REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - CAD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	$ 472	$ 470
Total long - term regulatory assets	7,147	5,237
Total regulatory assets	7,619	5,707
Regulatory Liabilities [Line Items]
Total current regulatory liabilities	616	307
Total long - term regulatory liabilities	6,112	3,521
Total regulatory liabilities	6,728	3,828
Purchase gas variance
Regulatory Liabilities [Line Items]
Total current regulatory liabilities	292	31
U.S income Taxes
Regulatory Liabilities [Line Items]
Total current regulatory liabilities	44	0
Total long - term regulatory liabilities	2,021	854
Other regulatory assets (liabilities)
Regulatory Liabilities [Line Items]
Total current regulatory liabilities	280	276
Total long - term regulatory liabilities	242	86
Future removal and restoration reserves
Regulatory Liabilities [Line Items]
Total long - term regulatory liabilities	2,964	1,693
Pipeline future abandonment costs
Regulatory Liabilities [Line Items]
Total long - term regulatory liabilities	826	745
Pension plan receivable
Regulatory Liabilities [Line Items]
Total long - term regulatory liabilities	59	143
Purchase gas variance
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	74	15
Under-recovery of fuel costs
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	4	75
Other regulatory assets (liabilities)
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	304	380
Total long - term regulatory assets	447	198
Deferred income taxes
Regulatory Assets [Line Items]
Total long - term regulatory assets	4,698	4,456
Deferred project costs
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	90	0
Total long - term regulatory assets	1,045	0
Long-term debt
Regulatory Assets [Line Items]
Total long - term regulatory assets	318	348
Negative salvage
Regulatory Assets [Line Items]
Total long - term regulatory assets	136	180
Demand-side management costs
Regulatory Assets [Line Items]
Total long - term regulatory assets	237	54
Pension plan receivable
Regulatory Assets [Line Items]
Total long - term regulatory assets	$ 266	$ 1