Variable Interest Entities (Summary of Unconsolidated Tax Structures) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Variable Interest Entity [Line Items]
Investment Carrying Amount	$ 1,026.9	$ 876.7
Unfunded Commitments(2)	373.0	227.1
Affordable Housing
Variable Interest Entity [Line Items]
Investment Carrying Amount	834.0	657.0
Unfunded Commitments(2)	373.0	227.1
New Markets
Variable Interest Entity [Line Items]
Investment Carrying Amount	192.9	219.7
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investment Carrying Amount	1,000.0	849.3
Unfunded Commitments(2)	$ 369.7	$ 221.0