Postretirement benefit plans - Expense Related to Defined Benefit and Retiree Health Care Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 4
Interest cost	7	6
Expected return on plan assets	(6)	(8)
Recognized net actuarial losses (gains)	2	0
Net periodic benefit costs (credits)	5	2
Settlement losses	0	2
Total, including other postretirement losses (gains)	5	4
U.S. | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1
Interest cost	4	3
Expected return on plan assets	(5)	(4)
Recognized net actuarial losses (gains)	(1)	0
Net periodic benefit costs (credits)	(2)	0
Settlement losses	0	0
Total, including other postretirement losses (gains)	(2)	0
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	7
Interest cost	14	10
Expected return on plan assets	(15)	(18)
Recognized net actuarial losses (gains)	3	0
Net periodic benefit costs (credits)	6	(1)
Settlement losses	0	1
Total, including other postretirement losses (gains)	$ 6	$ 0