Postretirement Benefit Plans - Amount Recognized in Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ (2.6)	$ 9.9
Prior service cost (benefit)	(12.0)	(18.2)
Total	(14.6)	(8.3)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	3.4	9.5
Prior service cost (benefit)	0.8	0.3
Total	4.2	9.8
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(6.0)	0.4
Prior service cost (benefit)	(12.8)	(18.5)
Total	$ (18.8)	$ (18.1)