QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - CAD ($) $ / shares in Units, $ 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
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 13,424	$ 11,573	$ 13,215	$ 15,097	$ 12,470	$ 11,466	$ 10,948	$ 12,187	$ 53,309	$ 47,071	$ 39,087
Operating income/(loss)	(540)	1,778	1,520	2,420	2,053	1,388	1,816	2,548	5,178	7,805	7,957
Earnings	(1,109)	1,383	607	2,057	1,965	814	1,521	2,014	2,938	6,314	3,416
Earnings/(loss) attributable to controlling interests	(983)	1,362	595	2,029	1,933	780	1,484	1,992	3,003	6,189	3,363
Earnings/(loss) attributable to common shareholders	$ (1,067)	$ 1,279	$ 450	$ 1,927	$ 1,840	$ 682	$ 1,394	$ 1,900	$ 2,589	$ 5,816	$ 2,983
Earnings/(loss) per common share
Earnings (loss) per common share attributable to common shareholders (in CAD per share)	$ (0.53)	$ 0.63	$ 0.22	$ 0.95	$ 0.91	$ 0.34	$ 0.69	$ 0.94	$ 1.28	$ 2.87	$ 1.48
Diluted earnings per common share attributable to common shareholders (in CAD per share)	$ (0.53)	$ 0.63	$ 0.22	$ 0.95	$ 0.91	$ 0.34	$ 0.69	$ 0.94	$ 1.28	$ 2.87	$ 1.48