Net Gains (Losses) Recorded in the Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used For Customer Accommodation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest Rate Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ 23	$ 19	$ 29
Interest Rate Contract | Customer Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	(1)	(3)	(3)
Interest Rate Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	1	3	7
Interest Rate Contract | Interest Rate Lock Commitments | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	111	124	58
Commodity Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	5	6	7
Commodity Contract | Customer Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	(2)
Commodity Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	6	(7)
Foreign Exchange Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ 70	$ 72	69
Foreign Exchange Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings			$ (2)