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, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Interest Rate Contract | Forward Contracts | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (11)	$ 174	$ (23)	$ 171
Interest Rate Contract | Servicing Rights | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	38	(30)	61	(37)
Foreign Exchange Contract | Forward Contracts | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(5)	3	(1)	5
Equity Contract | Warrant | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	63	76	28	110
Equity Contract | Swap | Other Noninterest Income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (16)	$ (5)	$ (15)	$ (12)