Defined Benefit Pension Plans and Other Post-Employment Benefit Plans - Net Period Benefit Costs (Income) for Post-retirement Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Components of net periodic benefit cost:
Interest cost	$ 7.0	$ 3.9	$ 21.0	$ 12.0
Amortization of net prior service credit	0.1	0.1	0.2	0.2
Amortization of net actuarial gain	(1.2)	(1.5)	(3.6)	(4.2)
Net periodic cost (income)	2.1	(0.5)	6.0	(1.8)
Other post-retirement employee benefit plans
Components of net periodic benefit cost:
Interest cost	0.4	0.2	1.2	0.6
Amortization of net prior service credit	(0.1)	0.0	(0.2)	(0.2)
Amortization of net actuarial gain	0.0	0.1	0.1	0.1
Net periodic cost (income)	$ 0.3	$ 0.1	$ 0.9	$ 0.3