COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Noncontrolling Interest [Line Items]
Dividends on preferred stock	$ 7,519	$ 7,519	$ 7,519
Noncontrolling interest - preferred stock of subsidiaries	155,569	155,570
CL&P and NSTAR Electric
Noncontrolling Interest [Line Items]
Dividends on preferred stock	$ 7,500	$ 7,500	$ 7,500