Shareholders' Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	$ 12,726	$ 11,659
Balance at end of period	11,316	11,984
AOCI Attributable to Parent [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(1,119)	(1,066)
Balance at end of period	(1,662)	(1,024)
Unrealized (Loss) Gain on Hedges [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(49)	9
Other comprehensive (loss) income, net of tax	(117)	(15)
Balance at end of period	(166)	(6)
Defined Benefit Plans [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	1	1
Other comprehensive (loss) income, net of tax	0	0
Balance at end of period	1	1
Foreign Currency Translation Adjustment [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(1,071)	(1,076)
Other comprehensive (loss) income, net of tax	(426)	57
Balance at end of period	$ (1,497)	$ (1,019)