Fair Value Option - Components of Gain on Instruments 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
Components Of Gain On Instruments At Fair Value And Related Derivatives [Line Items]
Interest rate and other components	$ (408)	[1]	$ (775)	[1]	$ (741)	[1]
Credit risk component	(19)	[2],[3]	(387)		475	[2],[3]
Total mark-to-market on financial instruments designated at fair value	(427)		(1,162)		(266)
Net realized loss on the financial instruments	(8)		(1)		(1)
Mark-to-market on the related derivatives	337		758		674
Net realized gain on the related long-term debt derivatives	66		63		64
Gain (loss) on instruments designated at fair value and related derivatives	(32)		(342)		471
Loans [Member]
Components Of Gain On Instruments At Fair Value And Related Derivatives [Line Items]
Interest rate and other components	0	[1]	3	[1]	(5)	[1]
Credit risk component	21	[2],[3]	49		(14)	[2],[3]
Total mark-to-market on financial instruments designated at fair value	21		52		(19)
Net realized loss on the financial instruments	(8)		(1)		(1)
Mark-to-market on the related derivatives	0		0		0
Net realized gain on the related long-term debt derivatives	0		0		0
Gain (loss) on instruments designated at fair value and related derivatives	13		51		(20)
Long-term Debt [Member]
Components Of Gain On Instruments At Fair Value And Related Derivatives [Line Items]
Interest rate and other components	289	[1]	13	[1]	(345)	[1]
Credit risk component	(165)	[2],[3]	(361)		376	[2],[3]
Total mark-to-market on financial instruments designated at fair value	124		(348)		31
Net realized loss on the financial instruments	0		0		0
Mark-to-market on the related derivatives	(294)		(38)		369
Net realized gain on the related long-term debt derivatives	66		63		64
Gain (loss) on instruments designated at fair value and related derivatives	(104)		(323)		464
Hybrid Instruments [Member]
Components Of Gain On Instruments At Fair Value And Related Derivatives [Line Items]
Interest rate and other components	(697)	[1]	(791)	[1]	(391)	[1]
Credit risk component	125	[2],[3]	(75)		113	[2],[3]
Total mark-to-market on financial instruments designated at fair value	(572)		(866)		(278)
Net realized loss on the financial instruments	0		0		0
Mark-to-market on the related derivatives	631		796		305
Net realized gain on the related long-term debt derivatives	0		0		0
Gain (loss) on instruments designated at fair value and related derivatives	$ 59		$ (70)		$ 27

[1] As it relates to hybrid instruments, interest rate and other components includes interest rate, foreign exchange and equity contract risks.

[2] For 2013 and 2012, the losses in the credit risk component for long-term debt were attributable to the tightening of our own credit spreads, while the widening of our own credit spreads resulted in the gain for 2011.

[3] For 2013, the gain in the credit risk component for hybrid instruments was attributable primarily to the widening of credit spreads on structured deposits. For 2012, the the losses in the credit risk component for hybrid instruments was attributable primarily to the tightening of our own credit spreads related to structured notes, while the widening of our own credit spreads related to structured notes resulted in the gain for 2011.