COMMON EQUITY (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018
Schedule of Capitalization, Equity [Line Items]
Retained Earnings, Appropriated	$ 120.4	$ 115.0
Common Stock, Shares Authorized	50,000,000		200,000,000
Shares, Issued	40.3
Preferred Stock, Shares Outstanding	0
Proceeds from Contributions from Parent	$ 675.0
SCEG
Schedule of Capitalization, Equity [Line Items]
Common Stock, Shares Authorized			50,000,000
Common Stock, Shares, Outstanding	40,300,000	40,300,000
Preferred Stock, Shares Authorized			20,000,000
Preferred Stock, Shares Outstanding			0