Derivative Financial Instruments Nature and Amount of Collateral Received From and Posted To Our Derivative Counterparties (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Derivative
Derivative Asset, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	$ 9.6	$ 5.8
Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	249.2	244.3
Cash
Derivative
Cash Collateral from Counterparties	0.5	1.6
Derivative, Collateral, Right to Reclaim Cash	13.3	0.0
Fixed Maturity Securities
Derivative
Carrying Value of Fixed Maturity Securities Posted as Collateral to Counterparties	9.1	4.2
Carrying Value of Fixed Maturity Securities Posted as Collateral to Counterparties	$ 235.9	$ 244.3