Pension and other postretirement benefits - Schedule of Weighted Average Assumptions Used to Determine Benefit Obligation (Details)	Dec. 31, 2025	Dec. 31, 2024
Pension Plans | United States
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.20%	5.55%
Pension Plans | Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.78%	3.41%
Rate of compensation increase	2.77%	2.88%
OPEB Plans (i)
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.08%	5.34%
Rate of compensation increase	2.27%	2.33%