v3.26.1
Segment Information - Schedule of Income Statements and Capital Expenditures By Segment (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]                
Operating revenues $ 879,059     $ 838,774     $ 4,184,046 $ 3,965,275
Operation and maintenance expense 224,669     221,476     631,601 640,210
Depreciation and amortization expense 201,521     185,786     591,853 549,069
Interest charges 33,144     41,537     115,288 144,476
Income tax expense 60,594     44,201     312,902 241,053
Other segment items 345,094     360,091     1,940,943 1,947,101
Net income 242,689 $ 581,899 $ 402,964 186,429 $ 485,576 $ 351,858 1,227,552 1,023,863
Capital expenditures 1,039,346     866,930     3,076,281 2,597,787
Distribution                
Segment Reporting [Line Items]                
Operating revenues 773,909     766,380     3,908,869 3,756,691
Operation and maintenance expense 169,195     165,979     490,481 479,972
Depreciation and amortization expense 148,349     137,106     441,088 405,279
Interest charges 12,870     22,271     66,445 86,607
Income tax expense 15,558     9,731     186,414 147,833
Other segment items 339,301     361,564     1,930,813 1,947,967
Net income 89,385     70,481     795,923 691,337
Capital expenditures 858,790     669,452     2,380,444 1,889,954
Pipeline and Storage                
Segment Reporting [Line Items]                
Operating revenues 105,150     72,394     275,177 208,584
Operation and maintenance expense 55,474     55,497     141,120 160,238
Depreciation and amortization expense 53,172     48,680     150,765 143,790
Interest charges 20,274     19,266     48,843 57,869
Income tax expense 45,036     34,470     126,488 93,220
Other segment items 5,793     (1,473)     10,130 (866)
Net income 153,304     115,948     431,629 332,526
Capital expenditures 180,556     197,478     695,837 707,833
Intersegment eliminations                
Segment Reporting [Line Items]                
Operating revenues (228,652)     (200,746)     (636,093) (580,497)
Intersegment eliminations | Distribution                
Segment Reporting [Line Items]                
Operating revenues (749)     (752)     (2,295) (2,304)
Intersegment eliminations | Pipeline and Storage                
Segment Reporting [Line Items]                
Operating revenues (227,903)     (199,994)     (633,798) (578,193)
Operating Segments                
Segment Reporting [Line Items]                
Operating revenues 1,107,711     1,039,520     4,820,139 4,545,772
Operating Segments | Distribution                
Segment Reporting [Line Items]                
Operating revenues 774,658     767,132     3,911,164 3,758,995
Operating Segments | Pipeline and Storage                
Segment Reporting [Line Items]                
Operating revenues $ 333,053     $ 272,388     $ 908,975 $ 786,777