Income Taxes (Details) - Unrecognized Tax Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of unrecognized tax benefits [Roll Forward]
Unrecognized tax benefits, balance at January 1	$ 37	$ 31
Additions for tax positions of prior years	16	8
Reductions for tax positions of prior years	0	0
Reductions based on tax positions related to current year	0	0
Expiration of statute of limitations	(4)	(2)
Unrecognized tax benefits, balance at December 31	49	37	$ 31
Unrecognized tax benefits that, if recognized, would affect the annual effective tax rate	48	34
Amount of unrecognized tax benefits that are tax positions for which the ultimate deductibility is certain, but for which there is uncertainty about the timing of deductibility	1	3
Amount of interest recognized on unrecognized tax benefits in income taxes	0
Amount of interest benefit recognized on unrecognized tax benefits in income taxes		(1)	$ (10)
Accrued payment of interest balance for unrecognized tax benefits	$ 13	$ 13