Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the total gross unrecognized tax benefits
Balance, January 1	$ 120	$ 92	$ 91
Additions based on tax positions related to current year	7	24	17
Unrecognized tax benefits, decrease resulting from prior period tax positions			(2)
Unrecognized tax benefits, increase resulting from prior period tax positions	26	18
Reductions for closure of tax audits and settlements	0	(8)	(20)
Reductions for lapse in statute of limitations	(6)	0	(1)
Unrecognized tax benefits, increase resulting from foreign currency translation			7
Unrecognized tax benefits, decrease resulting from foreign currency translation	(1)	(6)
Balance, December 31	146	120	$ 92
Income tax penalties and interest expense	15	10
Unrecognized tax benefits that would impact effective tax rate	144
Income tax penalties and interest accrued on unrecognized tax benefits	46	$ 32
Other Current Liabilities [Member]
Reconciliation of the total gross unrecognized tax benefits
Balance, December 31	$ 5