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, 2013		Mar. 31, 2012
Interest Income, Interest and Fees on Loans
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (114)
Fair Value Hedging | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Fixed Rate Debt
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(5)	[1]	(1)	[1]
Amount of gain on related Hedged Items recognized in Income	6	[1]	1	[1]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1	[1]	0	[1]
Fair Value Hedging | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Net			1
Amount of gain on related Hedged Items recognized in Income			(1)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0	[1]
Cash Flow Hedging
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			(8)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			83
Cash Flow Hedging | Equity Contract | Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			(58)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0
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	1	[2]	50	[2]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	87	[2]	83	[3]
Nondesignated
Derivative Instruments, Gain (Loss) Recognized in Income, Net	108		128
Nondesignated | Trading Account Profits And Commissions [Member] | Equity Contract | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	1		4
Nondesignated | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	8		27
Nondesignated | Trading Account Profits And Commissions [Member] | Foreign Exchange Contract | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	12		3
Nondesignated | Trading Account Profits And Commissions [Member] | Foreign Exchange Contract | Foreign-Denominated Debt and Commercial Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	2		15
Nondesignated | Trading Account Profits And Commissions [Member] | Credit Risk Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net			(3)
Nondesignated | Trading Account Profits And Commissions [Member] | Credit Risk Contract [Member] | Trading Activity
Derivative Instruments, Gain (Loss) Recognized in Income, Net	5		6
Nondesignated | Mortgage Servicing Income | Interest Rate Contract [Member] | Mortgage Servicing Rights [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(56)		(73)
Nondesignated | Mortgage Production Income [Member] | Interest Rate Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	35		(35)
Nondesignated | Mortgage Production Income [Member] | Other Contract | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	102		184
Nondesignated | Other Income [Member] | Credit Risk Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ (1)

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

[2] During the three months ended March 31, 2013, the Company reclassified $27 million in 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] During the three months ended March 31, 2012, the Company also reclassified $69 million in 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.