Financial Instruments - Other Comprehensive Income (Loss) (Details) - Net investment hedge - Other comprehensive income (loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Foreign currency
Derivative Instruments, Gain (Loss)
Gains and (losses) on derivative instruments	$ 0	$ 0	$ 1	$ 0
Cross-currency swaps
Derivative Instruments, Gain (Loss)
Gains and (losses) on derivative instruments	(17)	(4)	18	5
Foreign currency-denominated debt
Derivative Instruments, Gain (Loss)
Gains and (losses) on derivative instruments	$ (10)	$ (7)	$ (2)	$ 5