v3.25.4
POST-EMPLOYMENT BENEFITS - Remeasurement Recognized in OCI and Equity (Details) - CAD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of net defined benefit liability (asset) [line items]    
Return on plan assets (excluding interest income) $ 140 $ 209
Change in asset ceiling (40) (10)
Domestic defined benefit plans    
Disclosure of net defined benefit liability (asset) [line items]    
Return on plan assets (excluding interest income) 26 101
Change in financial assumptions 119 70
Effect of experience adjustments 7 15
Remeasurement gain, recognized in other comprehensive income and equity $ 112 $ 176