SHARE CAPITAL - COMMON SHARES (Details) - CAD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Common Shares
Balance at beginning of period (in shares)	2,026
Balance at end of period (in shares)	2,026	2,026
Common Shares
Common Shares
Balance at beginning of period (in shares)	2,026	2,025	2,022
Balance at beginning of period, Amount	$ 64,768	$ 64,746	$ 64,677
Shares issued on exercise of stock options (in shares)	0	1	3
Shares issued on exercise of stock options	$ 31	$ 22	$ 69
Balance at end of period (in shares)	2,026	2,026	2,025
Balance at end of period, Amount	$ 64,799	$ 64,768	$ 64,746