Loans and Leases (Loans and Leases) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	$ 33,378.4	$ 31,640.2
Allowance for Credit Losses Assigned to Loans and Leases	(242.2)	(267.0)
Net Loans and Leases	33,136.2	31,373.2
Commercial
Financing Receivable, Recorded Investment [Line Items]
Commercial and Institutional	9,478.6	8,381.9
Commercial Real Estate	3,814.6	3,333.3
Lease Financing, net	807.2	916.3
Non-U.S.	1,250.2	1,530.6
Other	166.8	191.5
Total Loans and Leases	15,517.4	14,353.6
Allowance for Credit Losses Assigned to Loans and Leases	(130.0)	(143.8)
Personal
Financing Receivable, Recorded Investment [Line Items]
Residential Real Estate	9,077.5	9,782.6
Private Client	8,751.3	7,466.9
Other	32.2	37.1
Total Loans and Leases	17,861.0	17,286.6
Allowance for Credit Losses Assigned to Loans and Leases	$ (112.2)	$ (123.2)