Business Segment Information (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Asset Impairment Charges	$ 0	$ 0	$ 0	$ 131,775
Depreciation, Depletion and Amortization	579,152	559,556	1,148,024	1,112,598
Investment Income, Net	87,419	70,587	120,825	221,283
Interest Expense, Nonoperating	322,074	289,577	651,865	556,777
Income Tax Expense (Benefit)	138,399	33,634	238,440	54,627
Assets	68,383,140		68,383,140		$ 64,790,032
Segment, Expenditure, Addition to Long-Lived Assets			3,799,058	2,458,376
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Asset Impairment Charges				0
Depreciation, Depletion and Amortization	0	0	0	0
Investment Income, Net	(74,975)	(80,647)	(150,433)	(160,569)
Interest Expense, Nonoperating	(434)	(1,763)	(643)	(2,124)
Income Tax Expense (Benefit)	0	0	0	0
Assets	(4,905,758)		(4,905,758)		(4,882,991)
Segment, Expenditure, Addition to Long-Lived Assets			0	0
Utility [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Asset Impairment Charges				131,775
Depreciation, Depletion and Amortization	577,386	557,962	1,144,573	1,109,452
Investment Income, Net	160,248	141,249	267,423	366,499
Interest Expense, Nonoperating	261,033	225,511	528,164	437,659
Income Tax Expense (Benefit)	152,836	113,017	267,109	147,565
Assets	72,511,224		72,511,224		68,951,564
Segment, Expenditure, Addition to Long-Lived Assets			3,798,452	2,457,683
Corporate Segment and Other Operating Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Asset Impairment Charges				0
Depreciation, Depletion and Amortization	1,766	1,594	3,451	3,146
Investment Income, Net	2,146	9,985	3,835	15,353
Interest Expense, Nonoperating	61,475	65,829	124,344	121,242
Income Tax Expense (Benefit)	(14,437)	$ (79,383)	(28,669)	(92,938)
Assets	$ 777,674		777,674		$ 721,459
Segment, Expenditure, Addition to Long-Lived Assets			$ 606	$ 693