Accumulated Other Comprehensive Loss - Reclassification of Component of Accumulated Other Comprehensive Loss Associated with Cash Flow Hedges (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other, net		$ (43)		$ (53)
Income (loss) before income taxes	$ 570	459	$ 1,004	855
Tax (expense) benefit	(209)	(173)	(346)	(313)
Total reclassifications for the period, Net of tax	361	286	658	542
Reclassification out of Accumulated Other Comprehensive Income [Member] | Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before income taxes	(3)	(3)	(6)	(26)
Tax (expense) benefit	1	1	2	10
Total reclassifications for the period, Net of tax	(2)	(2)	(4)	(16)
Interest Rate Swaps [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	$ (3)	$ (3)	$ (6)	(6)
Foreign Currency Derivatives [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other, net				$ (20)