Derivative Financial Instruments Nature and Amount of Collateral Received From and Posted To Our Derivative Counterparties (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Derivative
Derivative Asset, Fair Value, Amount Offset Against Collateral	$ 7.0	$ 5.8
Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	178.4	244.3
Cash
Derivative
Cash Collateral from Counterparties	0.0	1.6
Cash Collateral Posted to Counterparties	0.2	0.0
Fixed Maturity Securities
Derivative
Fixed Maturity Securities received as Collateral	7.0	4.2
FMS Collateral Posted to Counterparties	$ 178.2	$ 244.3