Changes in Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	$ 38	$ 86	$ (54)	$ 165
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(19)	(26)	(65)	(59)
Total other comprehensive income (loss)	20	60	(119)	105
Accumulated Other Comprehensive Income (Loss), Net of Tax	151	138	151	138	$ 131	$ 270	$ 78	$ 33
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	88	7	(90)	30
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	(5)	(9)	(14)	(25)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	84	(2)	(104)	4
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	38	(48)	38	(48)	(46)	142	(46)	(53)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	(50)	78	36	136
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(14)	(16)	(52)	(34)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	(64)	62	(15)	102
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	158	213	158	213	222	173	150	111
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	0	0	0	(1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	0	0	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	0	0	(1)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	$ (45)	$ (26)	$ (45)	$ (26)	$ (45)	$ (45)	$ (26)	$ (25)