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				6 Months Ended
	Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 217		$ (86)		$ 371		$ 120
Other Trading [Member] | Other Trading [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(3)		25		13		40
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	34		(20)		16		36
Other Trading [Member] | Credit Risk Contract [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	5		7		10		13
Other Trading [Member] | Equity Contract [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1		0		3		3
Other Trading [Member] | Commodity Contract [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1		1		1		1
Mortgage Servicing Income [Member] | Mortgage Servicing Rights [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	122		(163)		292		(74)
Mortgage Production Income [Member] | Loans [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(65)		52		(127)		9
Mortgage Production Income [Member] | Other Contract [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	124		12		168		93
Other Income [Member] | Loans [Member]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(1)				(3)
Other Income [Member] | Credit Risk Contract [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(1)		0		(2)		(1)
Cash Flow Hedging [Member] | Interest Income [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	180		9		487		134
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	38	[1]	44	[2]	77	[1]	79	[2]
Fair Value Hedging | Other Trading [Member]
Derivative, Gain (Loss) on Derivative, Net	32	[3]	(8)	[4]	31	[3]	7	[4]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(33)	[3]	7	[4]	(31)	[3]	(7)	[4]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	(1)	[3]	(1)	[4]	0		0
Fair Value Hedging | Other Trading [Member] | Fixed Income Interest Rate [Member]
Derivative, Gain (Loss) on Derivative, Net	32	[3]	(8)	[4]	31	[3]	7	[4]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(33)	[3]	7	[4]	(31)	[3]	(7)	[4]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	(1)	[3]	(1)	[4]	0		0
Fair Value Hedging | Other Trading [Member] | Brokered Time Deposits [Member]
Derivative, Gain (Loss) on Derivative, Net	0		0		0		0
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0		0		0		0
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	$ 0		$ 0		$ 0		$ 0

[1] During the three and six months ended June 30, 2016, the Company also reclassified $26 million and $54 million 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 six months ended June 30, 2015, the Company also reclassified $19 million and $38 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.