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				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Interest Income, Interest and Fees on Loans
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 100		$ 121		$ 214		$ 272
Cash Flow Hedging
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(45)		14		(45)		6
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	79		83		166		166
Cash Flow Hedging | Equity Contract [Member] | Available-for-sale Securities [Member]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			(103)				(161)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0				0
Cash Flow Hedging | Interest Income, Interest and Fees on Loans | Interest Rate Contract [Member] | forecasted debt [Member]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(2)				(2)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0				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	(43)	[1]	117	[2]	(43)	[1]	167	[2]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	79	[1]	83	[2]	166	[1]	166	[2]
Fair Value Hedging
Derivative Instruments, Gain (Loss) Recognized in Income, Net			8	[3]			8	[3]
Amount of gain on related Hedged Items recognized in Income			(8)	[3]			(8)	[3]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0				0
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			0				1	[3]
Amount of gain on related Hedged Items recognized in Income			0				(1)	[3]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0				0
Fair Value Hedging | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Fixed Rate Debt
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(18)	[3]	8	[3]	(23)	[3]	7	[3]
Amount of gain on related Hedged Items recognized in Income	18	[3]	(8)	[3]	24	[3]	(7)	[3]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	[3]	0		1	[3]	0
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	42		557		150		686
Not Designated as Hedging Instrument [Member] | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Fixed Rate Debt
Derivative Instruments, Gain (Loss) Recognized in Income, Net	2		(2)		2		(1)
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	18		27		26		54
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	14		11		26		14
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	(3)		115		(1)		130
Not Designated as Hedging Instrument [Member] | Trading Account Profits And Commissions [Member] | Credit Risk Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net							(3)
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	5		6		10		12
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	(16)		10		(15)		13
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	(158)		269		(214)		196
Not Designated as Hedging Instrument [Member] | Mortgage Production Income [Member] | Interest Rate Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	256		(135)		291		(170)
Not Designated as Hedging Instrument [Member] | Mortgage Production Income [Member] | Other Contract | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(75)		257		27		442
Not Designated as Hedging Instrument [Member] | Other Income [Member] | Credit Risk Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ (1)		$ (1)		$ (2)		$ (4)	[4]

[1] During the three and six months ended June 30, 2013, the Company also reclassified $21 million and $48 million, respectively, 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.

[2] During the three and six months ended June 30, 2012, the Company also reclassified $37 million and $105 million, respectively, 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] Amounts are recognized in trading income in the Consolidated Statements of Income.

[4] For the six months ended June 30, 2012, losses of $3 million were recorded in trading income.