Pension and other postretirement benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other postretirement benefits plan
Amortization of:
Net periodic benefit cost (ii) (iii)	$ 1.0	$ 1.0
U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	0.0
Interest cost	6.0	6.0
Expected return on assets	(5.0)	(5.0)
Amortization of:
Prior service credit	0.0	0.0
Actuarial loss	1.0	1.0
Settlement gain (i)	0.0	0.0
Net periodic benefit cost (ii) (iii)	2.0	2.0
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	10.0	8.0
Interest cost	21.0	24.0
Expected return on assets	(22.0)	(23.0)
Amortization of:
Prior service credit	(3.0)	(3.0)
Actuarial loss	1.0	0.0
Settlement gain (i)	(3.0)	0.0
Net periodic benefit cost (ii) (iii)	$ 4.0	$ 6.0