Amortization of Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 11.9	$ 11.3	$ 23.2	$ 23.4
Operating Segments
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	6.3	5.3	12.1	11.2
Operating Segments | Specialty Property & Casualty Insurance
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	4.6	3.9	8.8	8.6
Operating Segments | Life Insurance
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	1.7	1.4	3.3	2.6
Corporate and Other
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	4.9	5.6	9.8	11.5
Non-Core Operations
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 0.7	$ 0.4	$ 1.3	$ 0.7