SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Millions	9 Months Ended
Sep. 30, 2015 USD ($) MW	Dec. 31, 2014 USD ($)
Significant Accounting Policies
Property, Plant and Equipment, Net	$ 281.0	$ 284.0
SCEG
Significant Accounting Policies
Property, Plant and Equipment, Net	$ 67.0	$ 67.0
Genco
Significant Accounting Policies
Power Generation Capacity Megawatts \| MW	605
Property, Plant and Equipment, Net	$ 489.0
PSNC Energy [Member]
Significant Accounting Policies
Percentage of natural gas inventory held by counterparties under asset management and supply service agreements (as a percent)	50.00%	48.00%
Natural gas inventory, carrying amount	$ 19.1	$ 26.1
PercentOfStorageFeesCreditedToRatePayers	75.00%

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 7

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant