SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) MW shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares	Dec. 31, 2012
Significant Accounting Policies
Effect of equity forward contracts, diluted earnings higher than basic earnings | shares			400,000.0
Unbilled Receivables, Current	$ 129,100,000	$ 186,400,000
Goodwill	$ 210,000,000	$ 210,000,000
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.61%	2.84%	2.93%
Public Utilities, Allowance for Funds Used During Construction, Additions	6.10%		7.20%	6.90%
Asset Management and Supply Service Agreements
Natural gas inventory, carrying amount		$ 26,100,000
Property, Plant and Equipment, Net	$ 280,000,000	$ 284,000,000
Accrual period of nuclear refueling charges (in months)	18
Earnings Per Share
Weighted Average Shares Outstanding - Basic | shares	142,900,000	141,900,000	138,700,000
Weighted Average Number of Shares Outstanding, Diluted | shares	142,900,000	141,900,000	139,100,000
SCEG and GENCO [Member]
Significant Accounting Policies
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.56%	2.84%	2.94%
SCE&G
Significant Accounting Policies
Maintenance Costs	$ 18,400,000
Environmental Remediation Costs Recognized in Regulatory Assets	34,800,000
Decommissioning Liability, Noncurrent	$ 696,800,000
Decommissioning safe storage	60
Unbilled Receivables, Current	$ 101,500,000	$ 115,800,000
Utilities Operating Expense, Maintenance	16,500,000	19,400,000
Anount accrued monthly for nuclear fuel outages			$ 1,400,000
Nuclear refueling outage cost	$ 40,200,000	$ 43,700,000
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.55%	2.85%	2.96%
Public Utilities, Allowance for Funds Used During Construction, Additions	5.60%	6.50%	6.90%
Asset Management and Supply Service Agreements
Property, Plant and Equipment, Net	$ 68,000,000	$ 67,000,000
Payments to Acquire Investments to be Held in Decommissioning Trust Fund	$ 3,200,000
Genco
Significant Accounting Policies
Power Generation Capacity Megawatts | MW	605
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.66%	2.66%	2.66%
Asset Management and Supply Service Agreements
Property, Plant and Equipment, Net	$ 491,000,000
CGT [Member]
Significant Accounting Policies
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	0.00%	2.11%	2.19%
PSNC Energy
Significant Accounting Policies
Goodwill	$ 210,000,000
Accumulated Amortization and Write-down, Goodwill	$ 230,000,000
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.94%	2.98%	3.01%
Asset Management and Supply Service Agreements
Percentage of natural gas inventory held by counterparties under asset management and supply service agreements (as a percent)	46.00%	48.00%
Natural gas inventory, carrying amount	$ 17,700,000
Summer Station Unit 1 [Domain]
Significant Accounting Policies
Jointly Owned Utility Plant, Proportionate Ownership Share	66.70%	66.70%
Asset Management and Supply Service Agreements
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service	$ 1,200,000,000	$ 1,200,000,000
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation	620,400,000	578,300,000
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress	214,600,000	199,300,000
Summer Station Unit 1 [Domain] | SCE&G
Asset Management and Supply Service Agreements
Accounts Receivable, Net	$ 178,800,000	$ 88,900,000
Summer Station New Units [Domain]
Significant Accounting Policies
Jointly Owned Utility Plant, Proportionate Ownership Share	55.00%	55.00%
Asset Management and Supply Service Agreements
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress	$ 3,400,000,000	$ 2,700,000,000
SCE&G
Significant Accounting Policies
Nuclear refueling outage cost	$ 26,800,000	$ 29,100,000
Jointly Owned Utility Plant, Proportionate Ownership Share	5.00%
Debt issuance costs [Member]
Significant Accounting Policies
Debt Issuance Cost	$ 34,000,000
Debt issuance costs [Member] | SCE&G
Significant Accounting Policies
Debt Issuance Cost	29,000,000
Deferred tax asset or liability [Member]
Significant Accounting Policies
Debt Issuance Cost	65,500,000
Deferred tax asset or liability [Member] | SCE&G
Significant Accounting Policies
Debt Issuance Cost	$ 27,900,000