LONG-TERM INVESTMENTS - Schedule of Combined Financial Information (Details) - CAD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income statement information
Revenues	$ 16,217	$ 14,882	$ 11,336	$ 11,038	$ 11,298	$ 9,844	$ 10,432	$ 12,075	$ 53,473	$ 43,649	$ 53,309
Earnings	618	1,447	2,001	1,565	1,568	623	2,001	1,866	5,631	6,058	2,938
Earnings attributable to controlling interests	595	$ 1,391	$ 1,943	$ 1,512	1,818	$ 621	$ 1,935	$ 1,817	5,441	6,191	3,003
Balance sheet information
Current assets	13,163				14,399				13,163	14,399
Current liabilities	23,812				17,435				23,812	17,435
Noncontrolling interests	2,993				3,029				2,993	3,029
Unconsolidated equity method investments
Income statement information
Revenues									20,657	22,586	30,026
Operating expenses									14,692	17,111	23,835
Earnings									5,177	4,818	5,123
Earnings attributable to controlling interests									2,304	1,816	$ 2,056
Balance sheet information
Current assets	8,611				5,842				8,611	5,842
Non-current assets	69,381				61,141				69,381	61,141
Current liabilities	7,240				6,194				7,240	6,194
Non-current liabilities	27,491				23,957				27,491	23,957
Noncontrolling interests	$ 4,979				$ 4,124				$ 4,979	$ 4,124