Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (1,145)	$ (829)	$ (845)	$ (925)
Other comprehensive income (loss) before reclassifications	91	1	(148)	11
Amounts reclassified from accumulated other comprehensive (income) loss	42	(3)	(19)	(14)
Adjustment to adopt reclassification of certain tax effects from AOCI				97
Other comprehensive income (loss)	133	(2)	(167)	94
Balance at end of period	(1,012)	(831)	(1,012)	(831)
Foreign currency translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(1,083)	(778)	(777)	(889)
Other comprehensive income (loss) before reclassifications	126	20	(180)	33
Amounts reclassified from accumulated other comprehensive (income) loss	0	0	0	0
Adjustment to adopt reclassification of certain tax effects from AOCI				98
Other comprehensive income (loss)	126	20	(180)	131
Balance at end of period	(957)	(758)	(957)	(758)
Derivative financial instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(62)	(51)	(68)	(36)
Other comprehensive income (loss) before reclassifications	(35)	(19)	32	(22)
Amounts reclassified from accumulated other comprehensive (income) loss	42	(3)	(19)	(14)
Adjustment to adopt reclassification of certain tax effects from AOCI				(1)
Other comprehensive income (loss)	7	(22)	13	(37)
Balance at end of period	$ (55)	$ (73)	$ (55)	$ (73)