OTHER INCOME/(EXPENSE) (Details) - CAD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Other Income and Expenses [Abstract]
Realized foreign currency gain/(loss)	$ (34)	$ 31	$ 80	$ 177
Unrealized foreign currency gain/(loss)	255	(652)	(816)	(348)
Net defined pension and OPEB credit	44	34	133	101
Other	111	122	397	282
Total	$ 376	$ (465)	$ (206)	$ 212