Loans and Leases (Troubled Debt Restructurings) (Details) - Class of Financing Receivable $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) Contract	Sep. 30, 2014 USD ($) Contract	Sep. 30, 2015 USD ($) Contract	Sep. 30, 2014 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | Contract	26	34	106	108,000,000
Recorded Investment	$ 7.6	$ 21.3	$ 24.7	$ 29.5
Unpaid Principal Balance	$ 9.4	$ 22.5	$ 30.5	$ 32.3
Commercial
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | Contract	0	6	3	9,000,000
Recorded Investment	$ 0.0	$ 3.3	$ 0.9	$ 4.2
Unpaid Principal Balance	$ 0.0	$ 3.8	$ 0.9	$ 4.9
Commercial | Commercial and Institutional
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | Contract	0	1	2	3,000,000
Recorded Investment	$ 0.0	$ 0.4	$ 0.1	$ 0.7
Unpaid Principal Balance	$ 0.0	$ 0.4	$ 0.1	$ 0.8
Commercial | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | Contract	0	5	1	6,000,000
Recorded Investment	$ 0.0	$ 2.9	$ 0.8	$ 3.5
Unpaid Principal Balance	$ 0.0	$ 3.4	$ 0.8	$ 4.1
Personal
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | Contract	26	28	103	99,000,000
Recorded Investment	$ 7.6	$ 18.0	$ 23.8	$ 25.3
Unpaid Principal Balance	$ 9.4	$ 18.7	$ 29.6	$ 27.4
Personal | Residential Real Estate
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | Contract	26	28	102	96,000,000
Recorded Investment	$ 7.6	$ 18.0	$ 23.2	$ 25.3
Unpaid Principal Balance	$ 9.4	$ 18.7	$ 29.0	$ 27.1
Personal | Private Client
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | Contract	0	0	1	3,000,000
Recorded Investment	$ 0.0	$ 0.0	$ 0.6	$ 0.0
Unpaid Principal Balance	$ 0.0	$ 0.0	$ 0.6	$ 0.3