Income Taxes (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Current portion of income tax provision:
Federal		$ (1)	$ 0
State		(12)	(12)
Total current portion		(13)	(12)
Deferred portion of income tax provision:
Federal		(4)	(4)
State		(7)	(5)
Total deferred portion		(11)	(9)
Total provision for income taxes		(24)	$ (21)
Deferred tax liabilities:
Attributable to investment in OTA	[1]	470		$ 462
Attributable to property, plant and equipment		157		151
Attributable to investments in other entities		4		5
Other		98		98
Total deferred tax liabilities		729		716
Deferred tax assets:
Net operating loss carryovers	[2]	59		56
Temporary differences related to Texas Margin Tax		3		4
Total deferred tax assets		62		60
Total net deferred tax liabilities		$ 667		$ 656

[1] Represents the deferred tax liability balance held by our wholly owned subsidiary, OTA Holdings, Inc. ("OTA"), which we acquired in March 2020.

[2] The loss amount presented as of March 31, 2025 has an indefinite carryover period.  All losses are subject to limitations on their utilization.