RATE AND OTHER REGULATORY MATTERS (Details) (USD $)	3 Months Ended		12 Months Ended		9 Months Ended	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2015	Mar. 31, 2013	Dec. 31, 2012
Rate Matters [Line Items]
Estimated undercollected base fuel and variable environmental costs	$ 36,100,000
Carrying cost recovery	(3,000,000)	(2,000,000)
Regulatory Assets, Noncurrent	1,890,000,000		1,823,000,000
Public Utilities Base Fuel under Collected Balance Recovery Period	12
SCEG
Rate Matters [Line Items]
Forecasted incremental capital costs, 2015 petition	698,000,000
Forecasted Capital Cost, 2015 Petition	5,200,000,000
Amounts Recovered Through Electric Rates to offset Nuclear Related Outage Costs	17,200,000
Net Lost Revenues associated with DSM programs			6,600,000
Fuel Costs	10,300,000
Undercollected balance fuel	46,000,000
Estimated undercollected base fuel and variable environmental costs	36,100,000
Carrying costs on deferred income tax assets	1,900,000	1,200,000
Carrying cost recovery	(3,000,000)	(2,000,000)
Regulatory Assets, Noncurrent	1,817,000,000		1,745,000,000
Number of coal fired units to be retired	3							6
Allowable return on common equity (as a percent)	11.00%
Demand Side Management Program Costs, Noncurrent	32,000,000	15,400,000					16,900,000
Regulatory Asset Recovery Assessments		12
Increase (decrease) in retail electric rate requested under the BLRA			66,200,000	67,200,000
Public Utilities, Percent Increase (Decrease) in Retail Electric Rates			2.80%	2.90%
Public Utilities, Percent Increase (Decrease) in Retail Natural Gas Rates			0.60%
Public Utilities changes in Retail Natural Gas Rates Approved under RSA			2,600,000
Public Utilities, Rate Calculation Basis	12-month rolling average
Public Utilities Base Fuel under Collected Balance Recovery Period	12
Derivative, Gain on Derivative			17,800,000
Storm Damage Reserve Cost Applied			5,000,000
Reduction to Net Lost Revenues from DSM programs			25.00%
Reduction to DSM Program costs deferred			6,600,000
Number of Units retired	3			3
Demand side management recovery period	5
Amount Allowed to be Recovered through Electric Rates to Offset Incremental Storm Damage Costs	100,000,000
PSNC Energy
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	1,000,000
Public Utilities, Rate Calculation Basis		12
Pension Costs [Member]
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	337,000,000		350,000,000
Pension Costs [Member] | SCEG
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	305,000,000		310,000,000
Regulatory Noncurrent Asset Amortization Period	12		14	30
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority	14,000,000							63,000,000
Other Regulatory Assets [Member]
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	37,000,000		35,000,000
Regulatory Noncurrent Asset Amortization Period	30				30
Other Regulatory Assets [Member] | SCEG
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	37,000,000		35,000,000
Regulatory Noncurrent Asset Amortization Period	50					50
Deferred Pollution Control Costs
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	35,000,000		36,000,000
Deferred Pollution Control Costs | SCEG
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	35,000,000		36,000,000
Franchise agreement Costs
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	25,000,000		26,000,000
Franchise agreement Costs | SCEG
Rate Matters [Line Items]
Regulatory Assets, Noncurrent	25,000,000		26,000,000
Capital costs, construction delays [Domain] | SCEG
Rate Matters [Line Items]
Forecasted incremental capital costs, 2015 petition	539,000,000
Grossconstructioncosts [Member] | SCEG
Rate Matters [Line Items]
Forecasted Capital Cost, 2015 Petition	6,800,000,000
Planned major maintenance [Member] | SCEG
Rate Matters [Line Items]
Amounts Recovered through Electric Rates to offset Turbine Expense	18,400,000
Storm damage reserve [Member]
Rate Matters [Line Items]
Storm Damage Reserve Applied To Offset Net Lost Margin Related To DSM			5,000,000
Amount Allowed to be Recovered through Electric Rates to Offset Incremental Storm Damage Costs	$ 100,000,000