v3.25.4
Business combinations - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Mar. 31, 2024
Disclosure of detailed information about business combination [Line Items]        
Gain on sale of assets   $ 0 $ 1  
Cariboo Pulp & Paper Company        
Disclosure of detailed information about business combination [Line Items]        
Proportion of ownership interest in joint operation 50.00% 100.00% 50.00%  
Gain on sale of assets   $ 1    
Cariboo Pulp & Paper Company        
Disclosure of detailed information about business combination [Line Items]        
Percentage of voting equity interests acquired       50.00%