v3.25.4
Income taxes - Deferred Taxes Resulting From Temporary Differences (Details) - CAD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Reconciliation of changes in deferred tax liability (asset) [abstract]    
Beginning balance, deferred tax liability (asset) $ (5,108) $ (4,773)
Income statements (142) (95)
Business acquisitions (218) (94)
Other comprehensive (loss) income (464) (128)
Deficit 1 (26)
Net foreign exchange differences 2  
Reclassified to liabilities (assets) held for sale 0 0
Other 2 8
Ending balance, deferred tax liability (asset) (5,927) (5,108)
Non-capital loss carry-forwards    
Reconciliation of changes in deferred tax liability (asset) [abstract]    
Beginning balance, deferred tax liability (asset) 73 36
Income statements 84 31
Business acquisitions 243  
Net foreign exchange differences (3)  
Other   6
Ending balance, deferred tax liability (asset) 397 73
Post-employment benefit plans    
Reconciliation of changes in deferred tax liability (asset) [abstract]    
Beginning balance, deferred tax liability (asset) (634) (443)
Income statements 12 25
Business acquisitions 20 (3)
Other comprehensive (loss) income (229) (213)
Ending balance, deferred tax liability (asset) (831) (634)
Indefinite-life intangible assets    
Reconciliation of changes in deferred tax liability (asset) [abstract]    
Beginning balance, deferred tax liability (asset) (1,662) (1,805)
Income statements 90 148
Business acquisitions (37) (5)
Other (4)  
Ending balance, deferred tax liability (asset) (1,613) (1,662)
Property, plant and equipment and finite-life intangible assets    
Reconciliation of changes in deferred tax liability (asset) [abstract]    
Beginning balance, deferred tax liability (asset) (4,393) (4,069)
Income statements (167) (213)
Business acquisitions (520) (116)
Net foreign exchange differences 5  
Reclassified to liabilities (assets) held for sale 2 3
Other (3) 2
Ending balance, deferred tax liability (asset) (5,076) (4,393)
Lease liabilities    
Reconciliation of changes in deferred tax liability (asset) [abstract]    
Beginning balance, deferred tax liability (asset) 1,215 1,288
Income statements 88 102
Business acquisitions 12 32
Reclassified to liabilities (assets) held for sale (2) (3)
Ending balance, deferred tax liability (asset) 1,137 1,215
Other    
Reconciliation of changes in deferred tax liability (asset) [abstract]    
Beginning balance, deferred tax liability (asset) 293 220
Income statements (73) 16
Business acquisitions 64 (2)
Other comprehensive (loss) income (235) 85
Deficit 1 (26)
Other 9  
Ending balance, deferred tax liability (asset) $ 59 $ 293