Loans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans transferred from loans held for sale to loans					$ 31		$ 46
Value of loans transferred from LHFI to LHFS					1,116		198
Loans held for investment sold	454		277		454		277
Gain on sale of loans held for investment					23		10
PrincipalForgivenessRestructuringImpact	1		8		1		9
Loans and Leases Receivable, Impaired, Commitment to Lend	4				4				5
Concentration of credit risk, maximum exposure, percentage of total loans	37.00%				37.00%
Financing Receivable, Amount Restructured During Period, Principal Forgiveness Granted	7	[1]	26	[2]	14	[1]	76	[2]
Lower Limit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum amount of modified loan in a TDR to evaluate individually for impairment	3				3
Guaranteed Student Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Student loan portfolio percentage current	79.00%				79.00%				79.00%
Accrual Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing TDRs included in impaired loan balances	2,600				2,600				2,576
Accruing TDRs current	94.00%				94.00%				93.00%
Cross-Border Outstanding Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure	680				680				630
Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure, percentage of total loans									38.00%
Concentration of credit risk, maximum exposure	46,200				46,200				46,700
Government guaranteed percent	12.00%				12.00%				14.00%
Residential Mortgage | Risk Level, High
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure	14,200				14,200				14,700
Commitments to Extend Credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure	12,200				12,200				12,700
Loan Origination Commitments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure	9,100				9,100				7,800
Interest Only Loans | Risk Level, High
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure	8,700				8,700				9,400
Interest Only Loans, High LTV First Lien and Junior Lien, With No Mortgage Insurance [Member] | Risk Level, High
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure	1,700				1,700				1,900
Amortizing Loans, High LTV First Lien and Junior Lien, With No Mortgage Insurance [Member] | Risk Level, High
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk, maximum exposure	$ 5,500				$ 5,500				$ 5,278

[1] Restructured loans which had forgiveness of amounts contractually due under the terms of the loan typically have had multiple concessions including rate modifications and/or term extensions. The total amount of charge-offs associated with principal forgiveness was $1 million during both the three and six months ended June 30, 2012.

[2] Restructured loans which had forgiveness of amounts contractually due under the terms of the loan typically have had multiple concessions including rate modifications and/or term extensions. The total amount of charge-offs associated with principal forgiveness during the three and six months ended June 30, 2011 was $8 million and $9 million, respectively.