v3.25.4
Goodwill - Changes in carrying amounts of goodwill (Details) - CAD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Sep. 30, 2024
Dec. 31, 2025
Dec. 31, 2024
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   $ 10,261 $ 10,942
Impairment loss recognised in profit or loss, goodwill $ (1,132)    
Goodwill, end of period   13,231 10,261
Cost      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   11,393 10,942
Acquisitions and disposition   2,989  
Additional recognition, goodwill     451
Net foreign exchange differences   (19)  
Goodwill, end of period   14,363 11,393
Accumulated impairment      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   (1,132) 0
Impairment loss recognised in profit or loss, goodwill     (1,132)
Goodwill, end of period   (1,132) (1,132)
Bell CTS      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   8,266 8,099
Goodwill, end of period     8,266
Bell CTS | Canadian      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   8,266  
Goodwill, end of period   8,286 8,266
Bell CTS | Foreign      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   0  
Goodwill, end of period   3,003 0
Bell CTS | Cost      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   8,266 8,099
Additional recognition, goodwill     167
Goodwill, end of period     8,266
Bell CTS | Cost | Canadian      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   8,266  
Acquisitions and disposition   20  
Net foreign exchange differences   0  
Goodwill, end of period   8,286 8,266
Bell CTS | Cost | Foreign      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   0  
Acquisitions and disposition   3,022  
Net foreign exchange differences   (19)  
Goodwill, end of period   3,003 0
Bell CTS | Accumulated impairment      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   0 0
Impairment loss recognised in profit or loss, goodwill     0
Goodwill, end of period     0
Bell CTS | Accumulated impairment | Canadian      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   0  
Goodwill, end of period   0 0
Bell CTS | Accumulated impairment | Foreign      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   0  
Goodwill, end of period   0 0
Bell Media      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   1,995 2,843
Impairment loss recognised in profit or loss, goodwill $ (1,132)    
Goodwill, end of period   1,942 1,995
Bell Media | Cost      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   3,127 2,843
Acquisitions and disposition   (53)  
Additional recognition, goodwill     284
Net foreign exchange differences   0  
Goodwill, end of period   3,074 3,127
Bell Media | Accumulated impairment      
Reconciliation of changes in intangible assets and goodwill [abstract]      
Goodwill at beginning of period   (1,132) 0
Impairment loss recognised in profit or loss, goodwill     (1,132)
Goodwill, end of period   $ (1,132) $ (1,132)