LHFI by Credit Quality Indicator (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 124,340	[1]	$ 121,470	[1]
Residential Guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,527		4,252
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	24,106	[2],[3]	23,389	[2],[4]
Federally Guaranteed Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	5,489		5,357
FICO Score 700 and Above [Member] | Residential Guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,500		4,300
FICO Score 700 and Above [Member] | Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 18,593	[2]	$ 17,410	[2]

[1] 2 Includes loans of consolidated VIEs336 365

[2] Excludes $3.5 billion and $4.3 billion at September 30, 2013 and December 31, 2012, respectively, of guaranteed residential loans. At September 30, 2013 and December 31, 2012, the majority of these loans had FICO scores of 700 and above.

[3] 1Includes $316 million of loans carried at fair value, the majority of which were accruing current.

[4] Includes $379 million of loans carried at fair value, the majority of which were accruing current.