Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Derivatives, Fair Value [Line Items]
Notional Amount	$ 68,911	$ 78,589	$ 84,457
Derivative Assets	374	530	611
Derivative Liabilities	140	109	225
Derivative Instruments, Netting adjustments
Derivative Asset, Netting adjustments	(992)	(1,270)	(1,382)
Derivative Liability, Netting adjustments	(633)	(803)	(880)
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	15,859	19,281	16,334
Derivative assets	380	579	588
Derivative liabilities	59	37	40
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	53,052	59,308	68,123
Derivative assets	1,073	1,384	1,612
Derivative liabilities	1,030	1,350	1,603
Net Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	68,911	78,589	84,457
Derivative Assets	461	693	818
Derivative Liabilities	456	584	763
Other Collateral [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	(87)	(163)	(207)
Derivative Liabilities	(316)	(475)	(538)
Interest Rate [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	15,670	19,085	15,903
Derivative assets	377	579	586
Derivative liabilities	59	30	32
Interest Rate [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	45,104	51,633	58,222
Derivative assets	851	1,144	1,273
Derivative liabilities	812	1,122	1,278
Foreign Exchange [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	189	196	431
Derivative assets	3		2
Derivative liabilities		7	8
Foreign Exchange [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	4,934	5,025	5,579
Derivative assets	97	75	105
Derivative liabilities	93	68	97
Energy and Commodity [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,896	1,688	1,691
Derivative assets	119	156	209
Derivative liabilities	114	150	204
Credit [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,118	955	2,613
Derivative assets	6	9	25
Derivative liabilities	11	10	24
Equity [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount		$ 7	$ 18