OTHER INCOME/(EXPENSE) (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Other Income and Expenses [Abstract]
Realized foreign currency gain/(loss)	$ (104)	$ (8)	$ (286)	$ 114
Unrealized foreign currency gain/(loss)	1,194	(213)	1,249	(1,071)
Net defined pension and OPEB credit	72	48	144	89
Other	207	142	382	286
Total	$ 1,369	$ (31)	$ 1,489	$ (582)