RATE AND OTHER REGULATORY MATTERS (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2018	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jan. 01, 2019
Rate Matters [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%	35.00%	35.00%
SCPSC Order for Increase of Total Fuel Cost Component of Retail Electric Rates to produce a projected under recovery			$ 0.035
Public Utilities Percentage Change in Retail Electric Rates Approved under BLRA			18.00%
Change in Retail Electric Rates Approved Under BLRA			$ 0.032
Public Utilities, Requested Rate Increase (Decrease), Amount			$ 31,000,000
Asset Retirement Obligation Costs [Member]
Rate Matters [Line Items]
Regulatory Noncurrent Asset Amortization Period			107 years
Environmental Restoration Costs [Member]
Rate Matters [Line Items]
MPG environmental remediation			17
SCEG
Rate Matters [Line Items]
Refund to Customer Related to Tax Act			$ 61,000,000
SCPSC Order, Recovery Of Projected DER Program Costs			29,300,000
SCPSC Order for Increase of Total Fuel Cost Component of Retail Electric Rates to produce a projected under recovery			1,300,000
SCPSC Order, Annual DSM Program Rate Rider Recovery Amount			33,000,000
Public Utilities changes in Retail Natural Gas Rates Approved under RSA	$ 19,700,000
Public Utilities, Percent Increase (Decrease) in Retail Natural Gas Rates	4.61%
SCEG | Pension costs, electric [Member]
Rate Matters [Line Items]
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority			2,000,000
SCEG | Pension costs, gas [Member]
Rate Matters [Line Items]
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority			1,000,000
SCANA [Member]
Rate Matters [Line Items]
Refund to Customer Related to Tax Act			3,800,000
PSNC Energy
Rate Matters [Line Items]
Proposed Merger Credits						$ 1,250,000
Refund to Customer Related to Tax Act			$ 10,100,000
MPG environmental remediation			4.2
Pipeline integrity mgmt annual revenue requirement approved by NCUC		$ 14,700,000