RATE AND OTHER REGULATORY MATTERS (Details 3) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Regulatory Liabilities [Line Items]
Regulatory Assets, Noncurrent	$ 6,690	$ 2,130
Regulatory Liabilities	2,015	930
SCEG
Regulatory Liabilities [Line Items]
Regulatory Assets, Noncurrent	6,582	2,030
Regulatory Liabilities	1,779	695
Settlement Proceeds [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	1,095	0
Asset Retirement Obligation Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	764	755
Asset Retirement Obligation Costs [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	535	529
Deferred gains on interest rate derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	135	151
Deferred gains on interest rate derivatives [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	135	151
Other Regulatory Liability [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	21	24
Other Regulatory Liability [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 14	$ 15