RATE AND OTHER REGULATORY MATTERS (Details 2) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Regulatory Assets
Regulatory Liabilities	$ 847.0		$ 855.0
MPG environmental remediation	24
Regulatory Assets, Noncurrent	$ 2,068.0		1,937.0
SCEG
Regulatory Assets
Regulatory Liabilities	623.0		635.0
Carrying costs on deferred income tax assets	3.1	$ 1.9
Regulatory Assets, Noncurrent	$ 1,986.0		1,857.0
Demand side management recovery period	5
Other Regulatory Liability [Member]
Regulatory Assets
Regulatory Liabilities	$ 27.0		27.0
Other Regulatory Liability [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	20.0		20.0
Asset Retirement Obligation Costs [Member]
Regulatory Assets
Regulatory Liabilities	739.0		732.0
Asset Retirement Obligation Costs [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	522.0		519.0
Deferred gains on interest rate derivatives [Member]
Regulatory Assets
Regulatory Liabilities	81.0		96.0
Deferred gains on interest rate derivatives [Member] | SCEG
Regulatory Assets
Regulatory Liabilities	$ 81.0		96.0
Pension costs, electric [Member] | SCEG
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period	30 years
Deferred Losses On Interest Rate Derivatives [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	$ 666.0		535.0
Deferred Losses On Interest Rate Derivatives [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	$ 666.0		535.0
Asset Retirement Obligation Costs [Member]
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period	110 years
Regulatory Assets, Noncurrent	$ 402.0		405.0
Asset Retirement Obligation Costs [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	381.0		384.0
unrecovered plant [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	125.0		127.0
unrecovered plant [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	125.0		127.0
Demand Side Management programs [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	61.0		61.0
Demand Side Management programs [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	$ 61.0		61.0
Deferred Income Tax Charges [Member]
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period	85 years
Regulatory Assets, Noncurrent	$ 297.0		298.0
Deferred Income Tax Charges [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	290.0		291.0
Environmental Restoration Costs [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	41.0		42.0
Environmental Restoration Costs [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	34.0		35.0
Pension Costs [Member]
Regulatory Assets
Regulatory Assets, Noncurrent	$ 323.0		325.0
Pension Costs [Member] | SCEG
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period	12 years
Regulatory Assets, Noncurrent	$ 293.0		295.0
Other Regulatory Assets [Member]
Regulatory Assets
Regulatory Noncurrent Asset, Amortization Period	30 years
Regulatory Assets, Noncurrent	$ 153.0		144.0
Other Regulatory Assets [Member] | SCEG
Regulatory Assets
Regulatory Assets, Noncurrent	$ 136.0		$ 129.0