Schedule V - Valuation and Qualifying Accounts (Details) - Reserve for unrecoverable reinsurance [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023		Dec. 31, 2022	Dec. 31, 2021
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 43.0		$ 40.1	$ 36.5
Charged to Cost and Expenses	0.6	[1]	2.9	3.5
Charged to Other Accounts - Describe	0.0		0.0	0.0
Deductions - Describe	0.0		0.0	0.0
Balance at End of Period	43.6		$ 43.0	$ 40.1
Disposal Group, Not Discontinued Operations
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Charged to Cost and Expenses	$ 0.1

[1] RFIG Run-off credit loss reserve of $0.1 has been classified as held-for-sale as of December 31, 2023. See Note 2 in the Notes to Consolidated Financial Statements included in the Annual Report on Form 10-K for further discussion.