Income Taxes - Reconciliation of Total Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of the Company's total gross unrecognized tax benefits
Balance at beginning of the period	$ 99	$ 87	$ 79
Additions and reductions for tax positions of prior years		16
Additions and reductions for tax positions of prior years	(20)		(4)
Additions based on tax positions related to the current year	11	12	15
Reductions due to settlements		(16)
Foreign currency translation			(3)
Foreign currency translation	3
Balance at ending of the period	93	99	87
Unrecognized tax benefits, which if recognized, would impact the Company's effective income tax rate	80	86	78
Accrued interest and penalties	14	11	10
Interest and penalties included in tax expense	$ 3	$ 1	$ 2