Loans and Leases - Troubled Debt Restructurings (Detail) - Lease Financing, net $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($) Contract	Dec. 31, 2018 USD ($) Contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	48	52
Troubled debt restructurings, recorded investment	$ 44.9	$ 30.8
Troubled debt restructurings, unpaid principal balance	$ 47.6	$ 34.2
Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	3	3
Troubled debt restructurings, recorded investment	$ 7.5	$ 3.1
Troubled debt restructurings, unpaid principal balance	$ 8.8	$ 3.3
Commercial \| Commercial and Institutional
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	1	1
Troubled debt restructurings, recorded investment	$ 7.5	$ 0.3
Troubled debt restructurings, unpaid principal balance	$ 8.8	$ 0.5
Commercial \| Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	2	2
Troubled debt restructurings, recorded investment	$ 0.0	$ 2.8
Troubled debt restructurings, unpaid principal balance	$ 0.0	$ 2.8
Personal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	45	49
Troubled debt restructurings, recorded investment	$ 37.4	$ 27.7
Troubled debt restructurings, unpaid principal balance	$ 38.8	$ 30.9
Personal \| Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	45	48
Troubled debt restructurings, recorded investment	$ 37.4	$ 27.7
Troubled debt restructurings, unpaid principal balance	$ 38.8	$ 30.8
Personal \| Private Client
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans or leases modified in trouble debt restructuring \| Contract	0	1
Troubled debt restructurings, recorded investment	$ 0.0	$ 0.0
Troubled debt restructurings, unpaid principal balance	$ 0.0	$ 0.1

Financing Receivable, Modifications, Recorded Investment, Modified During Period

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- Definition

Financing Receivable, Modifications, Unpaid Principal Balance

+ References

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- Definition

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+ References

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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