Employee plans - Schedule of Weighted-Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Plans | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percentage)	6.04%	3.18%	2.85%
Expected long-term rate of return on assets (as a percentage)	7.10%	6.50%	6.07%
Weighted-average assumptions used to determine benefit obligations at December 31 were as follows:
Discount rate (as a percentage)	5.70%	6.04%	3.18%
Pension Plans | International Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percentage)	4.80%	1.73%	1.23%
Expected long-term rate of return on assets (as a percentage)	4.44%	3.88%	3.30%
Weighted-average assumptions used to determine benefit obligations at December 31 were as follows:
Discount rate (as a percentage)	4.24%	4.80%	1.73%
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percentage)	5.39%	2.70%	2.21%
Expected long-term rate of return on assets (as a percentage)	5.50%	5.50%	5.50%
Weighted-average assumptions used to determine benefit obligations at December 31 were as follows:
Discount rate (as a percentage)	5.03%	5.39%	2.70%