Pension and Postretirement Benefits (Components of Net Periodic Benefit) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.5	$ 0.5
Interest cost	0.5	0.5
Expected return on plan assets	(0.8)	(0.8)
Amortization of prior service cost	(0.2)	(0.2)
Amortization of net (gain) loss	0.1	0.0
Net periodic expense (benefit)	0.1	0.0
Postretirement
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	0.0
Interest cost	0.1	0.2
Expected return on plan assets	0.0	0.0
Amortization of prior service cost	(0.2)	(0.3)
Amortization of net (gain) loss	(0.2)	(0.1)
Net periodic expense (benefit)	$ (0.3)	$ (0.2)