Impact of Derivative Instruments on Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	$ 27,902	[1],[2]	$ 33,305	[1],[2]
Asset derivatives fair value, effect of master netting agreements	(23,059)	[1]	(26,047)	[1]
Asset derivatives fair value, fair value after effect of master netting agreements	4,843	[1]	7,258	[1]
Liability derivatives fair value	27,719	[1],[2]	32,444	[1],[2]
Liability derivatives fair value, effect of master netting agreements	(22,085)	[1]	(25,009)	[1]
Liability derivatives fair value, fair value after effect of master netting agreements	5,634	[1]	7,435	[1]
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	1,035	[1],[3]	1,600	[1],[3]
Liability derivatives fair value	189	[1],[3]	319	[1],[3]
Designated as Hedging Instrument | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Notional value	19,783	[3]	18,281	[3]
Asset derivatives fair value	986	[1],[3]	965	[1],[3]
Liability derivatives fair value	178	[1],[3]	298	[1],[3]
Designated as Hedging Instrument | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional value	14,599	[3]	14,160	[3]
Asset derivatives fair value	49	[1],[3]	635	[1],[3]
Liability derivatives fair value	11	[1],[3]	21	[1],[3]
Nondesignated
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	26,867	[1],[4]	31,705	[1],[4]
Liability derivatives fair value	27,530	[1],[4]	32,125	[1],[4]
Nondesignated | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Notional value	962,564	[4]	975,308	[4]
Asset derivatives fair value	22,249	[1],[4]	26,652	[1],[4]
Liability derivatives fair value	23,215	[1],[4]	27,440	[1],[4]
Nondesignated | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional value	406,788	[4]	379,235	[4]
Asset derivatives fair value	4,120	[1],[4]	4,632	[1],[4]
Liability derivatives fair value	3,853	[1],[4]	4,355	[1],[4]
Nondesignated | Equity Contract
Derivatives, Fair Value [Line Items]
Notional value	9,746	[4]	8,205	[4]
Asset derivatives fair value	498	[1],[4]	418	[1],[4]
Liability derivatives fair value	461	[1],[4]	330	[1],[4]
Nondesignated | Credit Contracts
Derivatives, Fair Value [Line Items]
Notional value	270	[4]	333	[4]
Asset derivatives fair value			3	[1],[4]
Liability derivatives fair value	$ 1	[1],[4]

[1] Derivative financial instruments are reported net of cash collateral received and paid of $1,148 million and $174 million, respectively, at March 31, 2012, and $1,269 million and $231 million, respectively at Dec. 31, 2011.

[2] Fair values are on a gross basis, before consideration of master netting agreements, as required by ASC 815.

[3] The fair value of asset derivatives and liability derivatives designated as hedging instruments is recorded as other assets and other liabilities, respectively, on the balance sheet.

[4] The fair value of asset derivatives and liability derivatives not designated as hedging instruments is recorded as trading assets and trading liabilities, respectively, on the balance sheet.