Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011		Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	$ 2,126	[1]	$ 2,255	[1]	$ 2,805	[1]	$ 3,004
Portfolio loans and leases	82,046	[2]	80,953	[3],[4]	77,411	[5],[6]
Leveraged Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	14		14		14
Portfolio loans and leases	1,027		1,022		1,039
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Portfolio loans and leases at fair value	$ 67		$ 65		$ 54

[1] Includes $19, $30 and $54 of cash, $4, $7 and $7of other short-term investments, $50, $50 and $29 of commercial mortgage loans, $217, $223 and $236 of home equity loans, $105, $259 and $529 of automobile loans, ($7), ($10) and ($12) of ALLL, $3, $4 and $5 of other assets, $3, $4 and $10 of other liabilities, $125, $191and $492 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2012, December 31, 2011 and March 31, 2011, respectively. See Note 8.

[2] Excludes $67 of loans measured at fair value.

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

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

[5] Excludes $54 of residential mortgage loans measured at fair value, includes $1,039 of leveraged leases, net of unearned income.

[6] Excludes $54 of loans measured at fair value.