ACQUISITION AND DISPOSITIONS - Narrative (Details) $ / shares in Units, $ in Millions, $ in Millions										1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 08, 2023 CAD ($) $ / shares shares	Sep. 05, 2023 CAD ($)	Sep. 05, 2023 USD ($)	Apr. 03, 2023 CAD ($)	Apr. 03, 2023 USD ($)	Sep. 27, 2022 CAD ($)	Sep. 27, 2022 USD ($)	Aug. 17, 2022 CAD ($)	Aug. 17, 2022 USD ($)	Sep. 30, 2023 CAD ($) offering	Sep. 30, 2023 USD ($) offering	Sep. 30, 2023 CAD ($) offering	Sep. 30, 2022 CAD ($)	Sep. 30, 2023 CAD ($) offering	Sep. 30, 2022 CAD ($)	Apr. 03, 2023 USD ($)	Oct. 05, 2022 CAD ($)	Sep. 28, 2022 pipeline _community	Sep. 27, 2022 USD ($)	Aug. 16, 2022
Business Acquisition [Line Items]
Proceeds from sale of equity method investments								$ 522.0	$ 404					$ 0.0	$ 522.0
Gain on joint venture merger transaction								$ 1,100.0	$ 832			$ 0.0	$ 1,076.0	0.0	$ 1,076.0
Public Offering
Business Acquisition [Line Items]
Public offering common shares (in shares) | shares	102,913,500
Offering price per share ( in cad per share) | $ / shares	$ 44.7
Proceeds of common shares value	$ 4,600.0													$ 4,600.0
Private Placement
Business Acquisition [Line Items]
Sale of stock, number of offerings | offering										2	2	2		2
Private Placement, One
Business Acquisition [Line Items]
Sale of stock, consideration received on transaction											$ 2,000
Private Placement, Two
Business Acquisition [Line Items]
Sale of stock, consideration received on transaction										$ 1,000.0
Athabasca Indigenous Investments Limited Partnership
Business Acquisition [Line Items]
Number of communities represented | _community																		23
Athabasca Regional Oil Sands System
Business Acquisition [Line Items]
Number of pipelines to be sold | pipeline																		7
Total consideration																	$ 1,100.0
Gray Oak Holdings LLC
Business Acquisition [Line Items]
Ownership interest (in percent)								58.50%	58.50%											22.80%
DCP LLC
Business Acquisition [Line Items]
Ownership interest (in percent)								13.20%	13.20%											28.30%
Athabasca Regional Oil Sands System | Athabasca Regional Oil Sands System
Business Acquisition [Line Items]
Non-operating interest (percent)																		11.60%
Noncontrolling interest (percent)																		88.40%
The East Ohio Gas Company, Questar Gas Company, And Wexpro Companies
Business Acquisition [Line Items]
Purchase price		$ 19,100.0	$ 14,000
Cash consideration		12,800.0	9,400
Assumed debt		$ 6,300.0	$ 4,600
Tres Palacios Holdings LLC
Business Acquisition [Line Items]
Cash consideration				$ 451.0	$ 335
Property, plant and equipment				790.0												$ 588
Cavern right-of-use assets				254.0												189
Current portion of long-term debt				7.0												5
Long-term debt				$ 248.0												$ 184
Tri Global Energy, LLC
Business Acquisition [Line Items]
Purchase price						$ 344.0
Cash consideration						295.0	$ 215
Property, plant and equipment						3.0
Long-term debt						18.0
Business combination, additional contingent consideration (up to)						$ 72.0													$ 53