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
	Mar. 31, 2012	Mar. 31, 2011
Interest Rate Contract | Forward Contracts | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ 57	$ (83)
Interest Rate Contract | Mortgage Servicing Rights | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	4	(27)
Interest Rate Contract | Interest Rate Swap | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	1	2
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	45	(2)
Equity Contract | Put Option | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	1
Equity Contract | Swap | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ (19)	$ (9)