Income Taxes - Components of Net Deferred Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Advances and contributions	$ 478	$ 351
Tax losses and credits	17	19
Regulatory income tax assets	191	203
Pension and other postretirement benefits	75	64
Other	172	140
Total deferred tax assets	933	777
Valuation allowance	(11)	(11)	$ (10)	$ (19)
Total deferred tax assets, net of allowance	922	766
Deferred tax liabilities:
Property, plant and equipment	3,269	2,872
Deferred pension and other postretirement benefits	84	64
Other	268	249
Total deferred tax liabilities	3,621	3,185
Total deferred tax liabilities, net of deferred tax assets	$ (2,699)	$ (2,419)