Loans and Leases (Troubled Debt Restructurings) (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021 USD ($) contract	Sep. 30, 2020 USD ($) contract	Sep. 30, 2021 USD ($) contract	Sep. 30, 2020 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
NUMBER OF LOANS AND LEASES \| contract	1	11	16	19
RECORDED INVESTMENT	$ 0.2	$ 18.4	$ 48.9	$ 43.6
UNPAID PRINCIPAL BALANCE	$ 0.2	$ 18.5	55.3	$ 44.2
Residential Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
RECORDED INVESTMENT			0.1
UNPAID PRINCIPAL BALANCE			$ 0.1
Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
NUMBER OF LOANS AND LEASES \| contract	0	1	8	3
RECORDED INVESTMENT	$ 0.0	$ 1.0	$ 47.9	$ 25.3
UNPAID PRINCIPAL BALANCE	$ 0.0	$ 1.0	$ 54.1	$ 25.5
Commercial \| Commercial and Institutional
Financing Receivable, Troubled Debt Restructuring [Line Items]
NUMBER OF LOANS AND LEASES \| contract	0	1	6	3
RECORDED INVESTMENT	$ 0.0	$ 1.0	$ 19.6	$ 25.3
UNPAID PRINCIPAL BALANCE	$ 0.0	$ 1.0	$ 19.6	$ 25.5
Commercial \| Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
NUMBER OF LOANS AND LEASES \| contract	0		2
RECORDED INVESTMENT	$ 0.0		$ 28.3
UNPAID PRINCIPAL BALANCE	$ 0.0		$ 34.5
Personal
Financing Receivable, Troubled Debt Restructuring [Line Items]
NUMBER OF LOANS AND LEASES \| contract	1	10	8	16
RECORDED INVESTMENT	$ 0.2	$ 17.4	$ 1.0	$ 18.3
UNPAID PRINCIPAL BALANCE	$ 0.2	$ 17.5	$ 1.2	$ 18.7
Personal \| Residential Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
NUMBER OF LOANS AND LEASES \| contract	1	10	8	16
RECORDED INVESTMENT	$ 0.2	$ 17.4	$ 1.0	$ 18.3
UNPAID PRINCIPAL BALANCE	$ 0.2	$ 17.5	$ 1.2	$ 18.7

Financing Receivable, Troubled Debt Restructuring, Postmodification, Unpaid Principal Balance

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- 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.

+ References

No definition available.

+ Details

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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=123577603&loc=SL6953676-111524

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- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

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