Postretirement benefit plans - Expense Related to Defined Benefit and Retiree Health Care Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 5
Interest cost	6	8
Expected return on plan assets	(8)	(8)
Recognized net actuarial loss	0	4
Net periodic benefit costs	2	9
Settlement losses	2	4
Total, including other postretirement losses	4	13
U.S. | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	3	3
Expected return on plan assets	(4)	(3)
Recognized net actuarial loss	0	0
Net periodic benefit costs	0	1
Settlement losses	0	0
Total, including other postretirement losses	0	1
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	9
Interest cost	10	9
Expected return on plan assets	(18)	(20)
Recognized net actuarial loss	0	2
Net periodic benefit costs	(1)	0
Settlement losses	1	1
Total, including other postretirement losses	$ 0	$ 1