Changes in Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Other Comprehensive Income (Loss) Net of Tax, Period Change [Abstract]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	$ (12)	$ 10	$ (92)	$ 79
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(25)	(19)	(47)	(34)
Total other comprehensive income (loss)	(37)	(9)	(139)	45
Accumulated Other Comprehensive Income (Loss), Net of Tax	131	78	131	78	$ 168	$ 270	$ 87	$ 33
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(6)	8	(178)	22
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	(5)	(8)	(9)	(16)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(11)	0	(187)	7
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	(46)	(46)	(46)	(46)	(35)	142	(46)	(53)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	(6)	2	86	58
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(20)	(11)	(37)	(18)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	(26)	(9)	48	40
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	222	150	222	150	248	173	160	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)