v3.25.4
REVENUE - Narrative (Details) - CAD ($)
$ in Millions
 12 Months Ended
Jul. 01, 2025
Jan. 01, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Decrease in amortization expense     $ 30 $ 115  
Other revenue recognized under IFRS 16 or IFRS 9     $ 241 $ 159  
Minimum          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Device, finance period     36 months    
Deferred commission cost assets, amortization period     12 months    
Maximum          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Device, finance period     48 months    
Deferred commission cost assets, amortization period     90 months    
Service revenue | Minimum          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Expected period of recognition     3 years    
Service revenue | Maximum          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Expected period of recognition     5 years    
Wireless          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Deferred commission cost assets, amortization period 35 months 32 months     24 months
Wireless | Service revenue          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Typical payment period     30 days    
Wireless | Equipment revenue          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Typical payment period     24 months    
Cable          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Deferred commission cost assets, amortization period   32 months     24 months
Cable | Service revenue          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Typical payment period     30 days    
Cable | Equipment revenue          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Typical payment period     24 months    
Media          
Disclosure of disaggregation of revenue from contracts with customers [line items]          
Typical payment period     30 days