Derivative Financial Instruments - Gains and Losses on Derivative Instruments Held For Trading Purpose (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	$ 241	$ (107)	$ 403	$ (9)
Trading revenue [Member] | Interest rate contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	71	(89)	541	(32)
Trading revenue [Member] | Foreign exchange contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	207	58	(149)	83
Trading revenue [Member] | Equity contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	4	0	3	0
Trading revenue [Member] | Precious metals contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	(27)	10	19	18
Trading revenue [Member] | Credit contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	4	(108)	(17)	(115)
Residential mortgage banking revenue [Member] | Interest rate contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	$ (18)	$ 22	$ 6	$ 37