RATE AND OTHER REGULATORY MATTERS GAS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SCE&G
Entity Information [Line Items]
Public Utilities, Percent Increase (Decrease) in Retail Natural Gas Rates	2.20%	1.20%
Public Utilities, Authorized Allowable Return on Common Equity, Percentage	10.50%	10.50%	11.00%
Public Utilities changes in Retail Natural Gas Rates Approved under RSA	$ 8.6	$ 4.1	$ 0.0
PSNC Energy [Member]
Entity Information [Line Items]
PSNC Energy Rate Case Application, Percentage Increase	4.39%
Public Utilities, Authorized Allowable Return on Common Equity, Percentage	9.70%
PSNC Energy Rate Case Application, Increase Amount	$ 19.1