Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2026	Jun. 30, 2026	Jun. 30, 2025
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance		$ 656.7	$ 630.0
Capitalizations		277.7	314.1
Amortization Expense		(258.6)	(284.3)
Ending balance	$ 675.8	675.8	659.8
Experience adjustments	(1.8)		(1.9)
Variable Interest Entity, Primary Beneficiary
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance		1.3	1.1
Ending balance	0.8	0.8	1.6
Operating Segments
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance		655.9	625.9
Capitalizations		275.8	310.9
Amortization Expense		(257.8)	(280.1)
Ending balance	673.9	673.9	656.7
Operating Segments \| Specialty
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance		158.8	162.8
Capitalizations		240.6	278.3
Amortization Expense		(243.0)	(266.0)
Ending balance	156.4	156.4	175.1
Operating Segments \| Life
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance		497.1	463.1
Capitalizations		35.2	32.6
Amortization Expense		(14.8)	(14.1)
Ending balance	517.5	517.5	481.6
Non-Core Operations
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance		0.8	4.1
Capitalizations		1.9	3.2
Amortization Expense		(0.8)	(4.2)
Ending balance	$ 1.9	$ 1.9	$ 3.1