Pension Benefits - Components of Comprehensive Pension Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Debt Extinguishment, Pension Settlement, and Other Charges	$ 70.2
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service Cost Earned During the Year	0.0	$ 0.0	$ 0.0
Interest Cost on Projected Benefit Obligation	8.4	8.7	7.2
Expected Return on Plan Assets	(7.9)	(7.4)	(9.5)
Amortization of Actuarial Loss	0.0	1.8	2.9
Debt Extinguishment, Pension Settlement, and Other Charges	70.2	0.0	0.0
Pension Expense Recognized in Consolidated Statements of (Loss) Income	71.1	3.8	0.6
Unrecognized Pension Loss Arising During the Year	0.0	(12.0)	(6.0)
Prior Service Cost Arising During the Year	0.0	0.0	18.3
Amortization of Prior Service Credit	0.0	0.7	0.0
Amortization of Prior Service Credit	(0.4)	(0.7)	0.0
Amortization of Accumulated Unrecognized Pension Loss	0.0	(1.8)	(2.9)
Comprehensive Pension (Income) Expense	$ 71.1	$ (10.7)	$ 10.0