Uncertain Tax Positions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 50	$ 57	$ 62
Additions for tax positions related to current year	8	2	7
Additions (reductions) for tax positions taken in prior years	(6)		(1)
Additions (reductions) for tax positions taken in prior years		5
Lapse of statute of limitations	(6)	(14)	(11)
Ending balance	$ 46	$ 50	$ 57