Pension and Postretirement Benefits (Components of Net Periodic (Benefit) Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1.9	$ 2.1	$ 2.6
Interest cost	2.1	0.9	0.7
Expected return on plan assets	(3.2)	(2.8)	(2.9)
Amortization of prior service cost	(0.7)	(0.7)	(0.7)
Amortization of net loss (gain)	0.0	0.6	1.5
Recognized curtailment gain	(0.1)	0.0	(2.2)
Settlement (gain) loss	(0.3)	0.0	0.1
Net periodic (benefit) cost	(0.3)	0.1	(0.9)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0.1	0.2
Interest cost	0.8	0.6	0.6
Expected return on plan assets	0.0	0.0	0.0
Amortization of prior service cost	(1.1)	(1.1)	(1.1)
Amortization of net loss (gain)	(0.7)	0.0	0.0
Recognized curtailment gain	0.0	0.0	0.0
Settlement (gain) loss	0.0	0.0	0.0
Net periodic (benefit) cost	$ (0.9)	$ (0.4)	$ (0.3)