Property and Casualty Insurance Reserves - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred Losses and LAE Related to Prior Years	$ 27.4	$ 158.5
Specialty Personal Automobile
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred Losses and LAE Related to Prior Years	5.1	110.9
Commercial Automobile
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred Losses and LAE Related to Prior Years		22.2
Non-Core Operations
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred Losses and LAE Related to Prior Years	$ (22.1)	$ 25.4