v3.25.4
Income taxes (Reconciliation of Income Tax Expense) (Details) - CAD ($)
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Amount      
Income tax expense at Canadian statutory federal tax rate $ 940,000,000 $ 878,000,000 $ 973,000,000
Canadian federal reconciling items:      
Nontaxable or nondeductible items, net (1,000,000)    
Canadian provincial income taxes, net of federal effect 537,000,000    
Provincial and foreign income taxes   582,000,000 633,000,000
Tax-deductible goodwill and related impacts   0 (713,000,000)
Foreign tax affects      
Federal tax rate differential 46,000,000    
Other   (56,000,000) (30,000,000)
Income tax expense 1,544,000,000 1,404,000,000 863,000,000
Net cash payments for income taxes $ 935,000,000 $ 1,221,000,000 $ 1,197,000,000
Rate      
Income tax expense at Canadian statutory federal tax rate 15.00% 15.00% 15.00%
Nontaxable or nondeductible items, net 0.00%    
Canadian provincial income taxes, net of federal effect 8.60%    
Federal tax rate differential 0.70%    
Effective tax rate 24.60%    
Unrecognized tax benefits $ 0    
Canada      
Foreign tax affects      
Other $ (14,000,000)    
Rate      
Other (0.20%)    
U.S.      
Foreign tax affects      
Other $ 36,000,000    
Rate      
Other 0.50%    
Non-US      
Rate      
Deferred income tax recovery     $ 767,000,000
Income tax expense related to the foregone tax deduction     85,000,000
Non-US | Tax Years Prior To 2023      
Rate      
Income tax expense related to the foregone tax deduction     $ 54,000,000