Postretirement benefit plans - Expense Related to Defined Benefit and Retiree Health Care Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 4	$ 4	$ 8
Interest cost	7	6	14	12
Expected return on plan assets	(5)	(8)	(11)	(16)
Recognized net actuarial losses (gains)	1	1	3	1
Net periodic benefit costs (credits)	5	3	10	5
Settlement losses	1	11	1	13
Total, including other postretirement losses (gains)	6	14	11	18
U.S. | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	0	1	1
Interest cost	3	2	7	5
Expected return on plan assets	(4)	(2)	(9)	(6)
Recognized net actuarial losses (gains)	(2)	0	(3)	0
Net periodic benefit costs (credits)	(2)	0	(4)	0
Settlement losses	0	0	0	0
Total, including other postretirement losses (gains)	(2)	0	(4)	0
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	6	8	13
Interest cost	15	9	29	19
Expected return on plan assets	(17)	(17)	(32)	(35)
Recognized net actuarial losses (gains)	3	0	6	0
Net periodic benefit costs (credits)	5	(2)	11	(3)
Settlement losses	1	8	1	9
Total, including other postretirement losses (gains)	$ 6	$ 6	$ 12	$ 6