REVENUE - Major Products and Services (Details) - CAD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									$ 24,199	$ 23,916	$ 19,432
Total revenue	$ 11,298	$ 9,844	$ 10,432	$ 12,075	$ 13,424	$ 11,573	$ 13,215	$ 15,097	$ 43,649	53,309	47,071
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]									Total revenue
Realized (loss) gain on derivative									$ (97)	(431)	59
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									155	127	70
Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									24,044	23,789	19,362
Transportation revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									17,991	17,077	14,532
Storage and other revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									1,073	893	648
Gas gathering and processing revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers										22	49
Gas distribution revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									4,859	5,643	4,026
Electricity and transmission revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									259	281	177
Commodity sales
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									17
Revenue not from contract with customers									18,964	29,150	26,873
Other Revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									486	243	766
Liquids Pipelines
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									12,132	11,518	9,639
Liquids Pipelines | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Liquids Pipelines | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									12,132	11,518	9,639
Gas Transmission and Midstream
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									5,780	5,384	4,668
Gas Transmission and Midstream | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									17	0	0
Gas Transmission and Midstream | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									5,763	5,384	4,668
Gas Distribution and Storage
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									6,028	6,733	4,948
Gas Distribution and Storage | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									138	127	70
Gas Distribution and Storage | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									5,890	6,606	4,878
Renewable Power Generation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									259	281	177
Renewable Power Generation | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Renewable Power Generation | Transferred Over Time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									259	281	177
Business Segments | Liquids Pipelines
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									12,132	11,518	9,639
Total revenue									12,863	12,052	10,581
Business Segments | Liquids Pipelines | Transportation revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									11,875	11,283	9,492
Business Segments | Liquids Pipelines | Storage and other revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									257	235	147
Business Segments | Liquids Pipelines | Gas gathering and processing revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers										0	0
Business Segments | Liquids Pipelines | Gas distribution revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Liquids Pipelines | Electricity and transmission revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Liquids Pipelines | Commodity sales
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0
Revenue not from contract with customers									0	0	0
Business Segments | Liquids Pipelines | Other Revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									257	(81)	375
Business Segments | Gas Transmission and Midstream
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									5,780	5,384	4,668
Total revenue									5,854	5,426	4,711
Business Segments | Gas Transmission and Midstream | Transportation revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									5,302	5,012	4,364
Business Segments | Gas Transmission and Midstream | Storage and other revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									461	350	255
Business Segments | Gas Transmission and Midstream | Gas gathering and processing revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers										22	49
Business Segments | Gas Transmission and Midstream | Gas distribution revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Gas Transmission and Midstream | Electricity and transmission revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Gas Transmission and Midstream | Commodity sales
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									17
Revenue not from contract with customers									0	0	0
Business Segments | Gas Transmission and Midstream | Other Revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									72	39	42
Business Segments | Gas Distribution and Storage
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									6,028	6,733	4,948
Total revenue									5,976	6,729	4,980
Business Segments | Gas Distribution and Storage | Transportation revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									814	782	676
Business Segments | Gas Distribution and Storage | Storage and other revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									355	308	246
Business Segments | Gas Distribution and Storage | Gas gathering and processing revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers										0	0
Business Segments | Gas Distribution and Storage | Gas distribution revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									4,859	5,643	4,026
Business Segments | Gas Distribution and Storage | Electricity and transmission revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Gas Distribution and Storage | Commodity sales
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0
Revenue not from contract with customers									0	0	0
Business Segments | Gas Distribution and Storage | Other Revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									(58)	(20)	13
Business Segments | Renewable Power Generation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									259	281	177
Total revenue									477	582	512
Business Segments | Renewable Power Generation | Transportation revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Renewable Power Generation | Storage and other revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Renewable Power Generation | Gas gathering and processing revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers										0	0
Business Segments | Renewable Power Generation | Gas distribution revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Renewable Power Generation | Electricity and transmission revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									259	281	177
Business Segments | Renewable Power Generation | Commodity sales
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0
Revenue not from contract with customers									0	0	0
Business Segments | Renewable Power Generation | Other Revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									215	305	336
Business Segments | Energy Services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Total revenue									18,989	29,175	26,917
Business Segments | Energy Services | Transportation revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Energy Services | Storage and other revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Energy Services | Gas gathering and processing revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers										0	0
Business Segments | Energy Services | Gas distribution revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Energy Services | Electricity and transmission revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Business Segments | Energy Services | Commodity sales
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0
Revenue not from contract with customers									18,964	29,150	26,873
Business Segments | Energy Services | Other Revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									0	0	0
Eliminations and Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Total revenue									(510)	(655)	(630)
Eliminations and Other | Transportation revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Eliminations and Other | Storage and other revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Eliminations and Other | Gas gathering and processing revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers										0	0
Eliminations and Other | Gas distribution revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Eliminations and Other | Electricity and transmission revenue
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0	0	0
Eliminations and Other | Commodity sales
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers									0
Revenue not from contract with customers									0	0	0
Eliminations and Other | Other Revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									0	0	0
Intersegment revenue
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									(510)	(655)	(630)
Intersegment revenue | Liquids Pipelines
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									474	615	567
Intersegment revenue | Gas Transmission and Midstream
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									2	3	1
Intersegment revenue | Gas Distribution and Storage
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									6	16	19
Intersegment revenue | Renewable Power Generation
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									3	(4)	(1)
Intersegment revenue | Energy Services
Disaggregation of Revenue [Line Items]
Revenue not from contract with customers									$ 25	$ 25	$ 44