RATE AND OTHER REGULATORY MATTERS (Details 2) $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Jun. 30, 2015	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Sep. 30, 2013 USD ($)
Regulatory Assets
Regulatory Liabilities	$ 859.0				$ 859.0		$ 814.0
Public Utilities Base Fuel under Collected Balance Recovery Period					12
Regulatory Assets, Noncurrent	1,884.0				$ 1,884.0		$ 1,823.0
SCEG
Regulatory Assets
Public Utilities, Percent Increase (Decrease) in Retail Electric Rates					0.00%		0.00%	2.90%
Public Utilities Increase (Decrease) in Retail Electric Rates Approved under BLRA					$ 65.0		$ 66.0	$ 67.2
Public Utilities, Rate Calculation Basis					12-month rolling average
Fuel Costs					$ 10.3
Undercollected balance fuel	46.0				46.0
Public Utilities, Percent Increase (Decrease) in Retail Natural Gas Rates							0.60%
Regulatory Liabilities	641.0				641.0		$ 610.0
Annual Storm Damage Costs not offset by Amounts Recovered through Electric Rates					2.5
Carrying costs on deferred income tax assets	2.4	$ 1.6			6.5	$ 4.1
Derivative, Gain on Derivative							17.8
Storm Damage Reserve Cost Applied							5.0
Demand Side Management Program Costs, Noncurrent	32.0	$ 15.4			32.0	$ 15.4			$ 16.9
Amount Allowed to be Recovered through Electric Rates to Offset Incremental Storm Damage Costs					$ 100.0
Public Utilities Base Fuel under Collected Balance Recovery Period					12
Regulatory Assets, Noncurrent	1,808.0				$ 1,808.0		1,745.0
Demand side management recovery period					5
Storm Damage Reserve Applied To Offset Net Lost Margin Related To DSM			$ 5.0
Public Utilities changes in Retail Natural Gas Rates Approved under RSA							2.6
Amounts Recovered Through Electric Rates to offset Nuclear Related Outage Costs					$ 17.2
Public Utilities, Authorized Allowable Return on Common Equity, Percentage				11.00%	11.00%
PSNC Energy [Member]
Regulatory Assets
Public Utilities, Rate Calculation Basis			12
Other Regulatory Liability [Member]
Regulatory Assets
Regulatory Liabilities	3.0				$ 3.0		1.0
Asset Retirement Obligation Costs [Member]
Regulatory Assets
Regulatory Liabilities	729.0				729.0		703.0
Asset Retirement Obligation Costs [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	520.0				520.0		505.0
Deferred Income Tax Charges [Member]
Regulatory Assets
Regulatory Liabilities	22.0				22.0		22.0
Deferred Income Tax Charges [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	16.0				16.0		17.0
Storm damage reserve [Member]
Regulatory Assets
Regulatory Liabilities	6.0				6.0		6.0
Annual Storm Damage Costs not offset by Amounts Recovered through Electric Rates					2.5
Amount Allowed to be Recovered through Electric Rates to Offset Incremental Storm Damage Costs					100.0
Storm Damage Reserve Applied To Offset Net Lost Margin Related To DSM							5.0
Storm damage reserve [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	6.0				6.0		6.0
Planned major maintenance [Member]
Regulatory Assets
Regulatory Liabilities	12.0				12.0		0.0
Planned major maintenance [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	12.0				12.0		0.0
Amounts Recovered through Electric Rates to offset Turbine Expense					18.4
Deferred gains on interest rate derivatives [Member]
Regulatory Assets
Regulatory Liabilities	87.0				87.0		82.0
Deferred gains on interest rate derivatives [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	87.0				$ 87.0		82.0
Pension costs, electric [Member] | SCEG
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period					30 years
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority	63.0				$ 63.0
Franchise agreement Costs [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	23.0				23.0		26.0
Franchise agreement Costs [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	23.0				23.0		26.0
Deferred Losses On Interest Rate Derivatives [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	538.0				538.0		453.0
Deferred Losses On Interest Rate Derivatives [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	538.0				538.0		453.0
Deferred Pollution Control Cost [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	35.0				35.0		36.0
Deferred Pollution Control Cost [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	35.0				35.0		36.0
Regulatory Clause Revenues, under-recovered [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	0.0				0.0		20.0
Regulatory Clause Revenues, under-recovered [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	0.0				0.0		20.0
Planned major maintenance [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	0.0				0.0		2.0
Planned major maintenance [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	0.0				$ 0.0		2.0
Asset Retirement Obligation Costs [Member]
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period					110 years
Regulatory Assets, Noncurrent	376.0				$ 376.0		366.0
Asset Retirement Obligation Costs [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	356.0				356.0		347.0
unrecovered plant [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	128.0				128.0		137.0
unrecovered plant [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	128.0				128.0		137.0
Demand Side Management programs [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	59.0				59.0		56.0
Demand Side Management programs [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	59.0				59.0		56.0
Carrying cost on nuclear construction [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	15.0				15.0		9.0
Carrying cost on nuclear construction [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	15.0				15.0		9.0
Pipeline integerity management costs [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	16.0				$ 16.0		9.0
Deferred Income Tax Charges [Member]
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period					85 years
Regulatory Assets, Noncurrent	284.0				$ 284.0		284.0
Deferred Income Tax Charges [Member] | SCEG
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period					85 years
Regulatory Assets, Noncurrent	278.0				$ 278.0		278.0
Environmental Restoration Costs [Member]
Regulatory Assets
MPG enviromental remediatio					24
Regulatory Assets, Noncurrent	39.0				$ 39.0		40.0
Environmental Restoration Costs [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	35.0				35.0		36.0
Pension Costs [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	328.0				$ 328.0		350.0
Pension Costs [Member] | SCEG
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period					12 years			30 years
Regulatory Assets, Noncurrent	296.0				$ 296.0		310.0
Pension costs, gas [Member] | SCEG
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period								14 years
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority	14.0				$ 14.0
Other Regulatory Assets [Member]
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period					30 years
Regulatory Assets, Noncurrent	43.0				$ 43.0		35.0
Other Regulatory Assets [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	$ 45.0				$ 45.0		$ 35.0