Pension and other postretirement benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Other postretirement benefits plan
Amortization of:
Net periodic benefit cost	$ 1	$ 1
U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	6	6
Expected return on assets	(6)	(5)
Amortization of:
Prior service credit	0	0
Actuarial loss	0	0
Net periodic benefit cost	0	1
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	10
Interest cost	23	20
Expected return on assets	(26)	(23)
Amortization of:
Prior service credit	(3)	(3)
Actuarial loss	1	1
Net periodic benefit cost	$ 4	$ 5