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
	Mar. 31, 2014	Mar. 31, 2013
Interest Rate Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 4	$ 5
Interest Rate Contract | Customer Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings		(1)
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	1	1
Interest Rate Contract | Interest Rate Lock Commitments | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	36	56
Commodity Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	1	2
Foreign Exchange Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	15	18
Foreign Exchange Contract | Customer Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 2