DERIVATIVE FINANCIAL INSTRUMENTS FAIR VALUE ON BALANCE SHEET (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 38	$ 67
Derivative Liability	37	64
Derivative Asset	59	86
Derivative Asset, Fair Value, Gross Asset	59	90
Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset	1	72
Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability	28	29
Other Current Assets [Member]
Derivative [Line Items]
Derivative Liability	2
Derivative Asset	58	5
Prepayments [Member]
Derivative [Line Items]
Derivative Asset		9
Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	32	58
Derivative Liability	32	58
Derivative Asset	54	71
Derivative Asset, Fair Value, Gross Asset	54	71
Commodity Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	3
Derivative Liability	3	0
Derivative Asset	1	9
Derivative Asset, Fair Value, Gross Asset	1	9
Other Energy Management Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	3	9
Derivative Liability	2	6
Derivative Asset	4	6
Derivative Asset, Fair Value, Gross Asset	4	10
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	30	28
Derivative Asset, Fair Value, Gross Asset	0	6
Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	3	4
Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	24	24
Designated as Hedging Instrument [Member] \| Commodity Contract [Member] \| Other Current Assets [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	1
Derivative Asset, Fair Value, Gross Asset		1
Designated as Hedging Instrument [Member] \| Commodity Contract [Member] \| Prepayments [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	2
Derivative Asset, Fair Value, Gross Asset		5
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	8	39
Derivative Asset, Fair Value, Gross Asset	59	84
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Derivative Financial Instruments, Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	54
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	1	27
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		71
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	4	3
Not Designated as Hedging Instrument [Member] \| Commodity Contract [Member] \| Other Current Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	3
Not Designated as Hedging Instrument [Member] \| Other Energy Management Contract [Member] \| Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	2	4
Not Designated as Hedging Instrument [Member] \| Other Energy Management Contract [Member] \| Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	2
Not Designated as Hedging Instrument [Member] \| Other Energy Management Contract [Member] \| Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability		2
Not Designated as Hedging Instrument [Member] \| Other Energy Management Contract [Member] \| Other Current Assets [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability		1
Derivative Asset, Fair Value, Gross Asset	3	2
Not Designated as Hedging Instrument [Member] \| Other Energy Management Contract [Member] \| Prepayments [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	1	2
Derivative Asset, Fair Value, Gross Asset		6
SCE&G
Derivative [Line Items]
Derivative Liability	15	39
Derivative Asset	54	71
SCE&G \| Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset		71
SCE&G \| Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability	13	11
SCE&G \| Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	15	39
Derivative Liability	15	39
Derivative Asset	54	71
Derivative Asset, Fair Value, Gross Asset	54	71
SCE&G \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	10	9
SCE&G \| Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	1	1
SCE&G \| Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	9	8
SCE&G \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	5	30
Derivative Asset, Fair Value, Gross Asset	54	71
SCE&G \| Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Derivative Financial Instruments, Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	54
SCE&G \| Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	1	27
SCE&G \| Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Other Deferred Debits and Other Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		71
SCE&G \| Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Other Deferred Credits and Other Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 4	$ 3

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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