Income Taxes - Income (Loss) Before Income Taxes and Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income before income tax expense:
Domestic	$ 432	$ 185	$ 228
Foreign	1,445	966	878
Income before income tax expense	1,877	1,151	1,106
Current:
Federal	(228)	696	(15)
State	(15)	26	16
Foreign	280	335	150
Total current	37	1,057	151
Deferred:
Federal	(98)	(111)	40
State	106	(32)	(13)
Foreign	19	(36)	(38)
Total deferred	27	(179)	(11)
Income tax expense	64	878	140
Benefit credited to income tax provision:
Excess tax benefits from share-based payments	$ 58	$ 113	$ 81