Impact of Derivative Instruments on Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	$ 32,482	[1]	$ 33,305	[1]
Asset derivatives fair value, effect of master netting agreements	(27,357)	[2]	(26,047)	[2]
Asset derivatives fair value, fair value after effect of master netting agreements	5,125		7,258
Liability derivatives fair value	32,658	[1]	32,444	[1]
Liability derivatives fair value, effect of master netting agreements	(26,316)	[2]	(25,009)	[2]
Liability derivatives fair value, fair value after effect of master netting agreements	6,342		7,435
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	1,232	[3]	1,600	[3]
Liability derivatives fair value	462	[3]	319	[3]
Designated as Hedging Instrument | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Notional value	20,325	[3]	18,281	[3]
Asset derivatives fair value	995	[3]	965	[3]
Liability derivatives fair value	458	[3]	298	[3]
Designated as Hedging Instrument | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional value	12,729	[3]	14,160	[3]
Asset derivatives fair value	237	[3]	635	[3]
Liability derivatives fair value	4	[3]	21	[3]
Nondesignated
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	31,250	[4]	31,705	[4]
Liability derivatives fair value	32,196	[4]	32,125	[4]
Nondesignated | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Notional value	896,213	[4]	975,308	[4]
Asset derivatives fair value	27,672	[4]	26,652	[4]
Liability derivatives fair value	28,637	[4]	27,440	[4]
Nondesignated | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional value	379,003	[4]	379,235	[4]
Asset derivatives fair value	3,179	[4]	4,632	[4]
Liability derivatives fair value	3,114	[4]	4,355	[4]
Nondesignated | Equity Contract
Derivatives, Fair Value [Line Items]
Notional value	11,612	[4]	8,205	[4]
Asset derivatives fair value	399	[4]	418	[4]
Liability derivatives fair value	445	[4]	330	[4]
Nondesignated | Credit Risk Contract
Derivatives, Fair Value [Line Items]
Notional value	221	[4]	333	[4]
Asset derivatives fair value			$ 3	[4]

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

[2] Master netting agreements are reported net of cash collateral received and paid of $1,298 million and $257 million, respectively, at June 30, 2012, and $1,269 million and $231 million, respectively at Dec. 31, 2011.

[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.