Derivative Instruments- Impact of Derivative Instruments on Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	$ 18,275	[1]	$ 20,288	[1]
Asset derivatives fair value, effect of master netting agreements	(14,401)	[2],[3]	(15,806)	[2],[3]
Liability derivatives fair value	18,321	[1]	20,254	[1]
Liability derivatives fair value, effect of master netting agreements	(13,856)	[2],[4]	(14,421)	[2],[4]
Liability derivatives fair value, amount not offset against collateral	4,465		5,833
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	1,005	[5]	1,282	[5]
Liability derivatives fair value	395	[5]	503	[5]
Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional value	21,424	[5]	21,402	[5]
Asset derivatives fair value	945	[5]	1,206	[5]
Liability derivatives fair value	172	[5]	167	[5]
Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional value	7,863	[5]	7,382	[5]
Asset derivatives fair value	60	[5]	76	[5]
Liability derivatives fair value	223	[5]	336	[5]
Nondesignated
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	17,270	[6]	19,006	[6]
Liability derivatives fair value	17,926	[6]	19,751	[6]
Nondesignated | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional value	763,323	[6]	767,341	[6]
Asset derivatives fair value	14,492	[6]	14,712	[6]
Liability derivatives fair value	15,058	[6]	15,212	[6]
Nondesignated | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional value	465,202	[6]	420,142	[6]
Asset derivatives fair value	2,209	[6]	3,610	[6]
Liability derivatives fair value	2,066	[6]	3,536	[6]
Nondesignated | Equity contracts
Derivatives, Fair Value [Line Items]
Notional value	24,611	[6]	24,123	[6]
Asset derivatives fair value	569	[6]	684	[6]
Liability derivatives fair value	802	[6]	1,003	[6]
Nondesignated | Credit contracts
Derivatives, Fair Value [Line Items]
Notional value	51	[6]	101	[6]
Asset derivatives fair value	0	[6]	0	[6]
Liability derivatives fair value	$ 0	[6]	$ 0	[6]

[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 $1,119 million and $574 million, respectively, at March 31, 2014, and $1,841 million and $456 million, respectively, at Dec. 31, 2013.

[3] Includes the effect of netting agreements and net cash collateral paid. The offset related to the over-the-counter derivatives was allocated to the various types of derivatives based on the net positions.

[4] Includes the effect of netting agreements and net cash collateral received. The offset related to the over-the-counter derivatives was allocated to the various types of derivatives based on the net positions.

[5] 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.

[6] 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.