v3.25.4
POST-EMPLOYMENT BENEFITS - Present Value of Accrued Plan Benefits and Estimated Market Values of Net Assets (Details) - CAD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of defined benefit plans [line items]    
Net deferred pension asset $ (93) $ (93)
Domestic defined benefit plans    
Disclosure of defined benefit plans [line items]    
Plan assets, at fair value 2,514 2,385
Accrued benefit obligations (2,249) (2,197)
Surplus of plan assets over accrued benefit obligations 265 188
Effect of asset ceiling limit (53) (13)
Net deferred pension asset 212 175
Deferred pension asset 217 183
Deferred pension liability $ (5) $ (8)