COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Commitments and contingencies
Emission Rate Standard For Coal Fired Power Plants Under Clean Air Act	1,400
Emission Rate Standard for Natural Gas	1,000
Increase (Decrease) in Client Funds Held	$ 2,000,000
Utilities Operating Loss, Impairment, Net of Taxes	79,000
Impairment loss write off	105,000
Utilities Operating Expense, Impairments	262,000	$ 4,000
Long-term Line of Credit	1,000,000
Customer Refundable Fees, Refund Payments, Post Merger	(985,000)
Customer Refundable Fees, Alternative Plan	1,007,000
Customer refund fees alternative plan net of tax	756,000
Customer Refundable Fees, Alternative Plan over 20 yrs	1,032,000
Transmission Assets related to BLRA Capital Costs	334,000
Transmission Assets related to BLRA Regulatory Assets	21,000
Asset Impairment Charges	262,000	$ 4,000
Estimate of aggregate amount of subcontractor and vendor liens filed	285,000
Reduction of liens filed	60,000
Nuclear Insurance
Maximum liability assessment per reactor for each nuclear incident	137,700
Federal Limit on Public Liability Claims from Nuclear Incident Approximate	14,000,000
Maximum Federal Limit on Public Liability Claims Per Reactor for Each Year	20,500
Maximum Federal Limit on Public Liability Claims Per Incident for Each Year	13,700
Environmental
Refundable Gas Costs	2,450
Increase (Decrease) in Recoverable Refundable Gas Costs	1,800
Liability for charitable contributions	22,000
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Charitable Contributions, Amount	17,000
Excess deferred taxes	198,000
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
Managing Member or General Partner, Subsequent Distribution Amount	115,000
Legal Fees	60,000
Estimated maximum legal fees	85,000
Legal expense			$ 157,000
Legal Expense, net of taxes			118,000
Increase (Decrease) in Property and Other Taxes Payable	410,000
SCEG
Commitments and contingencies
Long-term Debt, Current Maturities	14,000		14,000
Short-term borrowings	0		73,000
Estimate of aggregate amount of subcontractor and vendor liens filed	33,000
Nuclear Insurance
Maximum Insurance Coverage For Each Nuclear Plant by ANI	450,000
Maximum Federal Limit on Public Liability Claims per Reactor for each Nuclear Incident at 2/3	$ 91,800
Inflation adjustment period for nuclear insurance	5
NEIL Maximum Insurance Coverage To Nuclear Facility For Property Damage And Outage Costs From Non-Nuclear Event	$ 2,330,000
NEIL Maximum Insurance Coverage of Accidental Property Damage	2,750,000
EMANI Maximum Retrospective Premium Assessment	2,000
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	23,400
NEIL Maximum Insurance Coverage to Nuclear Facility for Property Damage and Outage Costs	2,750,000
Environmental
Environmental Remediation Costs Recognized in Regulatory Assets	$ 23,600
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	$ 9,600
Environmental Exit Costs, Reasonably Possible Additional Loss			$ 8,000