COMMITMENTS AND CONTINGENCIES Nuclear (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2017	Dec. 31, 2015
SCE&G
EPC Contract Amendment, Payment And Performance Bonds, Percentage of Billing	15.00%
EPC Contract Amendment, Payment And Performance Bonds, Maximum Aggregate Nominal Coverage	$ 55
EPC Contract Amendment, Payment and Performance Bonds	$ 25
Dispute Review Board Resolution Without Recourse	less than $5 million
Dispute Review Board Resolution Subject To Litigation	greater than $5 million
EPC Amendment, Fixed Price Option, Price for subcontractor and other supplier-related costs subject to Dec 2016 DRB order	$ 873
Total New Nuclear Project Cost Approved By SCPSC In September 2015	6,800
EPC Contract Amendment, Total New Nuclear Project Cost Including Amendment Increase	7,700
EPC Contract Amendment, Fixed Price Option, Price For New Nuclear Construction After June 2015	3,345
EPC Contract Amendment, Fixed Price Option, Cap On Delay Oriented Liquidated Damages Per New Nuclear Unit	186
EPC Contract Amendment, Fixed Price Option, New Nuclear Construction Completion Bonus	83
November 2016 SCPSC Approved Project Costs above SCPSC 2015 order	831
Summer Station New Units and Transmission Assets [Domain]
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress	4,500
Summer Station New Units [Domain]
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress	4,200					$ 3,400
jointly owned utility plant ownership, construction financing cost	3,800
EPC Contract Amendment, Payment And Performance Bonds, Maximum Aggregate Nominal Coverage	100
EPC Contract Amendment, Payment and Performance Bonds	45
EPC Contract Amendment, Fixed Price Option, Price For New Nuclear Construction After June 2015	6,082
EPC Contract Amendment, Fixed Price Option, Cap On Delay Oriented Liquidated Damages Per New Nuclear Unit	338
EPC Contract Amendment, Fixed Price Option, New Nuclear Construction Completion Bonus	150
Nuclear Production Tax Credits	$ 1,400
Nuclear Production Tax Credit realization period	8
Scenario, Forecast [Member]
Estimated Toshiba impairment loss					$ 6,000
Scenario, Forecast [Member] | SCE&G
Additional ownership in new units		2.00%	2.00%	1.00%
Maximum [Member] | SCE&G
Additional ownership in new units, dollars	$ 850