Net Gains (Losses) Recorded in the Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used For Risk Management (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Interest Rate Contract | Forward Contracts | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 174	$ (39)	$ 171	$ 17
Interest Rate Contract | Servicing Rights | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(30)	38	(37)	42
Interest Rate Contract | Interest Rate Swap | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings		1		2
Foreign Exchange Contract | Forward Contracts | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	3		5
Equity Contract | Warrant | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	76	56	110	102
Equity Contract | Put Option | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings				1
Equity Contract | Swap | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (5)	$ (11)	$ (12)	$ (29)