CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Investments
Amortized Cost of Fixed Maturity Securities	$ 38,269.9	$ 38,410.6
Debt Securities, Available-for-sale, Allowance for Credit Loss for Fixed Maturity Securities	2.8	2.2
Allowance for credit losses for Mortgage Loans	16.1	10.2
Other Assets
Premium Receivable, Allowance for Credit Loss	26.8	29.5
Reinsurance Recoverable, Allowance for Credit Loss	$ 1.5	$ 1.7
Stockholders' Equity, Number of Shares, Par Value and Other Disclosure
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	195,460,723	194,588,625
Treasury Stock, Shares at Cost	16,871,752	1,216,528