Loans and Leases (Borrower Ratings) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	$ 34,144.9	$ 33,180.9
1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	18,409.9	17,910.4
4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	15,134.1	14,688.3
6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	600.9	582.2
Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	16,240.1	15,156.5
Commercial | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	9,598.2	8,968.9
Commercial | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	6,372.5	5,945.5
Commercial | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	269.4	242.1
Commercial | Commercial and Institutional
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	9,941.1	9,431.5
Commercial | Commercial and Institutional | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	6,743.8	6,360.6
Commercial | Commercial and Institutional | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	2,999.5	2,897.2
Commercial | Commercial and Institutional | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	197.8	173.7
Commercial | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	3,902.9	3,848.8
Commercial | Real Estate | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	1,876.2	1,822.6
Commercial | Real Estate | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	1,988.8	1,992.7
Commercial | Real Estate | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	37.9	33.5
Commercial | Lease Financing, net
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	470.6	544.4
Commercial | Lease Financing, net | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	312.5	377.0
Commercial | Lease Financing, net | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	125.1	133.1
Commercial | Lease Financing, net | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	33.0	34.3
Commercial | Non-U.S.
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	1,769.9	1,137.7
Commercial | Non-U.S. | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	598.7	313.8
Commercial | Non-U.S. | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	1,170.5	823.3
Commercial | Non-U.S. | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	0.7	0.6
Commercial | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	155.6	194.1
Commercial | Other | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	67.0	94.9
Commercial | Other | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	88.6	99.2
Commercial | Other | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	0.0	0.0
Personal
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	17,904.8	18,024.4
Personal | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	8,811.7	8,941.5
Personal | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	8,761.6	8,742.8
Personal | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	331.5	340.1
Personal | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	8,652.6	8,850.7
Personal | Real Estate | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	3,009.4	3,014.9
Personal | Real Estate | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	5,335.2	5,516.7
Personal | Real Estate | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	308.0	319.1
Personal | Private Client
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	9,232.6	9,136.4
Personal | Private Client | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	5,793.9	5,908.3
Personal | Private Client | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	3,415.2	3,207.1
Personal | Private Client | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	23.5	21.0
Personal | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	19.6	37.3
Personal | Other | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	8.4	18.3
Personal | Other | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	11.2	19.0
Personal | Other | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	$ 0.0	$ 0.0