REGULATORY CAPITAL REQUIREMENTS - Narratives (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Regulatory capital requirements
Actual, Ratio (as a percent)	4.5	7.0
Actual, Ratio (as a percent)	6.0	8.5
Actual, Ratio (as a percent)	8.0	10.5
Basel III
Regulatory capital requirements
Additional capital conservation buffer (as a percentage)	2.50%
Actual, Ratio (as a percent)	10.3	10.2
Actual, Ratio (as a percent)	10.3	10.2
Actual, Ratio (as a percent)	13.0	13.1