Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Liabilities, Gross
Deferred Tax Liabilities, Property, Plant and Equipment	$ 1,853,450	$ 1,892,692
Deferred tax liability, unrealized gain or loss on derivative instruments	158,175	50,971
Deferred Tax Liabilities, Other	365,035	313,270
Deferred Tax Liabilities, Gross, Total	2,376,660	2,256,933
Deferred Tax Assets, Gross
Deferred Tax Assets, Operating Loss Carryforwards	(234,825)	(254,007)
Deferred Tax Assets, Net Regulatory Liability for Income Taxes	(811,161)	(865,976)
Deferred Tax Assets, Tax Credit Carryforwards, Production		0
Deferred Tax Assets, Other	(299,597)	(184,023)
Deferred tax asset, unrealized loss on derivative instruments	(45,130)	(40,443)
Deferred Tax Assets, Gross	(1,390,713)	(1,344,449)
Deferred Tax Liabilities, Net, Total	985,947	912,484
Subsidiaries [Member]
Deferred Tax Liabilities, Gross
Deferred Tax Liabilities, Property, Plant and Equipment	1,852,644	1,892,674
Deferred tax liability, unrealized gain or loss on derivative instruments	143,147	31,940
Deferred Tax Liabilities, Other	279,612	225,753
Deferred Tax Liabilities, Gross, Total	2,275,403	2,150,367
Deferred Tax Assets, Gross
Deferred Tax Assets, Net Regulatory Liability for Income Taxes	(811,724)	(866,541)
Deferred Tax Assets, Other	(293,977)	(178,211)
Deferred tax asset, unrealized loss on derivative instruments	(30,102)	(21,412)
Deferred Tax Assets, Gross	(1,135,803)	(1,066,164)
Deferred Tax Liabilities, Net, Total	$ 1,139,600	$ 1,084,203