Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Liabilities, Gross
Deferred Tax Liabilities, Property, Plant and Equipment	$ 1,799,505	$ 1,853,450
Deferred tax liability, unrealized gain or loss on derivative instruments	34,175	158,175
Deferred Tax Liabilities, Other	373,667	365,035
Deferred Tax Liabilities, Gross, Total	2,207,347	2,376,660
Deferred Tax Assets, Gross
Deferred Tax Assets, Operating Loss Carryforwards	(210,238)	(234,825)
Deferred Tax Assets, Net Regulatory Liability for Income Taxes	(760,961)	(811,161)
Deferred Tax Assets, Other	(285,919)	(344,727)
Deferred Tax Assets, Gross	(1,257,118)	(1,390,713)
Deferred Tax Liabilities, Net, Total	950,229	985,947
Subsidiaries [Member]
Deferred Tax Liabilities, Gross
Deferred Tax Liabilities, Property, Plant and Equipment	1,796,476	1,852,644
Deferred tax liability, unrealized gain or loss on derivative instruments	23,005	143,147
Deferred Tax Liabilities, Other	296,323	279,612
Deferred Tax Liabilities, Gross, Total	2,115,804	2,275,403
Deferred Tax Assets, Gross
Deferred Tax Assets, Net Regulatory Liability for Income Taxes	(761,621)	(811,724)
Deferred Tax Assets, Other	(275,336)	(324,079)
Deferred Tax Assets, Gross	(1,036,957)	(1,135,803)
Deferred Tax Liabilities, Net, Total	$ 1,078,847	$ 1,139,600