Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized Tax Benefits
Unrecognized tax benefits	$ 29	$ 30	$ 28
Unrecognized tax benefit, if recognized, would have an impact on effective tax rate	29
Activity for unrecognized tax benefits [Roll Forward]
Balance at beginning of period	30	28	34
Tax positions related to current year additions	0	1	1
Additions for tax positions of prior years	0	2	0
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(1)	0	0
Reductions due to lapse of statute of limitations on tax positions	0	(1)	(7)
Balance at end of period	$ 29	$ 30	$ 28