RATE AND OTHER REGULATORY MATTERS (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Regulatory Liabilities [Line Items]
Defined Benefit Pension Plan, Liabilities, Noncurrent		$ 0	$ 0
Regulatory Noncurrent Liability, Amortization Period			30
Accrual period of nuclear refueling charges (in months)			18
Amount Recovered Through Electric Rates to Offset Turbine Expenses			18.4
Regulatory Liability, Noncurrent		882	882	778
Accumulated deferred income taxes
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		21	21	23
Asset Retirement Obligation Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		692	692	662
Storm damage reserve
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		27	27	32
Monetization of bankruptcy claim
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		32	32	34
Deferred gains on interest rate derivatives
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		110	110	24
Other.
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		0	0	3
SCE&G
Regulatory Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period			30
Defined Benefit Pension Plan, Liabilities, Noncurrent		63	63
Regulatory Noncurrent Liability, Amortization Period			30
Accrual period of nuclear refueling charges (in months)			18
Amount Recovered Through Electric Rates to Offset Turbine Expenses	17.2	18.4
Amount Allowed to be Recovered through Electric Rates to Offset Incremental Storm Damage Costs			100
Regulatory Liability, Noncurrent		665	665	575
Annual Storm Damage Costs not offset by Amounts Recovered through Electric Rates			2.5
SCE&G | Accumulated deferred income taxes
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		21	21	23
SCE&G | Asset Retirement Obligation Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		507	507	493
SCE&G | Storm damage reserve
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		27	27	32
SCE&G | Deferred gains on interest rate derivatives
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		110	110	24
SCE&G | Other
Regulatory Liabilities [Line Items]
Regulatory Liability, Noncurrent		$ 0	$ 0	$ 3
Deferred losses on interest rate derivatives
Regulatory Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period			30
Pension Costs [Member] | SCE&G
Regulatory Liabilities [Line Items]
Regulatory Noncurrent Asset, Amortization Period			12