v3.25.4
Miscellaneous financial information - Narrative (Detail) - CAD ($)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2025
Sep. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]          
Effect of LIFO inventory liquidation on income (loss)     $ 61 $ 61 $ 5
Difference between LIFO carrying values and replacement cost of inventories $ 1,500   1,500 2,000  
Research and development costs charged to expenses     134 118 84
Accounts payable and accrued liabilities included accrued taxes other than income taxes 393   393 524  
Dividends payable 350   350 307  
Miscellaneous current liabilities 1,151   1,151 739  
Production and manufacturing [1]     7,269 6,599 6,879
Employee Severance          
Restructuring Cost and Reserve [Line Items]          
Restructuring charges   $ 330 $ 330    
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]   Selling and general Selling and general    
Corporate and other          
Restructuring Cost and Reserve [Line Items]          
Production and manufacturing     $ 21 17 0
Corporate and other | Calgary Imperial Campus          
Restructuring Cost and Reserve [Line Items]          
Tangible asset impairment charges   $ 406      
Operating Segments | Upstream          
Restructuring Cost and Reserve [Line Items]          
Production and manufacturing     $ 5,015 $ 4,644 $ 4,917
Operating Segments | Norman Wells | Upstream          
Restructuring Cost and Reserve [Line Items]          
Tangible asset impairment charges 142        
Impairment charges and contractual obligations expense 421        
Production and manufacturing $ 279        
[1]
(c) Amounts to related parties included in production and manufacturing,
       and selling and general expenses (note 16).
568541473