Impacts of Derivative Financial Instruments on the Consolidated Statements of Income/(Loss) and the Consolidated Statements of Shareholders' Equity (Detail) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2015		Sep. 30, 2014
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 318		$ 132		$ 438		$ 330
Interest Income [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	23				61
Other Trading [Member] | Other Trading [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	5		9		46		34
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	21		44		57		43
Other Trading [Member] | Credit Risk Contract [Member] | Other Trading [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	6		4		19		13
Other Trading [Member] | Equity Contract [Member] | Other Trading [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0		1		3		4
Other Trading [Member] | Other Contract [Member] | Other Trading [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1				2
Mortgage Servicing Income [Member] | Mortgage Servicing Rights [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	298		17		223		138
Mortgage Production Income [Member] | Loans [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(69)		4		(60)		(92)
Mortgage Production Income [Member] | Other Contract [Member] | Loans [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	58		52		151		190
Other Income [Member] | Loans [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(2)				(2)
Other Income [Member] | Credit Risk Contract [Member] | Loans [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0		1		(1)		0
Cash Flow Hedging [Member] | Interest Income [Member] | Interest Rate Contract [Member] | Adjustable Rate Loans [Member]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	204	[1]	(31)	[2]	338		36
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	47	[1]	76	[2]	126	[1]	225	[2]
Fair Value Hedging | Other Trading [Member] | Interest Rate Contract [Member] | Fixed Income Interest Rate [Member]
Derivative, Gain (Loss) on Derivative, Net	0	[3]	(7)	[4]	7	[3]	10	[4]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(1)	[3]	7	[4]	(8)	[3]	(9)	[4]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	$ (1)	[3]	$ 0		$ (1)		$ 1	[4]

[1] During the three and nine months ended September 30, 2015, the Company also reclassified $23 million and $61 million, respectively, of pre-tax gains from AOCI into net interest income. These gains related to hedging relationships that have been terminated or de-designated and are reclassified into earnings consistent with the pattern of net cash flows expected to be recognized.

[2] During the three and nine months ended September 30, 2014, the Company also reclassified $23 million and $77 million, respectively, of pre-tax gains from AOCI into net interest income. These gains related to hedging relationships that have been terminated or de-designated and are reclassified into earnings consistent with the pattern of net cash flows expected to be recognized.

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

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