Financial Instruments - Cash Flow Hedges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in AOCI	$ 2	$ 2	$ (6)	$ 3
Cash flow hedging | Currency exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in AOCI	3	1	(5)	2
Gain (loss) reclassified from AOCI to earnings	$ 2	$ (1)	$ 2	$ (2)