Fair Value Option - Components of Gain (Loss) on Debt Designated at Fair Value and Related Derivatives (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Mark-to-market on debt designated at fair value :
Interest rate component	$ 314	[1]	$ 166	[1]	$ 25	[1]
Credit risk component	(71)	[1]	(758)	[1]	616	[1]
Total mark-to-market on debt designated at fair value	243	[1]	(592)	[1]	641	[1]
Mark-to-market on the related derivatives	(333)	[1]	(260)	[1]	(81)	[1]
Net realized gains on the related derivatives	318		403		604
Gain (loss) on debt designated at fair value and related derivatives	$ 228		$ (449)		$ 1,164

[1] Mark-to-market on debt designated at fair value and related derivatives excludes market value changes due to fluctuations in foreign currency exchange rates. Foreign currency translation gains (losses) recorded in derivative related income (expense) associated with debt designated at fair value was a loss of $73 million, a loss of $35 million and a gain of $63 million during 2013, 2012 and 2011, respectively. Offsetting gains (losses) recorded in derivative related income (expense) associated with the related derivatives was and a gain of $73 million, a gain of $35 million and a loss of $63 million during 2013, 2012 and 2011, respectively.