SHARE CAPITAL - Common Shares (Details) - CAD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Common Shares
Balance at beginning of period (in shares)	2,026
Share purchases at stated value (in shares)	(3)	0	0
Share purchases at stated value	$ (88)	$ 0	$ 0
Other	$ (4)	$ 0	$ 0
Other ( in shares)	0	0	0
Balance at end of period (in shares)	2,025	2,026
Common Shares
Common Shares
Balance at beginning of period (in shares)	2,026	2,026	2,025
Balance at beginning of period, Amount	$ 64,799	$ 64,768	$ 64,746
Shares issued on exercise of stock options (in shares)	2	0	1
Shares issued on exercise of stock options	$ 53	$ 31	$ 22
Share purchases at stated value	$ (88)	$ 0	$ 0
Balance at end of period (in shares)	2,025	2,026	2,026
Balance at end of period, Amount	$ 64,760	$ 64,799	$ 64,768