Loans and Leases (Loans and Leases) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	$ 43,991.9	$ 40,480.6
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	22,789.3	18,487.4
Commercial | Commercial and Institutional
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	12,413.5	11,489.2
Commercial | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	4,570.8	4,326.3
Commercial | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	4,617.3	1,990.2
Commercial | Lease Financing, net
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	0.0	11.0
Commercial | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	1,187.7	670.7
Personal
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	21,202.6	21,993.2
Personal | Private Client
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	13,945.2	15,256.3
Personal | Residential Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	6,445.9	6,319.9
Personal | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	616.4	381.8
Personal | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	$ 195.1	$ 35.2