Pension Benefits - Components of Comprehensive Pension Expense (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Service Cost Earned During the Year	$ 0.0	$ 0.0	$ 0.0
Interest Cost on Projected Benefit Obligation	0.0	8.4	8.7
Expected Return on Plan Assets	0.0	(7.9)	(7.4)
Amortization of Prior Service Credit	0.0	(0.4)	(0.7)
Amortization of Actuarial Loss	0.0	0.0	1.8
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(2.6)	70.2	0.0
Pension (Income) Expense Recognized in Consolidated Statements of Income (Loss)	(2.6)	71.1	3.8
Unrecognized Pension Loss Arising During the Year	0.0	0.0	(12.0)
Prior Service Cost Arising During the Year	0.0	0.0	0.0
Amortization of Prior Service Credit	0.0	0.0	0.7
Amortization of Accumulated Unrecognized Pension Loss	0.0	0.0	(1.8)
Comprehensive Pension (Income) Expense	$ (2.6)	$ 71.1	$ (10.7)