Summary of Gains (Losses) Recognized in Earnings for Fair Value Hedges, Other Economic Hedges and Customer-Related Positions (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Interest rate contracts | Other noninterest income expense | Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 2	[1]	$ 1	[1]	$ 5	[1]	$ 25	[1]
Foreign exchange cross-currency swaps | Other noninterest income expense | Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings			(111)	[1]	42	[1]	(13)	[1]
Futures and forwards interest rate contract | Mortgage banking revenue | Other economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(44)		17		67		(7)
Purchased and written options interest rate contract | Mortgage banking revenue | Other economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	290		181		689		323
Receive fixed pay floating swaps interest rate contract | Other noninterest income expense
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(16)		366		(10)		352
Receive fixed pay floating swaps interest rate contract | Mortgage banking revenue | Other economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	48		377		186		479
Pay fixed receive floating swaps interest rate contracts | Other noninterest income expense
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	19		(376)		15		(365)
Pay fixed receive floating swaps interest rate contracts | Mortgage banking revenue | Other economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings			4				4
Foreign exchange forward contracts | Commercial products revenue | Other economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(25)		(48)		(62)		(66)
Equity contracts | Compensation expense | Other economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	1		1		2		2
Credit contracts | Other noninterest income expense | Other economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(2)		4		(8)		2
Forwards spots and swaps foreign exchange contract | Commercial products revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 13		$ 14		$ 36		$ 41

[1] Gains (Losses) on items hedged by interest rate contracts and foreign exchange forward contracts, included in noninterest income (expense), were $(2) million and zero for the three months ended September 30, 2012, respectively, and $(3) million and $117 million for the three months ended September 30, 2011, respectively. Gains (Losses) on items hedged by interest rate contracts and foreign exchange forward contracts, included in noninterest income (expense), were $(5) million and $(44) million for the nine months ended September 30, 2012, respectively, and $(27) million and $20 million for the nine months ended September 30, 2011, respectively. The ineffective portion was immaterial for the three and nine months ended September 30, 2012 and 2011.