Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011		Jun. 30, 2011		Mar. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ (308)	[1]		$ (350)	[2]	$ (445)	[3]
Collectively evaluated for impairment	1,585	[1]		1,767	[2]	2,037	[3]
Loans acquired with deteriorated credit quality	2	[1]		2	[2]	2	[3]
Unallocated	121	[1]		136	[2]	130	[3]
Total allowance for loan and lease losses	2,016	[4]	2,126	2,255	[4]	2,614	[4]	2,805	3,004
Individually evaluated for impairment	3,025	[5]		3,002	[6]	2,990	[7]
Collectively evaluated for impairment	79,248	[5]		77,940	[6]	74,904	[7]
Loans acquired with deteriorated credit quality	10	[5]		11	[6]	14	[7]
Total Loans and Leases	82,283	[5],[8],[9]		80,953	[10],[11],[6]	77,908	[12],[13],[7]
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	(116)	[1]		(155)	[2]	(245)	[3]
Collectively evaluated for impairment	1,230	[1]		1,371	[2]	1,518	[3]
Loans acquired with deteriorated credit quality	1	[1]		1	[2]	1	[3]
Total allowance for loan and lease losses	1,347	[1]	1,424	1,527	[2]	1,764	[3]	1,855	1,989
Individually evaluated for impairment	1,198	[5]		1,170	[6]	1,181	[7]
Collectively evaluated for impairment	45,363	[5]		44,299	[6]	42,252	[7]
Loans acquired with deteriorated credit quality	2	[5]		3	[6]	3	[7]
Total Loans and Leases	46,563	[5]		45,472	[6]	43,436	[7]
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	(129)	[1]		(130)	[2]	(126)	[3]
Collectively evaluated for impairment	102	[1]		96	[2]	141	[3]
Loans acquired with deteriorated credit quality	1	[1]		1	[2]	1	[3]
Total allowance for loan and lease losses	232	[1]	233	227	[2]	268	[3]	286	310
Individually evaluated for impairment	1,265	[5]		1,258	[6]	1,220	[7]
Collectively evaluated for impairment	10,080	[5]		9,341	[6]	8,559	[7]
Loans acquired with deteriorated credit quality	8	[5]		8	[6]	11	[7]
Total Loans and Leases	11,353	[5]		10,607	[6]	9,790	[7]
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	(63)	[1]		(65)	[2]	(74)	[3]
Collectively evaluated for impairment	253	[1]		300	[2]	378	[3]
Total allowance for loan and lease losses	316	[1]	341	365	[2]	452	[3]	519	555
Individually evaluated for impairment	562	[5]		574	[6]	589	[7]
Collectively evaluated for impairment	23,805	[5]		24,300	[6]	24,093	[7]
Total Loans and Leases	24,367	[5]		24,874	[6]	24,682	[7]
Unallocated (Member)
Financing Receivable, Allowance for Credit Losses [Line Items]
Unallocated	121	[1]		136	[2]	130	[3]
Total allowance for loan and lease losses	$ 121	[1]	$ 128	$ 136	[2]	$ 130	[3]	$ 145	$ 150

[1] Includes $15 related to leveraged leases.

[2] Includes $14 related to leveraged leases.

[3] Includes $18 related to leveraged leases.

[4] Includes $9, $30 and $42 of cash, $4, $7 and $7of other short-term investments, $51, $50 and $29 of commercial mortgage loans, $0, $223 and $231 of home equity loans, $75, $259 and $424 of automobile loans, ($3), ($10) and ($11) of ALLL, $3, $4 and $4 of other assets, $2, $4 and $8 of other liabilities, $73, $191and $365 of long-term debt from consolidated VIEs that are included in their respective captions above at June 30, 2012, December 31, 2011 and June 30, 2011, respectively. See Note 8.

[5] Excludes $76 of residential mortgage loans measured at fair value, and includes $967 of leveraged leases, net of unearned income.

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

[7] Excludes $59 of residential mortgage loans measured at fair value, includes $1,015 of leveraged leases, net of unearned income.

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

[9] Includes $1 of government insured commercial loans 30-89 days past due and accruing whose repayments are insured by the Small Business Administration at June 30, 2012 and an immaterial amount of government insured commercial loans 90 days past due and still accruing

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

[11] 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.

[12] Excludes $59 of loans measured at fair value.

[13] Includes $1 of government insured loans 30-89 days past due and accruing of government insured commercial loans whose repayments are insured by the Small Business Administration at June 30, 2011 and an immaterial amount of government insured commercial loans 90 days past due and still accruing.