v3.26.3
Closure and Restructuring and Impairment of Long-Lived Assets - Additional Information (Detail)
$ in Millions
 1 Months Ended 3 Months Ended 9 Months Ended
May 31, 2026
T
Employee
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges   $ 1 $ 11 $ 28 $ 23
Write-off inventory       15 17
Property, Plant and Equipment [Member]          
Restructuring Cost And Reserve [Line Items]          
Long-lived assets impairment charges   1   7  
Operating Lease Right-of-Use Assets [Member]          
Restructuring Cost And Reserve [Line Items]          
Long-lived assets impairment charges   0   9  
Pulp and Tissue [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges   0   1  
Wood Products [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges   1   7  
Paper And Packaging [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges   0   6  
Corporate Segment and Other Operating Segment [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges   0   2  
Other Costs [Member]          
Restructuring Cost And Reserve [Line Items]          
Severance and termination costs   0 0 4 1
Other cost   7 2 27 3
Idling and Sale of Espanola, Ontario Mill [Member] | Espanola, Ontario mill [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges     2   14
Power Generation Assets Impairment Costs [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges     8    
Cost Reduction Measures [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges     1    
Severance and termination costs     8    
Other cost     3    
Write-off inventory     17    
Catalyst Restructuring And Impairment Costs [Member] | Catalyst British Columbia Mills [Member]          
Restructuring Cost And Reserve [Line Items]          
Accelerated depreciation     2   9
Severance and termination costs     $ 1   $ 1
Environmental closure costs   1   1  
Other cost   1   3  
Write-off inventory   0   2  
Idling of Coosa Pines Alabama Mill [Member]          
Restructuring Cost And Reserve [Line Items]          
Reduction in annual market pulp production capacity | T 270,000        
Reduction of workforce | Employee 285        
Idling of Coosa Pines Alabama Mill [Member] | Coosa Pines, Alabama Mill [Member]          
Restructuring Cost And Reserve [Line Items]          
Asset Impairment Charges   0   9  
Write-off of operating lease right-of-use assets   0   3  
Severance and termination costs   2   10  
Other cost   0   3  
Write-off inventory   $ 1   $ 13