LEASES - LEASE COMMITMENTS (Details) - CAD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Operating leases
2022	$ 117
2023	98
2024	91
2025	84
2026	72
Thereafter	455
Total undiscounted lease payments	917
Less imputed interest	(213)
Total	704	$ 761
Finance leases
2022	15
2023	13
2024	9
2025	2
2026	1
Thereafter	11
Total undiscounted lease payments	51
Less imputed interest	(5)
Total finance lease liabilities	$ 46	$ 53