DERIVATIVE FINANCIAL INSTRUMENTS Derivative Financial Instruments Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 223	$ 289
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	223	289
Derivative, Collateral, Right to Reclaim Securities	(3)	0
Derivative, Collateral, Right to Reclaim Cash	(148)	(152)
Derivative Asset, Fair Value, Gross Asset	21	21
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset	21	21
Derivative, Collateral, Obligation to Return Securities	(3)	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	18	21
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	72	137
Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset	11	5
Other Current Assets [Member]
Derivative [Line Items]
Derivative Liability	3	6
Derivative Asset	10	16
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	125	233
Other Deferred Credits and Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability	95	50
Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	202	257
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	202	257
Derivative, Collateral, Right to Reclaim Securities	(3)	0
Derivative, Collateral, Right to Reclaim Cash	(135)	(131)
Derivative Asset, Fair Value, Gross Asset	6
Derivative Asset, Fair Value, Gross Liability	0
Derivative Asset	6
Derivative, Collateral, Obligation to Return Securities	(3)
Derivative Asset, Fair Value, Amount Offset Against Collateral	3
Derivative, Collateral, Right to Reclaim Cash	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	64	126
Commodity Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	7	12
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	7	12
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	(6)	(10)
Derivative Asset, Fair Value, Gross Asset		1
Derivative Asset, Fair Value, Gross Liability		0
Derivative Asset		1
Derivative, Collateral, Obligation to Return Securities		0
Derivative Asset, Fair Value, Amount Offset Against Collateral		1
Derivative, Collateral, Right to Reclaim Cash		0
Derivative Liability, Fair Value, Amount Offset Against Collateral	1	2
Other Energy Management Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	14	20
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	14	20
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	(7)	(11)
Derivative Asset, Fair Value, Gross Asset	15	20
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset	15	20
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	15	20
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	7	9
SCEG
Derivative [Line Items]
Derivative Liability	178	233
SCEG | Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset	6
SCEG | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	108	208
SCEG | Other Deferred Credits and Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability	70	25
SCEG | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	178	233
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability	178	233
Derivative, Collateral, Right to Reclaim Securities	(3)	0
Derivative, Collateral, Right to Reclaim Cash	(109)	(107)
Derivative Asset, Fair Value, Gross Asset	6
Derivative Asset, Fair Value, Gross Liability	0
Derivative Asset	6
Derivative, Collateral, Obligation to Return Securities	(3)
Derivative Asset, Fair Value, Amount Offset Against Collateral	3
Derivative, Collateral, Right to Reclaim Cash	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ 66	$ 126