Employee benefit plans - Schedule of Pension Plan Weighted-Average Asset Allocations (Details) - Pension Benefits	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure
Weighted-average asset allocations	100.00%	100.00%
Cash and cash equivalents
Defined Benefit Plan Disclosure
Weighted-average asset allocations	4.40%	4.70%
Equity securities
Defined Benefit Plan Disclosure
Weighted-average asset allocations	63.30%	60.30%
Corporate bonds
Defined Benefit Plan Disclosure
Weighted-average asset allocations	18.10%	19.50%
U.S. government securities
Defined Benefit Plan Disclosure
Weighted-average asset allocations	14.20%	15.50%