PENSION AND OTHER POSTRETIREMENT BENEFITS - RECONCILIATIONS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in Plan Assets:
Employer Contributions	$ 5,400,000	$ 0	$ 0
South Jersey Gas Company
Change in Plan Assets:
Employer Contributions	5,000,000	0	0
Pension Benefits
Change in Benefit Obligations:
Benefit Obligation at Beginning of Year	481,848,000	439,373,000
Service Cost	5,887,000	5,871,000	5,583,000
Interest Cost	13,028,000	15,017,000	17,294,000
Actuarial (Gain) Loss	(10,823,000)	48,316,000
Retiree Contributions	0	0
Plan Amendments	0	0
Benefits Paid	(19,193,000)	(19,569,000)
Settlement	(9,173,000)	(7,160,000)
Benefit Obligation at End of Year	461,574,000	481,848,000	439,373,000
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Year	330,987,000	312,497,000
Actual Return on Plan Assets	39,690,000	41,344,000
Employer Contributions	9,287,000	3,875,000
Retiree Contributions	0	0
Benefits Paid	(19,193,000)	(19,569,000)
Settlement	(9,173,000)	(7,160,000)
Fair Value of Plan Assets at End of Year	351,598,000	330,987,000	312,497,000
Funded status at end of year	(109,946,000)	(151,356,000)
Amounts Recognized in the Statement of Financial Position Consist of:
Noncurrent Assets	0	0
Current Liabilities	(3,969,000)	(3,704,000)
Noncurrent Liabilities	(105,977,000)	(147,652,000)
Net Amount Recognized at End of Year	(109,946,000)	(151,356,000)
Amounts Recognized in Regulatory Assets Consist of:
Prior Service Costs (Credits)	109,000	197,000
Net Actuarial Loss	46,990,000	72,332,000
Amount recognized in regulatory assets	47,099,000	72,529,000	61,584,000
Amounts Recognized in Accumulated Other Comprehensive Loss Consist of (pre-tax):
Prior Service Costs (Credits)	12,000	22,000
Net Actuarial Loss	43,262,000	57,467,000
Amount recognized in accumulated other comprehensive loss	43,274,000	57,489,000	51,285,000
Projected benefit obligation	371,900,000	388,300,000
Accumulated benefit obligation	355,300,000	370,200,000
Pension Benefits | South Jersey Industries Inc.
Change in Plan Assets:
Funded status at end of year	(109,976,000)	(150,861,000)
Pension Benefits | Amounts Related to Unconsolidated Affiliate
Change in Plan Assets:
Funded status at end of year	30,000	(495,000)
Pension Benefits | South Jersey Gas Company
Change in Benefit Obligations:
Benefit Obligation at Beginning of Year	318,262,000	286,517,000
Service Cost	3,778,000	3,797,000	3,621,000
Interest Cost	8,481,000	9,695,000	11,067,000
Actuarial (Gain) Loss	(11,714,000)	27,561,000
Retiree Contributions	0	0
Plan Amendments	1,800,000	3,464,000
Benefits Paid	(13,261,000)	(12,772,000)
Benefit Obligation at End of Year	307,346,000	318,262,000	286,517,000
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Year	181,940,000	170,959,000
Actual Return on Plan Assets	19,399,000	19,914,000
Employer Contributions	8,862,000	3,840,000
Retiree Contributions	0	0
Benefits Paid	(13,261,000)	(12,773,000)
Fair Value of Plan Assets at End of Year	196,940,000	181,940,000	170,959,000
Funded status at end of year	(110,406,000)	(136,322,000)
Amounts Recognized in the Statement of Financial Position Consist of:
Noncurrent Assets	0	0
Current Liabilities	(3,935,000)	(3,669,000)
Noncurrent Liabilities	(106,471,000)	(132,653,000)
Net Amount Recognized at End of Year	(110,406,000)	(136,322,000)
Amounts Recognized in Regulatory Assets Consist of:
Prior Service Costs (Credits)	109,000	197,000
Net Actuarial Loss	44,978,000	65,479,000
Amount recognized in regulatory assets	45,087,000	65,676,000	60,668,000
Amounts Recognized in Accumulated Other Comprehensive Loss Consist of (pre-tax):
Net Actuarial Loss	35,487,000	47,437,000
Amount recognized in accumulated other comprehensive loss	35,487,000	47,437,000	42,190,000
Projected benefit obligation	209,600,000	218,400,000
Accumulated benefit obligation	201,400,000	207,800,000
Other Postretirement Benefits
Change in Benefit Obligations:
Benefit Obligation at Beginning of Year	75,540,000	73,659,000
Service Cost	814,000	681,000	533,000
Interest Cost	1,920,000	2,367,000	2,884,000
Actuarial (Gain) Loss	(4,025,000)	3,933,000
Retiree Contributions	0	84,000
Plan Amendments	0	(753,000)
Benefits Paid	(4,309,000)	(4,431,000)
Settlement	0	0
Benefit Obligation at End of Year	69,940,000	75,540,000	73,659,000
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Year	87,870,000	82,522,000
Actual Return on Plan Assets	15,100,000	5,348,000
Employer Contributions	4,309,000	4,347,000
Retiree Contributions	0	84,000
Benefits Paid	(4,309,000)	(4,431,000)
Settlement	0	0
Fair Value of Plan Assets at End of Year	102,970,000	87,870,000	82,522,000
Funded status at end of year	33,258,000	12,629,000
Amounts Recognized in the Statement of Financial Position Consist of:
Noncurrent Assets	33,258,000	12,629,000
Current Liabilities	0	0
Noncurrent Liabilities	0	0
Net Amount Recognized at End of Year	33,258,000	12,629,000
Amounts Recognized in Regulatory Assets Consist of:
Prior Service Costs (Credits)	(4,723,000)	(5,225,000)
Net Actuarial Loss	5,941,000	18,588,000
Amount recognized in regulatory assets	1,218,000	13,363,000	12,251,000
Amounts Recognized in Accumulated Other Comprehensive Loss Consist of (pre-tax):
Prior Service Costs (Credits)	(1,722,000)	(1,829,000)
Net Actuarial Loss	2,824,000	4,597,000
Amount recognized in accumulated other comprehensive loss	1,102,000	2,768,000	964,000
Other Postretirement Benefits | South Jersey Industries Inc.
Change in Plan Assets:
Funded status at end of year	33,030,000	12,330,000
Other Postretirement Benefits | Amounts Related to Unconsolidated Affiliate
Change in Plan Assets:
Funded status at end of year	228,000	299,000
Other Postretirement Benefits | South Jersey Gas Company
Change in Benefit Obligations:
Benefit Obligation at Beginning of Year	46,189,000	47,306,000
Service Cost	480,000	396,000	343,000
Interest Cost	1,181,000	1,463,000	1,863,000
Actuarial (Gain) Loss	(1,538,000)	(167,000)
Retiree Contributions	0	13,000
Plan Amendments	0	(436,000)
Benefits Paid	(3,496,000)	(2,386,000)
Benefit Obligation at End of Year	42,816,000	46,189,000	47,306,000
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Year	61,869,000	59,190,000
Actual Return on Plan Assets	11,453,000	2,679,000
Employer Contributions	3,496,000	2,373,000
Retiree Contributions	0	13,000
Benefits Paid	(3,496,000)	(2,386,000)
Fair Value of Plan Assets at End of Year	73,322,000	61,869,000	59,190,000
Funded status at end of year	30,506,000	15,680,000
Amounts Recognized in the Statement of Financial Position Consist of:
Noncurrent Assets	30,506,000	15,680,000
Current Liabilities	0	0
Noncurrent Liabilities	0	0
Net Amount Recognized at End of Year	30,506,000	15,680,000
Amounts Recognized in Regulatory Assets Consist of:
Prior Service Costs (Credits)	(4,723,000)	(5,225,000)
Net Actuarial Loss	7,140,000	16,975,000
Amount recognized in regulatory assets	2,417,000	11,750,000	11,342,000
Amounts Recognized in Accumulated Other Comprehensive Loss Consist of (pre-tax):
Net Actuarial Loss	0	0
Amount recognized in accumulated other comprehensive loss	0	0	0
Supplemental Employee Retirement Plan
Change in Plan Assets:
Employer Contributions	3,900,000	3,900,000	4,100,000
Amounts Recognized in Accumulated Other Comprehensive Loss Consist of (pre-tax):
Projected benefit obligation	89,700,000	93,600,000
Accumulated benefit obligation	88,400,000	90,600,000
Supplemental Employee Retirement Plan | South Jersey Gas Company
Change in Benefit Obligations:
Retiree Contributions	4,728,000	3,938,000	$ 3,541,000
Amounts Recognized in Accumulated Other Comprehensive Loss Consist of (pre-tax):
Projected benefit obligation	89,700,000	93,200,000
Accumulated benefit obligation	$ 88,400,000	$ 90,200,000