Pension Benefits - Components of Comprehensive Pension Expense (Details) - Pension Plans, Defined Benefit - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Service Cost Earned During the Year	$ 0.0	$ 0.0	$ 0.0
Interest Cost on Projected Benefit Obligation	8.7	7.2	16.5
Expected Return on Plan Assets	(7.4)	(9.5)	(27.6)
Amortization of Actuarial Loss	1.8	2.9	5.6
Pension Obligation Settlement Costs	0.0	0.0	64.1
Pension Expense Recognized in Consolidated Statements of (Loss) Income	3.8	0.6	58.6
Unrecognized Pension Loss Arising During the Year	(12.0)	(6.0)	(7.8)
Prior Service Cost Arising During the Year	0.0	18.3	0.0
Amortization of Prior Service Credit	0.7	0.0	0.0
Amortization of Prior Service Credit	(0.7)	0.0	0.0
Amortization of Accumulated Unrecognized Pension Loss	(1.8)	(2.9)	(69.8)
Comprehensive Pension (Income) Expense	$ (10.7)	$ 10.0	$ (19.0)