Loans Held for Sale - Loans Held for Sale (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	$ 1,056	$ 3,670
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	443	965
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	613	2,705
Consumer Loans [Member] \| Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	548	2,058
Consumer Loans [Member] \| Credit Card Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale		416
Consumer Loans [Member] \| Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	$ 65	$ 231

The aggregate carrying amount of loans receivable that will be sold to other entities. Includes mortgage and all other loans (collectively, loans) not classified as held for investment. Such loans are stated at the lower of cost or market, or elected fair value. Mortgage loans exclude mortgage-backed securities which are considered a debt security (other loan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 4, 5, 6, 7, 9, 12, 28, 29

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

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+ Details