Postretirement benefit plans - Expense Related to Defined Benefit and Retiree Health Care Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 2
Interest cost	6	7
Expected return on plan assets	(6)	(6)
Recognized net actuarial losses (gains)	1	2
Net periodic benefit costs (credits)	3	5
U.S. | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	3	4
Expected return on plan assets	(3)	(5)
Recognized net actuarial losses (gains)	(1)	(1)
Net periodic benefit costs (credits)	(1)	(2)
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4
Interest cost	14	14
Expected return on plan assets	(19)	(15)
Recognized net actuarial losses (gains)	3	3
Net periodic benefit costs (credits)	$ 2	$ 6