Pension and Postretirement Plans - Schedule of Pension and Postretirement (Benefits) Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation	5.0	5.5	10.1	11.0
Expected return on plan assets	(5.6)	(5.2)	(11.3)	(10.4)
Amortization of:
Prior service benefit	0.0	0.0	0.0	0.0
Actuarial gain	(0.1)	0.0	(0.1)	(0.1)
Pension settlement gain	(0.4)	0.0	(0.4)	0.0
Pension / postretirement (benefit) cost	(1.1)	0.3	(1.7)	0.5
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0.1	0.1	0.2	0.2
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation	1.3	1.3	2.5	2.6
Expected return on plan assets	0.0	0.0	0.0	0.0
Amortization of:
Prior service benefit	(0.2)	(0.2)	(0.4)	(0.4)
Actuarial gain	(1.0)	(1.4)	(1.9)	(2.3)
Pension settlement gain	0.0	0.0	0.0	0.0
Pension / postretirement (benefit) cost	$ 0.2	$ (0.2)	$ 0.4	$ 0.1