Derivative Instruments - Net Gains (Losses) from Changes in Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Total (loss) gain recognized in income	$ 42	$ 13	$ (8)
Derivative instruments not designated as hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Total (loss) gain recognized in income	(22)	9	(22)
Foreign exchange contracts | Foreign exchange loss | Derivative instruments not designated as hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Total (loss) gain recognized in income	(3)	1	(24)
Forward interest rate swaps | Interest expense, net | Derivative instruments not designated as hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Total (loss) gain recognized in income	$ (19)	$ 8	$ 2