ACQUISITIONS AND DISPOSITIONS - Equity Investment Transaction (Narrative) (Details) $ in Millions, $ in Millions	Jul. 17, 2025 CAD ($)	Jul. 17, 2025 USD ($)	May 29, 2024 CAD ($)	May 29, 2024 USD ($)
Whistler Parent JV
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)			19.00%	19.00%
Cash consideration includes an upfront payment			$ 487	$ 357
Reduction to property, plant and equipment, net and increase to long-term investments			$ 321	$ 235
Whistler Parent JV | WhiteWaterI Squared
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)			50.60%	50.60%
Whistler Parent JV | MPLX
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)			30.40%	30.40%
Whistler Parent JV | Subsequent Event
Schedule of Equity Method Investments [Line Items]
Net proceeds on redemption	$ 180	$ 130
Rio Bravo
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)			100.00%	100.00%
Economic interest in joint venture			25.00%	25.00%
Capital Expenditure, Discontinued Operations				$ 150