SHARE CAPITAL - Common Shares (Details) - CAD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)	2,025
Shares issued, net of issue costs (in shares)	103
Shares issued, net of issue costs	$ 4,485
Shares issued on vesting of RSU, net of tax (in shares)	0
Shares issued on vesting of RSUs, net of tax	$ 12
Balance at end of period (in shares)	2,125	2,025
Common Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)	2,025	2,026	2,026
Balance at beginning of period, amount	$ 64,760	$ 64,799	$ 64,768
Shares issued on exercise of stock options (in shares)	0	2	0
Shares issued on exercise of stock options	$ 3	$ 53	$ 31
Share purchases at stated value (in shares)	(3)	(3)	0
Share purchases at stated value	$ (80)	$ (88)	$ 0
Other ( in shares)	0	0	0
Other	$ 0	$ (4)	$ 0
Balance at end of period (in shares)	2,125	2,025	2,026
Balance at end of period, amount	$ 69,180	$ 64,760	$ 64,799