v3.25.4
SUBSEQUENT EVENTS (Details) - CAD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Feb. 12, 2026
Feb. 02, 2026
Jan. 02, 2026
Dec. 31, 2025
Dec. 31, 2024
Dec. 17, 2024
Subsequent Event [Line Items]            
Common share dividends       $ 788 $ 743  
Dividends per common share declared (in dollars per share)       $ 1.31 $ 1.24  
Hydro One Inc. | Chatham Lakeshore Limited Partnership            
Subsequent Event [Line Items]            
Business combination assets transferred       $ 16    
Ownership percentage           80.00%
Subsequent Event            
Subsequent Event [Line Items]            
Common share dividends $ 200          
Dividends per common share declared (in dollars per share) $ 0.3331          
Subsequent Event | Hydro One Inc. | Chatham Lakeshore Limited Partnership            
Subsequent Event [Line Items]            
Ownership percentage   50.00% 70.00%      
Subsequent Event | Chatham Lakeshore Limited Partnership | Walepole Island First Nation            
Subsequent Event [Line Items]            
Percentage of common shares acquired     10.00%      
Business combination assets transferred     $ 8      
Subsequent Event | Chatham Lakeshore Limited Partnership | Amjiwnaang First Nation And Chippewas of Kettle And Stony Point First Nation            
Subsequent Event [Line Items]            
Percentage of common shares acquired   20.00%        
Business combination assets transferred   $ 16