Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2009
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	$ 1,854	[1]	$ 2,255	[1]	$ 3,004	$ 3,749
Notes Receivable Net	85,706	[2],[3]	80,953	[4],[5],[6]
Leveraged Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	11		14
Portfolio loans and leases at fair value	862		1,022
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Portfolio loans and leases at fair value	$ 76		$ 65

[1] At December 31, 2012 and 2011, includes $0 and $30 of cash, $0 and $7 of other short-term investments, $50 and $50 of commercial mortgage loans, $0 and $223 of home equity loans, $0 and $259 of automobile loans, ($5) and ($10) of ALLL, $3 and $4 of other assets, $0 and $4 of other liabilities, $0 and $191 of long-term debt from consolidated VIEs that are included in their respective captions. See Note 10.

[2] Excludes $76 of loans measured at fair value.

[3] Includes an immaterial amount of government insured commercial loans 30-89 days and 90 days past due and accruing whose repayments are insured by the Small Business Administration at December 31, 2012.

[4] Excludes $65 of residential mortgage loans measured at fair value, and includes $1,022 of leveraged leases, net of unearned income.

[5] Excludes $65 of loans measured at fair value.

[6] Includes an immaterial amount of government insured commercial loans 30-89 and 90 days past due and accruing whose repayments are insured by the Small Business Administration at December 31, 2011.