Net Gains (Losses) Recorded in the Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used For Customer Accommodation (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Interest Rate Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 8	$ 7	$ 22	$ 20
Interest Rate Contract | Customer Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings		(1)	(3)	(2)
Interest Rate Contract | Fair Value Adjustments on Hedges and Derivative Contracts 1 [Member] | Other Noninterest Expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings		2	4	5
Interest Rate Contract | Interest Rate Lock Commitments | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	43	166	41	341
Commodity Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	1	1	5	6
Commodity Contract | Fair Value Adjustments on Hedges and Derivative Contracts 1 [Member] | Other Noninterest Expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings		1		1
Foreign Exchange Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	14	16	52	49
Foreign Exchange Contract | Fair Value Adjustments on Hedges and Derivative Contracts 1 [Member] | Other Noninterest Expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings		$ 1	$ (2)	$ 2