Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, tax	$ 10	$ 6	$ (5)	$ 18
Unrealized gains (losses), tax	(1)	(15)	1	(32)
Reclassification adjustment for losses (gains) included in “Other income (expense), net,” tax	$ 0	$ (1)	$ 0	$ (2)