RELATED PARTY TRANSACTIONS - Narrative (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
RELATED PARTY TRANSACTIONS
Affiliate loan receivable	$ 954	$ 1,108
Interest income	$ 39	$ 44	$ 40
Minimum
RELATED PARTY TRANSACTIONS
Annual interest rate on the loans (as a percent)	3.00%
Maximum
RELATED PARTY TRANSACTIONS
Annual interest rate on the loans (as a percent)	8.00%