v3.25.4
Retirement benefits - Defined benefit plans expense (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Pension defined benefit plans    
Disclosure of defined benefit plans [line items]    
Service cost $ 33 $ 41
Administration fees 2 2
Settlement loss 0 1
Curtailment gain related to disposal of pulp mills 0 2
Finance expense, net 2 1
Defined benefit plans expense 37 43
Other Post-Employment Defined Benefit Plans    
Disclosure of defined benefit plans [line items]    
Service cost 0 0
Administration fees 0 0
Settlement loss 0 0
Curtailment gain related to disposal of pulp mills 0 0
Finance expense, net 1 1
Defined benefit plans expense $ 1 $ 1