Pension and other postretirement benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Amortization of:
Net periodic benefit cost (income)	$ 21	$ 34	$ 31
Pension Plans | United States
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	1
Interest cost	25	24	24
Expected return on assets	(23)	(21)	(20)
Amortization of:
Prior service credit	0	0	0
Actuarial loss (gain)	0	2	3
Curtailment gain	0	0	0
Settlement (gain) loss	0	0	0
Net periodic benefit cost (income)	3	7	8
Pension Plans | Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	39	39	31
Interest cost	81	81	86
Expected return on assets	(99)	(87)	(91)
Amortization of:
Prior service credit	(12)	(12)	(11)
Actuarial loss (gain)	8	6	4
Curtailment gain	(3)	(3)	0
Settlement (gain) loss	0	(3)	1
Net periodic benefit cost (income)	14	21	20
OPEB Plans (i)
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	3	2
Interest cost	5	5	5
Expected return on assets	0	0	0
Amortization of:
Prior service credit	0	0	0
Actuarial loss (gain)	(3)	(2)	(3)
Curtailment gain	0	0	(1)
Settlement (gain) loss	0	0	0
Net periodic benefit cost (income)	4	$ 6	$ 3
OPEB Plans (i) | Non-U.S.
Amortization of:
Net periodic benefit cost (income)	$ 0