Change in the Fair Value for Interest Rate Contracts and the Related Hedged Items (Detail) (Fair Value Hedging, Interest Rate Contract, Interest Expense Long Term Debt [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value Hedging | Interest Rate Contract | Interest Expense Long Term Debt [Member]
Derivatives, Fair Value [Line Items]
Increase Decrease In Fair Value Of Interest Rate Fair Value Hedging Instruments	$ (279)	$ (104)	$ 220
Increase Decrease In Fair Value Of Hedged Item In Interest Rate Fair Value Hedge	$ 276	$ 107	$ (227)