CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Investments
Amortized Cost of Fixed Maturity Securities	$ 37,983.9	$ 38,269.9
Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities	14.4	2.8
Other Assets
Premium Receivable, Allowance for Credit Loss	27.6	26.8
Reinsurance Recoverable, Allowance for Credit Loss	$ 1.5	$ 1.5
Stockholders' Equity
Common Stock, Par Value (in dollars per share)	$ 0.10	$ 0.10
Common Stock, Shares Authorized	725,000,000	725,000,000
Common Stock, Shares Issued	196,106,652	195,460,723
Treasury Stock, Common, Shares	23,968,208	16,871,752