Change in Fair Value of Financial Instruments for which the FVO has been Elected (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Gain (Loss) on Sales of Loans, Net	$ 3		$ 22
Trading Account Assets [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	8	[1]	21	[2]	(3)	[3]
Loans Held-for-Sale
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	1,053	[1]	440	[2]	594	[3]
Loans Held For Investment [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	21	[1]	14	[2]	7	[3]
Mortgage Servicing Rights [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(322)	[1]	(726)	[2]	(498)	[3]
Brokered Deposits
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	5	[1]	32	[2]	(62)	[3]
Long-term Debt [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(65)	[1]	(12)	[2]	(168)	[3]
Trading Account Profits And Commissions [Member] | Trading Account Assets [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	8		21		(3)
Trading Account Profits And Commissions [Member] | Loans Held-for-Sale
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	10		(10)		26
Trading Account Profits And Commissions [Member] | Loans Held For Investment [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	1		3		0
Trading Account Profits And Commissions [Member] | Mortgage Servicing Rights [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Trading Account Profits And Commissions [Member] | Brokered Deposits
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	5		32		(62)
Trading Account Profits And Commissions [Member] | Long-term Debt [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(65)		(12)		(168)
Mortgage Production Income [Member] | Trading Account Assets [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Mortgage Production Income [Member] | Loans Held-for-Sale
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	1,043	[4]	450	[5]	568	[6]
Mortgage Production Income [Member] | Loans Held For Investment [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	20	[4]	11	[5]	7	[6]
Mortgage Production Income [Member] | Mortgage Servicing Rights [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	31	[4]	7	[5]	15	[6]
Mortgage Production Income [Member] | Brokered Deposits
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Mortgage Production Income [Member] | Long-term Debt [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Mortgage Servicing Income [Member] | Trading Account Assets [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Mortgage Servicing Income [Member] | Loans Held-for-Sale
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Mortgage Servicing Income [Member] | Loans Held For Investment [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Mortgage Servicing Income [Member] | Mortgage Servicing Rights [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(353)		(733)		(513)
Mortgage Servicing Income [Member] | Brokered Deposits
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Mortgage Servicing Income [Member] | Long-term Debt [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0
Nondesignated
Derivative Instruments, Gain (Loss) Recognized in Income, Net	1,134		779		767
Loans | Nondesignated | Other Contract | Mortgage Production Income [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	930		355		392
Loans Held-for-Sale
Gain (Loss) on Sales of Loans, Net	$ 882		$ 271

[1] Changes in fair value for the year ended December 31, 2012, exclude accrued interest for the period then ended. Interest income or interest expense on trading loans, LHFS, LHFI, brokered time deposits, and long-term debt that have been elected to be carried at fair value are recorded in interest income or interest expense in the Consolidated Statements of Income.

[2] Changes in fair value for the year ended December 31, 2011, exclude accrued interest for the period then ended. Interest income or interest expense on trading loans, LHFS, LHFI, brokered time deposits, and long-term debt that have been elected to be carried at fair value are recorded in interest income or interest expense in the Consolidated Statements of Income.

[3] Changes in fair value for the year ended December 31, 2010, exclude accrued interest for the periods then ended. Interest income or interest expense on trading loans, LHFS, LHFI, brokered time deposits, and long-term debt that have been elected to be carried at fair value are recorded in interest income or interest expense in the Consolidated Statements of Income.

[4] For the year ended December 31, 2012, income related to LHFS includes $882 million from IRLCs, which includes $304 million related to MSRs recognized upon the sale of loans reported at fair value. For the year ended December 31, 2012, income related to MSRs includes $31 million of MSRs recognized upon the sale of loans reported at LOCOM.

[5] For the year ended December 31, 2011, income related to LHFS includes $271 million from IRLCs, which includes $217 million related to MSRs recognized upon the sale of loans reported at fair value. For the year ended December 31, 2011, income related to MSRs includes $7 million of MSRs recognized upon the sale of loans reported at LOCOM.

[6] For the year ended December 31, 2010, income related to LHFS includes $392 million from IRLCs, which includes $274 million related to MSRs recognized upon the sale of loans reported at fair value. For the year ended December 31, 2010, income related to MSRs includes $15 million of MSRs recognized upon the sale of loans reported at LOCOM.