Income Taxes, Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Reconciliation of the benefit from (provision for) income taxes [Abstract]
Pre-Tax Net Book Income ("NBI")		$ 1,350	$ 1,373
Texas Margin Tax	[1]	(12)	(3)
State income tax provision, net of federal benefit		0	(1)
Federal income tax provision computed by applying the federal statutory rate to NBI of corporate entities		(3)	(3)
Valuation allowance	[2]	(4)	(3)
Total provision for income taxes		$ (19)	$ (10)
Effective income tax rate		(1.40%)	(0.70%)

[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] Management believes that it is more likely than not that the net deferred tax assets attributable to OTA will not be fully realizable.  Accordingly, we provided for a valuation allowance against OTA’s net deferred tax assets.