Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Derivatives, Fair Value [Line Items]
Notional Amount	$ 75,385	$ 78,589	$ 88,085
Derivative Assets	486	530	656
Derivative Liabilities	88	109	134
Derivative Instruments, Netting adjustments
Derivative Asset, Netting adjustments	(1,115)	(1,270)	(1,295)
Derivative Liability, Netting adjustments	(696)	(803)	(847)
Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	20,269	19,281	15,368
Derivative assets	500	579	532
Derivative liabilities	30	37	20
Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	55,116	59,308	72,717
Derivative assets	1,224	1,384	1,593
Derivative liabilities	1,190	1,350	1,581
Net derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	75,385	78,589	88,085
Derivative Assets	609	693	830
Derivative Liabilities	524	584	754
Other collateral [Member]
Derivatives, Fair Value [Line Items]
Notional Amount
Derivative Assets	(123)	(163)	(174)
Derivative Liabilities	(436)	(475)	(620)
Interest Rate [Member] | Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	20,067	19,085	15,368
Derivative assets	499	579	532
Derivative liabilities	27	30	20
Interest Rate [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	47,334	51,633	61,369
Derivative assets	1,027	1,144	1,190
Derivative liabilities	1,000	1,122	1,193
Foreign exchange [Member] | Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	202	196
Derivative assets	1
Derivative liabilities	3	7
Foreign exchange [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	4,925	5,025	6,316
Derivative assets	70	75	94
Derivative liabilities	65	68	84
Energy and Commodity [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,801	1,688	1,632
Derivative assets	120	156	271
Derivative liabilities	114	150	267
Credit [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,056	955	3,382
Derivative assets	7	9	35
Derivative liabilities	11	10	34
Equity [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount		7	18
Derivative assets			3
Derivative liabilities			$ 3