Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009	Dec. 31, 2008
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	$ 2,255	[1]	$ 3,004	[1]	$ 3,749	$ 2,787
Portfolio loans and leases at fair value	65		46
Portfolio loans and leases	80,953	[2]	77,445	[3],[4]
Leveraged Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	14		15
Portfolio loans and leases	1,022,000		1,039,000
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Portfolio loans and leases at fair value	$ 65		$ 46

[1] At December 31, 2011 and 2010, includes $30 and $52 of cash, $7 of other short-term investments, $50 and $29 of commercial mortgage loans, $223 and $241 of home equity loans, $259 and $648 of automobile loans, ($10) and ($14) of ALLL, $4 and $7 of other assets, $4 and $12 of other liabilities, $191 and $692 of long-term debt from consolidated VIEs that are included in their respective captions. See Note 11.

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

[3] Excludes $46 of residential mortgage loans measured at fair value, and includes $1,039 of leveraged leases, net of unearned income.

[4] Excludes $46 of loans measured at fair value.