Pension and other postretirement benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Other postretirement benefits plan
Amortization of:
Net periodic benefit cost	$ 1	$ 1	$ 3	$ 3
U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	0
Interest cost	6	6	18	18
Expected return on assets	(6)	(5)	(17)	(15)
Amortization of:
Past service credit	0	0	0	0
Actuarial loss	0	1	0	3
Settlement gain	0	0	0	0
Net periodic benefit cost	0	2	2	6
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	10	30	30
Interest cost	22	22	64	64
Expected return on assets	(25)	(23)	(74)	(67)
Amortization of:
Past service credit	(3)	(3)	(9)	(9)
Actuarial loss	1	1	4	3
Settlement gain	0	0	0	(3)
Net periodic benefit cost	$ 5	$ 7	$ 15	$ 18