v3.25.4
Long Term Debt - Carrying Value of Long-Term Debt Instruments (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2025
CAD ($)
Dec. 31, 2025
$ / shares
Dec. 31, 2024
CAD ($)
Disclosure of detailed information about borrowings [line items]      
Long-term debt $ 7,685   $ 6,629
3.050% Senior notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 3.05%    
Debt instrument, par value | $ / shares   $ 1,155  
Long-term debt $ 1,583   1,659
5.375% Senior notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 5.375%    
Debt instrument, par value | $ / shares   750  
Long-term debt $ 1,017   1,067
Debt instrument basis points 4000.00%    
4.986% Senior Notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 4.986%    
Debt instrument, par value | $ / shares   1,000  
Long-term debt $ 1,362   0
Debt instrument basis points 1500.00%    
3.703% Senior notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 3.703%    
Debt instrument, par value | $ / shares   750  
Long-term debt $ 1,024   1,074
Debt instrument basis points 2500.00%    
2.396% Senior notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 2.396%    
Debt instrument, par value | $ / shares   200  
Long-term debt $ 274   287
Debt instrument basis points 3000.00%    
2.484% Senior notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 2.484%    
Debt instrument, par value | $ / shares   500  
Long-term debt $ 684   717
Debt instrument basis points 3000.00%    
3.527% Senior notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 3.527%    
Debt instrument, par value | $ / shares   270  
Long-term debt $ 370   388
Debt instrument basis points 2000.00%    
4.150% Senior notes      
Disclosure of detailed information about borrowings [line items]      
Borrowings, interest rate 4.15%    
Debt instrument, par value | $ / shares   $ 1,000  
Long-term debt $ 1,371   $ 1,437
Debt instrument basis points 3500.00%