Pension and other postretirement benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Amortization of:
Net periodic benefit cost (income)	$ 34	$ 31	$ 30
Pension Plans | United States
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1	2
Interest cost	24	24	18
Expected return on assets	(21)	(20)	(30)
Amortization of:
Prior service cost (credit)	0	0	1
Actuarial loss (gain)	2	3	2
Curtailment loss (gain)	0	0	3
Settlement (gain) loss	0	0	0
Net periodic benefit cost (income)	7	8	(4)
Pension Plans | Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	39	31	55
Interest cost	81	86	43
Expected return on assets	(87)	(91)	(72)
Amortization of:
Prior service cost (credit)	(12)	(11)	(11)
Actuarial loss (gain)	6	4	15
Curtailment loss (gain)	(3)	0	0
Settlement (gain) loss	(3)	1	(2)
Net periodic benefit cost (income)	21	20	28
OPEB Plans (i)
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	2	3
Interest cost	5	5	3
Expected return on assets	0	0	0
Amortization of:
Prior service cost (credit)	0	0	0
Actuarial loss (gain)	(2)	(3)	0
Curtailment loss (gain)	0	(1)	0
Settlement (gain) loss	0	0	0
Net periodic benefit cost (income)	6	3	6
OPEB Plans (i) | Non-U.S.
Amortization of:
Net periodic benefit cost (income)	$ 0	$ 0	$ 1