v3.26.1
RELATED PARTY TRANSACTIONS - Tax consolidation transactions (Details) - CAD ($)
$ in Millions
12 Months Ended
Oct. 08, 2025
Apr. 17, 2024
Nov. 01, 2023
Dec. 31, 2024
Related Parties        
Subordinated loan from the parent corporation       $ (1,530.0)
Parent        
Related Parties        
Subordinated loan from the parent corporation       (1,530.0)
Subordinated loan granted during the period   $ 1,530.0    
Interest rate on subordinated loan (in percentage)   9.25%    
Parent | Series C preference shares        
Related Parties        
Repayment of subordinated loan     $ 1,595.0  
Parent | Series G preference shares        
Related Parties        
Repayment of subordinated loan $ 1,530.0      
9346-9963 Quebec Inc | Series C preference shares        
Related Parties        
Number of preferred shares redeemed     1,595,000  
Payments for redemption of preferred stock in cash     $ 1,595.0  
9511-8063 Quebec Inc | Series G preference shares        
Related Parties        
Investment in an affiliated corporation   $ 1,530.0    
Number of preferred shares redeemed 1,530,000      
Preferred stock annual dividend rate (in percentage)   9.35%    
Redeemable preferred shares acquired (in shares)   1,530,000    
Payments for redemption of preferred stock in cash $ 1,530.0      
Other affiliated corporations        
Related Parties        
Investment in an affiliated corporation       $ 1,530.0