Income Taxes - Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current
Current federal income tax expense (benefit)	$ 2	$ 1	$ 2
Current state income tax expense	4	3	(23)
Deferred
Deferred federal income tax expense (benefit)	28	19	49
Deferred state income tax expense (benefit)	19	14	(8)
Total income tax expense (benefit)	$ 53	$ 37	$ 20