v3.26.3
Postretirement benefit plans (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
U.S. | Defined benefit plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 2 $ 1 $ 5 $ 5
Interest cost 6 6 17 19
Expected return on plan assets (5) (3) (15) (13)
Recognized net actuarial losses (gains) 1 1 3 5
Amortization of prior service cost (credit) 0 0 0 0
Net periodic benefit costs (credits) 4 5 10 16
Settlement losses (gains) 2 4 4 7
Total, including other postretirement losses (gains) 6 9 14 23
U.S. | Retiree health care plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 1 0 1 1
Interest cost 3 3 9 9
Expected return on plan assets (3) (2) (8) (8)
Recognized net actuarial losses (gains) (1) 0 (1) (1)
Amortization of prior service cost (credit) 0 0 0 0
Net periodic benefit costs (credits) 0 1 1 1
Settlement losses (gains) 0 0 0 0
Total, including other postretirement losses (gains) 0 1 1 1
Non-U.S. | Defined benefit plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 3 4 11 11
Interest cost 16 16 49 45
Expected return on plan assets (17) (20) (56) (55)
Recognized net actuarial losses (gains) (1) 1 (3) 3
Amortization of prior service cost (credit) 1 0 3 0
Net periodic benefit costs (credits) 2 1 4 4
Settlement losses (gains) 0 0 (1) 0
Total, including other postretirement losses (gains) $ 2 $ 1 $ 3 $ 4