RATE AND OTHER REGULATORY MATTERS (Details 3) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Regulatory Liabilities [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%
Refund to Customer Related to Tax Act	$ 137
SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	3,323		$ 2,264
Settlement Proceeds [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	1,020		1,037
Deferred Income Tax Charge [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	837		607
Asset Retirement Obligation Costs [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	549		541
Deferred gains on interest rate derivatives [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	70		75
Other Regulatory Liability [Member] | SCEG
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 1		$ 4
Environmental Restoration Costs [Member]
Regulatory Liabilities [Line Items]
MPG environmental remediation	16