Derivative Instruments- Impact of Derivative Instruments on Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	$ 24,550	[1]	$ 24,658	[1]
Asset derivatives fair value, effect of master netting agreements	(17,874)	[2],[3]	(18,347)	[2],[3]
Derivative assets after impact of netting arrangements, net assets recognized on the balance sheet	6,676		6,311
Liability derivatives fair value	24,306	[1]	25,017	[1]
Liability derivatives fair value, effect of master netting agreements	(16,999)	[3],[4]	(17,797)	[3],[4]
Derivative liability after impact of netting arrangements, net liabilities recognized on the balance sheet	7,307		7,220
Master netting agreements, cash collateral received	1,591		1,589
Master netting agreements, cash collateral paid	716		1,039
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	1,038	[5]	851	[5]
Liability derivatives fair value	612	[5]	447	[5]
Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional value	23,066	[5]	23,145	[5]
Asset derivatives fair value	574	[5]	477	[5]
Liability derivatives fair value	553	[5]	385	[5]
Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional value	7,309	[5]	7,344	[5]
Asset derivatives fair value	464	[5]	374	[5]
Liability derivatives fair value	59	[5]	62	[5]
Nondesignated
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	23,512	[6]	23,807	[6]
Liability derivatives fair value	23,694	[6]	24,570	[6]
Nondesignated | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional value	689,734	[6]	731,628	[6]
Asset derivatives fair value	17,054	[6]	17,150	[6]
Liability derivatives fair value	17,236	[6]	17,654	[6]
Nondesignated | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional value	593,662	[6]	528,401	[6]
Asset derivatives fair value	6,199	[6]	6,280	[6]
Liability derivatives fair value	6,073	[6]	6,367	[6]
Nondesignated | Equity contracts
Derivatives, Fair Value [Line Items]
Notional value	6,820	[6]	10,842	[6]
Asset derivatives fair value	259	[6]	377	[6]
Liability derivatives fair value	$ 385	[6]	$ 549	[6]

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

[2] 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.

[3] aster netting agreements includes cash collateral received and paid of $1,591 million and $716 million, respectively, at March 31, 2015, and $1,589 million and $1,039 million, respectively, at Dec. 31, 2014.

[4] 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.

[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.