Derivative Financial Instruments - Gains and Losses on Derivative Instruments Held For Other Purpose (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	$ 379	$ (329)	$ 593	$ (87)
Gain (loss) on Instruments Designated at Fair Value and Related Derivatives [Member] | Interest rate contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	111	(176)	227	(238)
Gain (loss) on Instruments Designated at Fair Value and Related Derivatives [Member] | Foreign exchange contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	9	(44)	13	(55)
Gain (loss) on Instruments Designated at Fair Value and Related Derivatives [Member] | Equity contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	258	(75)	339	240
Gain (loss) on Instruments Designated at Fair Value and Related Derivatives [Member] | Precious metals contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	8	(42)	24	(42)
Gain (loss) on Instruments Designated at Fair Value and Related Derivatives [Member] | Credit contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	0	1	1	1
Residential mortgage banking revenue [Member] | Interest rate contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	0	4	0	4
Other Income [Member] | Credit contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	$ (7)	$ 3	$ (11)	$ 3