DERIVATIVE FINANCIAL INSTRUMENTS Derivative Financial Instruments Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 66	$ 90
Derivative Asset, Fair Value, Gross Liability	(3)	(4)
Derivative Asset	63	86
Derivative Liability, Fair Value, Gross Liability	77	67
Derivative Liability, Fair Value, Gross Asset	(3)	(3)
Derivative, Collateral, Right to Reclaim Securities	(7)	(9)
Derivative, Collateral, Right to Reclaim Cash	(33)	(29)
Derivative Liability, Fair Value, Amount Offset Against Collateral	34	26
Derivative Liability	74	64
Derivative, Collateral, Obligation to Return Securities	(7)	(9)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	56	77
Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Liability	43	35
Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset	60	72
Derivative Liability	1
Prepayments [Member]
Derivative [Line Items]
Derivative Asset	1	9
Other Current Assets [Member]
Derivative [Line Items]
Derivative Asset	2	5
Other Deferred Credits and Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability	30	29
Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	59	71
Derivative Asset	59	71
Derivative Liability, Fair Value, Gross Liability	70	58
Derivative, Collateral, Right to Reclaim Securities	(7)	(9)
Derivative, Collateral, Right to Reclaim Cash	(31)	(29)
Derivative Liability, Fair Value, Amount Offset Against Collateral	32	20
Derivative Liability	70	58
Derivative, Collateral, Obligation to Return Securities	(7)	(9)
Derivative Asset, Fair Value, Amount Offset Against Collateral	52	62
Commodity Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	2	9
Derivative Asset, Fair Value, Gross Liability	(1)
Derivative Asset	1	9
Derivative Liability, Fair Value, Gross Liability	2	0
Derivative Liability, Fair Value, Gross Asset	(1)
Derivative Liability, Fair Value, Amount Offset Against Collateral	1	0
Derivative Liability	1	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	1	9
Other Energy Management Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	5	10
Derivative Asset, Fair Value, Gross Liability	(2)	(4)
Derivative Asset	3	6
Derivative Liability, Fair Value, Gross Liability	5	9
Derivative Liability, Fair Value, Gross Asset	(2)	(3)
Derivative, Collateral, Right to Reclaim Cash	(2)
Derivative Liability, Fair Value, Amount Offset Against Collateral	1	6
Derivative Liability	3	6
Derivative Asset, Fair Value, Amount Offset Against Collateral	3	6
SCEG
Derivative [Line Items]
Derivative Asset	59	71
Derivative Liability	52	39
SCEG | Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Liability	39	28
SCEG | Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset	59	71
SCEG | Other Deferred Credits and Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability	13	11
SCEG | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	59	71
Derivative Asset	59	71
Derivative Liability, Fair Value, Gross Liability	52	39
Derivative, Collateral, Right to Reclaim Securities	(7)	(9)
Derivative, Collateral, Right to Reclaim Cash	(12)	(9)
Derivative Liability, Fair Value, Amount Offset Against Collateral	33	21
Derivative Liability	52	39
Derivative, Collateral, Obligation to Return Securities	(7)	(9)
Derivative Asset, Fair Value, Amount Offset Against Collateral	$ 52	$ 62