Business Segment Information (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Asset Impairment Charges	$ 12,795	$ 0	$ 12,795	$ 131,775
Depreciation, Depletion and Amortization	582,698	553,801	1,730,722	1,666,399
Investment Income, Net	106,090	64,316	226,915	285,600
Interest Expense, Nonoperating	324,878	295,143	976,743	851,920
Income Tax Expense (Benefit)	205,307	215,475	443,747	270,103
Assets	69,848,407		69,848,407		$ 64,790,032
Segment, Expenditure, Addition to Long-Lived Assets			5,726,780	4,016,120
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Asset Impairment Charges	0		0	0
Depreciation, Depletion and Amortization	0	0	0	0
Investment Income, Net	(73,375)	(77,476)	(223,807)	(238,046)
Interest Expense, Nonoperating	(195)	105	(838)	(2,017)
Income Tax Expense (Benefit)	0	0	0	0
Assets	(4,889,477)		(4,889,477)		(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	12,795		12,795	131,775
Depreciation, Depletion and Amortization	580,980	552,161	1,725,553	1,661,613
Investment Income, Net	177,587	137,518	445,010	504,018
Interest Expense, Nonoperating	268,090	228,493	796,254	666,151
Income Tax Expense (Benefit)	223,065	237,225	490,174	384,790
Assets	73,992,202		73,992,202		68,951,564
Segment, Expenditure, Addition to Long-Lived Assets			5,725,533	4,015,162
Corporate Segment and Other Operating Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Asset Impairment Charges	0		0	0
Depreciation, Depletion and Amortization	1,718	1,640	5,169	4,786
Investment Income, Net	1,878	4,274	5,712	19,628
Interest Expense, Nonoperating	56,983	66,545	181,327	187,786
Income Tax Expense (Benefit)	(17,758)	$ (21,750)	(46,427)	(114,687)
Assets	$ 745,682		745,682		$ 721,459
Segment, Expenditure, Addition to Long-Lived Assets			$ 1,247	$ 958