Income Taxes, Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reconciliation of the provision for income taxes [Abstract]
Pre-Tax Net Book Income ("NBI")		$ 1,296	$ 1,457	$ 2,728	$ 2,807
Texas Margin Tax	[1]	(10)	(7)	(16)	(19)
State income tax provision, net of federal benefit		0	(1)	(1)	(1)
Federal income tax provision computed by applying the federal statutory rate to NBI of corporate entities		(3)	(4)	(6)	(7)
Other		0	(5)	0	(9)
Total provision for income taxes		$ (13)	$ (17)	$ (23)	$ (36)
Effective income tax rate		(1.00%)	(1.20%)	(0.80%)	(1.30%)

[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.