v3.26.1
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS - Schedule of Unrealized Gains and Losses Associated With Changes in The Fair Value of Non-Qualifying Derivatives (Details) - CAD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives $ (893) $ 92
Non- Qualifying Derivative Instruments    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives (940) 84
Foreign exchange contracts | Non- Qualifying Derivative Instruments    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives (428) 38
Interest rate contracts | Non- Qualifying Derivative Instruments    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives 32 (73)
Commodity contracts | Non- Qualifying Derivative Instruments    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives (544) 122
Regulatory asset 47  
Regulatory liabilitiy   8
Commodity contracts | Non- Qualifying Derivative Instruments | Transportation revenue    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives (8) 86
Commodity contracts | Non- Qualifying Derivative Instruments | Commodity sales    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives (376) (24)
Commodity contracts | Non- Qualifying Derivative Instruments | Commodity costs    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives (95) 70
Commodity contracts | Non- Qualifying Derivative Instruments | Operating and administrative expense    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives (18) (2)
Other contracts | Non- Qualifying Derivative Instruments    
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income    
Unrealized gain (loss) on derivatives $ 0 $ 3