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, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Cash Flow Hedging
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			$ (45)				$ (45)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			79				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			(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	44	[1]	(43)	[2]	67	[1]	(43)	[2]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	74	[1]	79	[2]	149	[1]	166
Fair Value Hedging | Trading Account Profits And Commissions [Member] | Interest Rate Contract [Member] | Fixed Rate Debt
Derivative Instruments, Gain (Loss) Recognized in Income, Net	8	[3]	(18)	[3]	17	[3]	(23)	[3]
Amount of gain on related Hedged Items recognized in Income	(7)	[3]	18	[3]	(16)	[3]	24	[3]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1	[3]	0		1	[3]	1	[3]
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	93		42		198		150
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	(1)		2		(1)		2
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	12		18		26		26
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	(7)		14		(1)		26
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)				(1)
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		9		10
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	2		(16)		3		(15)
Not Designated as Hedging Instrument [Member] | Other Income [Member] | Credit Risk Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	0		(1)		(1)		(2)
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	66		(158)		120		(214)
Not Designated as Hedging Instrument [Member] | Mortgage Production Income [Member] | Interest Rate Contract [Member] | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(61)		256		(95)		291
Not Designated as Hedging Instrument [Member] | Mortgage Production Income [Member] | Other Contract | Loans
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ 78		$ (75)		$ 138		$ 27

[1] During the three and six months ended June 30, 2014, the Company also reclassified $27 million and $54 million, respectively, 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, 2013, the Company also reclassified $21 million and $48 million, respectively, 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.