SEGMENTED INFORMATION - Geographic Information (Details) - CAD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Geographic Information
Revenues (Note 4)	$ 13,424	$ 11,573	$ 13,215	$ 15,097	$ 12,470	$ 11,466	$ 10,948	$ 12,187	$ 53,309	$ 47,071	$ 39,087
Property, plant and equipment, net	104,460				100,067				104,460	100,067	94,571
Canada
Geographic Information
Revenues (Note 4)									27,498	20,474	16,453
Property, plant and equipment, net	47,602				47,102				47,602	47,102
US
Geographic Information
Revenues (Note 4)									25,811	26,597	$ 22,634
Property, plant and equipment, net	$ 56,858				$ 52,965				$ 56,858	$ 52,965