.4 274.7 274.2  274 274 273.9  273.9 273.8 273.6 0.2 272.5 272.4 272.3 0.2 271.7 271.2 270.3  
      diluted average common shares
    480.9 1.7 473.7 472.1 472.5 4.6 454.5 450.2 449.4 0.5 448.3 446.8 447.1 443.4 440.2 441.4 1.5 430.3 422.9 393.9 0.8 383.8 383.5 384.1 0.8 374.1 375.2 374.7 4.4 363.9 355.2 339 2.8 332.4 325.1 325.3 0.3 323.9 322.9  -0.9 321.5 317.5 317.4 0.6 316.6 316.1 315.1 0.6 313.8 313.2 312.1 3.7 300 1.1 289 287.1 285 1.2 279.9 278.4 277.5 -1.5 275.4 274.7 276.7  275.5 275.4 275.4  274.7 274.9 274.8 0.2 273.3 273.2 273.1 0.1 273.7 273.1 272.1  
      loss on sale of assets
     -300,000 -600,000 800,000  1,800,000 -500,000 1,600,000      1,100,000 -300,000  -105,000,000 800,000 -1,100,000 -100,000 8,100,000                     300,000 1,100,000                                        -500,000  
      preferred dividends
            -6,700,000 -8,200,000 -8,100,000 -12,700,000 -13,800,000 -13,700,000 -13,800,000 -13,800,000 -13,800,000 -13,700,000 -13,800,000 -13,800,000 -13,800,000 -13,700,000 -13,800,000 -13,800,000 -13,800,000 -13,700,000 -13,800,000 -13,800,000 -13,800,000 -8,100,000 -5,600,000 -1,300,000                                                     
      preferred redemption premium
            -14,000,000 -3,600,000  -6,200,000                                                                         
      gain on sale of assets
             -125,000 -200,000 -300,000                     -300,000        -5,300,000   -8,500,000 -5,000,000 -4,825,000 -2,900,000 -700,000 -15,700,000 -2,550,000 -9,800,000 -200,000 -200,000                                
      net loss attributable to noncontrolling interest
               -12,500,000  -2,250,000 -2,300,000 -11,200,000  -850,000 -1,000,000 -3,400,000                                                                 
      loss on early extinguishment of long-term debt
                         -100,000 -243,400,000        -33,000,000 -12,500,000    -111,500,000        -97,200,000                                         
      cost of sales
                         198,475,000 143,100,000 188,400,000 462,400,000 404,300,000 196,700,000 253,500,000 680,300,000 501,600,000 222,000,000 313,300,000 724,400,000 456,000,000 233,600,000 276,800,000 552,300,000 440,600,000 218,200,000 234,900,000  336,400,000 209,100,000 218,600,000 806,000,000 560,700,000 230,500,000 371,700,000 1,061,300,000 547,200,000 243,000,000 359,900,000 687,700,000 436,400,000 233,700,000 599,900,000 323,100,000 462,500,000 1,170,900,000 828,700,000 420,000,000 439,100,000 1,286,300,000 1,377,600,000 227,300,000 338,200,000 1,654,800,000 1,469,400,000 792,700,000 1,121,800,000 2,248,500,000 1,348,900,000 610,900,000 885,100,000 1,831,200,000 1,178,300,000 525,000,000 670,400,000 1,991,700,000 1,824,200,000 556,100,000 700,500,000 1,668,500,000  
      loss on classification as held for sale
                         100,050,000 35,600,000 84,400,000 280,200,000                                                            
      loss on sale of fixed assets and impairments
                         -100,000 300,000 -600,000 -100,000                                                            
      loss on sale of assets and impairments
                             -25,000 -200,000  200,000         -100,000 -100,000 -200,000                                             
      gain on sale of assets and impairments
                               -100,000  800,000 700,000   -25,000  -100,000                                                 
      dividends declared per common share
                                 0.195 0.195 0.195 0.39 0.175 0.175 0.175 0.35 0.16 0.165 0.165  0.208 0.31  0.52 0.255 0.26 0.26 0.5 0.245 0.25 0.25 0.48  0.24  0.23 0.23 0.46  0.23 0.23 0.46  0.23 0.23 0.46  0.23 0.23 0.46  0.23 0.23 0.46 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23  
      net revenues
                                            339,700,000                                            
      gas distribution
                                     660,200,000 239,400,000 327,100,000 836,500,000 606,600,000 212,300,000 294,200,000  486,400,000 208,900,000 305,900,000 1,080,700,000 719,000,000 240,300,000 423,500,000 1,215,000,000 685,700,000 255,100,000 393,300,000 892,200,000 577,200,000 226,300,000 718,800,000 326,700,000 500,400,000 1,372,000,000 971,600,000 327,000,000 454,300,000 1,341,100,000 827,200,000 297,300,000 448,800,000 1,716,900,000 1,473,400,000 544,400,000 923,800,000 2,229,700,000 1,314,400,000 461,400,000 771,400,000 1,899,300,000 1,192,900,000 392,900,000 605,300,000 1,998,200,000 1,735,200,000 380,100,000 658,300,000 1,826,800,000  
      gas transportation
                                     286,400,000 191,600,000 204,900,000 338,600,000 275,100,000 180,000,000 207,800,000  229,900,000 172,100,000                                          
      electric
                                     420,000,000 485,800,000 458,000,000 421,700,000 411,600,000 465,500,000 391,500,000  374,200,000 428,400,000 375,600,000 394,700,000 392,600,000 424,600,000 404,800,000 450,000,000 388,200,000 413,400,000 384,500,000 377,300,000 360,000,000 418,000,000 326,700,000 404,700,000 349,200,000 347,100,000 330,600,000 397,700,000 340,500,000 317,900,000 311,000,000 320,000,000 285,400,000 296,800,000 306,200,000 379,100,000 339,800,000 331,800,000 321,400,000 377,400,000 333,300,000 325,900,000 314,200,000 377,400,000 301,900,000 305,700,000 302,700,000 381,700,000 281,900,000 282,300,000  
      gross revenues
                                     876,575,000 917,000,000 990,700,000 1,598,600,000     1,097,800,000 817,200,000 1,169,000,000 2,149,700,000 1,691,100,000 1,123,900,000 1,335,100,000 2,320,500,000 1,596,800,000 1,076,800,000 1,212,300,000 1,794,300,000 1,380,300,000 973,500,000 1,489,900,000 1,068,700,000 1,228,300,000 2,232,200,000 1,754,100,000 1,138,100,000 1,171,100,000 2,358,300,000 2,317,900,000 884,800,000 1,009,200,000 2,720,200,000 2,385,500,000 1,409,100,000 1,792,100,000 3,289,700,000 2,228,000,000 1,241,000,000 1,577,100,000 2,893,700,000 2,049,200,000 1,156,500,000 1,311,900,000 2,972,800,000 2,698,600,000 1,163,800,000 1,355,200,000 2,681,500,000  
      total net revenues
                                     610,900,000 683,400,000 713,900,000 1,046,300,000 856,400,000 643,100,000 662,700,000  761,400,000 608,100,000 950,400,000 1,343,700,000 1,130,400,000 893,400,000 963,400,000 1,259,200,000 1,049,600,000 833,800,000 852,400,000 1,106,600,000 943,900,000 739,800,000 890,000,000 745,600,000 765,800,000 1,061,300,000 925,400,000 718,100,000 732,000,000 1,072,000,000 940,300,000 657,500,000 671,000,000 1,065,400,000 916,100,000 616,400,000 670,300,000 1,041,200,000 879,100,000 630,100,000 692,000,000 1,062,500,000 870,900,000 631,500,000 641,500,000 981,100,000 874,400,000 607,700,000 654,700,000 1,013,000,000  
      income from continuing operations before income taxes
                                     165,000,000 16,500,000 -70,900,000  140,300,000 32,200,000 46,100,000  131,000,000 20,600,000 -42,700,000 426,200,000 236,600,000 57,400,000 118,000,000 429,100,000 235,700,000 77,400,000 104,800,000 333,600,000 190,000,000 31,500,000 31,500,000 53,400,000 69,500,000 312,700,000   43,400,000 307,100,000 145,200,000 -2,900,000 -2,600,000 256,800,000 90,050,000 28,500,000 30,500,000 301,500,000     85,500,000 39,400,000 34,900,000 268,300,000 85,175,000 -11,600,000 20,200,000 332,100,000  
      income from continuing operations
                                     -52,400,000 14,000,000 -44,300,000  88,800,000 23,700,000 28,700,000  64,400,000 14,800,000 -27,400,000 275,300,000 154,300,000 31,500,000 78,500,000 266,400,000 153,000,000 49,500,000 72,100,000 215,400,000 126,600,000 20,000,000 23,200,000 36,300,000 39,500,000 204,800,000   28,000,000 197,300,000 89,900,000 -9,700,000 -8,700,000 159,300,000 60,700,000 32,600,000 21,000,000 189,400,000     55,075,000 25,900,000 21,500,000 171,800,000 52,700,000 -5,800,000 7,900,000 208,700,000  
      income from discontinued operations - net of taxes
                                          3,500,000 -100,000 82,700,000 -5,000,000 -19,700,000 -300,000  -100,000 -100,000 -300,000 -200,000 -1,200,000 100,000 -400,000 8,700,000 7,400,000 -700,000       100,000  525,000 500,000 12,700,000                   
      continuing operations
                                     -0.16 0.04 -0.14  0.28 0.07 0.09  0.21 0.05 -0.11 0.85 0.49 0.1 0.25 0.85 0.49 0.16 0.23 0.69 0.42 0.06 0.08 0.13 0.14 0.73 0.13 0.12 0.1 0.71 0.32 -0.03 -0.03 0.58 0.46 0.12 0.08 0.69 0.24 0.03 0.11 0.76 0.34 0.1 0.08 0.63 0.27 -0.02 0.03 0.77  
      discontinued operations
                                         -0.01 0.01   -0.03 -0.07       -0.01   0.15   -0.01 -0.01        -0.02 0.01 -0.04 0.13 -0.04 -0.82 -0.33  0.01 -0.01 0.03     -0.02 -0.01 0.12 -0.01  
      loss from discontinued operations - net of taxes
                                       -100,000                           -100,000                      
      net income before income taxes
                                        332,500,000                                                
      total gross revenues
                                         798,875,000 861,300,000 897,600,000                                             
      less: net income attributable to noncontrolling interest
                                               8,700,000 6,900,000                                        
      amounts attributable to nisource:
                                                                                        
      income from discontinued operations
                                          3,500,000 -100,000  -5,000,000 -19,700,000 -300,000                                         
      transportation and storage revenues
                                            301,100,000                                            
      total sales revenues
                                            339,800,000                                            
      yoy
                                                                                        
      qoq
                                                                                        
      less: cost of sales
                                            100,000                                            
      equity earnings in unconsolidated affiliates
                                            15,400,000   13,700,000 15,400,000 13,700,000 12,000,000 11,100,000 9,800,000 10,300,000 10,500,000 8,000,000 7,100,000 8,000,000 8,000,000 5,800,000 3,500,000 2,300,000 3,000,000 3,700,000 3,500,000 400,000 7,400,000 6,400,000 5,800,000 -2,600,000 6,400,000 5,300,000 3,400,000 1,600,000 2,000,000 1,600,000 2,600,000 3,700,000 1,500,000          
      operating income from discontinued operations
                                            143,700,000                                            
      total other income
                                            -14,600,000                      -96,100,000 -104,700,000 -102,500,000 -106,500,000 -91,500,000 -103,700,000 -79,400,000 -86,100,000 -93,300,000 -148,500,000 -99,400,000 -98,500,000 -101,400,000 -102,100,000 -97,000,000 -96,700,000 -100,200,000 -210,200,000 -104,800,000 -99,200,000 -105,600,000  
      income from discontinued operations before income taxes
                                            129,100,000                                            
      gas transportation and storage
                                               427,400,000 628,000,000 522,400,000 381,700,000 390,100,000 578,500,000 461,300,000 346,900,000 366,500,000 468,500,000 418,700,000 278,300,000 361,000,000 283,300,000 307,300,000 403,000,000 355,900,000 270,700,000 264,300,000 370,400,000 339,100,000 242,900,000 260,900,000 396,200,000 322,300,000 217,300,000 235,600,000 357,200,000 311,400,000 204,700,000 226,200,000 347,800,000 289,400,000 202,700,000 220,500,000 320,600,000 279,000,000 179,100,000 213,000,000 328,900,000  
      loss from discontinued operations
                                                                                        
      gain on disposition of discontinued operations - net of taxes
                                                      -1,500,000  36,400,000          100,000                      
      impairment and (gain)/loss on sale of assets
                                                         -950,000 -700,000                              
      impairment and loss on sale of assets
                                                           275,000 400,000  700,000 800,000 1,100,000  100,000 16,800,000 4,400,000  -2,000,000 10,400,000 -400,000 -900,000 -1,500,000 1,000,000 600,000   -700,000 -300,000 4,200,000  1,800,000  20,900,000   
      income tax benefit
                                                           38,750,000 17,100,000                            
      income from discontinued operations—net of taxes
                                                           -450,000 -1,600,000                            
      gain on disposition of discontinued operations—net of taxes
                                                                                        
      income tax expense
                                                             30,000,000                           
      (loss)/income from discontinued operations — net of taxes
                                                             -600,000                           
      gain on disposition of discontinued operations — net of taxes
                                                                       -3,900,000 -5,400,000 -2,800,000 -96,100,000 1,400,000 1,100,000 -800,000 6,600,000 100,000 200,000 200,000 1,000,000 -4,300,000 5,300,000 42,700,000   
      income from discontinued operations — net of taxes
                                                              400,000        -10,700,000 38,900,000 -7,200,000 -220,500,000 6,000,000 700,000 100,000 -700,000 1,000,000     -200,000 -6,300,000    
      gain on early extinguishment of long-term debt
                                                                   625,000  -700,000 3,200,000                  
      income/(loss) from continuing operations before income taxes
                                                               94,600,000 27,800,000                        
      income tax (benefit) expense
                                                               29,900,000 -5,600,000                        
      income/(loss) from continuing operations
                                                               64,700,000 33,400,000                        
      (loss)/income from discontinued operations - net of taxes
                                                               -75,000 -200,000                        
      loss on disposition of discontinued operations - net of taxes
                                                                   -3,800,000 -6,200,000 -8,800,000                   
      loss on disposition of discontinued operations — net of taxes
                                                                      -200,000                -200,000  
      dividend requirement on preferred stock of subsidiaries
                                                                                        
      loss on early redemption of preferred stock
                                                                                 -700,000       
      income from continuing operations before income taxes and cumulative effect of change in accounting principle
                                                                           92,600,000 13,500,000 44,800,000 333,200,000          
      income from continuing operations before cumulative effect of change in accounting principle
                                                                           64,900,000 9,800,000 28,200,000 209,100,000          
      income before change in accounting principle
                                                                           67,000,000 11,000,000 26,700,000 216,700,000          
      cumulative effect of change in accounting principle — net of taxes
                                                                                        
      impairment and gain on sale of assets
                                                                             6,300,000 2,900,000    -200,000      
      dividend requirements on preferred stock of subsidiaries
                                                                               -275,000   -1,000,000 -800,000 -1,000,000 -1,100,000 -1,100,000  
      loss from discontinued operations — net of taxes
                                                                               -350,000 -300,000 -700,000 -300,000   -11,600,000 -2,200,000  
      change in accounting — net of taxes
                                                                               100,000   400,000      
    Balance Sheets:
    Quarterly
    Annual
      Unit: USD2026-03-31 2025-12-31 2025-09-30 2025-06-30 2025-03-31 2024-12-31 2024-09-30 2024-06-30 2024-03-31 2023-12-31 2023-09-30 2023-06-30 2023-03-31 2022-12-31 2022-09-30 2022-06-30 2022-03-31 2021-12-31 2021-09-30 2021-06-30 2021-03-31 2020-12-31 2020-09-30 2020-06-30 2020-03-31 2019-12-31 2019-09-30 2019-06-30 2019-03-31 2018-12-31 2018-09-30 2018-06-30 2018-03-31 2017-12-31 2017-09-30 2017-06-30 2017-03-31 2016-12-31 2016-09-30 2016-06-30 2016-03-31 2015-12-31 2015-09-30 2015-06-30 2015-03-31 2014-12-31 2014-09-30 2014-06-30 2014-03-31 2013-12-31 2013-09-30 2013-06-30 2013-03-31 2012-12-31 2012-09-30 2012-06-30 2012-03-31 2011-12-31 2011-09-30 2011-06-30 2011-03-31 2010-12-31 2010-06-30 2010-03-31 2009-12-31 2009-09-30 2009-06-30 2009-03-31 2008-12-31 2008-09-30 2008-06-30 2008-03-31 2007-12-31 2007-09-30 2007-06-30 2007-03-31 2006-12-31 2006-09-30 2006-06-30 2006-03-31 2005-12-31 2005-09-30 2005-06-30 2005-03-31 2004-12-31 
                                                                                           
        assets
                                                                                           
        property, plant and equipment
                                                                                           
        plant
      39,043,900,000 38,058,800,000 37,201,700,000 36,448,300,000 35,312,500,000 34,152,900,000 33,453,800,000 32,031,100,000 31,300,600,000 30,482,100,000 29,816,100,000 29,135,400,000 28,065,600,000 27,551,300,000 26,641,100,000 26,046,100,000 25,538,300,000 25,171,300,000 25,438,200,000 24,948,200,000 24,524,700,000 24,179,900,000                                                                
        accumulated depreciation and amortization
      -9,616,500,000 -9,370,600,000 -9,201,600,000 -8,996,800,000 -8,822,600,000 -8,699,000,000 -8,572,400,000 -8,418,500,000 -8,354,500,000 -8,207,200,000 -8,104,100,000 -7,960,200,000 -7,838,000,000 -7,708,700,000 -7,650,100,000 -7,534,400,000 -7,417,600,000 -7,289,500,000 -7,917,100,000 -7,793,100,000 -7,688,000,000 -7,560,400,000 -5,659,000,000 -5,549,000,000 -7,293,700,000 -7,609,300,000 -7,563,200,000 -7,461,000,000 -7,356,900,000 -7,257,900,000 -7,171,000,000 -7,083,700,000 -7,048,100,000 -6,953,600,000 -6,906,200,000 -6,833,700,000 -6,701,500,000 -6,613,700,000 -7,020,200,000 -7,040,300,000 -6,957,300,000 -6,853,400,000 -6,811,500,000 -9,718,800,000 -9,686,700,000 -9,578,600,000 -9,533,200,000 -9,444,200,000 -9,358,600,000 -9,256,500,000 -9,258,600,000 -9,169,700,000 -9,075,400,000 -8,986,400,000 -8,956,800,000 -8,882,800,000 -8,805,900,000 -8,670,200,000 -8,672,300,000 -8,602,900,000 -8,528,000,000 -8,492,600,000 -8,547,300,000 -8,443,500,000 -8,353,700,000 -8,286,300,000 -8,232,900,000 -8,134,100,000 -8,080,800,000 -8,078,000,000 -7,982,500,000 -7,819,100,000 -7,850,500,000 -7,813,400,000 -8,000,000,000 -7,939,800,000 -7,850,000,000 -7,788,400,000 -7,710,600,000 -7,637,200,000 -7,556,800,000 -7,495,800,000 -7,416,000,000 -7,340,900,000 -7,247,600,000 
        net property, plant and equipment
      29,427,400,000 28,688,200,000 28,000,100,000 27,451,500,000 26,489,900,000 25,453,900,000 24,881,400,000 23,612,600,000 22,946,100,000 22,274,900,000 21,712,000,000 21,175,200,000 20,227,600,000 19,842,600,000 18,991,000,000 18,511,700,000 18,120,700,000 17,881,800,000 17,521,100,000 17,155,100,000 16,836,700,000 16,619,500,000 16,079,000,000 15,772,400,000 15,587,200,000 16,912,200,000 16,480,900,000 16,133,800,000 15,741,400,000 15,542,500,000 15,174,400,000 14,847,900,000 14,456,600,000 14,359,500,000 14,042,100,000 13,669,300,000 13,288,900,000 13,068,000,000 12,853,800,000 12,555,900,000 12,267,200,000 12,111,500,000 11,690,700,000 16,908,300,000 16,283,400,000 16,017,100,000 15,586,500,000 15,088,800,000 14,657,700,000 14,365,100,000 13,912,400,000 13,473,900,000 13,118,900,000 12,915,900,000 12,542,700,000 12,149,000,000 11,902,000,000 11,800,100,000 11,548,700,000 11,295,000,000 11,140,600,000 11,097,000,000 10,800,000,000 10,697,200,000 10,683,900,000 10,582,100,000 10,543,100,000 10,476,700,000 10,388,100,000 10,261,800,000 10,126,100,000 9,676,000,000 10,031,800,000 9,871,100,000 9,804,900,000 9,740,900,000 9,694,500,000 9,551,600,000 9,502,000,000 9,497,200,000 9,554,300,000 9,425,800,000 9,374,100,000 9,357,500,000 9,384,700,000 
        investments and other assets
                                                                                           
        unconsolidated affiliates
      8,200,000 8,100,000 7,700,000 7,800,000 6,800,000 6,500,000 6,500,000 5,400,000 5,400,000 5,300,000 5,200,000 3,800,000 2,200,000 1,600,000 1,600,000 800,000 800,000 800,000     900,000 1,400,000 1,300,000 1,300,000 2,200,000 2,300,000 2,100,000 2,100,000 2,600,000 4,200,000 5,000,000 5,500,000 5,600,000 6,000,000 6,500,000 6,600,000 6,500,000 6,700,000 6,700,000 6,900,000 6,700,000 452,300,000 447,900,000 452,600,000 443,500,000 437,100,000 407,100,000 373,700,000 327,800,000 279,400,000 260,800,000 243,300,000 215,700,000 211,500,000 204,800,000 204,700,000 200,200,000 197,200,000 202,600,000 200,900,000 141,800,000 166,800,000 165,800,000 149,500,000 146,400,000 114,100,000 86,800,000 70,500,000 76,000,000 74,400,000 72,700,000 59,100,000 94,500,000 66,100,000 59,600,000 70,900,000 80,700,000 72,500,000 75,000,000 70,400,000 67,100,000 97,800,000 108,100,000 
        available-for-sale debt securities
      156,700,000 146,100,000 159,000,000 144,900,000 81,200,000 86,700,000 137,900,000 145,500,000 150,100,000 159,100,000 161,900,000 154,900,000 150,400,000 151,600,000 157,800,000 149,800,000 156,700,000 171,800,000 168,900,000 166,300,000 167,900,000 170,900,000 161,800,000 155,200,000 144,600,000                                                             
        other investments
      116,300,000 118,600,000 116,200,000 107,000,000 84,600,000 85,500,000 89,000,000 84,900,000 86,800,000 82,700,000 76,400,000 78,500,000 74,300,000 71,000,000 68,800,000 73,500,000 82,400,000 87,100,000 84,400,000 85,200,000 81,500,000 81,100,000 75,300,000 72,600,000 66,100,000 228,900,000 217,500,000 215,300,000 208,500,000 204,000,000 214,500,000 199,600,000 201,300,000 204,100,000 207,700,000 195,100,000 194,100,000 193,300,000 200,500,000 190,200,000 194,800,000 187,700,000 195,800,000 200,700,000 208,700,000 210,400,000 211,700,000 201,900,000 203,100,000 204,000,000 201,600,000 189,100,000 190,400,000 194,400,000 196,000,000 156,800,000 156,500,000 150,900,000 164,300,000 150,800,000 136,300,000 139,700,000 128,000,000 129,100,000 129,200,000 128,200,000 111,600,000 115,700,000 117,900,000 119,800,000 110,800,000 113,400,000 117,200,000 119,800,000 106,700,000 112,300,000 116,100,000 118,200,000 100,100,000 101,400,000 114,200,000 115,200,000 116,900,000 82,800,000 72,500,000 
        total investments and other assets
      281,200,000 272,800,000 282,900,000 259,700,000 172,600,000 178,700,000 233,400,000 235,800,000 242,300,000 247,100,000 243,500,000 237,200,000 226,900,000 224,200,000 228,200,000 224,100,000 239,900,000 259,700,000 253,300,000 251,500,000 249,400,000 252,000,000 238,000,000 229,200,000 212,000,000 230,200,000 219,700,000 217,600,000 210,600,000 206,100,000 217,100,000 203,800,000 206,300,000 209,600,000 213,300,000 201,100,000 200,600,000 199,900,000 207,000,000 196,900,000 201,500,000 194,600,000 202,500,000 653,000,000 656,600,000 663,000,000 655,200,000 639,000,000 610,200,000 577,700,000 529,400,000 468,500,000 451,200,000 437,700,000 411,900,000 368,500,000 361,500,000 355,800,000 366,800,000 350,300,000 341,200,000 348,500,000 278,600,000 308,800,000 313,700,000 453,100,000 438,300,000 276,400,000 250,500,000 485,700,000 486,000,000 724,100,000 231,100,000 229,100,000 246,400,000 214,900,000 218,700,000     220,300,000 218,800,000   
        current assets
                                                                                           
        cash and cash equivalents
      71,900,000 110,100,000 95,000,000 335,400,000 259,400,000 156,600,000 126,200,000 101,200,000 102,200,000 2,245,400,000 56,000,000 151,300,000 106,400,000 40,800,000 35,800,000 77,800,000 114,500,000 84,200,000 38,500,000 77,500,000 89,100,000 116,500,000 58,600,000 142,200,000 203,800,000 139,300,000 28,000,000 23,700,000 151,000,000 112,800,000 41,800,000 68,200,000 35,000,000 29,000,000 19,300,000 17,900,000 28,400,000 26,400,000 16,100,000 15,700,000 23,700,000 15,500,000 31,700,000 496,600,000 42,000,000 25,400,000 17,700,000 18,000,000 38,000,000 26,800,000 14,900,000 44,500,000 101,400,000 36,300,000 12,300,000 52,800,000 38,500,000 11,500,000 22,200,000 59,900,000 62,500,000 9,200,000 7,400,000 110,600,000 16,400,000 83,800,000 248,900,000 135,200,000 20,600,000 25,100,000 45,900,000 77,400,000 36,000,000 17,700,000 23,000,000 102,200,000 33,100,000 22,800,000 57,900,000 83,400,000 69,400,000 932,500,000 258,200,000 588,000,000 30,100,000 
        restricted cash
      25,200,000 25,600,000 24,500,000 30,200,000 44,300,000 42,000,000 32,600,000 34,700,000 38,300,000 35,700,000 50,600,000 39,800,000 41,900,000 34,600,000 42,800,000 21,700,000 15,900,000 10,700,000 17,800,000 12,900,000 7,600,000 9,100,000 9,000,000 11,400,000 9,200,000 9,100,000 9,000,000 8,700,000 9,800,000 8,300,000 12,000,000 12,900,000 9,700,000 9,400,000 9,000,000 14,900,000 10,800,000 9,600,000 13,800,000 12,300,000 19,400,000 29,700,000 27,900,000 25,200,000 21,600,000 24,900,000 16,000,000 9,800,000 10,900,000 8,000,000 18,300,000 29,300,000 23,100,000 46,800,000 65,100,000 85,000,000 149,700,000 160,600,000 180,100,000 154,600,000 164,900,000 202,900,000 212,700,000 220,800,000 174,700,000 64,500,000 64,200,000 316,800,000 286,600,000 243,900,000 1,300,000 3,800,000 59,400,000 96,000,000 66,900,000 61,200,000 142,500,000 203,000,000 71,700,000 57,900,000 33,900,000 1,800,000 31,800,000 30,100,000 56,300,000 
        accounts receivable
      1,281,200,000 1,238,100,000 719,600,000 805,900,000 1,135,300,000 987,900,000 589,700,000 650,200,000 877,200,000 884,900,000 585,100,000 631,400,000 954,200,000 1,065,800,000 605,900,000 740,700,000 989,600,000 849,100,000 555,100,000 605,300,000 848,400,000 843,600,000 560,700,000 577,100,000 736,800,000 856,900,000 539,300,000 870,200,000 1,132,100,000 1,058,500,000 500,400,000 584,800,000 973,800,000 898,900,000 480,000,000 545,200,000 813,800,000 847,000,000 471,000,000 474,100,000 647,900,000 660,000,000 500,500,000 672,700,000 1,152,000,000 1,070,100,000 639,300,000 824,000,000 1,271,200,000 1,005,800,000 591,000,000 716,500,000 1,070,300,000 907,300,000 526,200,000 553,300,000 730,300,000 854,800,000 512,500,000 638,300,000 1,063,200,000 1,079,300,000 568,900,000 949,900,000 808,600,000 442,300,000 544,700,000 910,700,000 1,142,500,000 586,800,000 737,000,000 1,086,200,000 936,000,000 571,500,000 681,900,000 954,000,000 866,300,000 478,300,000 472,100,000 1,161,800,000 1,254,600,000 438,600,000 474,300,000 610,000,000 536,700,000 
        allowance for credit losses
      -46,100,000 -40,600,000 -18,600,000 -27,300,000 -29,600,000 -23,700,000 -17,700,000 -26,200,000 -31,600,000 -22,900,000 -15,500,000 -27,800,000 -31,400,000 -23,900,000 -19,200,000 -26,100,000 -28,500,000 -23,500,000 -28,300,000 -41,600,000 -53,900,000 -52,300,000 -39,300,000 -31,400,000 -20,300,000                                                             
        gas storage
      88,400,000 252,000,000 268,300,000 148,200,000 42,800,000 179,600,000 189,300,000 133,100,000 70,100,000 265,800,000                                                                            
        materials and supplies, at average cost
      193,800,000 189,000,000 183,300,000 187,700,000 183,000,000 173,300,000 167,100,000 180,800,000 187,200,000 172,100,000 183,700,000 180,100,000 172,600,000 151,400,000 141,400,000 142,900,000 146,900,000 139,100,000 137,100,000 143,500,000 145,600,000 141,500,000 127,000,000 131,800,000 130,900,000 120,200,000 115,100,000 111,900,000 107,300,000 101,000,000 97,700,000 99,900,000 104,300,000 105,900,000 102,300,000 96,700,000 97,500,000 101,700,000 100,100,000 102,600,000 94,800,000 86,800,000 84,200,000 112,400,000 109,000,000 106,000,000 106,400,000 106,000,000 104,800,000 101,200,000 99,900,000 114,900,000 111,400,000 97,400,000 99,700,000 99,500,000 89,800,000 87,600,000 87,000,000 87,000,000 84,400,000 83,800,000 99,400,000 98,500,000 102,300,000 94,100,000 98,400,000 96,300,000 95,100,000 83,500,000 82,100,000 79,400,000 88,400,000 91,900,000 87,600,000 89,700,000 89,000,000 85,300,000 84,900,000 73,700,000 72,000,000 71,100,000 73,600,000 72,500,000 70,800,000 
        electric production fuel, at average cost
      21,300,000 8,500,000 23,700,000 32,100,000 35,500,000 36,200,000 34,900,000 59,300,000 66,300,000 65,300,000 60,000,000 68,300,000 64,900,000 68,800,000 52,400,000 41,200,000 41,500,000 32,200,000 23,200,000 38,600,000 52,500,000 68,400,000 66,200,000 67,600,000 63,200,000 53,600,000 38,700,000 27,400,000 33,300,000 34,700,000 49,000,000 53,800,000 69,100,000 80,100,000 84,000,000 102,200,000 98,500,000 112,800,000 110,000,000 113,100,000 110,800,000 106,300,000 81,100,000 96,500,000 75,500,000 64,800,000 48,200,000 41,500,000 22,900,000 44,600,000 39,800,000 38,800,000 59,000,000 71,700,000 54,800,000 75,700,000 83,300,000 50,900,000 41,300,000 44,900,000 51,000,000 46,000,000 52,900,000 52,400,000 59,900,000 69,500,000 81,200,000 76,000,000 63,800,000 48,500,000 48,300,000 59,900,000 58,100,000 56,700,000 57,300,000 62,300,000 63,900,000 53,200,000 48,300,000 44,800,000 24,900,000 27,600,000 32,700,000 31,200,000 29,200,000 
        exchange gas receivable
      69,600,000 66,000,000 42,900,000 33,000,000 70,200,000 45,700,000 22,500,000 13,000,000 43,200,000 66,000,000 37,800,000 43,100,000 92,100,000 128,100,000 184,700,000 134,600,000 98,600,000 99,600,000 59,100,000 31,700,000 53,700,000 34,100,000 24,400,000 17,900,000 39,000,000 48,500,000 30,300,000 41,500,000 72,100,000 88,400,000 37,300,000 29,600,000 53,600,000 45,800,000 42,900,000 35,100,000 18,800,000 5,400,000 16,900,000 16,200,000 26,400,000 21,000,000 19,700,000 57,100,000 77,000,000 63,100,000 80,900,000 135,700,000 161,400,000 70,600,000 84,300,000 81,100,000 71,100,000 51,500,000 30,900,000 42,700,000 76,400,000 64,900,000 92,700,000 118,200,000 65,500,000 62,700,000 109,100,000 71,300,000 72,500,000 79,000,000 163,700,000 257,400,000 393,800,000 407,300,000 464,200,000 389,100,000 223,900,000 223,700,000 385,200,000 274,000,000 252,300,000 366,300,000 780,600,000 516,700,000 169,800,000 208,200,000 195,500,000 182,400,000 169,600,000 
        regulatory assets
      380,600,000 274,200,000 326,500,000 287,100,000 268,000,000 319,900,000 329,700,000 278,400,000 260,400,000 214,300,000 217,800,000 200,300,000 237,600,000 233,200,000 245,700,000 179,700,000 154,700,000 206,200,000 198,500,000 180,100,000 188,900,000 135,700,000 132,600,000 145,700,000 164,300,000 225,700,000 237,600,000 212,200,000 190,900,000 235,400,000 221,000,000 174,600,000 160,900,000 176,300,000 203,900,000 183,200,000 184,800,000 248,700,000 262,900,000 236,800,000 226,100,000 172,100,000 183,700,000 175,500,000 159,500,000 193,500,000 200,100,000 188,100,000 159,100,000 142,800,000 152,500,000 145,500,000 141,700,000 162,800,000 190,600,000 192,900,000 186,200,000 169,700,000 142,400,000 121,900,000 112,600,000 151,800,000 168,200,000 169,600,000 238,300,000 287,300,000 286,300,000 285,800,000 314,900,000 306,400,000 200,300,000 176,200,000 218,000,000 252,100,000 232,000,000 210,000,000 272,700,000 290,500,000 233,200,000 213,100,000 195,000,000 179,400,000 166,100,000 143,800,000 136,200,000 
        income tax receivable
      11,500,000                                                4,100,000 5,100,000 6,400,000 6,400,000 80,500,000 130,900,000 56,000,000 700,000 700,000 900,000 1,200,000 1,200,000 20,400,000 99,000,000 26,400,000 2,900,000 24,900,000 295,700,000                    
        prepayments
      209,100,000 149,300,000 157,400,000 143,500,000 138,200,000 138,500,000                                                                                
        other current assets
      102,500,000 105,000,000 25,600,000 23,000,000 37,500,000 24,200,000                                                                                
        total current assets
      2,409,000,000 2,377,200,000 1,848,200,000 1,998,800,000 2,184,600,000 2,080,200,000 1,616,000,000 1,943,800,000 2,060,200,000 4,499,400,000 1,815,400,000 1,856,900,000 2,336,500,000 2,584,300,000 2,228,600,000 1,911,700,000 1,871,900,000 1,920,800,000 1,471,400,000 1,384,200,000 1,593,500,000 1,659,400,000 2,820,800,000 2,859,600,000 3,225,400,000 1,853,900,000 1,378,300,000 1,578,000,000 1,915,800,000 2,055,400,000 1,369,100,000 1,315,700,000 1,633,800,000 1,763,300,000 1,332,400,000 1,280,800,000 1,471,200,000 1,762,100,000 1,378,500,000 1,259,600,000 1,395,400,000 1,577,200,000 1,637,800,000 2,335,700,000 2,261,000,000 2,466,500,000 2,011,600,000 2,054,500,000 2,320,100,000 2,159,200,000 1,745,500,000 1,707,600,000 2,031,800,000 2,352,400,000 1,838,700,000 1,751,600,000 1,970,300,000 2,248,200,000 1,860,500,000 1,745,100,000 1,985,200,000 2,448,900,000 1,893,400,000 2,197,200,000 2,223,600,000 2,563,200,000 2,436,700,000 2,632,400,000 3,410,800,000 3,126,000,000 2,680,400,000 2,521,500,000 2,454,900,000 2,268,800,000 2,149,600,000 2,261,300,000 2,782,900,000 2,522,800,000 2,289,000,000 2,743,100,000 3,060,700,000 3,213,100,000 1,730,500,000 2,404,300,000 2,285,600,000 
        other assets
                                                                                           
        goodwill
      1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,485,900,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 1,690,700,000 3,666,200,000 3,666,200,000 3,666,200,000 3,666,200,000 3,666,200,000 3,666,200,000 3,666,200,000 3,666,200,000 3,666,200,000 3,666,200,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,677,300,000 3,687,200,000 3,687,200,000 
        deferred charges and other
      695,600,000 809,400,000 652,900,000 654,600,000 609,800,000 432,000,000 403,100,000 397,800,000 371,900,000 324,000,000 293,900,000 288,300,000 257,600,000 252,000,000 402,400,000 371,600,000 370,800,000 322,700,000 291,500,000 260,000,000 237,700,000 228,900,000 162,200,000 163,100,000 160,200,000 163,700,000 157,000,000 146,800,000 134,000,000 86,500,000 117,200,000 104,900,000 98,000,000 82,000,000 90,400,000 84,200,000 86,900,000 91,800,000 72,100,000 66,600,000 65,000,000 65,000,000 70,300,000 111,600,000 86,600,000 92,400,000 82,300,000 85,000,000 85,300,000 87,300,000 89,000,000 88,100,000 94,100,000 94,400,000 94,500,000 143,100,000 150,200,000 130,900,000 134,600,000 120,700,000 140,600,000 132,700,000 125,400,000 140,200,000 152,100,000 125,300,000 125,600,000 117,400,000 123,500,000 117,800,000 114,200,000 120,800,000 123,500,000 154,300,000 163,600,000 162,100,000 170,200,000 188,000,000 191,700,000 178,400,000 167,400,000 181,400,000 185,900,000 185,600,000 189,500,000 
        total other assets
      4,483,400,000 4,520,500,000 4,271,700,000 4,318,900,000 4,258,000,000 4,075,300,000 4,097,300,000 4,105,400,000 4,089,500,000 4,055,800,000 4,057,300,000 4,074,400,000 4,062,700,000 4,085,500,000 4,128,600,000 4,166,300,000 4,133,000,000 4,094,600,000 3,532,800,000 3,523,000,000 3,514,900,000 3,509,600,000 3,563,700,000 3,575,300,000 3,568,100,000 3,663,500,000 4,053,400,000 4,044,800,000 4,022,100,000 4,000,000,000 3,938,800,000 3,940,500,000 3,801,800,000 3,629,300,000 3,681,700,000 3,671,500,000 3,675,200,000 3,661,900,000 3,627,900,000 3,604,800,000 3,607,300,000 3,609,200,000 3,524,900,000 5,709,900,000 5,697,900,000 5,719,700,000 5,456,800,000 5,475,500,000 5,519,300,000 5,551,900,000 5,896,800,000 5,971,600,000 6,034,500,000 6,138,700,000 6,045,300,000 6,140,300,000 6,212,100,000 6,304,200,000 5,966,100,000 5,955,900,000 6,011,800,000 6,044,400,000 6,076,100,000 6,148,400,000 6,050,500,000 5,792,700,000 5,805,200,000 5,964,500,000 5,982,800,000 5,224,300,000 5,323,700,000 5,265,100,000 5,287,000,000 5,282,400,000 5,303,700,000 5,338,100,000 5,460,400,000 5,006,400,000 5,059,600,000 5,097,700,000 5,119,700,000 5,122,900,000 5,135,500,000 5,120,500,000 5,113,700,000 
        total assets
      36,601,000,000 35,858,700,000 34,402,900,000 34,028,900,000 33,105,100,000 31,788,100,000 30,828,100,000 29,897,600,000 29,338,100,000 31,077,200,000 27,828,200,000 27,343,700,000 26,853,700,000 26,736,600,000 25,576,400,000 24,813,800,000 24,365,500,000 24,156,900,000 22,778,600,000 22,313,800,000 22,194,500,000 22,040,500,000 22,701,500,000 22,436,500,000 22,592,700,000 22,659,800,000 22,132,300,000 21,974,200,000 21,889,900,000 21,804,000,000 20,699,400,000 20,307,900,000 20,098,500,000 19,961,700,000 19,269,500,000 18,822,700,000 18,635,900,000 18,691,900,000 18,067,200,000 17,617,200,000 17,471,400,000 17,492,500,000 17,055,900,000 25,606,900,000 24,898,900,000 24,866,300,000 23,710,100,000 23,257,800,000 23,107,300,000 22,653,900,000 22,084,100,000 21,621,600,000 21,636,400,000 21,844,700,000 20,838,600,000 20,409,400,000 20,445,900,000 20,708,300,000 19,742,100,000 19,346,300,000 19,478,800,000 19,938,800,000 19,048,100,000 19,351,600,000 19,271,700,000 19,391,100,000 19,223,300,000 19,350,000,000 20,032,200,000 19,097,800,000 18,616,200,000 18,186,700,000 18,004,800,000 17,651,400,000 17,504,600,000 17,555,200,000 18,156,500,000 17,316,700,000 17,088,700,000 17,561,600,000 17,958,500,000 17,982,100,000 16,458,900,000 17,103,700,000 16,988,000,000 
        capitalization and liabilities
                                                                                           
        capitalization
                                                                                           
        stockholders’ equity
                                                                                           
        common stock - 0.01 par value...
      4,800,000 4,800,000 4,800,000 4,700,000 4,700,000 4,700,000 4,700,000 4,500,000 4,500,000 4,500,000 4,200,000 4,200,000 4,200,000 4,200,000 4,100,000 4,100,000 4,100,000 4,100,000 3,900,000 3,900,000 3,900,000 3,900,000 3,800,000 3,800,000 3,800,000 3,800,000 3,800,000 3,800,000 3,800,000 3,800,000 3,700,000 3,700,000 3,400,000 3,400,000 3,400,000 3,300,000 3,300,000 3,300,000 3,300,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,200,000 3,100,000 3,100,000 3,100,000 3,100,000 2,900,000 2,900,000 2,800,000    2,800,000  2,800,000  2,800,000                   2,700,000 
        treasury stock
      -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,900,000 -99,500,000 -95,900,000 -94,600,000 -94,600,000 -93,100,000 -88,700,000 -87,400,000 -87,200,000 -86,700,000 -79,300,000 -79,200,000 -79,100,000 -79,000,000 -58,900,000 -58,900,000 -58,800,000 -58,600,000 -48,600,000 -48,600,000 -48,500,000 -48,100,000 -40,500,000 -40,500,000 -40,500,000 -40,400,000 -30,500,000  -30,400,000 -30,200,000 -27,400,000 -27,400,000 -27,400,000 -25,900,000 -24,200,000 -24,200,000 -24,100,000 -23,300,000 -23,500,000 -23,400,000 -23,300,000 -23,300,000 -23,300,000 -23,300,000 -22,700,000 -21,200,000 -21,100,000        
        additional paid-in capital
      9,859,100,000 9,866,600,000 9,798,300,000 9,538,000,000 9,522,600,000 9,521,500,000 9,404,700,000 8,894,200,000 8,886,800,000 8,879,500,000 7,393,000,000 7,383,100,000 7,372,900,000 7,375,300,000 7,224,800,000 7,218,600,000 7,208,900,000 7,204,300,000 6,735,300,000 6,728,000,000 6,892,900,000 6,890,100,000 6,684,200,000 6,676,500,000 6,671,500,000 6,666,200,000 6,426,500,000 6,417,100,000 6,406,500,000 6,403,500,000 6,161,000,000 6,151,200,000 5,540,500,000 5,529,100,000 5,518,500,000 5,225,300,000 5,174,700,000 5,153,900,000 5,135,600,000 5,118,300,000 5,102,500,000 5,078,000,000 5,078,600,000 5,065,100,000 5,048,400,000 4,787,600,000 4,764,700,000 4,734,700,000 4,715,600,000 4,690,100,000 4,672,900,000 4,646,000,000 4,627,500,000 4,597,600,000 4,579,300,000 4,221,000,000 4,198,900,000 4,167,700,000  4,132,900,000 4,120,100,000 4,103,900,000 4,080,400,000 4,068,500,000 4,057,600,000 4,043,200,000 4,032,700,000 4,023,000,000 4,020,300,000 4,017,800,000 4,015,400,000 4,013,200,000 4,011,000,000 4,008,900,000 4,007,600,000 4,001,100,000 3,998,300,000         
        retained deficit
      -96,600,000 -315,200,000 -572,000,000 -532,100,000 -501,400,000 -711,700,000 -934,900,000 -896,200,000 -861,700,000 -967,000,000 -1,200,600,000 -1,173,800,000 -1,114,800,000 -1,213,600,000 -1,458,100,000 -1,408,900,000 -1,372,300,000 -1,580,900,000 -1,746,800,000 -1,704,100,000 -1,669,800,000 -1,765,200,000 -1,849,600,000 -1,576,700,000 -1,483,400,000 -1,370,800,000 -1,231,600,000 -1,144,000,000 -1,358,000,000 -1,399,300,000 -1,387,500,000 -965,500,000 -919,200,000 -1,073,100,000 -1,020,600,000 -975,600,000 -874,200,000 -972,200,000 -1,060,900,000 -1,067,400,000 -1,042,900,000                                             
        accumulated other comprehensive loss
      -9,200,000 -6,200,000 -13,000,000 -28,200,000 -29,200,000 -30,400,000 -29,600,000 -33,600,000 -33,800,000 -33,600,000 -36,900,000 -35,800,000 -34,700,000 -37,100,000 -23,500,000 -35,800,000 -85,400,000 -126,800,000 -117,400,000 -123,600,000 -75,500,000 -156,700,000 -193,600,000 -221,900,000 -230,600,000 -92,600,000 -130,300,000 -80,800,000 -52,800,000 -37,200,000  -20,900,000 -19,000,000 -43,400,000 -43,700,000 -35,600,000 -19,600,000 -25,100,000 -179,000,000 -156,300,000 -103,800,000 -35,100,000 -19,600,000 -44,400,000 -46,600,000 -50,600,000 -41,600,000 -41,400,000 -42,500,000 -43,600,000 -60,400,000 -62,000,000 -62,300,000 -65,500,000 -56,800,000 -59,000,000 -60,900,000 -59,700,000  -54,500,000 -56,700,000 -57,900,000 -60,400,000 -50,400,000 -45,900,000 -58,300,000 -74,000,000 -187,200,000          -106,300,000        
        total nisource stockholders’ equity
      9,658,200,000  9,118,200,000 8,882,500,000 8,896,800,000  8,345,000,000 7,869,000,000 7,895,900,000  7,212,400,000 7,230,400,000 7,674,200,000  7,193,900,000 7,224,600,000 7,201,900,000  6,494,900,000 6,523,100,000 5,931,600,000                                                                 
        noncontrolling interest in consolidated subsidiaries
      2,269,300,000 2,209,800,000 2,123,600,000 2,114,400,000 2,049,200,000 1,984,100,000 1,983,800,000 1,950,600,000 1,899,000,000 1,866,700,000 556,900,000 341,000,000 329,500,000 326,400,000 311,800,000 315,800,000 329,500,000 325,600,000 89,200,000 90,400,000 94,100,000 85,600,000                      950,000,000 946,200,000                                         
        total stockholders’ equity
      11,927,500,000 11,659,900,000 11,241,800,000 10,996,900,000 10,946,000,000 10,668,300,000    10,136,300,000    7,901,800,000    7,272,900,000    5,837,800,000 5,424,900,000 5,661,800,000 5,741,400,000 5,986,700,000 5,848,500,000 5,976,200,000 5,779,600,000 5,750,900,000 5,073,700,000 5,463,000,000                                                      
        long-term debt, excluding amounts due within one year
      15,458,900,000 15,457,800,000 14,472,100,000 14,473,800,000 12,833,100,000 12,074,500,000 12,086,300,000 12,809,600,000 11,724,600,000 11,055,500,000 11,011,300,000 11,002,800,000 10,264,700,000 9,523,600,000 9,521,200,000 9,520,200,000 9,179,800,000 9,183,400,000 9,188,200,000 9,201,600,000 9,202,300,000 9,219,800,000 9,208,900,000 8,810,200,000 7,817,900,000 7,856,200,000 7,853,800,000 7,109,700,000 7,110,100,000 7,105,400,000 7,094,500,000 7,092,500,000 7,286,800,000 7,512,200,000 7,518,600,000 6,777,400,000 5,590,700,000 6,058,200,000 6,096,200,000 5,857,200,000 5,905,500,000 5,948,500,000 6,133,500,000 8,881,100,000 7,957,900,000 8,155,900,000 8,397,400,000 7,640,600,000 7,638,500,000 7,593,200,000 7,089,100,000 7,616,700,000 6,803,900,000 6,819,100,000 6,819,700,000 6,806,900,000 5,834,400,000 6,267,100,000  6,340,000,000 5,927,600,000 5,936,100,000 5,977,300,000 5,963,900,000 5,965,100,000 6,560,700,000 6,564,400,000 6,451,900,000 5,943,900,000 6,323,300,000 6,059,900,000 5,383,000,000 5,594,400,000 5,923,400,000 5,124,300,000 5,153,100,000 5,146,200,000 5,173,400,000 5,163,500,000 5,229,600,000 5,271,200,000  4,807,300,000 4,809,700,000 4,835,900,000 
        total capitalization
      27,386,400,000 27,117,700,000 25,713,900,000 25,470,700,000 23,779,100,000 22,742,800,000 22,415,100,000 22,629,200,000 21,519,500,000 21,191,800,000 18,780,600,000 18,574,200,000 18,268,400,000 17,425,400,000 17,026,900,000 17,060,600,000 16,711,200,000 16,456,300,000 15,772,300,000 15,815,100,000 15,228,000,000 15,057,600,000 14,633,800,000 14,472,000,000 13,559,300,000 13,842,900,000 13,702,300,000 13,085,900,000 12,889,700,000 12,856,300,000 12,168,200,000 12,555,500,000 11,793,000,000 11,832,300,000 11,881,600,000 10,900,200,000 9,781,800,000 10,129,400,000 9,907,800,000 9,667,800,000 9,777,800,000 9,792,000,000 9,933,800,000 16,337,000,000 15,427,600,000 14,331,200,000 14,404,700,000 13,668,900,000 13,650,600,000 13,479,800,000 12,790,000,000 13,319,400,000 12,494,600,000 12,373,400,000 12,230,500,000 11,912,200,000 10,914,900,000 11,264,400,000  11,343,400,000 10,941,900,000 10,859,300,000 10,872,200,000 10,892,700,000 10,819,200,000 11,300,500,000 11,356,800,000 11,189,600,000 10,672,700,000 10,994,100,000 10,870,800,000 10,447,200,000 10,671,000,000 10,927,600,000 10,198,800,000 10,280,400,000 10,159,800,000 9,978,800,000 10,035,200,000 10,235,200,000 10,285,300,000  9,783,300,000 9,833,800,000 9,704,100,000 
        current liabilities
                                                                                           
        current portion of long-term debt
      16,800,000 19,700,000 31,300,000 1,282,200,000 1,281,000,000 1,281,200,000 1,271,200,000 23,400,000 24,000,000 23,800,000 26,800,000 29,400,000 30,300,000 30,000,000 28,600,000 37,300,000 57,900,000 58,100,000 55,700,000 45,300,000 44,400,000 23,300,000 21,400,000 15,600,000 7,900,000 13,400,000 10,900,000 10,700,000 51,400,000 50,000,000 48,600,000 597,700,000 262,700,000 284,300,000 289,800,000 561,200,000 809,300,000 363,100,000 582,600,000 311,900,000 263,800,000 433,700,000 442,600,000 442,600,000 462,700,000 266,600,000 18,700,000 530,000,000 530,500,000 542,100,000 541,200,000 70,700,000 89,300,000 507,200,000 823,300,000 766,900,000 750,800,000 327,300,000  30,000,000 36,400,000 34,200,000 718,800,000 723,100,000 719,300,000 433,800,000 424,000,000 436,000,000 469,300,000 19,900,000 43,100,000 89,300,000 33,900,000 60,900,000 56,700,000 90,100,000 93,300,000 461,800,000 441,800,000 442,700,000 440,700,000  1,260,100,000 1,299,600,000 1,299,900,000 
        short-term borrowings
      1,291,000,000 736,000,000 1,260,000,000  771,000,000 604,600,000 257,000,000 644,000,000 1,222,300,000 3,048,600,000 2,219,900,000 1,589,900,000 1,281,600,000 1,761,900,000 1,274,200,000 555,000,000 520,000,000 560,000,000 380,000,000  520,000,000 503,000,000 1,388,200,000 1,163,500,000 2,046,400,000 1,773,200,000 1,615,100,000 2,081,000,000 2,080,000,000 1,977,200,000 1,611,000,000 600,000,000 1,567,300,000 1,205,700,000 843,200,000 901,300,000 1,514,200,000 1,488,000,000 1,059,000,000 1,100,700,000 845,300,000 567,400,000 107,200,000 161,800,000 314,000,000 1,576,900,000 1,311,100,000 1,101,100,000 812,500,000 698,700,000 820,800,000 377,700,000 1,131,200,000 776,900,000 225,300,000 327,600,000 1,264,200,000 1,359,400,000  870,400,000 1,263,000,000 1,382,500,000 212,800,000 370,700,000 103,000,000 200,000,000   1,163,500,000 1,263,000,000 506,000,000 624,700,000 1,061,000,000 673,000,000 1,021,500,000 620,000,000 1,193,000,000 861,000,000 420,000,000 379,200,000 898,000,000    307,600,000 
        accounts payable
      999,300,000 1,124,500,000 712,000,000 683,900,000 726,300,000 863,100,000 614,600,000 584,000,000 612,500,000 749,400,000 648,200,000 718,400,000 642,200,000 899,500,000 666,500,000 650,300,000 628,500,000 697,800,000 487,200,000 480,400,000 554,900,000 589,000,000 410,300,000 402,500,000 505,600,000 666,000,000 494,900,000 552,200,000 675,200,000 883,800,000 433,700,000 455,000,000 497,300,000 625,600,000 447,400,000 451,100,000 461,600,000 539,400,000 352,200,000 371,200,000 392,700,000 433,400,000 349,200,000 429,200,000 563,900,000 670,600,000 427,700,000 459,600,000 714,400,000 619,000,000 369,600,000 393,000,000 527,400,000 538,900,000 300,100,000 292,100,000 380,700,000 434,800,000  316,200,000 429,600,000 581,800,000 278,900,000 407,100,000 502,100,000 214,000,000 240,900,000 531,600,000 693,300,000 498,000,000 665,200,000 755,900,000 719,900,000 449,700,000 546,300,000 659,500,000 713,100,000 461,000,000 329,800,000 538,700,000 866,700,000  390,900,000 502,300,000 648,400,000 
        dividends payable - common stock
      147,400,000  137,400,000 135,100,000 134,400,000  125,300,000 120,000,000 119,000,000  103,800,000 103,400,000 103,400,000  95,600,000 95,400,000 95,300,000  86,400,000 86,300,000 86,300,000  80,500,000 80,400,000 80,400,000  74,700,000 74,600,000 74,600,000  70,800,000                                                       
        customer deposits and credits
      148,100,000 283,400,000 273,500,000 159,900,000 143,200,000 268,800,000 261,600,000 187,700,000 189,500,000 294,400,000 286,600,000 207,600,000 225,500,000 324,700,000 314,500,000 184,700,000 155,200,000 237,900,000 232,500,000 148,100,000 146,700,000 243,300,000 229,200,000 163,100,000 163,200,000 256,400,000 242,800,000 159,100,000 152,600,000 238,900,000 238,400,000 158,000,000 154,700,000 262,600,000 253,100,000 168,600,000 166,300,000 264,100,000 255,200,000 186,700,000 212,800,000 316,300,000 255,400,000 206,900,000 172,600,000 294,300,000 257,100,000 241,700,000 239,400,000 262,600,000 249,200,000 164,700,000 167,600,000 269,600,000 263,600,000 201,800,000 215,100,000 313,600,000  183,100,000 181,600,000 318,100,000 196,500,000 176,500,000 301,200,000                     
        taxes accrued
      240,800,000 228,800,000 179,000,000 172,400,000 215,900,000 173,400,000 134,700,000 163,700,000 169,500,000 166,200,000 176,100,000 208,700,000 268,700,000 246,200,000 189,700,000 232,300,000 313,500,000 277,100,000 199,600,000 232,000,000 301,500,000 244,100,000 147,100,000 195,700,000 223,800,000 231,600,000 157,800,000 167,300,000 232,800,000 222,700,000 150,000,000 165,800,000 212,800,000 208,100,000 148,400,000 152,200,000 216,600,000 195,400,000 130,900,000 140,900,000 203,100,000 183,500,000 137,000,000 221,500,000 287,100,000 266,700,000 189,300,000 216,100,000 278,600,000 254,800,000 181,300,000 202,100,000 258,200,000 235,500,000 172,000,000 185,500,000 237,300,000 220,900,000  179,500,000 244,400,000 221,100,000 227,800,000 296,800,000 212,900,000 148,000,000 209,100,000 259,400,000 206,500,000 145,100,000 223,700,000 327,100,000 188,700,000 168,100,000 241,300,000 335,000,000 196,000,000 137,200,000 238,800,000 381,000,000 217,500,000  244,200,000 376,800,000 160,900,000 
        interest accrued
      218,800,000 206,200,000 198,200,000 177,800,000 142,300,000 157,000,000 147,400,000 146,400,000 148,600,000 136,100,000 150,400,000 125,000,000 139,200,000 138,400,000 124,100,000 124,400,000 94,300,000 105,500,000 94,100,000 105,200,000 94,600,000 104,700,000 95,400,000 106,000,000 95,100,000 99,400,000 95,600,000 90,400,000 93,700,000 90,700,000 108,000,000 103,300,000 93,900,000 112,300,000 89,200,000 104,900,000 67,500,000 120,300,000 71,100,000 121,400,000 72,200,000 129,000,000 77,500,000 141,600,000 81,400,000 140,700,000 81,700,000 142,000,000 75,300,000 136,400,000 71,600,000 125,200,000 68,200,000 133,700,000 82,900,000 116,600,000 70,200,000 111,900,000  114,400,000 61,200,000 114,400,000 130,600,000 84,100,000 125,400,000 87,500,000 125,400,000 96,700,000 120,100,000 101,800,000 99,900,000 90,300,000 99,300,000 106,800,000 84,500,000 101,200,000 107,100,000 111,500,000 90,100,000 105,300,000 86,200,000  79,700,000 146,700,000 84,100,000 
        asset retirement obligations
      49,900,000 55,000,000 66,300,000 58,200,000 50,700,000 84,600,000 74,900,000 69,600,000 78,000,000 72,500,000 57,100,000 50,700,000 48,100,000 478,100,000 458,700,000 464,100,000 472,000,000 469,700,000 427,900,000 437,000,000 479,700,000 477,100,000 424,800,000 447,100,000 435,900,000 416,900,000 373,100,000 367,600,000 358,400,000 352,000,000 346,900,000 334,600,000 269,900,000 268,700,000 268,500,000 267,200,000 261,300,000 262,600,000 272,300,000 257,400,000 253,100,000 254,000,000 181,200,000 204,700,000 160,900,000 159,400,000 175,200,000 178,000,000 176,500,000 174,400,000 175,500,000 167,100,000 165,300,000 160,400,000 152,000,000 149,700,000 148,400,000 146,400,000  138,900,000 140,100,000 138,800,000 136,800,000 139,700,000 138,200,000 134,000,000 127,500,000 125,700,000 126,000,000 128,400,000 128,200,000 129,600,000 131,100,000 136,900,000 135,100,000 133,300,000 131,600,000 125,300,000 123,500,000 121,600,000 119,800,000     
        exchange gas payable
      56,500,000 125,400,000 100,000,000 80,700,000 59,100,000 91,800,000 56,100,000 34,700,000 17,100,000 50,500,000 44,100,000 33,000,000 19,600,000 147,600,000 170,900,000 91,200,000 37,800,000 107,700,000 73,200,000 34,900,000 25,500,000 48,500,000 46,300,000 27,700,000 18,500,000 59,700,000 54,800,000 42,300,000 15,500,000 85,500,000 58,200,000 36,900,000 11,500,000 59,600,000 68,000,000 46,600,000 23,300,000 83,700,000 58,200,000 37,700,000 25,800,000 62,300,000 66,800,000 63,900,000 65,800,000 136,200,000 143,100,000 139,200,000 143,100,000 186,400,000 207,300,000 126,300,000 76,000,000 146,200,000 124,700,000 101,400,000 66,300,000 168,200,000  155,400,000 139,400,000 266,100,000 207,100,000 151,400,000 222,200,000 240,100,000 319,400,000 339,000,000 555,500,000 649,700,000 687,000,000 571,300,000 441,600,000 393,900,000 500,500,000 361,700,000 396,600,000 465,100,000 854,300,000 660,100,000 425,200,000  254,000,000 237,000,000 325,100,000 
        regulatory liabilities
      204,300,000 260,100,000 192,000,000 194,900,000 233,500,000 150,500,000 151,700,000 193,400,000 237,600,000 278,600,000 320,200,000 362,000,000 359,100,000 236,800,000 288,900,000 300,400,000 229,100,000 137,400,000 173,200,000 154,000,000 169,600,000 161,300,000 156,000,000 184,900,000 177,900,000 160,200,000 103,000,000 150,500,000 152,100,000 140,900,000 81,900,000 121,500,000 97,300,000 58,700,000 55,100,000 83,700,000 131,600,000 116,700,000 107,200,000 142,500,000 176,800,000 83,300,000 120,200,000 136,100,000 102,000,000 62,400,000 79,900,000 88,700,000 79,100,000 60,200,000 75,500,000 80,000,000 106,500,000 171,600,000 171,100,000 93,300,000 99,900,000 112,000,000  83,500,000 87,400,000 92,900,000 83,600,000 51,700,000 43,800,000 42,600,000 35,100,000 40,200,000 40,400,000 51,800,000 113,100,000 70,400,000 89,700,000 79,300,000 41,500,000 42,600,000 40,700,000 42,300,000 35,600,000 37,300,000 46,300,000  29,100,000 40,500,000 30,200,000 
        accrued compensation and employee benefits
      153,500,000 246,800,000 218,000,000 161,300,000 141,500,000 268,200,000 239,300,000 174,000,000 136,000,000 227,600,000 183,300,000 151,700,000 124,500,000 167,500,000 150,500,000 142,900,000 130,500,000 182,700,000 178,400,000 149,800,000 131,200,000 141,800,000 141,700,000 120,300,000 129,400,000 156,300,000 145,700,000 134,300,000 111,000,000 149,700,000 153,400,000 135,800,000 115,200,000 195,400,000 167,000,000 143,700,000 107,000,000 161,400,000 136,000,000 124,700,000 102,800,000 136,400,000 125,900,000                                           
        other accruals
      200,400,000 171,500,000 165,700,000 305,900,000 343,000,000 170,200,000 151,700,000 167,100,000 170,900,000 217,400,000 170,800,000 503,200,000 298,100,000 360,700,000 588,200,000 592,900,000 313,100,000 382,000,000 266,900,000 262,800,000 164,700,000 113,600,000 119,100,000 140,500,000 180,900,000 144,100,000 120,700,000 86,200,000 79,500,000 58,800,000 54,500,000 75,600,000 109,500,000 90,800,000 119,200,000 78,700,000 76,200,000 82,700,000 67,500,000 68,200,000 103,100,000 114,700,000 121,700,000 313,800,000 317,100,000 378,100,000 408,600,000 347,400,000 323,800,000 327,600,000 308,700,000 283,800,000 269,700,000 309,700,000 232,700,000 219,800,000 239,700,000 301,000,000  230,000,000 249,200,000 336,400,000 244,200,000 257,500,000 310,300,000 354,900,000 249,200,000 289,300,000 487,400,000 381,700,000 314,000,000 429,700,000 509,900,000 417,800,000 405,900,000 696,100,000 526,300,000 391,300,000 319,300,000 499,500,000 549,100,000  341,700,000 597,100,000 478,400,000 
        total current liabilities
      3,726,800,000 3,457,400,000 3,533,400,000 3,412,300,000 4,241,900,000 4,113,400,000 3,485,500,000 2,508,000,000 3,125,000,000 5,265,100,000 4,395,400,000 4,091,200,000 3,906,900,000 4,660,500,000 3,911,100,000 3,015,000,000 2,594,600,000 2,746,200,000 2,246,600,000 1,706,900,000 2,258,800,000 2,279,400,000 3,446,800,000 3,227,700,000 4,161,800,000 3,745,800,000 3,339,700,000 3,813,700,000 4,015,200,000 4,036,800,000 3,411,200,000 2,560,400,000 3,226,200,000 3,178,400,000 2,566,800,000 2,778,300,000 3,664,100,000 3,452,200,000 2,911,600,000 2,696,200,000 2,495,900,000 2,657,500,000 2,073,300,000 2,524,300,000 2,758,400,000 3,954,900,000 3,048,500,000 3,431,400,000 3,340,800,000 3,178,400,000 3,005,600,000 2,068,000,000 2,974,400,000 3,301,600,000 2,727,100,000 2,662,300,000 3,718,400,000 3,646,400,000  2,558,100,000 3,096,100,000 3,649,400,000 2,717,400,000 2,997,200,000 3,149,600,000 2,909,700,000 2,942,400,000 3,278,000,000 4,583,400,000 4,019,200,000 3,648,800,000 3,753,300,000 3,392,600,000 2,706,200,000 3,246,500,000 3,222,400,000 3,821,200,000 3,588,400,000 3,237,400,000 3,508,700,000 3,843,200,000  3,003,200,000 3,545,300,000 3,602,200,000 
        other liabilities
                                                                                           
        deferred income taxes
      2,588,200,000 2,500,100,000 2,405,400,000 2,387,200,000 2,353,900,000 2,281,600,000 2,206,700,000 2,198,200,000 2,159,500,000 2,080,400,000 2,011,400,000 1,986,000,000 1,950,100,000 1,854,500,000 1,803,700,000 1,830,900,000 1,789,800,000 1,659,400,000 1,620,800,000 1,587,500,000 1,573,600,000 1,470,600,000 1,439,500,000 1,477,400,000 1,451,300,000 1,485,300,000 1,466,600,000 1,472,900,000 1,391,600,000 1,330,500,000 1,291,700,000 1,396,700,000 1,384,800,000 1,292,900,000 2,619,400,000 2,617,000,000 2,644,300,000 2,528,000,000 2,384,200,000 2,413,300,000 2,426,900,000 2,365,300,000 227,100,000 303,800,000 277,200,000 272,100,000 231,700,000 3,471,900,000 3,392,300,000 3,277,800,000 3,133,500,000 3,062,700,000 2,980,100,000 2,953,300,000 2,758,500,000 2,730,500,000 2,650,700,000 2,541,900,000  2,369,100,000 2,340,200,000 2,209,700,000 2,074,300,000 2,053,300,000 2,018,200,000 2,001,500,000 1,672,100,000 1,606,200,000 1,549,800,000 1,540,700,000 1,522,200,000 1,494,500,000 1,563,300,000 1,549,400,000 1,537,600,000 1,544,900,000 1,553,700,000 1,485,100,000 1,497,600,000 1,542,700,000 1,591,900,000  1,624,600,000 1,695,700,000 1,665,900,000 
        deferred credits
      79,600,000                                      95,200,000 93,600,000 91,200,000 90,700,000 99,400,000 105,100,000 105,500,000 101,100,000 102,700,000 103,900,000 100,200,000 91,900,000 94,900,000 92,100,000 88,300,000 84,100,000 86,000,000 85,000,000 80,700,000 78,900,000  75,500,000 72,400,000 68,600,000 75,400,000 71,900,000 72,400,000 70,100,000 73,000,000 76,100,000 76,700,000 76,200,000 85,500,000 78,500,000 98,300,000 119,700,000 117,800,000 117,000,000 119,300,000 89,800,000 91,300,000 83,400,000 81,100,000  65,000,000 63,300,000 58,000,000 
        accrued liability for postretirement and postemployment benefits
      157,900,000 153,100,000 174,400,000 200,500,000 204,000,000 207,500,000 238,400,000 241,800,000 244,800,000 250,100,000 236,000,000 237,000,000 239,600,000 245,500,000 277,200,000 280,500,000 285,300,000 292,500,000 308,800,000 323,300,000 328,900,000 336,100,000 344,400,000 351,300,000 359,400,000 373,200,000 365,500,000 372,100,000 377,300,000 389,100,000 300,900,000 311,700,000 323,400,000 337,100,000 397,300,000 688,100,000 700,000,000 713,400,000 738,200,000 746,100,000 4,900,000 4,900,000 5,200,000 5,900,000 5,900,000 5,900,000 6,200,000 6,200,000 6,200,000 6,200,000 6,100,000 6,100,000 6,100,000 6,100,000 26,600,000 26,600,000 26,600,000 26,600,000  23,300,000 23,300,000 23,300,000 7,600,000 7,600,000 23,600,000 7,800,000 7,100,000 6,400,000 6,400,000 4,900,000 4,900,000 4,900,000 4,800,000 4,800,000 4,700,000 4,700,000 4,700,000 59,400,000 61,000,000 61,100,000 61,100,000    85,500,000 
        other noncurrent liabilities
      289,600,000              288,500,000 329,700,000 669,500,000 690,200,000 527,400,000 566,800,000 444,500,000 286,100,000 214,700,000 198,800,000 187,300,000 218,500,000 224,700,000 222,800,000 218,300,000 177,900,000 215,000,000 184,800,000 191,700,000 194,400,000 187,800,000 188,900,000 199,200,000 200,500,000 182,800,000 187,000,000 188,400,000 208,100,000 186,600,000 270,600,000 294,000,000 291,100,000 297,700,000 224,300,000 219,400,000 216,000,000 219,100,000 216,400,000 225,000,000 226,200,000 246,200,000 242,100,000 247,800,000 244,700,000  157,800,000 163,400,000 162,000,000 175,000,000 183,000,000 152,600,000 155,600,000 164,800,000 163,800,000 153,800,000 168,400,000 187,800,000 169,800,000 185,800,000 190,900,000 186,700,000 195,100,000 184,100,000 177,600,000 179,700,000 178,400,000 177,500,000  195,400,000 187,900,000 204,300,000 
        total other liabilities
      5,487,800,000 5,283,600,000 5,155,600,000 5,145,900,000 5,084,100,000 4,931,900,000 4,927,500,000 4,760,400,000 4,693,600,000 4,620,300,000 4,652,200,000 4,678,300,000 4,678,400,000 4,650,700,000 4,638,400,000 4,738,200,000 5,059,700,000 4,954,400,000 4,759,700,000 4,791,800,000 4,707,700,000 4,703,500,000 4,620,900,000 4,736,800,000 4,871,600,000 5,071,100,000 5,090,300,000 5,074,600,000 4,985,000,000 4,910,900,000 5,120,000,000 5,192,000,000 5,079,300,000 4,951,000,000 4,821,100,000 5,144,200,000 5,190,000,000 5,110,300,000                                                
        commitments and contingencies
                                                                                           
        total capitalization and liabilities
      36,601,000,000 35,858,700,000 34,402,900,000 34,028,900,000 33,105,100,000 31,788,100,000 30,828,100,000 29,897,600,000 29,338,100,000 31,077,200,000 27,828,200,000 27,343,700,000 26,853,700,000 26,736,600,000 25,576,400,000 24,813,800,000 24,365,500,000 24,156,900,000 22,778,600,000 22,313,800,000 22,194,500,000 22,040,500,000 22,701,500,000 22,436,500,000 22,592,700,000 22,659,800,000 22,132,300,000 21,974,200,000 21,889,900,000 21,804,000,000 20,699,400,000 20,307,900,000 20,098,500,000 19,961,700,000 19,269,500,000 18,822,700,000 18,635,900,000 18,691,900,000 18,067,200,000 17,617,200,000 17,471,400,000 17,492,500,000 17,055,900,000 25,606,900,000 24,898,900,000 24,866,300,000 23,710,100,000 23,257,800,000 23,107,300,000 22,653,900,000 22,084,100,000 21,621,600,000 21,636,400,000 21,844,700,000 20,838,600,000 20,409,400,000 20,445,900,000 20,708,300,000  19,346,300,000 19,478,800,000 19,938,800,000 19,048,100,000 19,351,600,000 19,271,700,000 19,391,100,000 19,223,300,000 19,350,000,000 20,032,200,000 19,097,800,000 18,616,200,000 18,186,700,000 18,004,800,000 17,651,400,000 17,504,600,000 17,555,200,000 18,156,500,000 17,316,700,000 17,088,700,000 17,561,600,000 17,958,500,000  16,458,900,000 17,103,700,000 16,988,000,000 
        total nisource stockholders' equity
       9,450,100,000    8,684,200,000    8,269,600,000    7,575,400,000    6,947,300,000    5,752,200,000                                                                
        other noncurrent liabilities and deferred credits
       335,200,000 337,400,000 344,400,000 336,700,000 313,000,000 311,800,000 308,300,000 297,700,000 298,600,000 291,500,000 294,600,000 298,500,000 296,800,000                                                                        
        deposits to renewable generation asset developer
             381,100,000 285,800,000 454,200,000 179,500,000 137,400,000 281,200,000 143,800,000                                                                        
        preferred stock - 0.01 par value...
               486,100,000 1,152,600,000 1,152,600,000 1,546,500,000 1,546,500,000 1,546,500,000 1,546,500,000 1,546,500,000 1,546,500,000 1,719,800,000 1,718,800,000 880,000,000 880,000,000 880,000,000 880,000,000 880,000,000 880,000,000 880,000,000 880,000,000 880,000,000 880,000,000                                                        
        prepayments and other
            141,700,000 138,200,000 161,100,000 118,600,000 162,600,000 218,700,000 278,200,000 210,000,000 332,800,000 291,700,000 263,900,000 104,800,000 159,300,000 187,400,000 109,300,000 86,000,000 112,600,000 142,600,000 182,800,000 149,700,000 85,400,000 103,100,000 144,200,000 129,500,000 89,700,000 109,100,000 155,500,000 132,800,000 65,800,000 91,300,000 139,100,000 130,600,000 64,100,000 89,800,000 133,500,000 107,500,000 75,900,000 133,200,000 187,300,000 169,500,000 103,600,000 320,900,000 321,100,000 330,600,000 246,100,000 224,400,000 228,100,000 357,200,000 280,800,000 274,200,000 277,400,000 261,800,000 119,700,000 100,400,000 119,700,000 120,800,000 118,600,000 136,700,000 125,500,000 131,600,000 180,300,000 291,000,000 249,100,000 228,900,000 173,900,000 103,500,000 112,700,000 66,200,000 61,700,000 87,200,000 111,700,000 70,300,000 70,500,000 99,300,000 109,300,000 86,400,000 101,700,000 84,700,000 96,200,000 
        total stockholders' equity
            10,328,800,000 9,819,600,000 9,794,900,000          6,584,100,000 6,613,500,000 6,025,700,000                                                                 
        obligations to renewable generation asset developer
                  347,200,000 347,200,000                                                                        
        gas inventory
                297,800,000 214,300,000 138,800,000 531,700,000 606,300,000 307,500,000 74,800,000 327,400,000 311,100,000 148,800,000 48,100,000 191,200,000 203,300,000 112,400,000 59,900,000 250,900,000 294,900,000 179,300,000 75,100,000 286,800,000 320,200,000 182,800,000 71,900,000 285,100,000 325,200,000 194,300,000 79,500,000 279,900,000 323,600,000 199,000,000 112,800,000 343,500,000 398,900,000 259,200,000 134,400,000 445,100,000 513,000,000 321,600,000 97,900,000 354,600,000 454,800,000 266,000,000 70,300,000 326,600,000 385,200,000 252,900,000 181,100,000 427,600,000 467,000,000 278,000,000 81,500,000 298,200,000 230,600,000 79,000,000 384,800,000 528,200,000 247,000,000 87,000,000 511,800,000 706,000,000 270,100,000 74,000,000 458,200,000 679,600,000 283,800,000 96,500,000 550,500,000 682,800,000 244,100,000 165,000,000 526,900,000 666,500,000 213,800,000 70,100,000 452,900,000 
        total equity
                7,769,300,000 7,571,400,000 8,003,700,000  7,505,700,000 7,540,400,000 7,531,400,000                           7,455,900,000 7,469,700,000                                         
        dividends payable - preferred stock
                8,100,000 8,200,000 19,400,000  19,400,000 8,200,000 19,400,000  19,400,000 8,100,000 19,400,000  19,400,000 8,100,000 19,400,000  19,400,000 8,200,000 19,400,000  11,600,000                                                       
        deferred property taxes
                       91,000,000   104,200,000 85,600,000                                                                
        risk management liabilities
                           78,200,000 96,900,000 120,000,000 312,100,000 134,000,000 125,000,000 80,700,000 55,800,000 5,000,000 4,800,000 4,000,000 4,600,000 43,200,000 28,700,000 58,500,000 52,900,000 44,500,000 264,500,000 221,100,000 135,400,000                                             
        claims accrued
                           28,600,000 26,300,000 22,400,000 24,900,000 165,400,000 184,300,000 235,100,000 258,500,000 114,700,000 365,900,000                                                       
        accrued insurance liabilities
                           84,800,000 82,400,000 85,400,000 82,400,000 81,500,000 85,300,000 82,900,000 84,500,000 84,400,000 81,800,000 86,000,000 83,900,000 80,100,000 89,000,000 86,700,000 85,100,000 82,800,000                                                
        utility plant
                            20,843,400,000 20,427,100,000 22,862,300,000 24,502,600,000 24,026,100,000 23,576,500,000 23,079,700,000 22,780,800,000 22,328,200,000 21,914,800,000 21,374,000,000 21,026,600,000 20,657,600,000 20,206,400,000 19,680,600,000 19,368,000,000 19,856,900,000 19,578,800,000 19,206,900,000 18,946,900,000 18,484,800,000 26,225,200,000 25,593,900,000 25,234,800,000 24,775,700,000 24,202,600,000 23,695,700,000 23,303,700,000 22,869,700,000 22,346,000,000 21,910,100,000 21,642,300,000 21,303,800,000 20,888,600,000 20,571,100,000 20,337,800,000 20,095,500,000 19,783,800,000 19,575,800,000 19,494,900,000 19,314,200,000 19,049,300,000 18,946,100,000 18,774,200,000 18,664,800,000 18,498,200,000 18,356,800,000 18,227,700,000 18,040,900,000 17,428,000,000 17,543,500,000 17,345,800,000 17,462,900,000 17,333,800,000 17,194,900,000 16,987,200,000 16,857,900,000 16,745,900,000 16,684,400,000 16,500,500,000 16,367,000,000 16,270,900,000 16,194,100,000 
        net utility plant
                            15,184,400,000 14,878,100,000 15,568,600,000 16,893,300,000 16,462,900,000 16,115,500,000 15,722,800,000 15,522,900,000 15,157,200,000 14,831,100,000 14,325,900,000 14,073,000,000 13,751,400,000 13,372,700,000 12,979,100,000 12,754,300,000 12,836,700,000 12,538,500,000 12,249,600,000 12,093,500,000 11,673,300,000 16,506,400,000 15,907,200,000 15,656,200,000 15,242,500,000 14,758,400,000 14,337,100,000 14,047,200,000 13,611,100,000 13,176,300,000 12,834,700,000 12,655,900,000 12,347,000,000 12,005,800,000 11,765,200,000 11,667,600,000 11,423,200,000 11,180,900,000 11,047,800,000 11,002,300,000 10,766,900,000 10,605,800,000 10,592,400,000 10,487,900,000 10,431,900,000 10,364,100,000 10,276,000,000 10,149,700,000 10,058,400,000 9,608,900,000 9,693,000,000 9,532,400,000 9,462,900,000 9,394,000,000 9,344,900,000 9,198,800,000 9,147,300,000 9,108,700,000 9,127,600,000 9,004,700,000 8,951,000,000 8,930,000,000 8,946,500,000 
        other property, at cost, less accumulated depreciation
                            894,600,000 894,300,000 18,600,000 18,900,000 18,000,000 18,300,000 18,600,000 19,600,000 17,200,000 16,800,000 130,700,000 286,500,000 290,700,000 296,600,000 309,800,000 313,700,000 17,100,000 17,400,000 17,600,000 18,000,000 17,400,000 401,900,000 376,200,000 360,900,000 344,000,000 330,400,000 320,600,000 317,900,000 301,300,000 297,600,000 284,200,000 260,000,000 195,700,000 143,200,000 136,800,000 132,500,000 125,500,000 114,100,000 92,800,000 94,700,000 33,100,000 91,400,000 91,500,000 94,200,000 111,200,000 112,600,000 112,100,000 112,100,000 67,700,000 67,100,000 338,800,000 338,700,000 342,000,000 346,900,000 349,600,000 352,800,000 354,700,000 388,500,000 426,700,000 421,100,000 423,100,000 427,500,000 438,200,000 
        assets held for sale
                            1,565,700,000 1,542,300,000 1,655,800,000                                                             
        liabilities held for sale
                            451,800,000 455,400,000 470,900,000                                                             
        legal and environmental
                            17,200,000 21,600,000 17,500,000 20,100,000 20,000,000 21,800,000 18,900,000 18,900,000 20,400,000 36,000,000 33,600,000 32,100,000 27,500,000 29,300,000 33,800,000 37,400,000 38,600,000 37,300,000 37,400,000 37,600,000 36,800,000 34,500,000 25,400,000 24,200,000 15,300,000 18,900,000 25,500,000                                     
        deferred investment tax credits
                            8,800,000 9,100,000 9,400,000 9,700,000 10,100,000 10,500,000 10,800,000 11,200,000 11,700,000 11,900,000 12,100,000 12,400,000 12,600,000 12,900,000 13,100,000 13,400,000 13,800,000 14,100,000 14,400,000 14,800,000 15,400,000 16,100,000 16,700,000 17,300,000 18,200,000 19,100,000 20,000,000 20,900,000 21,900,000 22,900,000 23,800,000 24,800,000 25,800,000 26,900,000 27,900,000 29,000,000  31,300,000 32,500,000 33,700,000 36,600,000 38,100,000 39,600,000 41,300,000 42,900,000 44,500,000 46,100,000 47,900,000 49,800,000 51,600,000 53,500,000 55,500,000 57,500,000 59,500,000 61,500,000 63,700,000 65,800,000 67,900,000 69,900,000  74,000,000 76,200,000 78,400,000 
        nisource inc.condensed consolidated balance sheets
                                                                                           
        intangible assets
                                212,500,000 215,200,000 218,000,000 220,700,000 223,500,000 226,200,000 228,900,000 231,700,000 234,400,000 237,200,000 239,900,000 242,700,000 245,400,000 246,400,000 250,900,000 253,700,000 256,400,000 258,400,000 261,900,000 264,700,000 267,400,000 270,200,000 272,900,000 275,700,000 278,400,000 281,200,000 283,900,000 286,600,000 289,400,000 292,100,000 294,900,000 297,600,000 300,400,000 303,100,000 305,900,000 308,600,000 314,100,000 316,800,000 319,600,000 322,400,000 325,100,000 327,800,000 330,600,000 333,400,000 336,100,000 338,800,000 422,000,000 425,500,000 428,900,000 432,300,000 435,700,000 477,900,000 489,400,000 492,700,000 495,800,000 498,500,000 513,000,000 516,200,000 520,300,000 
        preferred stock - 1,000 par value, 20,000,000 shares authorized; 400,000 shares outstanding
                                    393,900,000 394,400,000                                                      
        accumulated other comprehensive income
                                    2,500,000                                      -172,000,000 -65,300,000 34,000,000 24,100,000 11,700,000 8,500,000 27,900,000 50,200,000 20,900,000         
        dividends payable
                                     70,800,000 65,800,000  58,900,000 57,000,000 56,700,000  53,100,000 53,000,000 49,700,000  49,300,000  82,400,000  82,100,000 82,000,000 78,700,000  78,300,000 78,100,000 74,800,000  74,300,000 68,300,000 65,300,000   64,600,000 64,500,000 100,000 64,100,000 64,000,000 200,000                     
        common stockholders’ equity
                                                                                           
        total common stockholders’ equity
                                      4,506,200,000 4,320,100,000 4,363,000,000 4,122,800,000 4,191,100,000 4,071,200,000 3,811,600,000 3,810,600,000 3,872,300,000 3,843,500,000 3,800,300,000   6,175,300,000 6,007,300,000 6,028,300,000 6,012,100,000 5,886,600,000 5,700,900,000 5,702,700,000 5,690,700,000 5,554,300,000 5,410,800,000 5,105,300,000 5,080,500,000 4,997,300,000  5,003,400,000 5,014,300,000 4,923,200,000 4,894,900,000 4,928,800,000 4,854,100,000 4,739,800,000 4,792,400,000 4,737,700,000 4,728,800,000 4,670,800,000 4,810,900,000 5,064,200,000 5,076,600,000 5,004,200,000 5,074,500,000 5,127,300,000          
        other liabilities and deferred credits
                                                                                           
        total other liabilities and deferred credits
                                            5,247,800,000 5,253,200,000 5,197,700,000 5,043,000,000 5,048,800,000 6,745,600,000 6,712,900,000 6,580,200,000 6,256,900,000 6,157,500,000 6,115,900,000 5,995,700,000 6,288,500,000 6,234,200,000 6,167,400,000 6,169,700,000 5,881,000,000 5,834,900,000 5,812,600,000 5,797,500,000  5,444,800,000 5,440,800,000 5,430,100,000 5,458,500,000 5,461,700,000 5,302,900,000 5,180,900,000 4,924,100,000 4,882,400,000 4,776,100,000 4,084,500,000 4,096,600,000 3,986,200,000 3,941,200,000 4,017,600,000 4,059,300,000 4,052,400,000 4,175,500,000 3,749,500,000 3,816,100,000 3,817,700,000 3,830,000,000  3,672,400,000 3,724,600,000 3,681,700,000 
        deferred revenue
                                              5,500,000 6,600,000 9,300,000 21,600,000 25,500,000 25,600,000 6,500,000 8,700,000 7,900,000 18,500,000 21,300,000 5,100,000 42,400,000 42,800,000 30,900,000 10,000,000 10,600,000 10,100,000  5,000,000 7,800,000 6,800,000 10,100,000 11,500,000 27,300,000 8,700,000 20,200,000 11,000,000 14,700,000 10,900,000 14,100,000 22,400,000 38,700,000 42,400,000 48,700,000 39,300,000 55,900,000 43,600,000 37,900,000 35,100,000 51,300,000  29,100,000 26,800,000  
        underrecovered gas costs
                                               34,800,000 7,100,000 3,500,000                                          
        assets of discontinued operations
                                                                                           
        retained earnings
                                               -1,123,300,000  1,561,100,000 1,597,500,000 1,494,000,000 1,339,900,000 1,390,600,000 1,394,400,000 1,285,500,000 1,133,800,000 1,164,100,000 1,170,500,000 1,059,600,000 925,700,000 980,900,000 980,000,000 917,000,000  952,600,000 978,300,000 901,800,000 899,500,000 935,300,000 865,500,000 776,300,000 855,100,000 923,300,000 901,100,000 739,100,000 782,200,000 1,047,500,000 1,074,500,000 1,007,400,000 1,059,600,000 1,096,000,000 1,012,900,000 950,400,000 987,400,000 1,029,100,000 981,600,000  983,200,000 1,006,800,000 925,400,000 
        overrecovered gas and fuel costs
                                               148,100,000 169,200,000 198,600,000 172,300,000 45,600,000 21,200,000 49,800,000 25,800,000 32,200,000 31,700,000 64,600,000 63,200,000 22,100,000 52,600,000 84,100,000 74,300,000 48,900,000  121,400,000 91,800,000 11,800,000 38,100,000 43,500,000 220,400,000 456,400,000 424,400,000 302,500,000 35,900,000  700,000 4,400,000 10,400,000 46,100,000 48,100,000 63,300,000 126,700,000 144,400,000 143,200,000 114,600,000 25,800,000  54,200,000 44,500,000 15,500,000 
        liabilities of discontinued operations
                                               300,000                                         300,000   
        retained (deficit) earnings
                                                -1,182,700,000                                           
        nisource common stockholders’ equity
                                                                                           
        total nisource common stockholders’ equity
                                                 6,505,900,000 6,523,500,000                                         
        accrued capital expenditures
                                                 146,300,000 80,300,000 61,100,000                                        
        underrecovered gas and fuel costs
                                                  25,500,000 32,000,000 54,700,000 75,700,000 114,300,000 46,400,000 16,400,000 600,000 16,900,000 45,000,000 33,500,000 1,900,000 15,000,000 20,700,000 57,700,000 24,700,000 25,400,000 135,700,000 110,300,000 114,400,000 40,200,000 11,200,000 1,800,000 500,000 180,200,000 313,100,000 344,500,000 245,300,000 162,000,000 99,000,000 134,100,000 195,600,000 163,200,000 70,000,000 81,200,000 190,800,000 421,800,000 230,000,000 85,600,000 183,500,000 293,800,000 
        price risk management assets
                                                     13,200,000 14,400,000 22,700,000 21,100,000 39,600,000 58,000,000 92,200,000 103,600,000 120,000,000 141,900,000 137,200,000 136,700,000 116,000,000 134,100,000 159,500,000 188,900,000 190,400,000 173,300,000 2,300,000 24,500,000 173,500,000 150,400,000 106,100,000 248,400,000 150,100,000 102,200,000 114,400,000 136,100,000 128,600,000 237,700,000 200,300,000 144,500,000 136,600,000 183,100,000 371,000,000 97,200,000 125,200,000 61,100,000 
        noncurrent deferred revenue
                                                      21,800,000  23,100,000 37,200,000   22,800,000                              87,400,000 
        assets of discontinued operations and assets held for sale
                                                            200,000 200,000 200,000 200,000 2,300,000 2,300,000 2,300,000 7,900,000 8,800,000 12,900,000 18,700,000 175,400,000 180,300,000 46,600,000 45,800,000 295,400,000 299,200,000 536,300,000 41,200,000 50,200,000 45,200,000 36,500,000 43,000,000 46,800,000 57,300,000 49,700,000 34,600,000 34,700,000 34,800,000 40,800,000 23,400,000 
        price risk management liabilities
                                                       1,400,000 8,800,000 47,500,000 52,700,000 95,200,000 110,200,000 132,700,000 180,400,000 167,800,000  135,000,000 146,100,000 173,900,000 206,900,000 211,100,000 190,100,000 44,600,000 101,100,000 336,000,000 286,500,000 201,500,000 117,400,000 67,500,000 80,300,000 91,700,000 75,300,000 35,400,000 259,400,000 242,100,000 98,300,000 85,700,000 72,300,000  74,100,000 28,400,000 46,900,000 
        liabilities of discontinued operations and liabilities held for sale
                                                           3,900,000          900,000 1,700,000 273,400,000 261,200,000 2,300,000 1,500,000 39,700,000 57,200,000 45,600,000 6,300,000 6,200,000 9,900,000 9,800,000 11,900,000 9,900,000 10,000,000       
        legal and environmental reserves
                                                       32,300,000 34,200,000 43,100,000 41,100,000 42,200,000 36,800,000 35,600,000 37,000,000 43,900,000  46,000,000 68,200,000 86,000,000 83,900,000 97,500,000 146,100,000 209,500,000 328,300,000 322,400,000 375,100,000 467,600,000 452,200,000               
        regulatory liabilities and other removal costs
                                                       1,669,800,000 1,615,900,000 1,610,500,000 1,611,400,000 1,593,300,000 1,617,100,000 1,615,700,000 1,616,200,000 1,663,900,000  1,624,800,000 1,612,000,000 1,595,800,000 1,591,800,000 1,571,400,000 1,558,800,000 1,433,800,000 1,413,400,000 1,411,200,000 1,386,100,000 1,400,300,000 1,427,300,000 1,344,600,000 1,353,100,000 1,319,700,000 1,313,500,000 1,293,400,000 1,253,800,000 1,250,500,000 1,237,200,000    1,205,400,000 1,189,000,000  
        postretirement and postemployment benefits assets
                                                            41,700,000 38,300,000 34,900,000 31,500,000 43,600,000 42,000,000 38,500,000 35,100,000 22,900,000 22,800,000 19,800,000 10,500,000 9,200,000 9,600,000 10,300,000 188,200,000 178,800,000 167,500,000 157,800,000             
        item 1.
                                                                                           
        common stock — 0.01 par value...
                                                                 2,800,000 2,800,000    2,800,000   2,700,000 2,700,000 2,700,000  2,700,000 2,700,000 2,700,000 2,700,000 2,700,000 2,700,000 2,700,000 2,700,000 2,700,000      
        temporary lifo liquidation credit
                                                                 300,000 2,200,000  6,400,000 42,200,000   8,300,000 111,300,000   174,800,000 472,300,000              
        common stock - - 0.01 par value...
                                                                    2,800,000                       
        dividends declared
                                                                       63,500,000 63,300,000 63,200,000  63,100,000 63,100,000 63,100,000  63,100,000 63,100,000 63,100,000          
        customer deposits
                                                                       124,900,000 125,400,000 130,700,000 127,300,000 120,500,000 112,400,000 114,400,000 114,400,000 108,600,000 108,400,000 110,400,000 108,400,000 104,900,000 104,500,000 104,600,000 101,900,000  92,700,000 95,300,000 87,100,000 
        and 274,261,799 shares issued and outstanding, respectively
                                                                        2,800,000                   
        as of december 31,
                                                                          2,008,000,000    2,007,000,000    2,006,000,000    2,005,000,000    2,004,000,000 
        and 274,176,752 shares issued and outstanding, respectively
                                                                            2,700,000               
        common stockholder’s equity
                                                                                           
        total common stockholder’s equity
                                                                                  5,013,600,000         
        preferred stocks—series without mandatory redemption provisions
                                                                                     81,100,000 81,100,000  81,100,000 81,100,000 81,100,000 
        dividends declared on common and preferred stocks
                                                                                   62,800,000 62,800,000 63,800,000 1,100,000  63,700,000 63,600,000 1,100,000 
        total investments
                                                                                   235,900,000 238,100,000 223,600,000 223,800,000   221,400,000 204,000,000 
        common stock equity
                                                                                           
        additional paid-in-capital
                                                                                   3,979,700,000     3,958,800,000 3,943,900,000  
        total common stock equity
                                                                                   4,805,400,000 4,871,700,000 4,924,500,000 4,933,000,000  4,894,900,000 4,943,000,000 4,787,100,000 
        preferred stock—series without mandatory redemption provisions
                                                                                           
        additional paid-in-capital, net of deferred stock compensation
                                                                                    3,972,800,000 3,970,600,000 3,969,400,000    3,924,000,000 
        accumulated other comprehensive loss and other common stock equity
                                                                                    -91,200,000 -77,900,000 -20,700,000  -49,800,000 -10,400,000 -65,000,000 
        common stock equity common stock — 0.01 par value...
                                                                                      2,700,000     
        preferred stock liabilities with mandatory redemption provisions
                                                                                        600,000 600,000 600,000 
        common stock — 0.01 par value - 400,000,000 shares authorized, 272,322,505 and 270,625,370 shares issued and outstanding, respectively
                                                                                        2,700,000   
        accrued liability for postretirement and pension benefits
                                                                                        89,700,000 86,700,000  
        unbilled revenue
                                                                                         282,800,000 352,700,000 
        common stock — 0.01 par value — 400,000,000 shares authorized, 271,665,136 and 270,625,370 shares issued and outstanding, respectively
                                                                                         2,700,000  
        current deferred revenue
                                                                                          31,500,000 
      Cashflow Statements:
      Quarterly
      Annual
        Unit: USD2026-09-30 2026-06-30 2026-03-31 2025-12-31 2025-09-30 2025-06-30 2025-03-31 2024-12-31 2024-09-30 2024-06-30 2024-03-31 2023-12-31 2023-09-30 2023-06-30 2023-03-31 2022-12-31 2022-09-30 2022-06-30 2022-03-31 2021-12-31 2021-09-30 2021-06-30 2021-03-31 2020-12-31 2020-09-30 2020-06-30 2020-03-31 2019-12-31 2019-09-30 2019-06-30 2019-03-31 2018-12-31 2018-09-30 2018-06-30 2018-03-31 2017-12-31 2017-09-30 2017-06-30 2017-03-31 2016-12-31 2016-09-30 2016-06-30 2016-03-31 2015-12-31 2015-09-30 2015-06-30 2015-03-31 2014-12-31 2014-09-30 2014-06-30 2014-03-31 2013-12-31 2013-09-30 2013-06-30 2013-03-31 2012-12-31 2012-09-30 2012-06-30 2012-03-31 2011-12-31 2011-09-30 2011-06-30 2011-03-31 2010-12-31 2010-09-30 2010-06-30 2010-03-31 2009-12-31 2009-09-30 2009-06-30 2009-03-31 2008-12-31 2008-09-30 2008-06-30 2008-03-31 2007-12-31 2007-09-30 2007-06-30 2007-03-31 2006-12-31 2006-09-30 2006-06-30 2006-03-31 2005-12-31 2005-09-30 2005-06-30 2005-03-31 
                                                                                               
          irp
                                                                                               
          iurc
                                                                                               
          investor
                                                                                               
          jv
                                                                                               
          lifo
                                                                                               
          liheap
                                                                                               
          llc agreement
                                                                                               
          mgp
                                                                                               
          miso
                                                                                               
          mmdth
                                                                                               
          mw
                                                                                               
          mwh
                                                                                               
          nipsco electric
                                                                                               
          nipsco gas
                                                                                               
          nipsco minority interest transaction
                                                                                               
          nipsco operations
                                                                                               
          defined terms
                                                                                               
          nymex
                                                                                               
          opeb
                                                                                               
          phmsa
                                                                                               
          ppa
                                                                                               
          rng
                                                                                               
          save
                                                                                               
          scope 1 ghg emissions
                                                                                               
          scope 2 ghg emissions
                                                                                               
          sec
                                                                                               
          smrp
                                                                                               
          sms
                                                                                               
          tcja
                                                                                               
          tdsic
                                                                                               
          templeton
                                                                                               
          vie
                                                                                               
          wam
                                                                                               
          index
                                                                                               
          condensed statements of consolidated income
                                                                                               
          condensed statements of consolidated comprehensive income
                                                                                               
          condensed consolidated balance sheets
                                                                                               
          condensed statements of consolidated cash flows
                                                                                               
          condensed statements of consolidated equity
                                                                                               
          notes to condensed consolidated financial statements
                                                                                               
          1. basis of accounting presentation
                                                                                               
          2. recent accounting pronouncements
                                                                                               
          3. revenue recognition
                                                                                               
          4. noncontrolling interests
                                                                                               
          5. earnings per share
                                                                                               
          6. equity
                                                                                               
          7. short-term borrowings
                                                                                               
          8. long-term debt
                                                                                               
          9. regulatory matters
                                                                                               
          10. risk management activities
                                                                                               
          11. fair value
                                                                                               
          12. income taxes
                                                                                               
          13. pension and other postemployment benefits
                                                                                               
          14. other commitments and contingencies
                                                                                               
          15. accumulated other comprehensive loss
                                                                                               
          16. business segment information
                                                                                               
          17. other
                                                                                               
          18. supplemental disclosures of cash flow information
                                                                                               
          19. subsequent event
                                                                                               
          operating revenues
                                                                                               
          customer revenues
                                                                                               
          other revenues
                                                                                               
          total operating revenues
                                                                                               
          operating expenses
                                                                                               
          cost of energy
                                                                                               
          operation and maintenance
                                                                                               
          depreciation and amortization
          288,300,000 315,400,000 306,900,000 286,700,000 258,600,000 278,100,000 269,500,000 253,500,000 242,100,000 257,300,000 210,900,000 233,100,000 206,900,000 216,200,000 203,200,000 208,700,000 192,700,000 188,200,000 188,900,000 186,300,000 185,000,000 183,500,000 180,600,000 177,500,000 184,300,000 182,200,000 182,200,000 177,900,000 175,100,000 161,800,000 148,500,000 144,600,000 144,700,000 141,800,000 143,000,000 142,200,000 143,300,000 141,100,000 136,300,000 136,900,000 132,800,000 133,400,000 66,100,000 167,400,000 157,500,000 154,700,000 153,000,000 149,100,000 148,700,000 145,900,000 144,500,000 143,300,000 143,600,000 141,800,000 126,000,000 148,000,000 146,100,000 129,900,000 134,900,000 134,500,000 138,900,000 141,800,000 153,100,000 151,600,000 149,800,000 148,900,000 148,200,000 291,899,856.2 143.8 142,900,000 141,000,000 147,700,000 135,600,000 139,800,000 142,200,000 138,200,000 139,000,000 137,800,000 136,500,000 138,000,000 136,900,000 137,600,000 136,100,000 136,400,000 135,100,000 
          loss on impairment of assets
                                                                   15,500,000 500,000 700,000 1,000,000    18,400,000    1,700,000 1,600,000 1,000,000 400,000 6,500,000 3,200,000 -700,000 3,400,000 2,500,000   
          gain on sale of assets
                    -200,000                                 -8,500,000 -5,000,000  -2,900,000 -700,000 -15,700,000  -9,800,000 -200,000 -200,000  -700,000 -1,500,000 -1,600,000 200,000       -100,000  -1,999,998 -2  -400,000 -800,000 -3,200,000  200,000 -200,000 -300,000  -300,000 1,900,000 -2,700,000     
          other taxes
                                                                                               
          total operating expenses
                                                                                               
          operating income
                                                                                               
          other income
                                                                                               
          interest expense
                                                                                               
          other
                                                                                               
          total other deductions
                                                                                               
          income before income taxes
                                                                                               
          income taxes
                                                                                               
          net income
          556,200,000 278,400,000 107,000,000 100,500,000 526,700,000 244,300,000 97,000,000 103,100,000 400,300,000 191,900,000 98,400,000 46,300,000 337,800,000 241,200,000 63,500,000 55,800,000 431,300,000 173,200,000 62,200,000 56,900,000 296,500,000 87,800,000 -172,900,000 -4,700,000 75,600,000 -139,300,000 6,600,000 296,900,000 218,900,000 -11,700,000 -339,500,000 24,500,000 276,100,000 -52,400,000 14,000,000 -44,400,000 211,300,000 88,800,000 34,400,000 28,600,000 179,700,000 59,400,000 -4,900,000 -27,700,000 275,300,000 154,200,000 31,400,000 78,200,000 266,200,000 151,800,000 48,100,000 71,700,000 260,500,000 134,000,000 19,300,000 69,400,000 193,400,000 20,300,000 34,700,000 38,900,000 205,200,000 33,400,000 33,200,000 28,100,000 197,300,000 89,500,000 -15,400,000 143,599,851.6 148.4 162,000,000 20,000,000 -202,300,000 99,300,000 67,000,000 11,000,000 26,700,000 216,700,000 62,500,000 25,800,000 21,000,000 172,900,000 68,000,000 -6,800,000 39,000,000 206,300,000 
          net income attributable to noncontrolling interest
                                                                                               
          net income attributable to nisource
                                                                                               
          preferred dividends
                                                                                               
          preferred redemption premium
                                                                                               
          net income available to common shareholders
                                                                                               
          earnings per share
                                                                                               
          basic earnings per share
                                                                                               
          diluted earnings per share
                                                                                               
          basic average common shares outstanding
                                                                                               
          diluted average common shares
                                                                                               
          other comprehensive income:
                                                                                               
          net unrealized gain on available-for-sale debt securities
                                                                                               
          reclassification adjustment for cash flow hedges
                                                                                               
          unrecognized pension and opeb benefit
                                                                                               
          total other comprehensive income
                                                                                               
          comprehensive income
                                                                                               
          assets
                                                                                               
          property, plant and equipment
                                                                                               
          plant
                                                                                               
          accumulated depreciation and amortization
                                                                                               
          net property, plant and equipment
                                                                                               
          investments and other assets
                                                                                               
          unconsolidated affiliates
                                                                                               
          available-for-sale debt securities
                                                                                               
          other investments
                                                                                               
          total investments and other assets
                                                                                               
          current assets
                                                                                               
          cash and cash equivalents
                                                                                               
          restricted cash
                                                                          -46,100,000 96,600,000 -400,000 15,700,030.2 -30.2 -42,700,000 -322,600,000 64,400,000 72,100,000 36,600,000 -29,100,000 -5,700,000 81,300,000 60,400,000 -131,200,000 -21,700,000 -21,800,000    26,200,000 
          accounts receivable
                                               -376,200,000 3,200,000 173,800,000 11,200,000 -158,100,000 34,700,000 479,400,000 -93,800,000 -425,700,000 186,200,000 441,500,000 -265,100,000 -413,200,000 123,900,000 355,800,000 -161,300,000 -385,200,000 28,700,000 177,300,000 127,900,000 -341,800,000 126,800,000 418,600,000 16,000,000 -543,100,000 54,100,000 383,500,000 -138,400,000 -263,300,000 109,000,000 413,199,827.9 172.1 -606,900,000 181,300,000 376,800,000 -152,900,000 -292,700,000 121,100,000 271,400,000 -103,200,000 -377,400,000 -8,700,000 683,600,000 110,200,000 -782,700,000 18,600,000   
          allowance for credit losses
                                                                                               
          gas storage
                                                                                               
          materials and supplies, at average cost
                                                                                               
          electric production fuel, at average cost
                                                                                               
          exchange gas receivable
                                                                                               
          regulatory assets
                                                                                               
          prepayments
                                                                                               
          other current assets
                                                                                               
          total current assets
                                                                                               
          other assets
                                                                                               
          goodwill
                                                                                               
          deferred charges and other
                                                                                               
          total other assets
                                                                                               
          total assets
                                                                                               
          capitalization and liabilities
                                                                                               
          capitalization
                                                                                               
          stockholders’ equity
                                                                                               
          common stock - 0.01 par value,750,000,000 shares authorized; 477,136,079 and 469,822,472 shares outstanding, respectively
                                                                                               
          treasury stock
                                                                                               
          additional paid-in capital
                                                                                               
          retained deficit
                                                                                               
          accumulated other comprehensive loss
                                                                                               
          total nisource stockholders’ equity
                                                                                               
          noncontrolling interest in consolidated subsidiaries
                                                                                               
          total stockholders’ equity
                                                                                               
          long-term debt, excluding amounts due within one year
                                                                                               
          total capitalization
                                                                                               
          current liabilities
                                                                                               
          current portion of long-term debt
                                                                                               
          short-term borrowings
                                                                                               
          accounts payable
                                               192,000,000 300,000 -48,300,000 -35,200,000 97,000,000 -37,900,000 -165,400,000 -84,200,000 255,700,000 -47,800,000 -296,800,000 126,500,000 245,500,000 -58,500,000 -144,600,000 25,400,000 208,300,000 -3,500,000 -106,200,000 -41,300,000 170,300,000 -74,700,000 -130,500,000 -119,900,000 304,500,000 -31,400,000 -132,400,000 -103,000,000 107,600,000 28,000,000 -327,099,838.9 -161.1 229,000,000 -185,600,000 -105,800,000 32,100,000 173,800,000 -92,900,000 -111,800,000 -34,300,000 221,500,000 149,300,000 -206,600,000 -340,600,000 302,900,000 152,800,000 -108,600,000 -141,400,000 
          dividends payable - common stock
                                                                                               
          customer deposits and credits
                                               8,800,000 68,600,000 -26,100,000 -103,600,000 61,000,000 89,300,000 6,900,000 -121,700,000 37,100,000 91,100,000 2,200,000 -23,100,000 13,500,000 84,500,000 -2,900,000 -102,000,000 6,000,000 61,700,000 -13,200,000 -98,500,000 32,300,000 98,100,000 1,600,000 -136,500,000 -14,300,000 94,000,000 20,000,000 -124,700,000                     
          taxes accrued
                                               63,400,000 -10,000,000 -66,900,000 25,600,000 39,300,000 14,100,000 -66,700,000 22,000,000 77,500,000 -24,500,000 -62,500,000 19,300,000 70,600,000 -22,600,000 -74,100,000 28,700,000 58,600,000 -13,900,000 -51,400,000 16,600,000 65,100,000 -22,100,000 -64,800,000 24,100,000 -20,900,000 -102,300,000 -90,200,000 96,400,000 67,400,000 -33,100,000 81,899,918 82 -38,500,000 -64,100,000 -115,500,000 128,400,000 17,200,000 -62,100,000 -95,600,000 129,800,000 148,200,000 -107,700,000 -138,700,000 151,600,000 29,000,000 -46,200,000 -179,500,000 218,000,000 
          interest accrued
                                               49,200,000 -50,300,000 49,200,000 -56,800,000 51,500,000 -64,000,000 60,200,000 -59,300,000 58,900,000 -60,100,000 66,600,000 -61,100,000 65,900,000 -53,600,000 57,000,000 -65,500,000 50,800,000 -33,700,000 46,400,000 -41,700,000 44,100,000   -53,000,000 29,300,000 -45,300,000 44,200,000 -38,900,000 37,900,000 -37,900,000 5,300,023.4 -23.4 18,300,000 1,900,000 9,600,000 -9,000,000 -7,600,000 22,300,000 -16,700,000 -700,000 -4,400,000 21,400,000 -15,200,000 19,100,000 -56,600,000 63,800,000 -62,600,000 61,700,000 
          asset retirement obligations
                                                                                               
          exchange gas payable
                                                                                               
          regulatory liabilities
                                                                                               
          accrued compensation and employee benefits
                                                                                               
          other accruals
                                               23,800,000 800,000 -1,000,000 -29,600,000 2,000,000 12,700,000 -9,500,000 -60,300,000 34,800,000 17,900,000 -17,500,000 -30,100,000 38,700,000 -3,200,000 -6,700,000 -26,600,000 64,700,000 1,900,000 -38,500,000 -54,300,000 65,400,000 -5,900,000 7,800,000 -34,100,000 79,100,000 7,800,000 -13,300,000 -17,200,000 100,400,000 109,300,000 -213,299,812.6 -187.4 63,300,000 131,800,000 -28,500,000 -120,900,000 62,200,000 63,900,000 -44,000,000 -97,200,000 77,700,000 87,800,000 -75,600,000 -80,100,000 20,600,000 70,300,000 31,400,000 -102,900,000 
          total current liabilities
                                                                                               
          other liabilities
                                                                                               
          deferred income taxes
                                                                                               
          accrued liability for postretirement and postemployment benefits
                                                                                               
          other noncurrent liabilities and deferred credits
           -4,000,000 6,500,000 -7,600,000 8,100,000 23,700,000 -900,000 12,100,000 -8,800,000 -10,300,000 -10,800,000 -19,200,000 -8,000,000                                                                         
          total other liabilities
                                                                                               
          commitments and contingencies
                                                                                               
          total capitalization and liabilities
                                                                                               
          nine months ended september 30,
                                                                                               
          operating activities
        467,900,000                                                                                       
          adjustments to reconcile net income to net cash from operating activities:
                                                                                               
          deferred income taxes and investment tax credits
          75,800,000 82,300,000 33,100,000 29,100,000 91,300,000  24,000,000 23,500,000 61,600,000 32,000,000 9,100,000 17,500,000 75,500,000 38,600,000 17,500,000 13,600,000 87,200,000 22,900,000 18,200,000 15,600,000 55,200,000 41,800,000 -59,400,000 8,500,000 -19,900,000 -2,200,000 -6,100,000 74,900,000 51,600,000 -161,800,000 -92,700,000 9,500,000 56,800,000 210,400,000 7,900,000 -21,000,000 109,400,000 44,600,000 13,400,000 22,300,000 102,000,000 75,200,000 -59,100,000 -15,900,000 135,100,000 78,300,000 34,000,000 37,900,000 148,900,000 88,300,000 31,700,000 50,900,000 116,500,000 164,500,000 11,100,000 36,800,000 92,200,000 13,200,000 33,100,000 32,700,000 99,400,000 69,500,000 92,000,000 11,400,000 27,200,000 23,800,000 320,300,000 34,099,976.9 23.1 45,700,000 40,000,000 35,400,000 16,700,000 34,900,000 -8,100,000 -15,700,000 1,600,000 16,000,000 -21,100,000 -67,800,000 -40,500,000 40,100,000 24,800,000 -51,800,000 -29,800,000 
          loss on sale of assets
            -600,000   1,800,000 -500,000        -300,000 -105,000,000 -800,000 -1,600,000 -100,000 8,100,000                                                             1,800,000 -900,000 -500,000 
          payments for asset retirement obligations
          -15,500,000 -23,000,000 -18,700,000 -20,900,000 -10,400,000  -20,000,000 -23,000,000 -12,000,000                                                                             
          other adjustments
          18,300,000 2,300,000 200,000 15,200,000 7,100,000 -37,900,000 -17,400,000 -5,300,000 7,800,000 -29,900,000 5,400,000 5,500,000 1,100,000 -22,000,000 13,600,000 6,100,000 8,000,000 -18,000,000 8,400,000 5,400,000 3,500,000 -13,100,000 5,600,000 -200,000 7,900,000 -19,700,000 5,200,000 7,100,000 6,500,000 -13,900,000 4,300,000 26,900,000 -15,600,000 -22,000,000 6,100,000 11,400,000 11,000,000 -1,500,000 -600,000 -1,300,000 -400,000                                       -2,600,000 -1,600,000 -1,900,000 -900,000 -600,000 200,000 
          changes in assets and liabilities:
                                                                                               
          components of working capital
          -531,500,000  38,800,000 140,500,000 -205,300,000  30,400,000 119,000,000 -235,200,000  23,000,000 229,500,000 71,100,000  -117,600,000 44,800,000 -42,400,000  -48,200,000 -16,900,000 -89,300,000  -72,700,000 71,200,000 -147,100,000  155,800,000 18,200,000 -27,200,000  430,500,000 190,800,000 -178,400,000  39,000,000 111,100,000 -117,500,000                                                 
          regulatory assets/liabilities
          50,500,000 75,200,000 4,200,000 -34,000,000 10,300,000 26,900,000 -29,700,000 -24,300,000 18,400,000 -41,300,000 2,500,000 1,600,000 11,000,000 -112,000,000 -9,200,000 -33,100,000 24,900,000 22,000,000 33,300,000 13,100,000 8,400,000 60,900,000 -7,100,000 4,100,000 12,900,000 -15,600,000 -29,100,000 -41,300,000 400,000 -114,500,000 -80,400,000 24,600,000 117,100,000 70,400,000 -36,100,000 -46,100,000 69,300,000 14,300,000 -66,600,000 -54,300,000 -81,300,000 -128,700,000 -14,300,000 34,800,000 90,600,000 -263,700,000 2,300,000 11,900,000 2,900,000 407,600,000 30,600,000 35,100,000 5,800,000 -148,000,000 89,000,000 8,500,000 -1,200,000 -362,100,000 10,900,000 9,700,000 18,600,000 60,000,000 5,600,000 50,500,000 47,800,000 35,100,000 17,900,000 52,199,967.7 32.3 -2,700,000 -35,400,000 -17,300,000 -36,400,000 37,400,000 8,300,000 -2,100,000 18,700,000 25,600,000 -36,500,000 -6,400,000 -19,100,000 -28,200,000 10,100,000 -23,500,000 -4,100,000 
          deferred charges and other noncurrent assets
           -9,100,000 -9,500,000   24,300,000 -12,400,000 -14,700,000 -18,000,000 1,700,000 6,600,000 -6,400,000 -12,000,000 12,700,000 -700,000 -8,700,000 -7,400,000   8,200,000 -10,700,000 9,600,000 -7,200,000 -5,300,000 -12,100,000 300,000 -8,000,000 -10,100,000 -58,300,000 3,000,000 -400,000 -700,000 1,900,000     1,800,000   200,000 -5,600,000 8,500,000 -2,900,000 5,200,000 -1,900,000 1,800,000 -100,000 -200,000 8,500,000 6,600,000 5,600,000 -400,000 43,800,000 46,400,000 5,000,000 -23,300,000 13,200,000 -18,400,000      -2,600,000 -22,100,000 -500,000 699,988.2 11.8 75,000,000 -23,100,000 -5,700,000 -7,500,000 -21,600,000 -5,900,000 3,100,000 2,000,000 -9,100,000 11,100,000 -3,200,000 -5,200,000 -16,000,000 16,300,000 -4,500,000 1,400,000 
          net cash flows from operating activities
          442,300,000 712,600,000 467,900,000 495,400,000 686,400,000 539,800,000 340,000,000 445,500,000 456,200,000 399,200,000 344,900,000 507,600,000 683,400,000 373,200,000 129,000,000 327,400,000 579,800,000 278,600,000 236,300,000 254,700,000 448,300,000 245,400,000 150,900,000 337,800,000 369,900,000 351,500,000 305,600,000 527,100,000 399,100,000 -387,100,000 117,700,000 421,300,000 388,200,000 212,600,000 -121,800,000 240,300,000 411,100,000 271,300,000 44,900,000 184,200,000 302,900,000 262,900,000 78,300,000 511,300,000 604,300,000 433,100,000 235,500,000 257,000,000 394,000,000 358,200,000 184,100,000 445,400,000 449,100,000 333,700,000 170,000,000 291,800,000 480,000,000 76,100,000 58,100,000 313,900,000 422,100,000 392,900,000 -70,000,000 319,200,000 83,300,000 546,000,000 -120,000,000 1,240,198,942.1 1,057.9 335,000,000 -388,100,000 -207,600,000 846,000,000 358,300,000 -189,000,000 -192,100,000 780,000,000 290,900,000 -155,400,000 294,400,000 726,300,000 -44,600,000 -180,800,000 -83,900,000 1,021,600,000 
          investing activities
        -830,300,000                                                                                       
          capital expenditures
          -805,200,000 -846,300,000 -640,500,000 -658,200,000 -637,300,000 -760,000,000 -634,700,000 -629,800,000 -589,500,000 -760,200,000 -723,700,000 -604,800,000 -557,100,000 -680,100,000 -606,000,000 -466,900,000 -450,100,000 -545,200,000 -494,700,000 -431,100,000 -367,000,000 -465,900,000 -472,900,000 -367,200,000 -452,100,000 -492,400,000 -466,500,000 -489,800,000 -353,700,000 -521,600,000 -464,100,000 -462,500,000 -370,000,000 -479,400,000 -484,200,000 -420,200,000 -312,000,000 -391,800,000 -410,900,000 -371,500,000 -301,000,000 -437,300,000 67,700,000 -583,600,000 -407,500,000 -586,800,000 -588,800,000 -466,600,000 -386,300,000 -582,600,000 -495,600,000 -432,400,000 -369,300,000 -474,500,000 -404,800,000 -326,900,000 -292,600,000 -351,000,000 -329,200,000 -235,600,000 -209,400,000 -250,100,000 -216,800,000 -198,100,000 -138,800,000 -191,500,000 -200,100,000 -385,599,793.1 -206.9 -290,500,000 -256,600,000 -232,100,000 -190,700,000 -268,500,000 -188,100,000 -179,600,000 -152,100,000 -239,100,000 -130,700,000 -146,000,000 -121,600,000 -183,500,000 -163,800,000 -139,000,000 -104,100,000 
          cost of removal
           -74,500,000    -57,900,000    -42,100,000    -43,100,000    -27,100,000 -34,900,000 -32,200,000 -26,900,000 -36,100,000 -35,400,000 -32,200,000 -34,500,000 -28,700,000 -28,800,000 -30,400,000 -25,300,000 -31,700,000 -26,500,000 -27,100,000 -19,000,000 -30,100,000 -23,300,000 -24,200,000 -31,400,000 -30,600,000                                                
          milestone payments to renewable generation asset developers
            -133,700,000                                                                                   
          advanced deposits
          -22,400,000  -400,000 -35,600,000 -125,300,000                                                                                 
          other investing activities
          -45,000,000 67,400,000 58,100,000 -116,000,000 -35,900,000 -24,600,000 81,100,000 -31,000,000 -22,900,000 8,600,000 64,000,000 -42,900,000 -33,400,000 6,500,000 54,900,000 -34,800,000 -25,300,000   3,000,000 -800,000 -400,000 900,000 -700,000 100,000 900,000 -600,000 -2,400,000 3,600,000 -1,500,000 -1,200,000 16,700,000 -9,900,000 2,400,000 3,600,000 -3,600,000 -800,000 6,900,000 38,400,000 -37,400,000 -25,600,000 -22,300,000 -16,500,000 -25,800,000 2,400,000 -12,900,000 -11,900,000 -8,100,000 7,000,000 -19,500,000 -24,800,000 -18,300,000 -5,300,000 -10,900,000 -18,200,000 -9,500,000 -10,400,000 -9,700,000 -23,700,000 -26,800,000 -9,200,000 -7,200,000 -26,000,000 -9,300,000 -10,600,000 15,700,000 -28,300,000 -29,399,979.1 -20.9 -19,200,000 -16,800,000 -700,000 -1,400,000 -4,900,000 33,500,000 -6,100,000 -2,900,000 2,200,000 -7,700,000 -10,900,000 14,000,000 -136,300,000 109,400,000 21,600,000 -11,900,000 
          net cash flows used for investing activities
          -872,600,000 -1,127,500,000 -830,300,000 -1,213,600,000 -1,352,700,000 -798,500,000 -820,500,000 -871,000,000 -723,000,000 -1,068,300,000 -1,127,700,000 -647,800,000 -727,800,000 -887,500,000 -731,600,000 -580,700,000 -370,400,000 -810,700,000 -531,800,000 -460,600,000 -401,800,000 520,800,000 -513,300,000 -402,000,000 -484,600,000 -528,600,000 -495,800,000 -522,600,000 -375,400,000 -549,600,000 -505,400,000 -472,200,000 -398,900,000  -514,900,000 -447,000,000 -344,200,000       -604,900,000 -388,900,000 -604,400,000 -614,600,000 -489,700,000 -407,900,000 -640,100,000 -533,200,000              -194,400,000 -151,900,000 -183,000,000 -319,899,803.6 -196.4 -145,400,000 -581,300,000 -283,000,000 -104,600,000   -190,600,000 -72,200,000 -172,100,000 -260,000,000 -174,900,000 -125,500,000 -291,700,000 -54,400,000 -115,800,000 -110,200,000 
          financing activities
        116,300,000                                                                                       
          proceeds from issuance of long-term debt
           990,000,000 1,620,500,000 741,500,000 -100,000 495,100,000 1,090,100,000 644,400,000 744,500,000 744,200,000                                                                        
          repayments of finance lease obligations
          -5,900,000 -4,700,000 -6,400,000 -5,400,000 -5,500,000  -6,900,000 -6,300,000 -7,200,000   -8,000,000 -8,100,000    -7,300,000                                                                     
          repayments of long-term debt
           -10,000,000                                                                                    
          repayment of short-term debt
                               -850,000,000   -150,000,000 -200,000,000 -350,000,000                                                         
          net change in commercial paper and other short-term borrowings
          555,000,000 -524,000,000 1,260,000,000 -771,000,000 166,400,000 347,600,000 -387,000,000 -578,300,000 -176,300,000                                                                             
          issuance of common stock, net of issuance costs
          3,900,000 53,000,000 252,300,000 3,600,000 3,200,000 104,700,000 502,300,000 2,900,000 2,700,000 3,300,000 3,300,000 3,300,000 3,000,000 145,200,000 3,200,000 3,100,000 2,800,000 290,800,000 2,800,000 3,200,000 2,800,000 200,200,000 3,700,000 3,800,000 3,700,000 233,500,000 3,800,000                                                           
          redemption of preferred stock
               -486,100,000                                                                           
          preferred stock redemption premium
               -14,000,000                                                                           
          equity costs, premiums and other debt related costs
          -22,700,000 -4,800,000 -4,300,000 -2,300,000 -15,400,000 -4,400,000 -2,900,000 -2,400,000 -57,600,000     -2,900,000 -1,000,000 -200,000 -8,900,000 -8,500,000 -3,800,000 -3,400,000 -2,500,000 -228,900,000 -12,500,000 -5,100,000                                                             
          contributions from nipsco minority interest holders
            11,000,000 99,500,000 34,800,000 39,800,000                                                                               
          distribution to nipsco minority interest holders
          -19,900,000  -11,100,000 -26,900,000 -17,500,000  -11,800,000                                                                               
          distributions to tax equity partners
          -3,200,000 -1,400,000 -3,000,000 -5,700,000 -4,100,000 -1,800,000 -6,100,000                                                                               
          dividends paid - common stock
          -149,000,000 -134,000,000 -132,200,000 -132,200,000 -132,000,000 -124,000,000 -119,100,000 -119,300,000 -118,600,000 -103,400,000 -103,500,000 -103,400,000 -103,200,000 -95,500,000 -95,400,000 -95,300,000 -95,300,000 -86,400,000 -86,300,000 -86,300,000 -86,200,000 -80,500,000 -80,400,000 -80,400,000 -80,300,000 -74,700,000 -74,700,000 -74,600,000 -74,500,000 -70,800,000 -70,800,000 -66,000,000 -65,700,000 -58,900,000 -57,000,000 -56,700,000 -56,500,000 -53,200,000 -53,000,000 -49,700,000 -49,600,000 -49,400,000 -49,300,000 -82,600,000 -82,100,000 -82,100,000 -82,000,000 -78,700,000 -78,500,000 -78,300,000 -78,100,000 -74,800,000 -74,700,000 -74,400,000 -68,400,000 -65,300,000 -65,100,000     -64,200,000 -63,800,000 -63,900,000 -63,700,000  -63,400,000                   
          dividends paid - preferred stock
               -100,000 -8,100,000 -8,100,000 -8,100,000 -19,500,000 -8,100,000 -19,400,000 -8,100,000 -19,500,000 -8,100,000 -19,400,000 -8,100,000 -19,500,000 -8,100,000 -19,400,000 -8,100,000 -19,500,000 -8,100,000 -19,400,000 -8,200,000 -19,400,000 -9,100,000                                                         
          net cash flows from (used for) financing activities
            116,300,000 780,100,000 771,400,000        117,300,000                        -64,900,000 153,700,000 408,700,000 207,500,000 20,600,000       212,700,000 25,100,000                                     
          change in cash, cash equivalents and restricted cash
          -38,600,000 16,200,000 -246,100,000 61,900,000 105,100,000 39,800,000 22,900,000 -4,600,000 -2,140,600,000 2,174,500,000 -84,500,000 42,800,000 72,900,000 -3,200,000 -20,900,000 -30,900,000 35,500,000 38,600,000 -34,100,000 -6,300,000 -28,900,000 58,000,000 -86,000,000 -59,400,000 64,600,000 111,400,000 4,600,000 -128,400,000 39,700,000 67,300,000 -27,300,000 36,400,000 6,300,000                                                     
          cash, cash equivalents and restricted cash at beginning of period
          135,700,000 198,600,000 2,281,100,000 75,400,000 94,900,000 125,600,000 148,400,000 121,100,000 38,400,000                                                     
          cash, cash equivalents and restricted cash at end of period
          97,100,000 16,200,000 -246,100,000 61,900,000 303,700,000 39,800,000 22,900,000 -4,600,000 140,500,000 2,174,500,000 -84,500,000 42,800,000 148,300,000 -3,200,000 -20,900,000 -30,900,000 130,400,000 38,600,000 -34,100,000 -6,300,000 96,700,000 58,000,000 -86,000,000 -59,400,000 213,000,000 111,400,000 4,600,000 -128,400,000 160,800,000 67,300,000 -27,300,000 36,400,000 44,700,000                                                     
          refer to note 18, "supplemental disclosures of cash flow information," for additional information.
                                                                                               
          total cash, cash equivalents and restricted cash
                                                                                               
          balance as of june 30, 2025
                                                                                               
          comprehensive income:
                                                                                               
          other comprehensive income, net of tax
                                                                                               
          dividends:
                                                                                               
          common stock
                                                                                               
          noncontrolling interests:
                                                                                               
          contributions from noncontrolling interests
                                                                                               
          distributions to noncontrolling interests
                  -3,000,000                                                                             
          stock issuances:
                                                                                               
          employee stock purchase plan
                                                                                               
          long-term incentive plan
                                                                                               
          401(k) and profit sharing
                                                                                               
          atm program
                                                                                               
          balance as of september 30, 2025
                                                                                               
          balance as of december 31, 2024
                                                                                               
          balance as of june 30, 2024
                                                                                               
          distributions to noncontrolling interest
                   -2,100,000 -2,000,000 -4,700,000 -5,300,000 -1,200,000 -1,800,000 -2,400,000 -600,000                                                                     
          balance as of september 30, 2024
                                                                                               
          balance as of december 31, 2023
                                                                                               
          preferred stock
                                                                                               
          stock issuances
                                                                                               
          series b and b-1 preferred stock redemption
                                                                                               
          series b and b-1 preferred stock redemption premium
                                                                                               
          shares
                                                                                               
          issued:
                                                                                               
          redeemed:
                                                                                               
          series b and b-1 preferred stock
                                                                                               
          three months ended september 30, 2025
                                                                                               
          gas distribution
                                                                                               
          residential
                                                                                               
          commercial
                                                                                               
          industrial
                                                                                               
          off-system
                                                                                               
          miscellaneous
                                                                                               
          subtotal
                                                                                               
          electric generation and power delivery
                                                                                               
          wholesale
                                                                                               
          total customer revenues
                                                                                               
          amounts included in columbia operations primarily relate to earnings share mechanisms and late fees. amounts included in nipsco operations primarily relate to late fees and property rentals. customer revenue amounts exclude intersegment revenues. see note 16, "business segment information," for discussion of intersegment revenues.amounts included in columbia operations primarily relate to alternative revenue programs including weather normalization adjustment mechanisms. amounts included in nipsco operations primarily relate to alternative revenue programs including weather normalization adjustment mechanisms, miso multi-value projects and revenue from non-jurisdictional transmission assets. amounts included in corporate and other primarily relate to products and services revenue.
                                                                                               
          three months ended september 30, 2024
                                                                                               
          public authority
                                                                                               
          amounts included in columbia operations primarily relate to earnings share mechanisms and late fees. amounts included in nipsco operations, primarily relate to revenue refunds, public repairs and property rentals. customer revenue amounts exclude intersegment revenues. see note 16, "business segment information," for discussion of intersegment revenues.amounts included in columbia operations primarily relate to alternative revenue programs including weather normalization adjustment mechanisms. amounts included in nipsco operations primarily relate to alternative revenue programs including weather normalization adjustment mechanisms, miso multi-value projects and revenue from non-jurisdictional transmission assets.
                                                                                               
          nine months ended september 30, 2025
                                                                                               
          nine months ended september 30, 2024
                                                                                               
          current period provisions
                                                                                               
          write-offs charged against allowance
                                                                                               
          recoveries of amounts previously written off
                                                                                               
          finance lease obligations
                                                                                               
          total liabilities
                                                                                               
          distributions to nipsco minority interest holders
                                                                                               
          numerator:
                                                                                               
          less: income allocated to participating securities
                                                                                               
          net income available to common shareholders - basic
                                                                                               
          net income available to common shareholders - diluted
                                                                                               
          denominator:
                                                                                               
          average common shares outstanding - basic
                                                                                               
          dilutive potential common shares:
                                                                                               
          shares contingently issuable under employee stock plans
                                                                                               
          shares restricted under employee stock plans
                                                                                               
          atm forward sale agreements
                                                                                               
          average common shares - diluted
                                                                                               
          earnings per common share:
                                                                                               
          basic
                                                                                               
          diluted
                                                                                               
          current
                                                                                               
          derivatives not designated as hedging instruments
                                                                                               
          total
                                                                                               
          noncurrent
                                                                                               
          losses on commodity price risk programs
                                                                                               
          gains on commodity price risk programs
                                                                                               
          recurring fair value measurements september 30, 2025
                                                                                               
          u.s. treasury debt securities
                                                                                               
          risk management assets
                                                                                               
          equity securities
                                                                                               
          liabilities
                                                                                               
          risk management liabilities
                                                                                               
          recurring fair value measurements december 31, 2024
                                                                                               
          september 30, 2025
                                                                                               
          corporate/other debt securities
                                                                                               
          december 31, 2024
                                                                                               
          long-term debt
                                                                                               
          three months ended september 30,
                                                                                               
          components of net periodic benefit cost
                                                                                               
          service cost
                                                                                               
          interest cost
                                                                                               
          expected return on assets
                                                                                               
          amortization of prior service credit
                                                                                               
          recognized actuarial loss
                                                                                               
          settlement loss
                                                                                               
          total net periodic benefit cost
                                                                                               
          the service cost component and all non-service cost components of net periodic benefit (income) cost are presented in "operation and maintenance" and "other, net," respectively, on the condensed statements of consolidated income (unaudited).
                                                                                               
          other comprehensive income before reclassifications
                                                                                               
          amounts reclassified from accumulated other comprehensive loss
                                                                                               
          net current-period other comprehensive income
                                                                                               
          all amounts are net of tax. amounts in parentheses indicate debits.
                                                                                               
          external revenue
                                                                                               
          intersegment revenue
                                                                                               
          total operating revenue
                                                                                               
          o&m
                                                                                               
          depreciation
                                                                                               
          total other taxes
                                                                                               
          other segment items
                                                                                               
          columbia operations
                                                                                               
          corporate and other
                                                                                               
          consolidated assets
                                                                                               
          interest income
                                                                                               
          afudc equity
                                               -2,800,000 -3,400,000 -3,000,000 -2,400,000 -3,800,000 5,600,000 -7,300,000 -6,000,000 -6,100,000 -6,400,000 -5,200,000 -4,000,000 -5,800,000 -4,700,000 -4,500,000 -3,500,000 -5,900,000 -1,700,000 -2,000,000 -1,000,000 800,000 -1,300,000 -500,000 -1,400,000 -1,200,000 -1,200,000 -2,300,000 -1,400,000 -4,800,000   0.9 -700,000 -600,000 -3,000,000 -1,100,000 -600,000 -1,100,000 -1,100,000 -800,000         
          pension and other postretirement non-service cost
                                                                                               
          tax penalties
                                                                                               
          total other
                                                                                               
          inventories
                                               39,600,000 -121,100,000 -97,900,000 218,300,000 27,100,000 -127,000,000 -150,400,000 297,200,000 50,900,000 -199,000,000 -245,800,000 274,000,000 94,500,000 -176,900,000 -181,500,000 254,700,000 42,800,000 -114,000,000 -77,600,000 211,200,000 29,600,000 -185,100,000 -194,800,000 208,500,000 136,100,000 -180,400,000 -185,100,000 332,700,000 151,600,000 -242,200,000 219,299,512.3 487.7 165,600,000 -609,900,000 -485,400,000 847,300,000 219,200,000 -411,200,000 -420,800,000 707,200,000 118,000,000 -449,300,000 -182,500,000 442,100,000 141,500,000 -454,300,000 -373,800,000 615,500,000 
          exchange gas receivable/payable
                                               37,000,000 19,800,000 22,100,000 -42,000,000 -5,600,000 40,100,000 18,100,000 -84,300,000 10,800,000 58,700,000 21,900,000 -134,200,000 -7,100,000 77,500,000 40,400,000 -89,800,000 900,000 35,200,000 68,700,000 -113,400,000 17,800,000 48,300,000 -36,600,000 -129,600,000 -1,300,000 38,400,000 15,400,000 -66,700,000 12,800,000 -400,000 -22,399,919.9 -80.1 -69,900,000 -9,600,000 51,600,000 -44,000,000 51,900,000 35,900,000 16,800,000 -60,300,000 48,500,000 13,100,000 -46,800,000 -126,000,000 110,000,000 39,800,000 18,900,000 -80,700,000 
          prepayments and other current assets
                                               -44,300,000 24,300,000 46,300,000 -26,700,000 -29,400,000 -6,600,000 52,900,000 -16,200,000 -66,200,000 13,100,000 38,500,000 4,500,000 -62,500,000 9,300,000 42,000,000 -5,800,000 -52,800,000 13,100,000 39,900,000 -4,700,000 -41,300,000 10,500,000 19,300,000 1,300,000 -43,900,000 4,300,000 22,700,000 5,400,000 13,400,000 -9,900,000 20,699,991.2 8.8 -14,900,000 -15,500,000 -900,000 3,700,000 -42,000,000 -4,600,000 25,500,000 24,500,000 -41,600,000 1,300,000 27,600,000 9,900,000     
          total change in working capital
                                                                                               
          non-cash transactions:
                                                                                               
          capital expenditures included in current liabilities
                                                                                               
          dividends declared but not paid
                                                                                               
          executive summary
                                                                                               
          summary of consolidated financial results
                                                                                               
          results and discussion of segment operations
                                                                                               
          liquidity and capital resources
                                                                                               
          regulatory, environmental and safety matters
                                                                                               
          market risk disclosures
                                                                                               
          other information
                                                                                               
          other operating expenses
                                                                                               
          preferred dividends and redemption premium
                                                                                               
          revenues
                                                                                               
          wholesale and other
                                                                                               
          sales and transportation
                                                                                               
          heating degree days
                                                                                               
          normal heating degree days
                                                                                               
          % warmer than normal
                                                                                               
          % (warmer) colder than prior year
                                                                                               
          columbia operations customers
                                                                                               
          changes in operating revenues
                                                                                               
          new rates from base rate proceedings and regulatory capital programs
                                                                                               
          the effects of weather in 2025 compared to 2024
                                                                                               
          the effects of customer growth
                                                                                               
          the effects of customer usage
                                                                                               
          change in operating revenues
                                                                                               
          operating revenues offset in operating expense
                                                                                               
          higher cost of energy billed to customers
                                                                                               
          higher tracker deferrals within operation and maintenance, depreciation, and tax
                                                                                               
          total change in operating revenues
                                                                                               
          changes in operating expenses
                                                                                               
          higher depreciation and amortization expense
                                                                                               
          higher employee and administrative related expenses
                                                                                               
          higher property tax
                                                                                               
          change in operating expenses
                                                                                               
          operating expenses offset in operating revenue
                                                                                               
          total change in operating expense
                                                                                               
          sales
                                                                                               
          cooling degree days
                                                                                               
          normal cooling degree days
                                                                                               
          % warmer (colder) than normal
                                                                                               
          % warmer than prior year
                                                                                               
          nipsco electric customers
                                                                                               
          sales and transportation volumes
                                                                                               
          nipsco gas customers
                                                                                               
          new rates from base rate proceedings, regulatory capital and dsm programs
                                                                                               
          renewable jv revenue, fully offset by jv operating expense and noncontrolling interest net income
                                                                                               
          higher tracker deferrals within operation and maintenance, depreciation and tax
                                                                                               
          higher depreciation and amortization expense driven by new base rates
                                                                                               
          higher outside services expenses
                                                                                               
          higher employee and administrative expenses
                                                                                               
          higher property taxes
                                                                                               
          higher jv expenses
                                                                                               
          (higher) lower environmental remediation costs
                                                                                               
          remaining renewables projects
                                                                                               
          carpenter
                                                                                               
          cash from
                                                                                               
          capital investments
                                                                                               
          company
                                                                                               
          approved
                                                                                               
          columbia of ohio
                                                                                               
          columbia of virginia
                                                                                               
          columbia of kentucky
                                                                                               
          nipsco - electric
                                                                                               
          nipsco - gas
                                                                                               
          pending commission approval
                                                                                               
          current liquidity
                                                                                               
          revolving credit facility
                                                                                               
          accounts receivable programs
                                                                                               
          less:
                                                                                               
          commercial paper
                                                                                               
          accounts receivable programs utilized
                                                                                               
          letters of credit outstanding under credit facility
                                                                                               
          add:
                                                                                               
          net available liquidity
                                                                                               
          s&p
                                                                                               
          rating
                                                                                               
          nisource
                                                                                               
          nipsco
                                                                                               
          approved rate cases
                                                                                               
          columbia of pennsylvania
                                                                                               
          columbia of maryland
                                                                                               
          pending rate cases
                                                                                               
          certification of chief executive officer pursuant to rule 13a-14(a)/15d-14(a), as adopted pursuant to section 302 of the sarbanes-oxley act of 2002.*
                                                                                               
          certification of chief financial officer pursuant to rule 13a-14(a)/15d-14(a), as adopted pursuant to section 302 of the sarbanes-oxley act of 2002.*
                                                                                               
          inline xbrl instance document - the instance document does not appear in the interactive data file because its xbrl tags are embedded within the inline xbrl document.
                                                                                               
          inline xbrl schema document
                                                                                               
          inline xbrl calculation linkbase document
                                                                                               
          inline xbrl labels linkbase document
                                                                                               
          inline xbrl presentation linkbase document
                                                                                               
          inline xbrl definition linkbase document
                                                                                               
          cover page interactive data file
                                                                                               
          *
                                                                                               
          **
                                                                                               
          date:
                                                                                               
          title of each class
                                                                                               
          common stock, par value 0.01 per share
                                                                                               
          other noncurrent liabilities and deferred credits and charges
          200,000                                                                                     
          contributions from nipsco and genco minority interest holders
          33,500,000                                                                                     
          net cash flows from financing activities
          391,700,000       420,900,000 -1,873,800,000 2,843,600,000 698,300,000    581,700,000   570,700,000 261,400,000   -708,200,000   179,300,000 288,500,000   16,000,000 1,004,000,000 360,400,000 87,300,000 17,000,000  638,100,000           179,000,000    293,800,000                                    
          refer to note 17, "supplemental disclosures of cash flow information," for additional information.
                                                                                               
          stock compensation expense and 401(k) profit sharing contribution
                                               12,900,000 11,800,000 10,900,000 10,900,000 12,100,000 5,200,000 14,000,000 19,400,000 17,700,000 26,700,000 14,000,000 13,900,000 11,000,000 16,700,000 12,400,000 10,600,000 12,000,000 13,300,000 10,800,000 8,900,000 11,800,000 10,200,000 9,400,000 7,800,000 7,700,000                        
          gas storage and other inventories
                                                                                               
          postretirement and postemployment benefits
                                       99,600,000    -66,400,000    -23,900,000 -7,500,000 -8,100,000 -5,300,000 86,600,000 -19,500,000 -19,900,000 -21,600,000 240,700,000 -40,700,000 -42,500,000 -19,300,000 -453,200,000 -16,600,000 -42,500,000 -36,800,000 134,600,000 1,000,000 -5,700,000 -6,900,000 70,800,000 -44,600,000 -24,500,000 -94,400,000 -4,300,000 -144,000,000 400,000 1,300,000 12,000,000 -80,100,000 18,999,988.7 11.3 -18,900,000 3,100,000 -13,800,000 18,800,000 -13,700,000 -35,700,000 6,000,000 -57,700,000 -43,900,000 -2,600,000 7,100,000 -6,000,000 8,500,000 25,800,000 6,900,000 8,900,000 
          purchases of available-for-sale securities
                              -16,600,000 -49,900,000   -43,500,000 -36,400,000    -18,600,000 -24,600,000   -29,000,000 -33,800,000                                                   
          sales of available-for-sale securities
                              16,900,000 42,500,000   45,400,000 28,000,000    23,800,000 11,000,000   33,700,000 22,800,000                                                   
          milestone and final payments to renewable generation asset developers
                                                                                               
          advanced deposits for project costs
                                                                                               
          repayment of short term credit agreements
               -1,650,000,000                                                                             
          issuance of short term credit agreements
                                                                                               
          payment of obligation to renewable generation asset developer
                                                                                               
          contributions from tax equity partners
                                                                                               
          contract liability payment
                   -16,700,000 -16,700,000 -16,600,000 -16,600,000 -16,500,000 -16,600,000 -16,500,000 -16,500,000 -16,300,000                                                                    
          net cash flows (used for) from financing activities
               298,500,000               -75,400,000                        -198,800,000                                         
          refer to note 19, "supplemental disclosures of cash flow information," for additional information.
                                                                                               
          milestone payments to renewable generation asset developer
              -554,200,000  -158,000,000 -210,200,000 -110,600,000                                                                             
          payments for assets retirement obligations
                                                                                               
          insurance recoveries
                       105,000,000                             4,500,000      3,500,000        1,500,000 3,000,000 500,000 1,300,000 6,800,000 54,599,948 52                 
          milestone and final payments to renewable generation asset developer
                                                                                               
          repayments of long-term debt and finance lease obligations
                   -9,000,000    -7,800,000 -17,800,000   -7,000,000 -6,500,000 -6,300,000 -5,900,000 -5,600,000 -1,608,600,000 -3,700,000 -4,100,000 -3,100,000                                                            
          contributions from equity tax partners
                                                                                               
          issuance of equity units, net of underwriting costs
                                                                                              
          payment to renewable generation asset developer
                    -349,300,000 -100,000 -137,300,000 -173,000,000 -71,900,000   -233,000,000 -7,400,000                                                                 
          change in short-term borrowings
                    630,000,000 308,200,000 -480,400,000  719,200,000 35,000,000 -40,000,000 180,000,000 380,000,000 -520,000,000 17,000,000 -35,100,000 224,700,000 -382,900,000 -226,800,000 308,100,000 -365,900,000 -499,000,000 452,800,000 16,100,000 1,011,100,000 -1,567,300,000 361,600,000 362,500,000 -58,200,000 -612,900,000 26,200,000 429,000,000 -41,700,000 255,400,000 277,900,000 460,200,000 18,500,000 -152,200,000 -1,262,900,000  210,000,000 288,600,000 113,800,000  443,100,000 -753,500,000 354,300,000  -102,300,000 -936,600,000 -94,800,000  363,700,000 -392,700,000 -119,500,000  511,800,000                       
          equity costs, grant withholdings, and debt related costs
                                                                                               
          contributions from noncontrolling interest
                    205,900,000 31,400,000 3,600,000                                                                         
          payment of financing obligation to renewable generation asset developer
                                                                                               
          equity costs, grant withholdings and debt related costs
                     -4,900,000 -11,800,000                                                                         
          loss on early extinguishment of debt
                               100,000        33,000,000                                                   
          proceeds from disposition of assets
                                                300,000 2,100,000 1,000,000 200,000 -12,400,000 5,000,000 11,700,000 5,200,000 1,400,000 900,000 5,300,000 100,000 17,200,000 200,000 500,000 2,000,000 21,400,000 100,000 2,100,000 3,900,000 5,500,000 200,000 100,000 200,000 3,300,000 300,000 2,099,997.9 2.1 5,800,000 -187,600,000 217,100,000 12,500,000 1,900,000 800,000 1,500,000 4,400,000 9,600,000 3,700,000 3,900,000 100,000 1,600,000 5,800,000 
          issuance of short-term debt
                               850,000,000 500,000,000 100,000,000   350,000,000                                                       
          change in short-term debt
                                                                          267,700,000 -97,100,000 200,100,000 -1,163,498,836.5 -1,163.5 -99,500,000 757,000,000 -118,700,000 -436,300,000 388,000,000 -348,500,000 400,700,000 -572,200,000 333,400,000 441,000,000 40,800,000 -518,800,000 898,000,000 -307,600,000 
          other noncurrent liabilities
                        -41,000,000 40,200,000 -9,500,000 19,600,000 -27,400,000 -13,800,000 -8,400,000 26,300,000 5,000,000 2,300,000 -11,900,000 27,000,000 -1,000,000 3,500,000 32,100,000 -32,800,000 55,800,000 -11,400,000 -14,400,000 -16,800,000 21,200,000 -24,400,000 -14,500,000 5,100,000 -4,500,000 -2,600,000 2,500,000 -6,700,000 -25,600,000 7,700,000 4,300,000 -9,400,000 -1,500,000 3,800,000 4,000,000 -3,200,000 3,100,000 -7,500,000 -1,900,000 -18,200,000 5,200,000 -5,100,000 4,000,000 49,400,000 37,400,000      5,300,000 -4,200,000 300,000   -18,200,000 12,300,000 -1,600,000 -29,000,000 -8,800,000 400,000 -8,300,000 7,200,000 5,300,000 -16,700,000 23,800,000 -7,300,000 8,200,000 5,300,000 9,200,000 -2,600,000 
          issuance of long-term debt, net of discount and underwriting costs
                                                                                              
          net cash flows used for financing activities
                          -173,900,000                                                205,300,000  137,500,000 -691,599,253.1 -746.9   457,400,000 -697,900,000   303,500,000 -638,700,000   -145,000,000 -586,800,000   -130,100,000 -352,900,000 
          impairment of goodwill and intangible assets
                                                                                               
          contributions from non-controlling interest, net of distributions
                                                                                               
          issuance of equity units, net of issuance costs
                                                                                               
          other financing activities
                                                                                               
          contributions from non-controlling interest, net of issuance costs
                              7,500,000                                                                 
          amortization of discount/premium on debt
                                               2,200,000 1,800,000 1,700,000 1,900,000                     2,200,000 2,700,000 2,700,000 2,700,000 3,100,000 3,700,000 6,199,997.9 2.1 2,000,000 2,000,000 1,900,000 1,800,000 1,800,000 1,900,000 1,800,000 1,800,000 1,900,000 1,900,000 1,900,000 2,000,000 2,900,000 4,900,000 4,900,000 4,800,000 
          issuance of preferred stock, net of issuance costs
                                                                                               
          acquisition of treasury stock
                                       -400,000 -3,600,000 -1,300,000 -1,500,000 -4,400,000 -1,300,000 -200,000 -500,000 -7,400,000 -100,000 -100,000 -100,000 -20,100,000 100,000 -100,000 -200,000 -10,000,000 -100,000 -100,000 -300,000 -7,600,000 -100,000 -9,900,000 -100,000 -300,000 -2,700,000 -100,000 -1,400,000 -1,700,000 -899,999.2 -0.8    -600,000 -1,500,000 -100,000 -100,000 -5,900,000 100,000 -100,000 -200,000 -1,400,000 
          loss on classification as held for sale
                                35,600,000 84,400,000 280,200,000                                                             
          issuance of long-term debt
                                        500,000,000 750,000,000             492,300,000     494,700,000       494,900,000 1,600,000 963,499,418.3 581.7 -800,000 254,100,000 705,100,000 900,000 900,000 800,400,000      100,000 907,900,000    
          impairment of goodwill and other intangible assets
                                                                                               
          premiums and other debt related costs
                                    -7,700,000 -200,000 -4,000,000 100,000 -30,900,000   -4,500,000 -9,100,000   -3,400,000 -300,000  22,500,000               -8,200,000                         
          repayments of long-term debt and capital lease obligations
                                     -43,700,000 -2,300,000 -2,100,000 -552,800,000 -212,200,000 -279,000,000 -502,600,000 -274,000,000 -1,041,800,000 -36,600,000 -223,700,000 -3,200,000 -3,400,000 -204,300,000 -233,100,000 -2,700,000 -1,848,400,000 -8,000,000 -3,900,000 -503,800,000 -4,200,000 -9,100,000 -5,700,000                                    
          issuance of common stock
                                      3,100,000  3,900,000 604,000,000 3,700,000 4,100,000 286,400,000 39,800,000 6,400,000 6,300,000 6,800,000 5,700,000 4,300,000 4,600,000 5,500,000 6,500,000 5,900,000 7,900,000 6,300,000 7,200,000 8,900,000 7,600,000 12,000,000 6,900,000 17,200,000 7,100,000 346,400,000 12,600,000 17,400,000 9,300,000 7,200,000 4,200,000 3,700,000 3,800,000 3,800,000 3,200,000 3,600,000 10,000,000 200,000 399,999.8 0.2 200,000 300,000 200,000 600,000 300,000 200,000 5,600,000 2,100,000 16,300,000 3,500,000 1,100,000 1,000,000 700,000    
          adjustments to reconcile net income to net cash from operating actvities:
                                                                                               
          issuance of preferred stock
                                        -100,000                                                       
          adjustments to reconcile net income to net cash from continuing operations:
                                                                                               
          (income) income from discontinued operations - net of taxes
                                                                                               
          net operating activities from continuing operations
                                           212,600,000 -122,000,000 240,400,000 411,100,000 271,300,000 45,000,000 184,600,000 303,200,000 257,100,000 -209,400,000 511,400,000 604,300,000 433,200,000 235,800,000 257,600,000 394,400,000 359,100,000 184,400,000 446,000,000 437,300,000 320,400,000 171,100,000 292,400,000 480,400,000 77,600,000 62,600,000 343,300,000 436,800,000 395,200,000 -59,900,000 332,900,000 114,400,000 561,400,000 42,100,000 1,317,198,880.2 1,119.8 323,700,000 -376,500,000 -207,800,000 848,100,000   -192,200,000 779,600,000 290,800,000 -159,400,000 293,800,000 726,200,000     
          net operating activities from (used for) discontinued operations
                                              -100,000 -400,000 -300,000         -900,000                                    
          cash contributions from cpg
                                                                                              
          net investing activities from (used for) continuing operations
                                               -414,700,000 -453,200,000 -399,700,000 -315,300,000 -461,200,000                                            
          net investing activities used for discontinued operations
                                                   -100,000                                            
          net cash flows from (used for) investing activities
                                               -414,700,000 -453,200,000 -399,700,000 -315,300,000 -461,300,000                                            
          cash of cpg at separation
                                                                                              
          net financing activities from (used for) continuing operations
                                               153,700,000 408,700,000 207,500,000 20,600,000                                             
          net financing activities from discontinued operations
                                                                                              
          change in cash, cash equivalents and restricted cash from (used for) continuing operations
                                                                                               
          change in cash, cash equivalents and restricted cash from (used for) discontinued operations
                                                                                               
          change in cash included in discontinued operations
                                                                                              
          other noncurrent assets
                                            -2,600,000 100,000 -1,200,000                                                 
          change in cash and cash equivalents from (used for) continuing operations
                                                          11,600,000                                     
          change in cash and cash equivalents from (used for) discontinued operations
                                                  -300,000                                             
          cash and cash equivalents at beginning of period
                                            26,400,000 15,500,000 -500,000 25,400,000 26,800,000 36,300,000 11,500,000 9,200,000 16,400,000 20,599,979.4 20.6                
          cash and cash equivalents at end of period
                                            1,400,000 -10,500,000 28,400,000 10,300,000 400,000 -8,000,000 23,700,000 -16,200,000 -464,900,000 454,600,000 42,000,000 7,700,000 -300,000 -20,000,000 38,000,000 11,900,000 -29,600,000 -56,900,000 101,400,000 24,000,000 -40,500,000 14,300,000 38,500,000 -10,700,000 -37,700,000 -2,600,000 62,500,000 -1,700,000 3,500,000 -103,200,000 110,600,000 -67,400,000 -165,100,000 248,899,864.8 135.2 -4,500,000 -20,800,000 -31,500,000 77,400,000 18,300,000 -5,300,000 -79,200,000 102,200,000 10,300,000 -35,100,000 -25,500,000 83,400,000 -863,100,000 674,300,000 -329,800,000 588,000,000 
          net operating activities used for discontinued operations
                                                                -1,100,000 -600,000 -400,000 -1,500,000 -4,500,000 -29,400,000 -14,700,000 -2,300,000 -10,100,000 -13,700,000 -31,100,000  -162,100,000 -76,999,938.1 -61.9                 
          change in cash and cash equivalents from continuing operations
                                             -10,400,000 2,000,000 10,300,000 500,000 -7,600,000 8,500,000 -21,900,000   16,600,000         14,000,000 -39,400,000 14,900,000 27,400,000 -9,200,000 -33,200,000 26,800,000 68,000,000 600,000 13,600,000 -89,500,000 124,900,000 1,800,000                    
          change in cash and cash equivalents used for discontinued operations
                                               -100,000   5,700,000 -33,700,000                                           
          income from discontinued operations - net of taxes
                                               -3,500,000   5,000,000 -108,800,000        800,000 400,000 -8,700,000 -7,400,000 700,000                               
          restricted cash withdrawals
                                               4,200,000 -1,500,000 7,100,000 10,300,000    3,300,000     10,200,000 11,100,000 -6,200,000 23,600,000  19,900,000 64,400,000 11,500,000  -25,500,000 10,300,000 38,000,000                         
          deferred credits
                                                1,700,000 2,400,000 500,000 -8,800,000 -5,000,000 -2,100,000 5,800,000 -800,000 2,700,000 2,700,000 8,400,000 -600,000 1,600,000 1,800,000 7,700,000 -2,700,000 -900,000 5,900,000 2,600,000 -300,000 -8,300,000 2,800,000 3,500,000 -2,400,000 3,400,000 -2,500,000 -1,100,000 11,600,000 2,300,000 -7,699,996.6 -3.4 34,000,000 600,000 7,300,000 -5,600,000 -1,200,000 4,100,000 -600,000 -3,000,000 21,400,000 -5,000,000 -10,000,000 2,300,000 12,400,000 2,600,000 2,400,000 -10,700,000 
          income tax receivable
                                                 900,000     1,200,000 1,100,000 100,000 900,000 1,300,000 100,000 74,100,000 50,400,000 -74,900,000 -55,300,000 200,000 300,000 19,200,000 78,600,000 26,600,000 100,000 2,700,000 22,100,000 270,800,000                    
          net changes in price risk management assets and liabilities
                                                   1,700,000 1,900,000 600,000 -500,000 700,000 500,000 600,000 800,000 700,000 -2,200,000 2,700,000 1,400,000 900,000 700,000 -45,000,000 24,900,000 24,000,000 -1,200,000 1,000,000 14,300,000 -1,300,000 -8,600,000 11,800,000 -7,400,000 -10,600,000 -200,000 1,700,001.7 -1.7 4,300,000 2,300,000 28,700,000 -9,600,000 1,600,000 1,600,000 -7,000,000 5,500,000 -61,300,000 33,700,000 6,500,000 10,200,000     
          deferred revenue
                                                   -100,000 500,000 1,500,000 5,300,000 -400,000 300,000 -200,000 1,800,000 -8,800,000 2,000,000 -400,000 -10,400,000 2,200,000 -600,000 500,000 6,700,000 -1,600,000 -3,300,000 700,000 2,300,000 -5,500,000 -1,400,000 -15,800,000 -100,000 -11,500,000 15,900,003.7 -3.7 3,900,000 -3,300,000 -8,300,000 -16,300,000 -6,200,000 -10,200,000 -5,900,000 -16,500,000 2,000,000 -3,500,000 -6,500,000 -26,000,000 5,000,000 800,000 -3,800,000 -8,600,000 
          loss on sale of assets and impairment
                                                                                               
          income from unconsolidated affiliates
                                                   -200,000 29,200,000 -13,900,000 -14,500,000 -13,500,000 -11,700,000 -11,000,000 -9,600,000 -10,200,000 -10,300,000 -7,900,000 -7,300,000 -8,000,000 -8,000,000 -8,300,000 -6,600,000 -5,700,000 -3,600,000 -1,300,000 -3,100,000 -3,700,000 -3,300,000 -400,000 -7,400,000 -5,900,000 -5,400,000 -3,799,993.6 -6.4  -19,200,000 600,000 -1,700,000  -3,900,000 -4,400,000 -3,300,000  -900,000 -1,400,000 -1,000,000  -700,000   
          gain on disposition of discontinued operations - net of taxes
                                                                                               
          overrecovered gas and fuel costs
                                                             17,600,000 69,300,000  -63,200,000 23,000,000 31,100,000                             
          net operating activities from discontinued operations
                                                   5,800,000          -600,000 11,800,000                       100,000 400,000    100,000     
          premium and other debt related costs
                                                                                               
          amortization of debt related costs
                                                    1,400,000 2,900,000 2,500,000  2,400,000 2,700,000 2,400,000  2,400,000 2,300,000 2,300,000  2,600,000 2,400,000 2,300,000  2,400,000 2,100,000 2,100,000                         
          changes in assets and liabilities
                                                                                               
          over (under) recovered gas and fuel costs
                                                    -33,000,000 48,300,000 133,200,000             -18,900,000 -74,300,000 30,300,000 190,400,000                         
          restricted cash deposits
                                                    -2,700,000                                           
          net financing activities (used for) from continuing operations
                                                                                               
          distributions of earnings received from equity investees
                                                     9,600,000 18,300,000 10,200,000 14,700,000 5,300,000 7,600,000 13,100,000 6,700,000 5,300,000 7,000,000  7,900,000 4,300,000 12,900,000                             
          distributions from (contributions to) equity investees
                                                     1,000,000 1,200,000                                         
          issuance of common units of cppl, net of issuance costs
                                                     1,168,400,000                                         
          loss from discontinued operations - net of taxes
                                                         300,000 200,000               100,000  -100,000                   
          gain on sale of assets and impairment
                                                                                               
          loss (income) from discontinued operations - net of taxes
                                                       100,000                                        
          net operating activities (used for) from discontinued operations
                                                       -100,000 -300,000 -600,000 -400,000                                     
          restricted cash (deposits) withdrawals
                                                       -9,000,000 -6,300,000 1,100,000 -2,900,000                                     
          contributions to equity investees
                                                       -5,400,000 -9,000,000 -23,800,000 -31,000,000 -48,300,000 -44,400,000 -15,600,000 -17,100,000 -9,100,000 -3,700,000 -2,300,000 -5,300,000 -6,200,000 -100,000   -200,000                        
          net investing activities used for continuing operations
                                                       -604,400,000 -614,600,000 -489,700,000 -407,900,000 -640,100,000 -530,100,000 -472,300,000 -367,600,000     -347,400,000 -378,500,000 -248,300,000 -175,100,000 -182,200,000 -367,200,000 -199,500,000 -194,800,000 -98,100,000 -221,700,000 -342,599,796.1 -203.9 -339,100,000 -783,600,000 -281,000,000 -107,500,000             
          net investing activities from (used for) discontinued operations
                                                           -3,100,000 300,000 121,500,000                                 
          change in cash and cash equivalents (used for) from continuing operations
                                                            -26,200,000 -56,600,000 -68,200,000                                 
          change in cash and cash equivalents (used for) from discontinued operations
                                                                                               
          (under) overrecovered gas and fuel costs
                                                        -7,600,000               39,500,000 -37,600,000 -1,200,000 -251,100,000 -265,000,000 22,600,000 566,799,553.7 446.3 168,900,000 30,600,000 -102,800,000 -93,100,000 -98,700,000 33,200,000 46,300,000 -95,800,000 -110,900,000 12,300,000 138,400,000 319,700,000 -182,300,000 -182,300,000 107,600,000 139,400,000 
          net investing activities from discontinued operations
                                                                       400,000  38,700,000 22,699,992.5 7.5                 
          change in cash and cash equivalents used for continuing operations
                                                                                              
          cash contributions (to) from discontinued operations
                                                        -300,000 -600,000 -400,000                                     
          (under)overrecovered gas and fuel costs
                                                          -74,200,000                                     
          (gain) loss on sale of assets
                                                                                               
          change in cash and cash equivalents from discontinued operations
                                                                                               
          gain on disposition of discontinued operations - net of tax
                                                            1,500,000 -36,400,000                                 
          over(under)recovered gas and fuel costs
                                                                                               
          cash contributions from (to) discontinued operations
                                                                                               
          retirement of long-term debt
                                                             -23,900,000 -427,100,000 -320,000,000 -3,800,000 -1,900,000 -5,900,000 -250,400,000 -23,500,000 -10,200,000 -2,800,000 -961,400,000 -11,100,000 -4,300,000 -900,000 -803,900,000 -1,000,000 -364,899,898.6 -101.4 -2,700,000 -25,900,000 -11,000,000 -1,000,000 -390,700,000 -21,600,000 -41,500,000 -4,100,000 -394,900,000 -1,300,000 -42,000,000 -500,000 -2,256,600,000 -34,900,000 -80,700,000 -300,000 
          cash contributions from discontinued operations
                                                             -300,000 133,300,000                                 
          net cash flow used for investing activities
                                                              -246,100,000  -382,400,000 -274,200,000 -294,700,000  -378,500,000 -248,300,000 -175,100,000  -367,200,000                       
          net cash flow used for financing activities
                                                              -137,900,000   -3,300,000 -158,300,000                             
          distribution received from equity earnings
                                                                                               
          (under) over recovered gas and fuel costs
                                                                                               
          net operating activities provided by discontinued operations
                                                                                               
          distributions from equity investees
                                                                                              
          net cash flow from financing activities
                                                                                               
          cash contributions to discontinued operations
                                                                -1,100,000 -600,000 -400,000 -1,500,000 -4,500,000 -29,400,000 -14,700,000  -10,100,000 -13,700,000 -30,700,000    -54.4    -700,000             
          gain from discontinued operations - net of taxes
                                                                  100,000                             
          (gain) loss on disposition of discontinued operations - net of taxes
                                                                                               
          premium and other costs to retire debt
                                                                                               
          gain on disposition of discontinued operations—net of taxes
                                                                                               
          income from discontinued operations—net of taxes
                                                                                               
          dividends paid—common stock
                                                                                               
          gain on disposition of discontinued operations — net of taxes
                                                                                    -1,100,000 800,000 -6,600,000         
          income from discontinued operations — net of taxes
                                                                                  -6,000,000             
          distributions of earnings received from equity investee
                                                                     8,100,000 1,800,000                        
          dividends paid — common stock
                                                                     -64,500,000 -64,200,000        -63.1 -63,200,000 -63,100,000 -63,000,000 -63,100,000 -63,000,000 -63,100,000 -63,000,000 -63,000,000 -62,700,000        
          (gain) income from discontinued operations — net of taxes
                                                                      -400,000                         
          deferred charges and other non current assets
                                                                      -3,600,000  5,300,000                       
          other non current liabilities
                                                                      900,000  -12,600,000      5.7                 
          net cash flow (used for) from financing activities
                                                                      -193,700,000                         
          loss on disposition of discontinued operations - net of taxes
                                                                         -100,000  6,200,000                   
          restricted cash (withdrawals) deposits
                                                                                               
          repurchase of long-term debt
                                                                               -55,000,000 -199,000,000             
          cash (contributions to) receipts from discontinued operations
                                                                           -69,200,000 -123,000,000                   
          gain on early extinguishment of debt
                                                                            -2,499,996.8 -3.2                 
          net cash flow from (used for) financing activities
                                                                                               
          stock compensation expense
                                                                         3,800,000 2,200,000 1,300,000 3,400,000 4,899,998.4 1.6 2,300,000 2,700,000 3,100,000 1,400,000 1,700,000 1,400,000 200,000 1,100,000 2,500,000 1,300,000 1,800,000 1,300,000     
          contributions to equity investments
                                                                                               
          loss on disposition of discontinued operations — net of taxes
                                                                              0.2  5,400,000 2,800,000 96,100,000             
          loss from discontinued operations — net of taxes
                                                                              10.7  7,000,000    -100,000 700,000 -1,000,000         
          net operating activities (used for) or provided by discontinued operations
                                                                                               
          sugar creek facility purchase
                                                                                               
          distributions from or (contributions to) equity investments
                                                                                               
          net investing activities from or (used for) discontinued operations
                                                                               193,700,000 202,300,000 -2,000,000 2,900,000             
          premiums and other costs to retire debt
                                                                                               
          net cash flows from or (used for) financing activities
                                                                                               
          customer deposits
                                                                            -500,000 -200,003.4 3.4 6,800,000 8,200,000 -2,100,000 1,600,000 5,900,000   2,000,000 3,400,000 500,000 -200,000 2,700,000 7,000,000 2,200,000 -2,600,000 3,100,000 
          sugar creek purchase
                                                                                             
          increase in cash and cash equivalents from continuing operations
                                                                             282,999,831 169                 
          loss on early extinguishment of long-term debt
                                                                                               
          loss on early redemption of preferred stock
                                                                                             
          cumulative effect of change in accounting principle, net of taxes
                                                                                       -400,000     
          loss from unconsolidated affiliates
                                                                                               
          loss on disposition of discontinued operations
                                                                                               
          loss from discontinued operations
                                                                                       30,300,000 300,000 800,000 300,000 200,000 6,300,000 11,600,000 2,200,000 
          net operating activities from or (used for) discontinued operations
                                                                               11,300,000 -11,600,000 200,000 -2,100,000     100,000 4,000,000       
          retirement of preferred stock
                                                                                       -500,000        
          cash inflows from or (contributions to) discontinued operations
                                                                               366,400,000                
          cash and cash equivalents at beginning of year
                                                                                  34,600,000 33,100,000 69,400,000 29,500,000 
          decrease in cash and cash equivalents
                                                                                    -5,300,000           
          supplemental disclosures of cash flow information
                                                                                               
          cash paid for interest
                                                                                102,200,000 83,500,000 104,500,000 113,900,000 81,000,000 117,700,000 100,600,000 108,800,000 76,100,000 108,800,000 76,300,000 163,600,000 40,100,000 164,400,000 36,400,000 
          interest capitalized
                                                                                5,800,000 6,900,000 5,500,000 5,000,000 4,300,000 4,700,000 3,100,000 3,700,000 3,200,000 2,600,000 1,600,000 1,900,000 900,000 600,000 -200,000 
          cash paid for income taxes
                                                                                1,700,000 36,300,000 2,000,000 35,500,000 62,900,000 83,400,000 3,400,000 43,100,000 79,100,000   4,000,000 4,600,000   
          increase in cash and cash equivalents
                                                                                 -33,200,000 43,500,000    69,100,000 10,300,000 -35,100,000 -25,500,000 14,000,000 -863,100,000 674,300,000 -329,800,000 558,500,000 
          cash inflows from discontinued operations
                                                                                               
          gain on disposition of discontinued operations
                                                                                               
          cumulative effect of change in accounting principle — net of taxes
                                                                                               
          net operating activities provided by continuing operations
                                                                                               
          net cash flows from investing activities
                                                                                               
          premium on debt retirement
                                                                                               
          gain on sale of discontinued operations
                                                                                        -200,000       
          afudc
                                                                                               
          net cash flows (used for) or from financing activities
                                                                                               
          retirement of preferred shares
                                                                                               
          dividends paid — common shares
                                                                                         -63,700,000 -62,700,000 -62,700,000 -62,700,000 -62,600,000 -62,300,000 
          loss on sale of discontinued operations
                                                                                          -1,000,000     
          cash paid (refunded) for income taxes
                                                                                          4,200,000    -25,300,000 
          net cash flows from continuing operations
                                                                                           -44,600,000 -179,600,000 -67,600,000 1,021,500,000 
          net cash flows (used for) or from discontinued operations
                                                                                               
          premium of debt retirement
                                                                                               
          net financing activities used for continuing operations
                                                                                               
          net financing activities used for discontinued operations
                                                                                               
          net changes in price risk management activities
                                                                                            -76,700,000 22,200,000 -31,200,000 
          amortization of unearned compensation
                                                                                            1,900,000 3,200,000 1,500,000 
          loss from sale of discontinued operations
                                                                                              200,000 
          prepayment and other current assets
                                                                                            11,200,000 -6,300,000 11,400,000 
          net cash flows used for discontinued operations
                                                                                            -1,200,000   
          gain from sale of discontinued operations
                                                                                               
          issuance of common stock and capital contributed
                                                                                             13,400,000 18,700,000 
          gain from unconsolidated affiliates
                                                                                              -2,000,000 
          changes in assets and liabilities, net of effect from acquisitions of businesses:
                                                                                               
          accounts receivable and unbilled revenue
                                                                                              100,000 
          net cash flows from discontinued operations
                                                                                              100,000 
          gain on sale or impairment of assets
                                                                                               
          change in accounting, net of tax
                                                                                               
          dividends paid - common shares
                                                                                               
          net cash flows for financing activities