v3.25.4
Post-employment benefit plans - Components of Post-Employment Benefit Plans Service Cost (Details) - CAD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of defined benefit plans [line items]    
DC pension $ (132) $ (136)
Capitalized benefit plans cost 60 63
Total post-employment benefit plans service cost (198) (208)
DB pension    
Disclosure of defined benefit plans [line items]    
Current service cost (125) (134)
OPEBs    
Disclosure of defined benefit plans [line items]    
Current service cost $ (1) $ (1)