Income Taxes - Schedule of Effect of Temporary Differences Giving Rise to Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Accrued postretirement benefits cost	$ 7.9	$ 8.0
Accrued pension cost	39.3	44.1
Other employee benefit accruals	10.7	14.3
Tax loss and credit carryforwards	89.1	84.9
Other, net	75.9	58.3
Valuation allowances	(48.7)	(39.3)
Total deferred tax assets	174.2	170.3
Deferred tax liabilities - principally depreciation and amortization	(308.2)	(312.5)
Net deferred tax liabilities	$ (134.0)	$ (142.2)