Income Taxes - Components of Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred income tax assets:
Regulatory liabilities	$ 1,349	$ 1,420
Federal, state and foreign carryforwards	820	677
AROs	304	304
Other	686	777
Total deferred income tax assets	3,159	3,178
Valuation allowances	(164)	(204)
Total deferred income tax assets, net	2,995	2,974
Deferred income tax liabilities:
Property-related items	(11,814)	(10,816)
Investments	(2,877)	(2,821)
Regulatory assets	(764)	(785)
Other	(478)	(327)
Total deferred income tax liabilities	(15,933)	(14,749)
Net deferred income tax liability	$ (12,938)	$ (11,775)