REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - CAD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	$ 470	$ 604
Total long - term regulatory assets	5,237	5,863
Total regulatory assets	5,707	6,467
Regulatory Liabilities [Line Items]
Total current regulatory liabilities	307	167
Total long - term regulatory liabilities	3,521	3,624
Total regulatory liabilities	3,828	3,791
Purchase gas variance
Regulatory Liabilities [Line Items]
Total current regulatory liabilities	31	0
Other regulatory assets (liabilities)
Regulatory Liabilities [Line Items]
Total current regulatory liabilities	276	167
Total long - term regulatory liabilities	86	250
Future removal and restoration reserves
Regulatory Liabilities [Line Items]
Total long - term regulatory liabilities	1,693	1,615
U.S income Taxes
Regulatory Liabilities [Line Items]
Total long - term regulatory liabilities	854	918
Pipeline future abandonment costs (Note 23)
Regulatory Liabilities [Line Items]
Total long - term regulatory liabilities		610
Pension plans and OPEB
Regulatory Liabilities [Line Items]
Total long - term regulatory liabilities	143	231
Purchase gas variance
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	15	190
Total long - term regulatory assets	0	244
Under-recovery of fuel costs
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	75	109
Other regulatory assets (liabilities)
Regulatory Assets [Line Items]
Total current regulatory assets (Note9)	380	305
Total long - term regulatory assets	252	244
Deferred income taxes
Regulatory Assets [Line Items]
Total long - term regulatory assets	4,456	4,473
Long-term debt
Regulatory Assets [Line Items]
Total long - term regulatory assets	348	378
Negative salvage
Regulatory Assets [Line Items]
Total long - term regulatory assets	180	265
Accounting policy changes
Regulatory Assets [Line Items]
Total long - term regulatory assets	0	219
Pension plans and OPEB
Regulatory Assets [Line Items]
Total long - term regulatory assets	$ 1	$ 40