Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 8,693
Other comprehensive (loss) income, net of tax	90	$ 152
Ending balance	8,992
AOCI Attributable to Parent [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Ending balance	(1,148)	(952)
Unrealized Loss on Cash Flow Hedges [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	17	0
Other comprehensive (loss) income, net of tax	(4)	0
Ending balance	13	0
Defined Benefit Plans [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(20)	(13)
Other comprehensive (loss) income, net of tax	0	(1)
Ending balance	(20)	(14)
Foreign Currency Translation Adjustment [Member]
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(1,235)	(1,091)
Other comprehensive (loss) income, net of tax	94	153
Ending balance	$ (1,141)	$ (938)