Loan and Lease Segment and Class Balances Segregated by Borrower Ratings into "1 to 3", "4 to 5" and "6 to 9" (Watch List) Categories (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	$ 29,156.3	$ 29,063.9
Commercial
Financing Receivable, Recorded Investment [Line Items]
Commercial and Institutional	7,088.4	6,918.7
Commercial Real Estate	2,997.4	2,981.7
Lease Financing, net	1,018.2	978.8
Non-U.S.	1,110.9	1,057.5
Other	470.6	417.6
Total Loans and Leases	12,685.5	12,354.3
Personal
Financing Receivable, Recorded Investment [Line Items]
Residential Real Estate	10,612.7	10,708.9
Private Client	5,409.6	5,651.4
Other	448.5	349.3
Total Loans and Leases	16,470.8	16,709.6
1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	12,579.4	12,567.0
1 to 3 Category \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Commercial and Institutional	3,826.9	3,681.8
Commercial Real Estate	1,194.8	1,247.1
Lease Financing, net	747.0	547.7
Non-U.S.	511.2	519.0
Other	240.8	241.4
Total Loans and Leases	6,520.7	6,237.0
1 to 3 Category \| Personal
Financing Receivable, Recorded Investment [Line Items]
Residential Real Estate	2,742.0	2,777.1
Private Client	3,126.7	3,390.6
Other	190.0	162.3
Total Loans and Leases	6,058.7	6,330.0
4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	15,646.4	15,556.0
4 to 5 Category \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Commercial and Institutional	3,082.9	3,029.1
Commercial Real Estate	1,526.0	1,467.2
Lease Financing, net	257.9	422.3
Non-U.S.	589.5	527.3
Other	229.8	176.2
Total Loans and Leases	5,686.1	5,622.1
4 to 5 Category \| Personal
Financing Receivable, Recorded Investment [Line Items]
Residential Real Estate	7,442.0	7,501.0
Private Client	2,259.8	2,245.9
Other	258.5	187.0
Total Loans and Leases	9,960.3	9,933.9
6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	930.5	940.9
6 to 9 Category (Watch List) \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Commercial and Institutional	178.6	207.8
Commercial Real Estate	276.6	267.4
Lease Financing, net	13.3	8.8
Non-U.S.	10.2	11.2
Total Loans and Leases	478.7	495.2
6 to 9 Category (Watch List) \| Personal
Financing Receivable, Recorded Investment [Line Items]
Residential Real Estate	428.7	430.8
Private Client	23.1	14.9
Total Loans and Leases	$ 451.8	$ 445.7

The total gross amount of commercial loans (money lent to commercial entities rather than consumers) made in the form of direct financing leases where the reporting entity (lessor) only recognizes interest revenue from the lease. It also includes the amount of lease financing arising from involvement with leveraged lease transactions where the Entity is in the position of long-term creditor.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

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-Publisher SEC

-Name Regulation S-X (SX)

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

-Publisher AICPA

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

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Leveraged Lease

-URI http://asc.fasb.org/extlink&oid=6516780

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

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-Topic 310

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+ Details

- Definition

Reflects the net carrying amount of foreign loans and leases held in portfolio, after deducting deferred income, but before deducting the allowance for losses on foreign loans and leases.

+ References+ Details

- Definition

Reflects the aggregate gross carrying amount of all categories of loans and leases held in portfolio, after deducting deferred income, but before deducting the allowance for losses on loans and leases.

+ References+ Details

- Definition

The gross amount of other loans and leases not otherwise specified in the taxonomy.

+ References+ Details

- Definition

Reflects the sum of the gross carrying amounts of unpaid loans issued to businesses to provide financing for cash needs, financial asset purchases, or farm-related purposes. Includes all loans not included in another category. This category includes, but is not limited to, loans to real estate investment trusts; mortgage companies, banks, and other financial institutions; loans for carrying securities; and loans for agricultural purposes. This element does not include loans secured primarily by developed real estate.

+ References

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

-Publisher AICPA

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-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.

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

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

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

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+ Details

- Definition

Reflects the sum of the gross carrying amounts of unpaid loans issued to businesses to acquire, develop, construct, improve, or refinance land or a building. Includes [but is not limited to] commercial mortgage loans, which are secured by a [legal] security interest in real property [commercial building or business real property] which thereby serves as collateral securing repayment of the loan; and construction financing, which is an obligation generally in the form of a [promissory] note, used for the funding of construction projects.

+ References

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

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+ Details