v3.26.1
Business Segment Information (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Segment Reporting Information [Line Items]          
Asset Impairment Charges $ 0 $ 0 $ 18,059 $ 0  
Depreciation, Depletion and Amortization 607,702 579,152 1,206,649 1,148,024  
Investment Income, Net 174,908 87,419 390,718 120,825  
Interest Expense, Nonoperating 410,253 322,074 789,993 651,865  
Income Tax Expense (Benefit) 131,678 138,399 219,468 238,440  
Assets 79,002,618   79,002,618   $ 71,890,730
Segment, Expenditure, Addition to Long-Lived Assets     5,230,850 3,799,058  
Consolidation, Eliminations          
Segment Reporting Information [Line Items]          
Depreciation, Depletion and Amortization 0 0 0 0  
Investment Income, Net (70,818) (74,975) (142,105) (150,433)  
Interest Expense, Nonoperating (798) (434) (1,329) (643)  
Income Tax Expense (Benefit) 0 0 0 0  
Assets (4,681,992)   (4,681,992)   (4,608,430)
Segment, Expenditure, Addition to Long-Lived Assets     0 0  
Utility [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Depreciation, Depletion and Amortization 607,131 577,386 1,204,493 1,144,573  
Investment Income, Net 243,168 160,248 526,847 267,423  
Interest Expense, Nonoperating 328,632 261,033 631,697 528,164  
Income Tax Expense (Benefit) 148,924 152,836 260,328 267,109  
Assets 82,679,238   82,679,238   75,726,104
Segment, Expenditure, Addition to Long-Lived Assets     5,231,590 3,798,452  
Corporate Segment and Other Operating Segment [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Depreciation, Depletion and Amortization 571 1,766 2,156 3,451  
Investment Income, Net 2,558 2,146 5,976 3,835  
Interest Expense, Nonoperating 82,419 61,475 159,625 124,344  
Income Tax Expense (Benefit) (17,246) $ (14,437) (40,860) (28,669)  
Assets $ 1,005,372   1,005,372   $ 773,056
Segment, Expenditure, Addition to Long-Lived Assets     $ (740) $ 606