Net Gains (Losses) Relating to Derivative Instruments Designated as Cash Flow Hedges (Detail) (Cash Flow Hedging, USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss recognized in OCI	$ 27		$ 59	$ (2)
Interest Income Expense Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from OCI into net interest income	(10)	17	21	46
Other Noninterest Income
Derivative Instruments, Gain (Loss) [Line Items]
Amount of ineffectiveness recognized in other noninterest income		$ 2	$ 2	$ 2