v3.26.1
Postretirement benefit plans (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
U.S. | Defined benefit plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 1 $ 2 $ 3 $ 4
Interest cost 5 7 11 13
Expected return on plan assets (4) (6) (10) (10)
Recognized net actuarial losses (gains) 1 2 2 4
Amortization of prior service cost (credit) 0 0 0 0
Net periodic benefit costs (credits) 3 5 6 11
Settlement losses (gains) 2 3 2 3
Total, including other postretirement losses (gains) 5 8 8 14
U.S. | Retiree health care plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 0 1 0 1
Interest cost 3 3 6 6
Expected return on plan assets (2) (3) (5) (6)
Recognized net actuarial losses (gains) 0 (1) 0 (1)
Amortization of prior service cost (credit) 0 0 0 0
Net periodic benefit costs (credits) 1 0 1 0
Settlement losses (gains) 0 0 0 0
Total, including other postretirement losses (gains) 1 0 1 0
Non-U.S. | Defined benefit plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 4 3 8 7
Interest cost 17 15 33 29
Expected return on plan assets (20) (17) (39) (35)
Recognized net actuarial losses (gains) (1) 1 (2) 2
Amortization of prior service cost (credit) 1 0 2 0
Net periodic benefit costs (credits) 1 2 2 3
Settlement losses (gains) (1) 0 (1) 0
Total, including other postretirement losses (gains) $ 0 $ 2 $ 1 $ 3