Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (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]
Individually evaluated for impairment	$ 294	[1]	$ 350	[2]
Collectively evaluated for impairment	1,447	[1]	1,767	[2]
Loans acquired with deteriorated credit quality	2	[1]	2	[2]
Unallocated	111	[1]	136	[2]
Total allowance for loan and lease losses	1,854	[3]	2,255	[3]	3,004	3,749
Individually evaluated for impairment	2,822	[4]	3,002	[5]
Collectively evaluated for impairment	82,877	[4]	77,940	[5]
Loans acquired with deteriorated credit quality	7	[4]	11	[5]
Total Loand and Leases	85,706	[6],[7]	80,953	[5],[8],[9]
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	95	[1]	155	[2]
Collectively evaluated for impairment	1,140	[1]	1,371	[2]
Loans acquired with deteriorated credit quality	1	[1]	1	[2]
Total allowance for loan and lease losses	1,236	[1]	1,527	[2]	1,989	2,517
Individually evaluated for impairment	980	[4]	1,170	[5]
Collectively evaluated for impairment	48,407	[4]	44,299	[5]
Loans acquired with deteriorated credit quality	1	[4]	3	[5]
Total Loand and Leases	49,388	[4]	45,472	[5]
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	137	[1]	130	[2]
Collectively evaluated for impairment	91	[1]	96	[2]
Loans acquired with deteriorated credit quality	1	[1]	1	[2]
Total allowance for loan and lease losses	229	[1]	227	[2]	310	375
Individually evaluated for impairment	1,298	[4]	1,258	[5]
Collectively evaluated for impairment	10,637	[4]	9,341	[5]
Loans acquired with deteriorated credit quality	6	[4]	8	[5]
Total Loand and Leases	11,941	[4]	10,607	[5]
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	62	[1]	65	[2]
Collectively evaluated for impairment	216	[1]	300	[2]
Total allowance for loan and lease losses	278	[1]	365	[2]	555	664
Individually evaluated for impairment	544	[4]	574	[5]
Collectively evaluated for impairment	23,833	[4]	24,300	[5]
Total Loand and Leases	24,377	[4]	24,874	[5]
Unallocated (Member)
Financing Receivable, Allowance for Credit Losses [Line Items]
Unallocated	111	[1]	136	[2]
Total allowance for loan and lease losses	$ 111	[1]	$ 136	[2]	$ 150	$ 193

[1] Includes $11 related to leveraged leases.

[2] Includes $14 related to leveraged leases.

[3] 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.

[4] Excludes $76 of residential mortgage loans measured at fair value, and includes $862 of leveraged leases, net of unearned income.

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

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

[7] 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.

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

[9] 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.