PENSION AND OTHER POSTRETIREMENT BENEFITS - DEFINED CONTRIBUTION PLAN (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) $ / employees	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Amount expensed and contributed | $	$ 4.0	$ 4.6	$ 3.4
Employees eligible for defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Matching percentage of participants' contributions	50.00%
Percentage of base compensation (up to)	6.00%
Employees ineligible for defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Matching percentage of participants' contributions	50.00%
Percentage of base compensation (up to)	8.00%
Year-end contribution (in dollars per employee) | $ / employees	1,500
Service threshold to determine year-end contribution (up to, more than)	10 years
Year-end contribution (in dollars per employee) | $ / employees	2,000
South Jersey Gas Company
Defined Benefit Plan Disclosure [Line Items]
Amount expensed and contributed | $	$ 1.2	$ 1.6	$ 1.2