RATE AND OTHER REGULATORY MATTERS (Details 2) (USD $) In Millions, unless otherwise specified			12 Months Ended				12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended				12 Months Ended		12 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Accumulated deferred income taxes	Dec. 31, 2010 Accumulated deferred income taxes	Dec. 31, 2011 Under-collections-electric fuel adjustment clause	Dec. 31, 2010 Under-collections-electric fuel adjustment clause	Dec. 31, 2011 Environmental remediation costs	Dec. 31, 2010 Environmental remediation costs	Dec. 31, 2011 Asset retirement obligations and related funding	Dec. 31, 2010 Asset retirement obligations and related funding	Dec. 31, 2011 Franchise agreements	Dec. 31, 2010 Franchise agreements	Dec. 31, 2011 Deferred employee benefit plan costs	Dec. 31, 2010 Deferred employee benefit plan costs	Dec. 31, 2011 Planned major maintenance	Dec. 31, 2010 Planned major maintenance	Dec. 31, 2011 Deferred losses on interest rate derivatives	Dec. 31, 2010 Deferred losses on interest rate derivatives	Dec. 31, 2011 Deferred pollution control costs	Dec. 31, 2010 Deferred pollution control costs	Dec. 31, 2011 Other Regulatory Assets [Member]	Dec. 31, 2010 Other Regulatory Assets [Member]	Jul. 31, 2010 SCE&G	Dec. 31, 2011 SCE&G	Dec. 31, 2011 Williams Stations
Regulatory Assets:
Regulatory assets	$ 1,279.0	$ 1,061.0	$ 243.0	$ 210.0	$ 28.0	$ 25.0	$ 30.0	$ 32.0	$ 316.0	$ 298.0	$ 40.0	$ 45.0	$ 392.0	$ 326.0	$ 6.0	$ 6.0	$ 154.0	$ 83.0	$ 25.0	$ 13.0	$ 45.0	$ 23.0			$ 9.4
Regulatory assets, expected recovery period (in years)			P70Y				P23Y		P95Y		P20Y		P14Y				P30Y		P30Y		P30Y
Amount recovered through electric rates to offset turbine maintenance expenditures																							$ 8.5	$ 18.4
Accrual period of nuclear refueling charges (in months)																								18 months