DERIVATIVE FINANCIAL INSTRUMENTS (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015 USD ($) MMBTU	Dec. 31, 2014 USD ($) MMBTU
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	57,604,782	55,733,059
Gas Distribution
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	9,270,000	6,840,000
Retail Gas Marketing
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	11,788,000	7,951,000
Energy Marketing [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	36,546,782	40,942,059
Commodity Contract
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	25,393,500	18,237,720
Commodity Contract | Gas Distribution
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	9,270,000	6,840,000
Commodity Contract | Retail Gas Marketing
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	11,788,000	7,951,000
Commodity Contract | Energy Marketing [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	4,335,500	3,446,720
Energy Related Derivative [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU	32,211,282	37,495,339
Energy Related Derivative [Member] | Gas Distribution
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	0
Energy Related Derivative [Member] | Retail Gas Marketing
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	0
Energy Related Derivative [Member] | Energy Marketing [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	32,211,282	37,495,339
Energy Related Derivative [Member] | Basis Swap [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	1,246,230	933,893
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives [Abstract]
Derivative, Notional Amount	$ 1,200.0	$ 1,100.0
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives [Abstract]
Derivative, Notional Amount	120.0	124.4
SCEG | Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives [Abstract]
Derivative, Notional Amount	1,200.0	1,100.0
SCEG | Cash Flow Hedging [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives [Abstract]
Derivative, Notional Amount	$ 36.4	$ 36.4