Income Taxes, Reconciliation of the Benefit From (Provision For) Income Taxes (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of the provision for income taxes [Abstract]
Pre-Tax Net Book Income ("NBI")		$ 5,701	$ 5,697	$ 4,825
Texas Margin Tax	[1]	(49)	(56)	(42)
State income tax provision, net of federal benefit		(2)	(1)	(1)
Federal income tax provision computed by applying the federal statutory rate to NBI of corporate entities		(16)	(15)	(13)
Change in valuation allowance	[2]	22	(8)	(14)
Other		1	(2)	0
Total provision for income taxes		$ (44)	$ (82)	$ (70)
Effective income tax rate		(0.80%)	(1.40%)	(1.50%)

[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.

[2] During 2023, management concluded that it is more likely than not that the deferred tax assets attributable to OTA will be fully realizable.  As a result, for the year-end December 31, 2023, we recorded a full release of the valuation allowance against OTA’s deferred tax assets.