REVENUE - Recognition and Measurement of Revenues (Details) - CAD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 5,733	$ 5,171	$ 18,438	$ 17,976
Revenues from products transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	68	38	208	105
Revenue from products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,665	5,133	18,230	17,871
Liquids Pipelines
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,971	2,921	9,108	8,991
Liquids Pipelines | Revenues from products transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
Liquids Pipelines | Revenue from products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,971	2,921	9,108	8,991
Gas Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,444	1,412	4,426	4,294
Gas Transmission | Revenues from products transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	37	0	115	0
Gas Transmission | Revenue from products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,407	1,412	4,311	4,294
Gas Distribution and Storage
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,282	759	4,767	4,471
Gas Distribution and Storage | Revenues from products transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	31	38	93	105
Gas Distribution and Storage | Revenue from products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,251	721	4,674	4,366
Renewable Power Generation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	36	79	137	220
Renewable Power Generation | Revenues from products transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0	0
Renewable Power Generation | Revenue from products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 36	$ 79	$ 137	$ 220