Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative Asset, Netting adjustments	$ (1,270)	$ (1,452)
Derivative Liability, Netting adjustments	(803)	(978)
Notional Amount	78,589	74,544
Derivative Asset	693	945
Derivative Liabilities	584	1,026
Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	19,281	15,621
Derivative assets	579	589
Derivative liabilities	37	174
Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	59,308	58,923
Derivative assets	1,384	1,808
Derivative liabilities	1,350	1,830
Interest Rate [Member] | Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	19,085	15,067
Derivative assets	579	589
Derivative liabilities	30	27
Interest Rate [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	51,633	48,537
Derivative assets	1,144	1,364
Derivative liabilities	1,122	1,371
Foreign exchange [Member] | Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	196	554
Derivative liabilities	7	147
Foreign exchange [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	5,025	5,549
Derivative assets	75	151
Derivative liabilities	68	141
Energy and Commodity [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,688	1,610
Derivative assets	156	253
Derivative liabilities	150	253
Credit [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	955	3,210
Derivative assets	9	37
Derivative liabilities	10	62
Equity [Member] | Derivatives not designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	7	17
Derivative assets		3
Derivative liabilities		$ 3