Income Taxes, Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Reconciliation of the provision for income taxes [Abstract]
Pre-Tax Net Book Income ("NBI")		$ 1,432	$ 1,350
Texas Margin Tax	[1]	(6)	(12)
State income tax provision, net of federal benefit		(1)	0
Federal income tax provision computed by applying the federal statutory rate to NBI of corporate entities		(3)	(3)
Other		0	(4)
Total provision for income taxes		$ (10)	$ (19)
Effective income tax rate		(0.70%)	(1.40%)

[1] Although the Texas Margin Tax is not considered a state income tax, it has the characteristics of an income tax since it is determined by applying a tax rate to a base that considers our Texas-sourced revenues and expenses.