Postretirement Benefit Plans - Summary of Funded Status (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.4	$ 0.4	$ 0.5
Projected benefit obligation	150.6	149.8	214.3
Funded status	(150.2)	(149.4)
Amounts reported within:
Non-current assets	0.2	0.2
Accrued liabilities	(11.7)	(12.4)
Non-current liabilities	(138.7)	(137.2)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.4	0.4
Projected benefit obligation	84.4	79.1
Funded status	(84.0)	(78.7)
Amounts reported within:
Non-current assets	0.2	0.2
Accrued liabilities	(5.5)	(5.6)
Non-current liabilities	(78.7)	(73.3)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0	0.0
Projected benefit obligation	66.2	70.7	$ 106.4
Funded status	(66.2)	(70.7)
Amounts reported within:
Non-current assets	0.0	0.0
Accrued liabilities	(6.2)	(6.8)
Non-current liabilities	$ (60.0)	$ (63.9)