INCOME TAXES - Effective income tax rate reconciliation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
INCOME TAXES
Tax at statutory rate	21.00%	21.00%
Nontaxable interest and dividends	(0.50%)	(0.40%)
Tax credits	(2.20%)	(1.70%)
State taxes	1.70%	1.50%
Other	1.20%	0.10%
Effective income tax rate reconciliation, percent, Total	21.20%	20.50%
Tax obligation under tax examinations		$ 4.0