COMMITMENTS AND CONTINGENCIES Nuclear (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Legal Settlements				$ 157,000
Deferred Tax Asset, Legal Settlement net of tax	$ 274,000			$ 274,000	$ 273,000
Loss Contingency, Actions Taken by Plaintiff				75
Public Utilities, Requested Rate Increase (Decrease), Amount				$ 31,000
Impairment loss write off	1,372,000	$ 4,000		1,372,000	1,118,000
Increase (Decrease) in Client Funds Held				2,000,000
Utilities Operating Expense, Impairments				1,376,000	1,118,000
Utilities Operating Loss, Impairment, Net of Taxes	870,000	$ 3,000		53,000	690,000
Guarantee Settlement Receipts				2,200,000
Estimate of aggregate amount of subcontractor and vendor liens filed				285,000
SCPSC Order Reduction Of Total Fuel Cost Component Of Retail Electric Rates To Reflect Lower Projected Fuel Costs And Eliminate Over-Collection Balances				2,000,000
SCPSC Order for Increase of Total Fuel Cost Component of Retail Electric Rates to produce a projected under recovery			$ 35,400	1,300
Monetization Settlement Exceeding Costs Incurred				1,997,000
Long-term Debt, Current Maturities	59,000			59,000	727,000
Short-term borrowings	173,000			173,000	$ 350,000
Public Utilities, Property, Plant and Equipment, Amount of Loss (Recovery) on Plant Abandonment				105,000
Customer Fees, Refunds Payments, Additional Liability Alternative Plan	1,007,000			1,007,000
Refundable Gas Costs	2,450			2,450
Multiemployer Plans, Minimum Contribution	22,000			22,000
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Impairment Losses	145,000			145,000
Increase (Decrease) in Property and Other Taxes Payable			$ 410,000
PSNC Energy [Member]
Public Utilities, Authorized Allowable Return on Common Equity, Percentage					9.70%
Multiemployer Plans, Minimum Contribution	1,000			1,000
SCE&G
Deferred Tax Asset, Legal Settlement net of tax	274,000			274,000	$ 273,000
EMANI Maximum Insurance Coverage for Summer Station Unit 1 For Property Damage And Outage Costs From Non-Nuclear Event				415,000
Federal Limit on Public Liability Claims from Nuclear Incident Approximate				14,000,000
EMANI Maximum Retrospective Premium Assessment				2,000
Utilities Operating Expense, Impairments				1,376,000	1,118,000
Utilities Operating Loss, Impairment, Net of Taxes				46,000
Guarantee Settlement Receipts				1,200,000
Estimate of aggregate amount of subcontractor and vendor liens filed				33,000
SCPSC Order Reduction Of Total Fuel Cost Component Of Retail Electric Rates To Reflect Lower Projected Fuel Costs And Eliminate Over-Collection Balances				31,000		$ 61,000
SCPSC Order for Increase of Total Fuel Cost Component of Retail Electric Rates to produce a projected under recovery					61,000
Monetization Settlement Exceeding Costs Incurred				1,098,000
Long-term Debt, Current Maturities	14,000			14,000	723,000
Short-term borrowings	73,000			73,000	$ 252,000
Maximum Insurance Coverage For Each Nuclear Plant by ANI	450,000			450,000
Summer Station Unit 2 and Unit 3 [Domain]
Transmission Assets related to BLRA Capital Costs	367,000			367,000
Estimate of aggregate amount of subcontractor and vendor liens filed				60,000
Summer Station Unit 2 and Unit 3 [Domain]
Transmission Assets related to BLRA Capital Costs	$ 15,000			$ 15,000