ACQUISITIONS AND DISPOSITIONS - Summary of Estimated Fair Values Assigned to Net Assets (Details) $ in Millions, $ in Millions	Nov. 01, 2023 CAD ($)	Sep. 27, 2022 CAD ($)	Sep. 27, 2022 USD ($)	Oct. 12, 2021 CAD ($)	Oct. 12, 2021 USD ($)	Dec. 31, 2023 CAD ($)	Nov. 01, 2023 USD ($)	Dec. 31, 2022 CAD ($)	Sep. 27, 2022 USD ($)	Dec. 31, 2021 CAD ($)	Oct. 12, 2021 USD ($)
Fair value of net assets acquired:
Goodwill						$ 31,848		$ 32,440		$ 32,775
Purchase price:
Goodwill expected tax deductible period	15 years
Aitken Creek Gas Storage Facility
Fair value of net assets acquired:
Current assets	$ 105
Property, plant and equipment	466
Current liabilities	20
Long-term liabilities	130
Goodwill	46					$ 46
Purchase price:
Cash	397
Contingent consideration	70
Purchase price	$ 467
Expected useful life	3 years 6 months						3 years 6 months
Tri Global Energy, LLC
Fair value of net assets acquired:
Current assets		$ 5
Property, plant and equipment		3
Long-term investments		8
Intangible assets		117
Long-term assets		3
Current liabilities		61
Long-term debt		18
Long-term liabilities		105
Goodwill		392						$ 392
Purchase price:
Cash		295	$ 215
Contingent consideration		49					$ 36
Purchase price		$ 344
Expected useful life		3 years 6 months							3 years 6 months
Goodwill expected tax deductible period		15 years	15 years
Contingent future payment (up to)		$ 72					$ 53		$ 53
Moda Midstream Operating, LLC (Moda)
Fair value of net assets acquired:
Current assets				$ 62
Property, plant and equipment				1,480
Long-term investments				427
Intangible assets				1,781
Current liabilities				59
Long-term liabilities				17
Goodwill				268
Purchase price:
Cash				3,755	$ 3,000
Contingent consideration				187							$ 150
Purchase price				$ 3,942
Ownership interest acquired (as a percent)				20.00%							20.00%
Amortized on a straight-line basis over an expected useful life				10 years	10 years
Tax deductible period				15 years	15 years