Pension and other postretirement benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Amortization of:
Net periodic benefit cost (income)	$ 31	$ 30	$ 61
Pension Plans | United States
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	3
Interest cost	24	18	19
Expected return on assets	(20)	(30)	(37)
Amortization of:
Prior service cost (credit)	0	1	0
Actuarial loss (gain)	3	2	4
Curtailment loss (gain)	0	3	0
Settlement loss (gain)	0	0	17
Net periodic benefit cost (income)	8	(4)	6
Pension Plans | Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	31	55	63
Interest cost	86	43	40
Expected return on assets	(91)	(72)	(71)
Amortization of:
Prior service cost (credit)	(11)	(11)	(11)
Actuarial loss (gain)	4	15	26
Curtailment loss (gain)	0	0	0
Settlement loss (gain)	1	(2)	1
Net periodic benefit cost (income)	20	28	48
OPEB Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	3	4
Interest cost	5	3	4
Expected return on assets	0	0	0
Amortization of:
Prior service cost (credit)	0	0	(1)
Actuarial loss (gain)	(3)	0	0
Curtailment loss (gain)	(1)	0	0
Settlement loss (gain)	0	0	0
Net periodic benefit cost (income)	3	6	7
OPEB Plans | Non-U.S.
Amortization of:
Net periodic benefit cost (income)	$ 0	$ 1	$ 1