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, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Interest Rate Contract | Forward Contracts | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ (39)	$ 4	$ 17	$ (79)
Interest Rate Contract | Mortgage Servicing Rights | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	38	129	42	102
Interest Rate Contract | Interest Rate Swap | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	1	3	2	4
Foreign Exchange Contract | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings				(1)
Equity Contract | Warrants | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	56	28	102	25
Equity Contract | Put Option | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings		2	1	1
Equity Contract | Swap | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ (11)	$ (4)	$ (29)	$ (13)