EMPLOYEE BENEFIT PLANS (Details) (USD $)	12 Months Ended								4 Months Ended	8 Months Ended	12 Months Ended									12 Months Ended				4 Months Ended	8 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2014 Other Postretirement Benefits	Dec. 31, 2013 Other Postretirement Benefits	Dec. 31, 2012 Other Postretirement Benefits	Dec. 31, 2011 Other Postretirement Benefits	Dec. 31, 2013 Pension Benefits	Aug. 31, 2013 Pension Benefits	Dec. 31, 2014 Pension Benefits	Dec. 31, 2013 Pension Benefits	Dec. 31, 2012 Pension Benefits	Dec. 31, 2011 Pension Benefits	Dec. 31, 2014 SCE&G	Dec. 31, 2013 SCE&G	Dec. 31, 2012 SCE&G	Dec. 31, 2011 SCE&G	Sep. 30, 2013 SCE&G	Dec. 31, 2014 SCE&G Other Postretirement Benefits	Dec. 31, 2013 SCE&G Other Postretirement Benefits	Dec. 31, 2012 SCE&G Other Postretirement Benefits	Dec. 31, 2011 SCE&G Other Postretirement Benefits	Dec. 31, 2013 SCE&G Pension Benefits	Aug. 31, 2013 SCE&G Pension Benefits	Dec. 31, 2014 SCE&G Pension Benefits	Dec. 31, 2013 SCE&G Pension Benefits	Dec. 31, 2012 SCE&G Pension Benefits	Dec. 31, 2011 SCE&G Pension Benefits	Sep. 30, 2013 Pension Costs [Member] SCE&G	Dec. 31, 2014 Pension Costs [Member] SCE&G	Dec. 31, 2013 Pension Costs [Member] SCE&G	Mar. 31, 2013 Pension Costs [Member] SCE&G
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority																	$ 63,000,000		$ 14,000,000													$ 0	$ 14
Transfers of fair value amounts into or out of Levels 1, 2 or 3		no	no													no	no
Defined benefit plan, future amortization of gain or loss from regulatory assets					400,000						4,300,000									300,000						3,700,000
Regulatory assets, pension and other postretirement benefit plans, net unamortized gain (loss) arising during the period, net of tax						(29,900,000)	31,400,000	6,000,000				(157,500,000)	45,000,000	70,900,000							(24,400,000)	25,700,000	5,000,000				(137,100,000)	37,900,000	61,800,000
pension and other postretirement benefit plans, regulated assets, net gains, before tax						24,400,000	57,000,000					124,800,000	297,000,000								20,100,000	46,700,000					107,700,000	257,500,000
Defined Benefit Plan Allocation, Equity Securities	58.00%
Defined Benefit Plan, Debt Securies	33.00%
Defined Contribution Plan, Cost Recognized		23.4	0	0												0	0	0
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate						4.19%	5.35%	5.72%	0.00%	0.00%			5.25%	5.56%							4.19%	5.35%	5.72%	0.00%	0.00%			5.25%	5.56%
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year															insignificant
Defined Benefit Plan, Period for which Annual Base Earnings are Considered Under Average Pay Formula																3
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax						1,700,000	3,700,000		5,200,000			5,200,000	10,700,000								600,000	1,100,000		1,800,000			1,800,000	2,700,000
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities						(11,500,000)	11,000,000														(7,800,000)	(8,500,000)
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent									47,000,000			47,000,000				96,000,000	0				0	0		96,400,000			96,400,000	0
Defined Benefit Pension Plan, Liabilities, Noncurrent		0							0			0	(132,500,000)			63,000,000												(56,400,000)
Defined Benefit Plan, Fair Value of Plan Assets		870,000,000	799,000,000			0	0		870,000,000			870,000,000	799,100,000	755,000,000		792,000,000	732,000,000				0	0		792,100,000			792,100,000	732,000,000	695,300,000
Defined Benefit Plan Health Care Cost Trend Rate, Assumed		7.40%														7.40%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate						5.19%	4.19%		5.03%			5.03%	4.10%								5.19%	4.19%		5.03%			5.03%	4.10%
Defined Benefit Plan, Accumulated Benefit Obligation		0	0													0	0
Defined Benefit Plan, Benefits Paid						(11,800,000)	(13,800,000)					(60,000,000)	(57,600,000)								(9,300,000)	(10,800,000)					(50,600,000)	(49,000,000)
Defined Benefit Plan, Curtailments		(25,500,000)										9,900,000				(21,600,000)											8,400,000
Defined Benefit Plan, Amounts Funded to Parent																					(3,000,000)	(3,200,000)					0	0
Defined Benefit Plan, Contributions by Plan Participants						2,600,000	2,900,000					0	0								2,000,000	2,300,000					0	0
Defined Benefit Plan, Benefit Obligation						238,000,000	265,300,000	226,100,000	823,000,000			823,000,000	931,600,000	830,100,000							181,700,000	206,000,000	178,400,000	695,700,000			695,700,000	788,400,000	705,000,000
Service cost						5,900,000	4,800,000	4,300,000				21,800,000	19,600,000	18,300,000							4,600,000	3,700,000	3,400,000				17,600,000	15,700,000	14,700,000
Interest cost						11,100,000	11,900,000	12,200,000				38,500,000	43,000,000	43,500,000							8,700,000	9,400,000	9,600,000				32,600,000	36,400,000	37,000,000
Expected return on assets												61,400,000	59,500,000	63,700,000													51,900,000	50,400,000	54,200,000
Defined Benefit Plan, Amortization of Transition Obligations (Assets)						300,000	700,000	700,000				0	0	0							0	0	(100,000)				0	0	0
Defined Benefit Plan, Actuarial Net (Gains) Losses						35,100,000	(33,400,000)					83,400,000	(96,500,000)								27,300,000	(26,200,000)					70,700,000	(80,300,000)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase						3.75%	3.75%		3.00%			3.00%	3.75%								3.75%	3.75%		3.00%			3.00%	3.75%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%				5.00%	5.00%	5.00%								5.00%					5.00%	5.00%	5.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation		1.3	0													0	0
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation		1.2	0													0	0
Defined Benefit Plan, Funded Status of Plan						(238,000,000)	(265,300,000)		47,000,000			47,000,000	(132,500,000)								(181,700,000)	(206,000,000)		96,400,000			96,400,000	(56,400,000)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax						100,000	100,000		500,000			500,000	1,000,000								0	0		200,000			200,000	200,000
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Transition Assets (Obligations), before Tax						0	100,000
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax						1,800,000	3,900,000		5,700,000			5,700,000	11,700,000								600,000	1,100,000		2,000,000			2,000,000	2,900,000
Defined Benefit Plan, Actual Return on Plan Assets												130,900,000	101,700,000														110,700,000	85,700,000
Other Postretirement Defined Benefit Plan, Liabilities, Noncurrent						(226,500,000)	(254,300,000)														(173,900,000)	(197,500,000)
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase						3.75%	4.00%	4.00%	0.00%	0.00%			4.00%	4.00%							3.75%	4.00%	4.00%	0.00%	0.00%			4.00%	4.00%
defined benefit plan, hedge funds	0.00%
Pension and other postretirement benefit plans, regulatory assets, net prior service costs (credit), before tax						900,000	1,500,000					12,800,000	26,900,000								700,000	1,200,000					11,100,000	23,300,000
Pension and other postretirement benefit plans, regulatory assets, net transition assets (obligations), before tax						0	200,000					0	0								0	100,000					0	0
Pension and other postretirement benefit plans, regulatory assets, before tax						25,300,000	58,700,000					137,600,000	323,900,000								20,800,000	48,000,000					118,800,000	280,800,000
Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax						(2,700,000)	(1,200,000)	(300,000)				(14,700,000)	(16,000,000)	(10,600,000)							(2,200,000)	(1,000,000)	(200,000)				(12,700,000)	(14,000,000)	(9,300,000)
Regulatory assets, amortization of prior service cost, pension and other postretirement benefit plans, net of tax						(600,000)	(800,000)	(900,000)				(5,200,000)	(6,400,000)	(6,400,000)							(500,000)	(700,000)	(700,000)				(4,500,000)	(5,700,000)	(5,500,000)
Regulatory assets, prior service cost (credit), pension and other postretirement benefit plans, net of tax						0	0	0				(8,900,000)	0	0							0	0	0				(7,700,000)	0	0
Regulatory assets, amortization of transition obligation, pension and other postretirement benefit plans, net of tax						(200,000)	(500,000)	(500,000)				0	0	0							(100,000)	(200,000)	(200,000)				0	0	0
Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax						(33,400,000)	28,900,000	4,300,000				(186,300,000)	22,600,000	53,900,000							(27,200,000)	23,800,000	3,900,000				(162,000,000)	18,200,000	47,000,000
Defined benefit plan, future amortization of prior service cost (credit) from regulatory assets					300,000						3,500,000									300,000						3,100,000
Defined benefit plan, amount to be amortized from regulatory assets next year					700,000						7,800,000									600,000						6,800,000
Defined Benefit Plan, Shared Costs Deferred						$ 12.6	$ 14.7		$ 14.1			$ 14.1	$ 26.8								$ 12.6	$ 14.7		$ 14.1			$ 14.1	$ 26.8
Regulatory assets, expected recovery period (in years)																														14	14	12