Change in Fair Value of Financial Instruments for which the FVO has been Elected (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Gain (Loss) on Sales of Loans, Net	$ 3		$ 30		$ 7		$ 36
Trading Account Assets [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	2	[1]	8	[2]	6	[1]	16	[2]
Trading Account Assets [Member] | Trading Account Profits And Commissions [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	2		8		6		16
Trading Account Assets [Member] | Mortgage Production Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Trading Account Assets [Member] | Mortgage Servicing Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Loans Held-for-Sale
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(87)	[1]	28	[2]	(106)	[1]	18	[2]
Loans Held-for-Sale | Trading Account Profits And Commissions [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(1)		(2)		1		5
Loans Held-for-Sale | Mortgage Production Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(86)	[3]	30	[4]	(107)	[3]	13	[4]
Loans Held-for-Sale | Mortgage Servicing Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Loans Held For Investment [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(6)	[1]	6	[2]	(9)	[1]	3	[2]
Loans Held For Investment [Member] | Trading Account Profits And Commissions [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		1		0		1
Loans Held For Investment [Member] | Mortgage Production Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	(6)	[3]	5	[4]	(9)	[3]	2	[4]
Loans Held For Investment [Member] | Mortgage Servicing Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Mortgage Servicing Rights [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	82	[1]	(261)	[2]	100	[1]	(184)	[2]
Mortgage Servicing Rights [Member] | Trading Account Profits And Commissions [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Mortgage Servicing Rights [Member] | Mortgage Production Income [Member]
Gain (Loss) on Sales of Loans, Net	1		20		2		30
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	1	[3]	20	[4]	2	[3]	30	[4]
Mortgage Servicing Rights [Member] | Mortgage Servicing Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	81		(281)		98		(214)
Brokered Deposits [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	2	[1]	7	[2]	4	[1]	7	[2]
Brokered Deposits [Member] | Trading Account Profits And Commissions [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	2		7		4		7
Brokered Deposits [Member] | Mortgage Production Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Brokered Deposits [Member] | Mortgage Servicing Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Long-term Debt [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	37	[1]	(10)	[2]	27	[1]	(14)	[2]
Long-term Debt [Member] | Trading Account Profits And Commissions [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	37		(10)		27		(14)
Long-term Debt [Member] | Mortgage Production Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	0		0		0		0
Long-term Debt [Member] | Mortgage Servicing Income [Member]
Fair Value Gain/(Loss) for Items Measured at Fair Value Pursuant to Election of the Fair Value Option	$ 0		$ 0		$ 0		$ 0

[1] Changes in fair value for the three and six months ended June 30, 2013 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 recognized in interest income or interest expense in the Consolidated Statements of Income.

[2] Changes in fair value for the three and six months ended June 30, 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 recognized in interest income or interest expense in the Consolidated Statements of Income.

[3] Income related to LHFS does not include income from IRLCs. For the three and six months ended June 30, 2013, income related to MSRs includes $1 million and $2 million of MSRs recognized upon the sale of loans reported at LOCOM.

[4] Income related to LHFS does not include income from IRLCs. For the three and six months ended June 30, 2012, income related to MSRs includes $20 million and $30 million of MSRs recognized upon the sale of loans reported at LOCOM.