Amount Recorded in Income Statements for Foreign Currency Forward Contracts Not Designated as Hedges (Detail) (Not Designated as Hedging Instrument, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ 20	$ (3)
Foreign Exchange Contracts | Other Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	21	(1)
Foreign Exchange Contracts | Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	2	0
Price Risk Derivative [Member] | Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	(2)	0
Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ (1)	$ (2)