v3.26.1
Share-based compensation plans (Narrative) (Details)
 12 Months Ended
Dec. 31, 2025
CAD ($)
shares
Number_employees
$ / shares
Dec. 31, 2024
CAD ($)
shares
Number_employees
$ / shares
Dec. 31, 2023
shares
Stock Option Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Authorized shares 43,017,198    
Outstanding shares 33,478,285    
Stock options held 114,063 259,958  
Options exercisable - Weighted average exercisable price | $ / shares $ 15.27 $ 15.05  
Weighted average share price, exercise date | $ / shares $ 106.44 $ 69.86  
Expiration period for share-based payment arrangement 8 years    
Number of options, reporting date 114,063 259,958 1,396,289
Stock Option Plan [Member] | Minimum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting term for share-based payment arrangement 1 year    
Stock Option Plan [Member] | Maximum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting term for share-based payment arrangement 3 years    
Performance Share Unit Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period description three-year vesting period    
Vesting term for share-based payment arrangement 3 years    
Number of options, reporting date 584,657 636,588 830,279
Restricted Share Unit Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period description The RSUs carry vesting periods of one to three years    
Number of options, reporting date 757,959 734,000 814,683
Restricted Share Unit Plan [Member] | Minimum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting term for share-based payment arrangement 1 year    
Restricted Share Unit Plan [Member] | Maximum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting term for share-based payment arrangement 3 years    
Employee Share Ownership Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period description Shares purchased with Company contributions and with dividends paid on such shares become unrestricted 12 months from the date on which such shares were purchased.    
Employers contribution per employee Under the plan, employees have the opportunity to participate in the program to a maximum of 6% of eligible earnings each year with Cameco matching the first 3% of employee-paid shares by 50%. Cameco contributes $1,000 of shares annually to each employee that is enrolled in the plan.    
Number of participants | Number_employees 3,378 3,065  
Total number of shares purchased 65,051 76,926  
Total amount of employer's contribution | $ $ 5,612,000 $ 4,881,000  
Deferred Share Unit Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period description Each DSU fully vests upon award    
Stock options held 335,436 310,604  
Description of method of settlement for share-based payment arrangement 60% of each director’s annual retainer is paid in DSUs. In addition, on an annual basis, directors can elect to receive 25%, 50%, 75% or 100% of the remaining 40% of their annual retainer and any additional fees in the form of DSUs    
Phantom Stock Option Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period description vest over three years and expire eight years from the date granted    
Exercise prices range | $ / shares $ 11.61    
Options exercisable - Weighted average exercisable price | $ / shares $ 11.61 $ 12.48  
Vesting term for share-based payment arrangement 3 years    
Expiration period for share-based payment arrangement 8 years    
Number of options, reporting date 12,500 35,361 45,551
Phantom Stock Option Plan [Member] | Minimum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Exercise prices range | $ / shares   $ 15.27  
Phantom Stock Option Plan [Member] | Maximum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Exercise prices range | $ / shares   $ 11.61  
Phantom Restricted Share Unit Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting period description The PRSUs carry vesting periods of one to three years    
Number of options, reporting date 24,023 25,560 28,000
Phantom Restricted Share Unit Plan [Member] | Minimum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting term for share-based payment arrangement 1 year    
Phantom Restricted Share Unit Plan [Member] | Maximum [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Vesting term for share-based payment arrangement 3 years    
Cash Settled Plan [Member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Liabilities from share-based payment transactions | $ $ 114,064,000 $ 65,881,000