v3.26.1
PENSION PLANS AND POSTRETIREMENT BENEFITS - Components of the net benefit costs (Details) - CAD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Employee costs:      
Defined contribution expense $ 17.1 $ 17.0 $ 16.3
Expected employer contributions in the next fiscal year 1.0    
Pension and postretirement benefits      
Employee costs:      
Service costs 14.1 14.6 10.6
Plan amendments, administrative fees and other 1.2 0.8 0.7
Interest on net defined benefit liability 1.7 1.7 1.0
Net benefit costs $ 17.0 $ 17.1 $ 12.3