LHFI by Credit Quality Indicator (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 122,031	[1]	$ 121,470	[1]
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	23,341	[2]	23,389	[2]
Guaranteed Student Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	5,400		5,400
FICO Score 700 and Above [Member] | Residential Guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,600		4,300
FICO Score 700 and Above [Member] | Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 17,671	[2]	$ 17,410	[2]

[1] 2 Includes loans of consolidated VIEs345 365

[2] Excludes $3.6 billion and $4.3 billion at June 30, 2013 and December 31, 2012, respectively, of guaranteed residential loans. At June 30, 2013 and December 31, 2012, the majority of these loans had FICO scores of 700 and above.