Loans and Leases (Loans and Leases) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	$ 41,207.8	$ 40,480.6
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	20,426.8	18,487.4
Commercial | Commercial and Institutional
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	12,138.4	11,489.2
Commercial | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	4,299.9	4,326.3
Commercial | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	2,881.1	1,990.2
Commercial | Lease Financing, net
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	11.0	11.0
Commercial | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	1,096.4	670.7
Personal
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	20,781.0	21,993.2
Personal | Private Client
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	13,887.1	15,256.3
Personal | Residential Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	6,383.2	6,319.9
Personal | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	491.7	381.8
Personal | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	$ 19.0	$ 35.2