ACQUISITIONS AND DISPOSITIONS - Schedule of Estimated Preliminary Fair Values Assigned to Net Assets (Details) - CAD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Goodwill	$ 35,765	$ 35,284

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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