Derivative Instruments- Impact of Derivative Instruments on Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	$ 23,127	[1]	$ 20,288	[1]
Asset derivatives fair value, effect of master netting agreements	(17,141)	[2],[3]	(15,806)	[2],[3]
Liability derivatives fair value	23,126	[1]	20,254	[1]
Liability derivatives fair value, effect of master netting agreements	(16,635)	[3],[4]	(14,421)	[3],[4]
Derivative assets after impact of netting arrangements, net assets recognized on the balance sheet	5,986		4,482
Derivative liability after impact of netting arrangements, net liabilities recognized on the balance sheet	6,491		5,833
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	777	[5]	1,282	[5]
Liability derivatives fair value	235	[5]	503	[5]
Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional value	24,271	[5]	21,402	[5]
Asset derivatives fair value	573	[5]	1,206	[5]
Liability derivatives fair value	178	[5]	167	[5]
Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional value	7,255	[5]	7,382	[5]
Asset derivatives fair value	204	[5]	76	[5]
Liability derivatives fair value	57	[5]	336	[5]
Nondesignated
Derivatives, Fair Value [Line Items]
Asset derivatives fair value	22,350	[6]	19,006	[6]
Liability derivatives fair value	22,891	[6]	19,751	[6]
Nondesignated | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional value	836,009	[6]	767,341	[6]
Asset derivatives fair value	15,591	[6]	14,712	[6]
Liability derivatives fair value	16,117	[6]	15,212	[6]
Nondesignated | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional value	566,093	[6]	420,142	[6]
Asset derivatives fair value	6,348	[6]	3,610	[6]
Liability derivatives fair value	6,180	[6]	3,536	[6]
Nondesignated | Equity contracts
Derivatives, Fair Value [Line Items]
Notional value	15,343	[6]	24,123	[6]
Asset derivatives fair value	411	[6]	684	[6]
Liability derivatives fair value	594	[6]	1,003	[6]
Nondesignated | Credit contracts
Derivatives, Fair Value [Line Items]
Notional value	0	[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] 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.

[3] aster netting agreements includes cash collateral received and paid of $1,122 million and $616 million, respectively, at Sept. 30, 2014, and $1,841 million and $456 million, respectively, at Dec. 31, 2013.

[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.