Variable Interest Entities (Summary of Unconsolidated Tax Structures) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Investment Carrying Amount	$ 876.7	$ 889.1
Unfunded Commitments	227.1	178.8
Affordable Housing
Variable Interest Entity [Line Items]
Investment Carrying Amount	657.0	622.8
Unfunded Commitments	227.1	178.8
New Markets
Variable Interest Entity [Line Items]
Investment Carrying Amount	219.7	266.3
Unfunded Commitments	0.0	0.0
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investment Carrying Amount	849.3	857.0
Unfunded Commitments	$ 221.0	$ 172.0