REVENUE - Schedule of Recognition and Measurement of Revenues (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 6,523	$ 5,927	$ 15,332	$ 12,705
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	59	71	119	140
Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	6,464	5,856	15,213	12,565
Liquids Pipelines
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,970	3,051	6,143	6,137
Liquids Pipelines | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
Liquids Pipelines | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,970	3,051	6,143	6,137
Gas Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,539	1,463	3,216	2,982
Gas Transmission | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	28	38	52	78
Gas Transmission | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,511	1,425	3,164	2,904
Gas Distribution and Storage
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,962	1,369	5,879	3,485
Gas Distribution and Storage | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	31	33	67	62
Gas Distribution and Storage | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,931	1,336	5,812	3,423
Renewable Power Generation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	52	44	94	101
Renewable Power Generation | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
Renewable Power Generation | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 52	$ 44	$ 94	$ 101