Change in Fair Value of Financial Instruments for which the FVO has been Elected (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Trading Account Assets
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	$ 8	[1]	$ 7	[2]
Loans Held-for-Sale
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	162	[1]	32	[2]
Mortgage Servicing Rights
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	77	[1]	19	[2]
Brokered Deposits
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		(11)	[2]
Long-term Debt [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(4)	[1]	(17)	[2]
Loans Held For Investment [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(3)	[1]	(1)	[2]
Trading Account Profits And Commissions [Member] | Trading Account Assets
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	8		7
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	7		2
Trading Account Profits And Commissions [Member] | Mortgage Servicing Rights
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	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	0		(11)
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	(4)		(17)
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	0		3
Mortgage Production Income [Member] | Trading Account Assets
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	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	155	[3]	30	[4]
Mortgage Production Income [Member] | Mortgage Servicing Rights
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	10	[3]	2	[4]
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
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
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	(3)	[3]	(4)	[4]
Mortgage Servicing Income [Member] | Trading Account Assets
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	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
Mortgage Servicing Income [Member] | Mortgage Servicing Rights
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	67		17
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
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
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

[1] Changes in fair value for the three months ended March 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 three months ended March 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] For the three months ended March 31, 2012, income related to LHFS includes $73 million related to MSRs recognized upon the sale of loans reported at fair value. For the three months ended March 31, 2012, income related to MSRs includes $10 million of MSRs recognized upon the sale of loans reported at LOCOM.

[4] For the three months ended March 31, 2011, income related to LHFS includes $86 million related to MSRs recognized upon the sale of loans reported at fair value. For the three months ended March 31, 2011, income related to MSRs includes $2 million of MSRs recognized upon the sale of loans reported at LOCOM. These MSRs are included in the table since the Company elected to report MSRs recognized in 2009 and beyond using the fair value method. Previously, MSRs were reported under the amortized cost method.