SCHEDULE V VALUATION AND QUALIFYING ACCOUNTS (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 20.7	$ 20.3	$ 27.9
Charged to Cost and Expense	0.0	0.0	0.0
Capital Loss Carryforward	(3.3)	0.0	3.3
Net Operating Loss Carryforward	0.5	0.4	(10.9)
Charged to Other Accounts	0.0	0.0	0.0
Deductions	0.0	0.0	0.0
Balance at End of Year	$ 17.9	$ 20.7	$ 20.3