Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current tax expense (benefit):
Federal	$ (45)	$ 6	$ 9
Total current tax expense (benefit)	(45)	6	9
Deferred tax expense (benefit):
Federal	208	(20)	23
Total deferred tax expense (benefit)	208	(20)	23
Income tax expense (benefit)	$ 163	$ (14)	$ 32