Income Taxes, Benefit from (provision for) income taxes (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Components of Benefit From (Provision For) Income Taxes:
Texas Margin Tax	[1]	$ (7)	$ (24)	$ (19)	$ (27)
Other		(3)	0	(3)	(1)
Provision for income taxes		(17)	(31)	(36)	(41)
OTA Holdings, Inc. [Member]
Components of Benefit From (Provision For) Income Taxes:
Provision for income taxes		$ (7)	$ (7)	$ (14)	$ (13)

[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.