v3.26.1
financial instruments - Accounts receivable (Details) - Customer accounts receivable - CAD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Credit risk            
Days after the billing date that accounts receivables are considered to be past due (in default) 30 days          
Total financial assets $ 3,095   $ 3,265      
Receivable account balances - Current 2,543   2,679      
Receivable account balances - Non-current 552   586      
Accounts receivable written off directly to doubtful accounts expense 0          
Cost/Gross amount            
Credit risk            
Total financial assets 3,234   3,408      
Receivable account balances - Current 2,669   2,809      
Receivable account balances - Non-current 565   599      
Allowance for doubtful accounts            
Credit risk            
Total financial assets (139) $ (145) (143) $ (139) $ (139) $ (134)
Receivable account balances - Current (126)   (130)      
Receivable account balances - Non-current (13)   (13)      
Less than 30 days past billing date            
Credit risk            
Total financial assets 1,113   979      
Less than 30 days past billing date | Cost/Gross amount            
Credit risk            
Total financial assets 1,131   1,002      
Less than 30 days past billing date | Allowance for doubtful accounts            
Credit risk            
Total financial assets (18)   (23)      
30-60 days past billing date            
Credit risk            
Total financial assets 319   447      
30-60 days past billing date | Cost/Gross amount            
Credit risk            
Total financial assets 336   466      
30-60 days past billing date | Allowance for doubtful accounts            
Credit risk            
Total financial assets (17)   (19)      
61-90 days past billing date            
Credit risk            
Total financial assets 75   125      
61-90 days past billing date | Cost/Gross amount            
Credit risk            
Total financial assets 96   146      
61-90 days past billing date | Allowance for doubtful accounts            
Credit risk            
Total financial assets (21)   (21)      
More than 90 days past billing date            
Credit risk            
Total financial assets 131   161      
More than 90 days past billing date | Cost/Gross amount            
Credit risk            
Total financial assets 177   206      
More than 90 days past billing date | Allowance for doubtful accounts            
Credit risk            
Total financial assets (46)   (45)      
Unbilled customer finance receivables            
Credit risk            
Total financial assets 1,457   1,553      
Unbilled customer finance receivables | Cost/Gross amount            
Credit risk            
Total financial assets 1,494   1,588      
Unbilled customer finance receivables | Allowance for doubtful accounts            
Credit risk            
Total financial assets $ (37)   $ (35)