OTHER INCOME/(EXPENSE) (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Other Income and Expenses [Abstract]
Realized foreign currency gain/(loss)	$ (8)	$ 1	$ 114	$ 146
Unrealized foreign currency gain/(loss)	(213)	492	(1,071)	304
Net defined pension and OPEB credit	48	34	89	67
Other	142	48	286	160
Total	$ (31)	$ 575	$ (582)	$ 677