Securities Sold Under Agreements to Repurchase (Repurchase Agreements Accounted for as Secured Borrowings) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	$ 799.4	$ 531.9
Net Amount of Recognized Liabilities for Repurchase Agreements in Note 24	799.4	531.9
Amounts related to agreements not included in Note 24	0.0	0.0
U.S. Treasury and Agency Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	799.4	531.9
OVERNIGHT AND CONTINUOUS
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	799.4	32.4
Net Amount of Recognized Liabilities for Repurchase Agreements in Note 24	799.4	32.4
Amounts related to agreements not included in Note 24	0.0	0.0
OVERNIGHT AND CONTINUOUS | U.S. Treasury and Agency Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	799.4	32.4
UP TO 30 DAYS
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	0.0	499.5
Net Amount of Recognized Liabilities for Repurchase Agreements in Note 24	0.0	499.5
Amounts related to agreements not included in Note 24	0.0	0.0
UP TO 30 DAYS | U.S. Treasury and Agency Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	$ 0.0	$ 499.5