OTHER INCOME (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Other Income and Expenses [Abstract]
Gain/(loss) on dispositions	$ 8	$ 1	$ 11	$ (1)
Realized foreign currency gain	1	2	146	4
Unrealized foreign currency gain/(loss)	492	(583)	304	(216)
Net defined pension and OPEB credit	34	59	67	117
Other	40	22	149	55
Total	$ 575	$ (499)	$ 677	$ (41)