Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Policy Acquisition Cost, Beginning Balance	$ 591.6	$ 635.6	$ 688.0
Capitalization	576.4	563.3	691.5
Capitalization			652.8
Amortization Expense	(538.0)	(607.3)	(705.2)
Deferred Policy Acquisition Cost	630.0
Deferred Policy Acquisition Cost, Ending Balance	628.9	591.6	635.6
Experience adjustment	(7.4)	(15.6)	(8.7)
Variable Interest Entity, Primary Beneficiary
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Policy Acquisition Cost, Beginning Balance	0.1
Deferred Policy Acquisition Cost, Ending Balance	1.1	0.1
Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalization	38.7
Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Policy Acquisition Cost, Beginning Balance	569.6	597.5	638.8
Capitalization	563.0	508.4	570.4
Amortization Expense	(506.7)	(536.3)	(611.7)
Deferred Policy Acquisition Cost	625.9
Deferred Policy Acquisition Cost, Ending Balance		569.6	597.5
Operating Segments | Specialty
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Policy Acquisition Cost, Beginning Balance	142.6	192.7	219.0
Capitalization	494.3	446.3	543.4
Amortization Expense	(474.1)	(496.4)	(569.7)
Deferred Policy Acquisition Cost	162.8
Deferred Policy Acquisition Cost, Ending Balance		142.6	192.7
Operating Segments | Life
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Policy Acquisition Cost, Beginning Balance	427.0	404.8	419.8
Capitalization	68.7	62.1	27.0
Amortization Expense	(32.6)	(39.9)	(42.0)
Deferred Policy Acquisition Cost	463.1
Deferred Policy Acquisition Cost, Ending Balance		427.0	404.8
Non-Core Operations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Policy Acquisition Cost, Beginning Balance	22.0	38.1	49.2
Capitalization	13.4	54.9	82.4
Amortization Expense	(31.3)	(71.0)	(93.5)
Deferred Policy Acquisition Cost	$ 4.1
Deferred Policy Acquisition Cost, Ending Balance		$ 22.0	$ 38.1