Net Gains (Losses) Recorded in the Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used for Risk Management and Other Business Purposes (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest Rate Contract | Forward Contracts | Loans Held-for-Sale | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ (18)	$ 24	$ 28
Interest Rate Contract | Servicing Rights | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	95	(30)	63
Interest Rate Contract | Swap | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings			2
Foreign Exchange Contract | Forward Contracts | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	14	5
Equity Contract | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings			1
Equity Contract | Warrant | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	31	206	66
Equity Contract | Swap | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ (38)	$ (31)	$ (45)