Summary of Loans Modified in a TDR (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended
Sep. 30, 2011 years number	Sep. 30, 2011 Commercial Portfolio Segment CommercialAndIndustrialLoansMember [Member] number	Sep. 30, 2011 Commercial Portfolio Segment CommercialAndIndustrialLoansMember [Member] Quarterly [Member] number	Sep. 30, 2011 Commercial Portfolio Segment Commercial Mortgage Loans Owner Occupied [Member] number	Sep. 30, 2011 Commercial Portfolio Segment Commercial Mortgage Loans Owner Occupied [Member] Quarterly [Member] number	Sep. 30, 2011 Commercial Portfolio Segment Commercial Mortgage Loans Non Owner Occupied [Member] number	Sep. 30, 2011 Commercial Portfolio Segment Commercial Mortgage Loans Non Owner Occupied [Member] Quarterly [Member] number	Sep. 30, 2011 Commercial Portfolio Segment Commercial Construction number	Sep. 30, 2011 Commercial Portfolio Segment Commercial Construction Quarterly [Member] number	Sep. 30, 2011 Commercial Portfolio Segment Commercial Leases [Member] number	Sep. 30, 2011 Consumer Portfolio Segment Home Equity number	Sep. 30, 2011 Consumer Portfolio Segment Home Equity Quarterly [Member] number	Sep. 30, 2011 Consumer Portfolio Segment Automobile Loans number	Sep. 30, 2011 Consumer Portfolio Segment Automobile Loans Quarterly [Member] number	Sep. 30, 2011 Consumer Portfolio Segment Credit Card number	Sep. 30, 2011 Consumer Portfolio Segment Credit Card Quarterly [Member] number	Sep. 30, 2011 Residential Mortgage Loans number	Sep. 30, 2011 Residential Mortgage Loans Quarterly [Member] number	Sep. 30, 2011 Quarterly [Member] number
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	12,684	35	7	15	7	28	15	9	4	2	999	347	1,135	371	9,188	2,781	1,273	384	3,916
Recorded Investment in Loans Modified in a TDR During the Period	$ 651	$ 113	$ 33	$ 20	$ 5	$ 77	$ 44	$ 43	$ 22	$ 0	$ 61	$ 21	$ 21	$ 7	$ 61	$ 17	$ 255	$ 79	$ 228
Increase (Decrease) to ALLL Upon Modification	13	2	(2)	(6)	(4)	(17)	(4)	(4)	0	0	1	1	2	1	9	2	26	8	2
Charge-offs Recognized Upon Modification	$ 11	$ 1	$ 0	$ 7	$ 0	$ 3	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0

Reflects the net amount of other additions and reductions in the reserve for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 7

-Subparagraph d

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5212-111524

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesAdjustmentsNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reflects the amount of loans and leases that have been removed, or charged off, from both loan receivables and the reserve for credit losses, typically because they are considered to be not salvageable or have been purchased by unconsolidated collection entities.

+ References

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 32

-URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953670-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts
Namespace Prefix:	us-gaap
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings after the financing receivable has been modified.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant