Pension and Postretirement Plans - Amounts Recognized in Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Other noncurrent assets	$ 166.7	$ 52.9
Pension and postretirement benefit obligations	111.3	127.9
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other noncurrent assets	2.1	2.1
Accrued payroll and benefits	1.4	1.5
Pension and postretirement benefit obligations	27.3	36.5
Total	26.6	35.9
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service cost, net of tax of ($0.6), ($0.4)	0.0	0.0
Actuarial gain, net of tax of ($0.6), ($0.8), $9.5, $8.9	6.3	5.8
Total	6.3	5.8
Actuarial gain (loss), tax	(0.6)	(0.8)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other noncurrent assets	0.0	0.0
Accrued payroll and benefits	7.7	7.9
Pension and postretirement benefit obligations	83.8	91.1
Total	91.5	99.0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service cost, net of tax of ($0.6), ($0.4)	(1.8)	(1.2)
Actuarial gain, net of tax of ($0.6), ($0.8), $9.5, $8.9	30.5	28.6
Total	28.7	27.4
Prior service costs, tax	(0.6)	(0.4)
Actuarial gain (loss), tax	$ 9.5	$ 8.9