Postretirement Benefit Plans - Amount Recognized in Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ (6.4)	$ (2.6)
Prior service cost (benefit)	(6.2)	(12.0)
Total	(12.6)	(14.6)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(2.7)	3.4
Prior service cost (benefit)	0.8	0.8
Total	(1.9)	4.2
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(3.7)	(6.0)
Prior service cost (benefit)	(7.0)	(12.8)
Total	$ (10.7)	$ (18.8)