Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ (1,060)
Balance as of end of period	$ (1,099)		(1,099)
Tax impact for the changes in each component of accumulated other comprehensive (loss) income
Foreign currency translation adjustments	(1)	$ 6	2	$ (25)
Net investment hedges	15	(1)	9	18
Total tax impact	14	5	11	(7)
Foreign Currency Translation Adjustment Gains (Losses) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,075)	(1,009)	(1,060)	(998)
Net translation losses of investments in foreign operations	(74)	(13)	(68)	(86)
Net gains (losses) related to hedges of investments in foreign operations	50	(3)	29	59
Net change in accumulated other comprehensive loss	(24)	(16)	(39)	(27)
Balance as of end of period	$ (1,099)	$ (1,025)	$ (1,099)	$ (1,025)