SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Asset Management and Supply Service Agreements
Percentage of natural gas inventory held by counterparties under asset management and supply service agreements (as a percent)	18.00%		44.00%
Natural gas inventory, carrying amount	$ 3.4		$ 19.6
Property, Plant and Equipment, Net	306		306
Plant to be retired coal plants	359
Earnings Per Share
Weighted Average Shares Outstanding - Basic	134.4	130.3
Incremental Common Shares Attributable to Share-based Payment Arrangements and Equity Forward Agreements	1.7	1.9
Weighted Average Number of Shares Outstanding, Diluted	136.1	132.2
SCEG
Significant Accounting Policies
Number of coal fired units to be retired	6
Asset Management and Supply Service Agreements
Property, Plant and Equipment, Net	56		57
Power generation capacity six coal fired units	730
Power Capacity of Retired Unit	90
Genco
Significant Accounting Policies
Power Generation Capacity Megawatts	605
Asset Management and Supply Service Agreements
Property, Plant and Equipment, Net	$ 472