Income Taxes - Components of Provision for Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current provision/(benefit):
Federal	$ 63	$ (2)	$ 147
State	24	(25)	19
Foreign	0	1	0
Total current provision/(benefit)	87	(26)	166
Deferred provision/(benefit):
Federal	0	173	56
State	(2)	35	(3)
Foreign	0	0	0
Total deferred provision/(benefit)	(2)	208	53
Provision for income tax expense/(benefit)	$ 85	$ 182	$ 219