Allowance for Credit Losses (Accrued Interest) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Receivables [Abstract]
Loans	$ 211.7	$ 241.7
Debt Securities
Held to Maturity	58.9	72.0
Available for Sale	173.9	129.2
Other Financial Assets	53.1	86.0
Interest Receivable	$ 497.6	$ 528.9
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets