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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 6	$ 8	$ 11
Interest cost	6	7	12	15
Expected return on plan assets	(8)	(9)	(16)	(17)
Recognized net actuarial loss	1	4	1	8
Net periodic benefit costs	3	8	5	17
Settlement losses	11	4	13	8
Total, including other postretirement losses	14	12	18	25
U.S. | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	1	2
Interest cost	2	2	5	5
Expected return on plan assets	(2)	(3)	(6)	(6)
Recognized net actuarial loss	0	0	0	0
Net periodic benefit costs	0	0	0	1
Settlement losses	0	0	0	0
Total, including other postretirement losses	0	0	0	1
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	9	13	18
Interest cost	9	10	19	19
Expected return on plan assets	(17)	(21)	(35)	(41)
Recognized net actuarial loss	0	2	0	4
Net periodic benefit costs	(2)	0	(3)	0
Settlement losses	8	0	9	1
Total, including other postretirement losses	$ 6	$ 0	$ 6	$ 1