Derivative Financial Instruments - Summary of Effect of Foreign Currency Exchange Contracts (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gains recognized in AOCI	$ 69	$ (6)	$ 98	$ 52
Gains (losses) reclassified from AOCI into product sales	31	(8)	96	(101)
Gains (losses) recognized in Other income (expense), net	$ 40	$ 15	$ 29	$ 11