COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Environmental
Goal For Reduced Carbon Dioxide Emissions From 2005 Levels By 2030 Under Clean Air Act	32.00%
NPDES permit renewal permit period	five
Nuclear Generation
Forecasted Incremental Capital Costs Associated With Schedule Delays, 2015 Petition	$ 539,000
EPC Contract Amendment, New Nuclear Construction Completion Bonus	151,000
EPC Contract Amendment, Payment and Performance Bonds	$ 45,000
EPC Contract Amendment, Payment And Performance Bonds, Percentage of Billing	15.00%
EPC Contract Amendment, Payment And Performance Bonds, Maximum Aggregate Nominal Coverage	$ 100,000
Dispute Review Board Resolution Without Recourse	less than $5 million
Dispute Review Board Resolution Subject To Litigation	greater than $5 million
SCEG
Commitments and contingencies
Storm Damage Provision	$ 2,000
Nuclear Insurance
Maximum liability assessment per reactor for each nuclear incident	127,300
Maximum Insurance Coverage For Each Nuclear Plant by ANI	375,000
Federal Limit on Public Liability Claims from Nuclear Incident Approximate	13,400,000
Maximum Federal Limit on Public Liability Claims Per Reactor for Each Year	18,900
Maximum Federal Limit on Public Liability Claims per Reactor for each Nuclear Incident at 2/3	84,800
Maximum Federal Limit on Public Liability Claims Per Incident for Each Year	$ 12,600
Inflation adjustment period for nuclear insurance	5
Maximum loss for a single nuclear incident	$ 2,750,000
NEIL Maximum Insurance Coverage of Accidental Property Damage	500,000
NEIL Maximum Insurance Coverage To Nuclear Facility For Property Damage And Outage Costs From Non-Nuclear Event	2,330,000
EMANI Maximum Retrospective Premium Assessment	1,800
EMANI Maximum Insurance Coverage for Summer Station Unit 1 For Property Damage And Outage Costs From Non-Nuclear Event	415,000
NEIL Maximum Prosepective Insurance Premium Per Nuclear Incident	45,800
NEIL Maximum Insurance Coverage to Nuclear Facility for Property Damage and Outage Costs	2,750,000
Environmental
Environmental Remediation Costs Recognized in Regulatory Assets	$ 26,000
Number of MGP decommissioned sites that contain residues of byproduct chemicals	4
Number Of States Required To Reduce Emissions Under CSAPR	28
Site Contingency MGP Estimated Environmental Remediation Costs	$ 10,300
Nuclear Generation
EPC Contract Amendment, Increase In Fixed Component Of Contract Price	165,000
EPC Contract Amendment, Credit Applied To Target Component Of New Units Contract Price	27,000
EPC Contract Amendment, Cap On Delay Oriented Liquidated Damages Per New Nuclear Unit	255,000
EPC Contract Amendment, Revised Construction Milestone Payment Schedule, Per Month	55,000
EPC Contract Amendment, Payment and Performance Bonds	25,000
EPC Contract Amendment, Payment And Performance Bonds, Maximum Aggregate Nominal Coverage	55,000
Transmission Capital Costs Forecast WIthdrawn	4,300
Total New Nuclear Project Cost Approved By SCPSC In September 2015	6,800,000
EPC Contract Amendment, Total New Nuclear Project Cost Including Amendment Increase	$ 7,200,000
SCEG
Nuclear Insurance
Jointly Owned Utility Plant, Proportionate Ownership Share	5.00%
Nuclear Generation
EPC Contract Amendment, Cap On Delay Oriented Liquidated Damages Per New Nuclear Unit	$ 186,000
EPC Contract Amendment, New Nuclear Construction Completion Bonus	83,000
EPC Contract Amendment, Fixed Price Option, Price For New Nuclear Construction After June 2015	3,345,000
EPC Contract Amendment, Increase In Fixed Component Of Contract Price, Payments	103,100
EPC Contract Amendment, Revised Construction Milestone Payment Schedule, Payments	$ 512,000
Summer Station New Units [Domain]
Nuclear Insurance
Jointly Owned Utility Plant, Proportionate Ownership Share	55.00%
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress	$ 4,200,000
Nuclear Generation
jointly owned utility plant ownership, construction financing cost	3,200,000
EPC Contract Amendment, Increase In Fixed Component Of Contract Price	300,000
EPC Contract Amendment, Credit Applied To Target Component Of New Units Contract Price	50,000
EPC Contract Amendment, Cap On Delay Oriented Liquidated Damages Per New Nuclear Unit	463,000
EPC Contract Amendment, Fixed Price Option, New Nuclear Construction Completion Bonus	150,000
EPC Contract Amendment, New Nuclear Construction Completion Bonus	275,000
EPC Contract Amendment, Revised Construction Milestone Payment Schedule, Per Month	100,000
Nuclear Production Tax Credits	$ 1,400,000
Nuclear Production Tax Credit realization period	8
EPC Contract Amendment, Fixed Price Option, Price For New Nuclear Construction After June 2015	$ 6,082,000
EPC Contract Amendment, Fixed Price Option, Cap On Delay Oriented Liquidated Damages Per New Nuclear Unit	338,000
EPC Contract Amendment, Increase In Fixed Component Of Contract Price, Payments	188,000
EPC Contract Amendment, Revised Construction Milestone Payment Schedule, Payments	930,000
Capital costs, owners [Domain]
Nuclear Generation
Forecasted incremental capital costs, 2015 petition	245,000
Forecasted Total Capital Costs, 2015 Petition	5,200,000
Forecasted Gross Capital Costs, 2015 Petition	6,800,000
Capital costs, Other [Domain] [Domain]
Nuclear Generation
Forecasted incremental capital costs, 2015 petition	453,000
Scenario, Forecast [Member] | SCEG
Nuclear Generation
Additional ownership in new units		2.00%	2.00%	1.00%
Maximum [Member] | SCEG
Nuclear Generation
Additional ownership in new units, dollars	$ 850,000