Impacts of Derivative Financial Instruments on the Consolidated Statements of Income/(Loss) and the Consolidated Statements of Shareholders' Equity (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Cash Flow Hedging | Interest Income, Interest and Fees on Loans | Interest Rate Contract [Member] | Floating Rate Loans
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 23	[1]	$ 1	[2]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	76	[1]	87
Fair Value Hedging | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Fixed Rate Debt
Derivative Instruments, Gain (Loss) Recognized in Income, Net	9	[3]	(5)	[3]
Amount of gain on related Hedged Items recognized in Income	(9)	[3]	6	[3]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	[3]	1	[3]
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	105		108
Not Designated as Hedging Instrument [Member] | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	14		8
Not Designated as Hedging Instrument [Member] | Trading Account Profits And Commissions [Member] | Foreign Exchange Contract | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	5		12
Not Designated as Hedging Instrument [Member] | Trading Account Profits And Commissions [Member] | Foreign Exchange Contract | Foreign-Denominated Debt and Commercial Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net			2
Not Designated as Hedging Instrument [Member] | Trading Account Profits And Commissions [Member] | Credit Risk Contract [Member] | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	4		5
Not Designated as Hedging Instrument [Member] | Trading Account Profits And Commissions [Member] | Equity Contract [Member] | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	1		1
Not Designated as Hedging Instrument [Member] | Other Income [Member] | Credit Risk Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net			(1)
Not Designated as Hedging Instrument [Member] | Mortgage Servicing Income [Member] | Interest Rate Contract [Member] | Mortgage Servicing Rights [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	55		(56)
Not Designated as Hedging Instrument [Member] | Mortgage Production Income [Member] | Interest Rate Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(34)		35
Not Designated as Hedging Instrument [Member] | Mortgage Production Income [Member] | Other Contract | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ 60		$ 102

[1] During the three months ended March 31, 2014, the Company also reclassified $26 million pre-tax gains from AOCI into net interest income. These gains related to hedging relationships that have been previously terminated or de-designated and are reclassified into earnings in the same period in which the forecasted transaction occurs.

[2] During the three months ended March 31, 2013, the Company also reclassified $27 million pre-tax gains from AOCI into net interest income. These gains related to hedging relationships that have been previously terminated or de-designated and are reclassified into earnings in the same period in which the forecasted transaction occurs.

[3] Amounts are recognized in trading income in the Consolidated Statements of Income.