Accumulated Other Comprehensive Income (Loss) - Reclassification of Component of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	$ (93)	$ (95)	$ (188)	$ (199)
Other, net	(40)	(1)	(49)	(1)
Income (loss) before income taxes	459	389	855	167
Tax (expense) benefit	(173)	(116)	(313)	(25)
Total reclassifications for the period, Net of tax	286	273	542	142
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before income taxes	(3)	(7)	(26)	13
Tax (expense) benefit	1	3	10	(5)
Total reclassifications for the period, Net of tax	(2)	(4)	(16)	8
Interest Rate Swaps [Member] | Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	$ (3)	(2)	(6)	(5)
Treasury Rate Locks [Member] | Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net				(3)
Foreign Currency Derivatives [Member] | Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Derivative Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other, net		$ (5)	$ (20)	$ 21