Cost-reduction actions - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restructuring Cost and Reserve [Line Items]
Cost-reduction charges and other costs	$ 9.3	$ 54.9	$ 23.2
Charges (credits) related to work-force reductions	8.3	7.5	0.4
Other charges related to the cost-reduction effort	1.0	47.4	22.8
Employee severance
Restructuring Cost and Reserve [Line Items]
Cost-reduction charges and other costs	15.2	7.1	12.3
Charges (credits) related to work-force reductions	15.2	7.1	12.3
Changes in estimates
Restructuring Cost and Reserve [Line Items]
Charges (credits) related to work-force reductions	(6.9)	0.4	(11.9)
Professional fees
Restructuring Cost and Reserve [Line Items]
Other charges related to the cost-reduction effort	4.7
Foreign currency (gains) losses related to exiting foreign countries
Restructuring Cost and Reserve [Line Items]
Other charges related to the cost-reduction effort	$ (3.7)	2.9	4.0
Asset held-for-sale
Restructuring Cost and Reserve [Line Items]
Other charges related to the cost-reduction effort		13.6
Asset impairments
Restructuring Cost and Reserve [Line Items]
Other charges related to the cost-reduction effort		10.9	12.6
Facility lease cost
Restructuring Cost and Reserve [Line Items]
Other charges related to the cost-reduction effort		11.3
Contract exit costs
Restructuring Cost and Reserve [Line Items]
Other charges related to the cost-reduction effort		9.3
Other expenses
Restructuring Cost and Reserve [Line Items]
Other charges related to the cost-reduction effort		$ (0.6)	$ 6.2