DERIVATIVE FINANCIAL INSTRUMENTS Derivative Financial Instruments Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 12	$ 31
Derivative Asset, Fair Value, Gross Liability	(2)	(1)
Derivative Asset	10	30
Derivative Liability, Fair Value, Gross Liability	268	107
Derivative Liability, Fair Value, Gross Asset	(2)	(1)
Derivative, Collateral, Right to Reclaim Securities	0	(8)
Derivative, Collateral, Right to Reclaim Cash	(171)	(50)
Derivative Liability, Fair Value, Amount Offset Against Collateral	95	48
Derivative Liability	266	106
Derivative, Collateral, Obligation to Return Securities	0	(8)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	10	22
Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset	2	8
Other Current Assets [Member]
Derivative [Line Items]
Derivative Asset	8	22
Derivative Liability		3
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	53	50
Other Deferred Credits and Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability	213	53
Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		15
Derivative Asset		15
Derivative Liability, Fair Value, Gross Liability	261	87
Derivative, Collateral, Right to Reclaim Securities		(8)
Derivative, Collateral, Right to Reclaim Cash	(169)	(36)
Derivative Liability, Fair Value, Amount Offset Against Collateral	92	43
Derivative Liability	261	87
Derivative, Collateral, Obligation to Return Securities		(8)
Derivative Asset, Fair Value, Amount Offset Against Collateral		7
Commodity Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	6	1
Derivative Asset, Fair Value, Gross Liability	(1)
Derivative Asset	5	1
Derivative Liability, Fair Value, Gross Liability	1	5
Derivative Liability, Fair Value, Gross Asset	(1)
Derivative, Collateral, Right to Reclaim Cash		(5)
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability	0	5
Derivative Asset, Fair Value, Amount Offset Against Collateral	5	1
Other Energy Management Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	6	15
Derivative Asset, Fair Value, Gross Liability	(1)	(1)
Derivative Asset	5	14
Derivative Liability, Fair Value, Gross Liability	6	15
Derivative Liability, Fair Value, Gross Asset	(1)	(1)
Derivative, Collateral, Right to Reclaim Cash	(2)	(9)
Derivative Liability, Fair Value, Amount Offset Against Collateral	3	5
Derivative Liability	5	14
Derivative Asset, Fair Value, Amount Offset Against Collateral	5	14
SCEG
Derivative [Line Items]
Derivative Asset		15
Derivative Liability	234	65
SCEG | Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset		5
SCEG | Other Current Assets [Member]
Derivative [Line Items]
Derivative Asset		10
SCEG | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	48	34
SCEG | Other Deferred Credits and Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability	186	31
SCEG | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		15
Derivative Asset		15
Derivative Liability, Fair Value, Gross Liability	234	65
Derivative, Collateral, Right to Reclaim Securities		(8)
Derivative, Collateral, Right to Reclaim Cash	(140)	(13)
Derivative Liability, Fair Value, Amount Offset Against Collateral	94	44
Derivative Liability	$ 234	65
Derivative, Collateral, Obligation to Return Securities		(8)
Derivative Asset, Fair Value, Amount Offset Against Collateral		$ 7