v3.26.1
Segment Information - Schedule of Income Statements and Capital Expenditures By Segment (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]            
Operating revenues $ 1,962,402   $ 1,950,502   $ 3,304,987 $ 3,126,501
Operation and maintenance expense 182,972   220,104   406,932 418,734
Depreciation and amortization expense 195,687   182,750   390,332 363,283
Interest charges 48,731   50,014   82,144 102,939
Income tax expense 151,690   117,521   252,308 196,852
Other segment items 1,005,990   1,085,562   1,595,849 1,587,010
Net income 581,899 $ 402,964 485,576 $ 351,858 984,863 837,434
Capital expenditures 1,003,589   839,666   2,036,935 1,730,857
Distribution            
Segment Reporting Information [Line Items]            
Operating revenues 1,876,911   1,881,742   3,134,960 2,990,311
Operation and maintenance expense 155,918   168,097   321,286 313,993
Depreciation and amortization expense 146,751   134,546      
Interest charges 29,130   30,087      
Income tax expense 109,714   86,432      
Other segment items 998,864   1,082,723   1,591,512 1,586,403
Net income 437,303   380,643      
Capital expenditures 717,079   594,853      
Pipeline and Storage            
Segment Reporting Information [Line Items]            
Operating revenues 85,491   68,760   170,027 136,190
Operation and maintenance expense 27,054   52,007   85,646 104,741
Depreciation and amortization expense 48,936   48,204      
Interest charges 19,601   19,927      
Income tax expense 41,976   31,089      
Other segment items 7,126   2,839   4,337 607
Net income 144,596   104,933      
Capital expenditures 286,510   244,813      
Intersegment Eliminations            
Segment Reporting Information [Line Items]            
Operating revenues (204,567)   (191,025)   (407,441) (379,751)
Intersegment Eliminations | Distribution            
Segment Reporting Information [Line Items]            
Operating revenues (769)   (786)   (1,546) (1,552)
Intersegment Eliminations | Pipeline and Storage            
Segment Reporting Information [Line Items]            
Operating revenues (203,798)   (190,239)   (405,895) (378,199)
Operating Segments            
Segment Reporting Information [Line Items]            
Operating revenues 2,166,969   2,141,527   3,712,428 3,506,252
Operating Segments | Distribution            
Segment Reporting Information [Line Items]            
Operating revenues 1,877,680   1,882,528   3,136,506 2,991,863
Depreciation and amortization expense         292,739 268,173
Interest charges         53,575 64,336
Income tax expense         170,856 138,102
Net income         706,538 620,856
Capital expenditures         1,521,654 1,220,502
Operating Segments | Pipeline and Storage            
Segment Reporting Information [Line Items]            
Operating revenues $ 289,289   $ 258,999   575,922 514,389
Depreciation and amortization expense         97,593 95,110
Interest charges         28,569 38,603
Income tax expense         81,452 58,750
Net income         278,325 216,578
Capital expenditures         $ 515,281 $ 510,355