v3.26.1
Financial Instruments - Maturity Dates for Financial Liabilities (Details) - CAD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of detailed information about financial instruments [line items]      
Accounts payable $ 1,105 $ 1,079  
Accrued liabilities 4,255 4,525  
Long-term debt 16,617 18,819  
Other long-term liabilities 11,936 9,302  
Interest and other financing expense 1,039 673 $ 691
Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 16,707 18,909  
Less than 1 year | Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 441    
Less than 1 year | Liquidity risk      
Disclosure of detailed information about financial instruments [line items]      
Accounts payable 1,105 1,079  
Accrued liabilities 4,255 4,525  
Other long-term liabilities 381 263  
Lease payments included In liablities 373 255  
Less than 1 year | Liquidity risk | Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 441 2,400  
Interest and other financing expense 971 1,024  
1 to less than 2 years | Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 5,637    
1 to less than 2 years | Liquidity risk      
Disclosure of detailed information about financial instruments [line items]      
Accounts payable 0 0  
Accrued liabilities 0 0  
Other long-term liabilities 268 187  
Lease payments included In liablities 268 187  
1 to less than 2 years | Liquidity risk | Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 5,637 941  
Interest and other financing expense 910 951  
2 to less than 5 years | Liquidity risk      
Disclosure of detailed information about financial instruments [line items]      
Accounts payable 0 0  
Accrued liabilities 0 0  
Other long-term liabilities 659 405  
Lease payments included In liablities 654 405  
2 to less than 5 years | Liquidity risk | Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 2,489 7,494  
Interest and other financing expense 1,860 1,978  
Thereafter | Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 8,140    
Thereafter | Liquidity risk      
Disclosure of detailed information about financial instruments [line items]      
Accounts payable 0 0  
Accrued liabilities 0 0  
Other long-term liabilities 1,863 617  
Lease payments included In liablities 1,811 617  
Thereafter | Liquidity risk | Gross carrying amount      
Disclosure of detailed information about financial instruments [line items]      
Long-term debt 8,140 8,074  
Interest and other financing expense $ 3,678 $ 3,574