Derivative Financial Instruments - Gains and Losses on Derivative Instruments Held For Other Purpose (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	$ 246	$ 384	$ 159	$ 787
Other Income [Member] | Credit contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	(3)	(1)	0	(6)
Residential mortgage banking revenue [Member] | Interest rate contracts [Member]
Derivatives, Fair Value [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	(9)	(5)	(5)	0
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	(15)	15	(253)	120
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	(2)	23	(57)	73
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	234	351	474	597
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	42	0	0	0
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	$ (1)	$ 1	$ 0	$ 3