Loans and Leases (Borrower Ratings) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	$ 34,557.1	$ 33,180.9
1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	18,682.0	17,910.4
4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	15,310.1	14,688.3
6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	565.0	582.2
Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	16,672.0	15,156.5
Commercial | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	9,803.0	8,968.9
Commercial | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	6,642.3	5,945.5
Commercial | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	226.7	242.1
Commercial | Commercial and Institutional
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	9,983.5	9,431.5
Commercial | Commercial and Institutional | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	6,728.7	6,360.6
Commercial | Commercial and Institutional | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	3,098.1	2,897.2
Commercial | Commercial and Institutional | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	156.7	173.7
Commercial | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	3,995.9	3,848.8
Commercial | Real Estate | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	2,073.3	1,822.6
Commercial | Real Estate | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	1,881.1	1,992.7
Commercial | Real Estate | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	41.5	33.5
Commercial | Lease Financing, net
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	381.5	544.4
Commercial | Lease Financing, net | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	248.0	377.0
Commercial | Lease Financing, net | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	106.7	133.1
Commercial | Lease Financing, net | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	26.8	34.3
Commercial | Non-U.S.
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	2,027.2	1,137.7
Commercial | Non-U.S. | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	590.6	313.8
Commercial | Non-U.S. | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	1,434.9	823.3
Commercial | Non-U.S. | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	1.7	0.6
Commercial | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	283.9	194.1
Commercial | Other | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	162.4	94.9
Commercial | Other | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	121.5	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	17,885.1	18,024.4
Personal | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	8,879.0	8,941.5
Personal | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	8,667.8	8,742.8
Personal | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	338.3	340.1
Personal | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	8,224.3	8,850.7
Personal | Real Estate | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	2,770.4	3,014.9
Personal | Real Estate | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	5,141.2	5,516.7
Personal | Real Estate | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	312.7	319.1
Personal | Private Client
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	9,624.9	9,136.4
Personal | Private Client | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	6,088.1	5,908.3
Personal | Private Client | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	3,511.2	3,207.1
Personal | Private Client | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	25.6	21.0
Personal | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	35.9	37.3
Personal | Other | 1 to 3 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	20.5	18.3
Personal | Other | 4 to 5 Category
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	15.4	19.0
Personal | Other | 6 to 9 Category (Watch List)
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases	$ 0.0	$ 0.0