Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (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]
Individually evaluated for impairment	$ 327	[1]	$ 350	[1]	$ 516	[1]
Collectively evaluated for impairment	1,669	[1]	1,767	[1]	2,141	[1]
Loans acquired with deteriorated credit quality	2	[1]	2	[1]	3	[1]
Unallocated	128	[1]	136	[1]	145	[1]
Total allowance for loan and lease losses	2,126	[2]	2,255	[2]	2,805	[2]	3,004
Individually evaluated for impairment	2,975	[3]	3,002	[4]	2,934	[5]
Collectively evaluated for impairment	79,061	[3]	77,940	[4]	74,454	[5]
Loans acquired with deteriorated credit quality	10	[3]	11	[4]	23	[5]
Total Loans and Leases	82,046	[6]	80,953	[4],[7]	77,411	[5],[8]
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	132	[1]	155	[1]	286	[1]
Collectively evaluated for impairment	1,291	[1]	1,371	[1]	1,568	[1]
Loans acquired with deteriorated credit quality	1	[1]	1	[1]	1	[1]
Total allowance for loan and lease losses	1,424	[1]	1,527	[1]	1,855	[1]	1,989
Individually evaluated for impairment	1,158	[3]	1,170	[4]	1,086	[5]
Collectively evaluated for impairment	45,317	[3]	44,299	[4]	42,111	[5]
Loans acquired with deteriorated credit quality	2	[3]	3	[4]	4	[5]
Total Loans and Leases	46,477	[3]	45,472	[4]	43,201	[5]
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	130	[1]	130	[1]	123	[1]
Collectively evaluated for impairment	102	[1]	96	[1]	161	[1]
Loans acquired with deteriorated credit quality	1	[1]	1	[1]	2	[1]
Total allowance for loan and lease losses	233	[1]	227	[1]	286	[1]	310
Individually evaluated for impairment	1,247	[3]	1,258	[4]	1,193	[5]
Collectively evaluated for impairment	9,772	[3]	9,341	[4]	8,272	[5]
Loans acquired with deteriorated credit quality	8	[3]	8	[4]	11	[5]
Total Loans and Leases	11,027	[3]	10,607	[4]	9,476	[5]
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	65	[1]	65	[1]	107	[1]
Collectively evaluated for impairment	276	[1]	300	[1]	412	[1]
Total allowance for loan and lease losses	341	[1]	365	[1]	519	[1]	555
Individually evaluated for impairment	570	[3]	574	[4]	655	[5]
Collectively evaluated for impairment	23,972	[3]	24,300	[4]	24,071	[5]
Loans acquired with deteriorated credit quality					8	[5]
Total Loans and Leases	24,542	[3]	24,874	[4]	24,734	[5]
Unallocated (Member)
Financing Receivable, Allowance for Credit Losses [Line Items]
Unallocated	128	[1]	136	[1]	145	[1]
Total allowance for loan and lease losses	$ 128	[1]	$ 136	[1]	$ 145	[1]	$ 150

[1] Includes $14 related to leveraged leases.

[2] 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.

[3] Excludes $67 of residential mortgage loans measured at fair value, and includes $1,027 of leveraged leases, net of unearned income.

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

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

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

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

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