Pensions and Postretirement Benefits - Summary of Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits
Components of net periodic benefit cost
Service costs	$ 4.3	$ 4.3	$ 4.2
Interest costs	3.5	1.8	1.4
Expected return on plan assets	(9.9)	(12.9)	(12.3)
Recognized net actuarial loss	3.6	0.0	0.8
Benefit costs (income) - continuing operations	1.5	(6.8)	(5.9)
Curtailment loss - discontinued operations	0.4	0.0	0.0
Total benefit (income) costs	1.9	(6.8)	(5.9)
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive (income) loss (“AOCI”)
AOCI at beginning of year	40.0	10.9	21.5
Net income arising during the year	(3.7)	0.0	(0.8)
Recognition of actuarial (gain) loss	(9.4)	29.1	(9.8)
Total recognized in accumulated other comprehensive loss at end of year	26.9	40.0	10.9
Postretirement Benefits
Components of net periodic benefit cost
Service costs	0.0	0.0	0.0
Interest costs	0.3	0.1	0.1
Expected return on plan assets	(0.3)	(0.3)	0.0
Recognized net actuarial loss	0.3	0.2	0.3
Benefit costs (income) - continuing operations	0.3	0.0	0.4
Curtailment loss - discontinued operations	0.0	0.0	0.0
Total benefit (income) costs	0.3	0.0	0.4
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive (income) loss (“AOCI”)
AOCI at beginning of year	2.4	2.2	3.0
Net income arising during the year	(0.3)	(0.2)	(0.3)
Recognition of actuarial (gain) loss	(0.1)	0.4	(0.5)
Total recognized in accumulated other comprehensive loss at end of year	$ 2.0	$ 2.4	$ 2.2