Amount and Location in the Income Statement for Derivatives Designated as Fair Value Hedges (Detail) - Fair Value Hedging - Interest Expense [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest Rate Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ (59)	$ 80	$ 56	$ 71
Fixed-Rate Debt and Capital Leases
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ 59	$ (80)	$ (56)	$ (71)