v3.26.1
Provisions (Details) - CAD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Provisions [Line Items]    
Beginning of year $ 1,035,807,000  
Changes in estimates and discount rates [Abstract]    
Capitalized in property, plant and equipment (5,575,000)  
Recognized in earnings (27,199,000)  
Provisions used during the period (27,583,000)  
Accretion 40,658,000  
Effect of movements in exchange rates (15,045,000)  
End of period 1,001,063,000  
Current 47,648,000 $ 37,974,000
Non-current 953,415,000 997,833,000
Outstanding letters of credit facility 1,529,574,000 1,527,815,000
Reclamation [Member]    
Provisions [Line Items]    
Beginning of year 1,025,039,000  
Changes in estimates and discount rates [Abstract]    
Capitalized in property, plant and equipment (5,575,000)  
Recognized in earnings (28,333,000)  
Provisions used during the period (26,591,000)  
Accretion 40,364,000  
Effect of movements in exchange rates (15,045,000)  
End of period 989,859,000  
Current 41,333,000  
Non-current 948,526,000  
Estimated total future decommissioning and reclamation costs $ 1,369,955,000 1,382,661,000
Description of period, majority of expenditures will occur between between 2026 and 2051  
Outstanding letters of credit facility $ 1,125,170,000 1,125,170,000
Reclamation [Member] | Uranium [Member]    
Provisions [Line Items]    
Beginning of year 865,574,000  
Changes in estimates and discount rates [Abstract]    
End of period 833,881,000  
Reclamation [Member] | Fuel Services [Member]    
Provisions [Line Items]    
Beginning of year 159,465,000  
Changes in estimates and discount rates [Abstract]    
End of period 155,978,000  
Waste Disposal [Member]    
Provisions [Line Items]    
Beginning of year 10,768,000  
Changes in estimates and discount rates [Abstract]    
Capitalized in property, plant and equipment 0  
Recognized in earnings 1,134,000  
Provisions used during the period (992,000)  
Accretion 294,000  
Effect of movements in exchange rates 0  
End of period 11,204,000  
Current 6,315,000  
Non-current $ 4,889,000  
Period in which majority of expenditures are expected to occur 3 years  
Waste Disposal [Member] | Fuel Services [Member]    
Changes in estimates and discount rates [Abstract]    
Estimated total future decommissioning and reclamation costs $ 10,027,000 $ 9,663,000