DERIVATIVE FINANCIAL INSTRUMENTS OFFSETTING ASSETS AND LIABILITIES (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Liability	$ 37	$ 64
Derivative Asset, Fair Value, Gross Liability	0	(4)
Derivative Assets, Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments	0	(9)
Derivative, Collateral, Obligation to Return Cash
Derivative Liability, Fair Value, Gross Asset	(1)	(3)
Derivative Liabilities, Net Amount	64	26
Derivative Liability, Fair Value, Gross Liability	38	67
Derivative Liabilities, Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments	0	(9)
Derivative Liabilities, Gross Amounts Not Offset in the Statement of Financial Position - Cash Collateral Posted	(27)	(29)
Derivative Assets, Net Amount	59	77
Other Current Assets [Member]
Derivative [Line Items]
Derivative Liability	2
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	7	35
Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability	28	29
SCE&G
Derivative [Line Items]
Derivative Liability	15	39
SCE&G | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	2	28
SCE&G | Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability	13	11
Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Liability	32	58
Derivative Assets, Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments	0	(9)
Derivative Liabilities, Net Amount	60	20
Derivative Liability, Fair Value, Gross Liability	32	58
Derivative Liabilities, Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments		(9)
Derivative Liabilities, Gross Amounts Not Offset in the Statement of Financial Position - Cash Collateral Posted	(28)	(29)
Derivative Assets, Net Amount	54	62
Interest Rate Contract [Member] | SCE&G
Derivative [Line Items]
Derivative Liability	15	39
Derivative Assets, Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments	0	(9)
Derivative Liabilities, Net Amount	15	21
Derivative Liability, Fair Value, Gross Liability	15	39
Derivative Liabilities, Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments	0	(9)
Derivative Liabilities, Gross Amounts Not Offset in the Statement of Financial Position - Cash Collateral Posted		(9)
Derivative Assets, Net Amount	54	62
Commodity Contract [Member]
Derivative [Line Items]
Derivative Liability	3	0
Derivative Liabilities, Net Amount	3	0
Derivative Liability, Fair Value, Gross Liability	3
Derivative Assets, Net Amount	1	9
Other Energy Management Contract [Member]
Derivative [Line Items]
Derivative Liability	2	6
Derivative Asset, Fair Value, Gross Liability	0	(4)
Derivative Liability, Fair Value, Gross Asset	(1)	(3)
Derivative Liabilities, Net Amount	1	6
Derivative Liability, Fair Value, Gross Liability	3	9
Derivative Liabilities, Gross Amounts Not Offset in the Statement of Financial Position - Cash Collateral Posted	(1)
Derivative Assets, Net Amount	$ 4	$ 6