EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Details 5) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		$ 0.0	$ 0.0	$ 0.0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax		$ 0.0	1.0	0.0
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%
Defined Contribution Plan, Maximum Percentage of Employer Contribution for up to Six Percent of Participant Contribution		100.00%
Defined Contribution Plan, Maximum Percentage of Participant Contribution Eligible for Employer Contribution Match		6.00%
Defined Contribution Plan, Cost		$ 27.9	27.5	26.2
Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		(1.0)	0.6	2.7
Amortization of deferred employee benefit plan costs reclassified to net income, net of tax		(0.6)	(0.6)	(0.4)
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Net of Tax		0.0	(0.1)	(0.1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax		(1.6)	(0.1)	2.2
Defined Benefit Plan, Service Cost		21.7	20.7	24.1
Defined Benefit Plan, Interest Cost		37.4	39.4	38.2
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		(54.7)	(55.9)	(62.0)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)		1.6	3.9	4.1
Defined Benefit Plan, Amortization of Gain (Loss)		16.3	14.8	13.6
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ 22.3	$ 22.9	$ 18.0
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate		4.22%	4.68%	4.20%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		7.25%	7.50%	7.50%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.00%	3.00%	3.00%
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		$ 1.1	$ 0.8	$ (1.2)
Amortization of deferred employee benefit plan costs reclassified to net income, net of tax		(0.1)	0.0	(0.1)
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Net of Tax		0.0	0.0	(0.1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax		1.0	0.8	(1.4)
Defined Benefit Plan, Service Cost		4.5	4.4	5.3
Defined Benefit Plan, Interest Cost		11.5	12.1	11.4
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)		0.0	0.3	0.4
Defined Benefit Plan, Amortization of Gain (Loss)		1.0	0.5	2.1
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ 17.0	$ 17.3	$ 19.2
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate		4.30%	4.78%	4.30%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.00%	3.00%	3.00%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		6.60%	7.00%	7.00%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%	5.00%	5.00%
SCE&G
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		$ 0.0		$ 0.0	$ 0.0
Amortization of deferred employee benefit plan costs reclassified to net income, net of tax		$ 0.0		0.0	$ 0.0
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%
Defined Contribution Plan, Maximum Percentage of Employer Contribution for up to Six Percent of Participant Contribution		100.00%
Defined Contribution Plan, Maximum Percentage of Participant Contribution Eligible for Employer Contribution Match		6.00%
Defined Contribution Plan, Cost		$ 23.4	$ 22.9	21.8
SCE&G | Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		0.3	0.0	0.2
Amortization of deferred employee benefit plan costs reclassified to net income, net of tax		(0.1)	(0.1)	(0.1)
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Net of Tax		0.0	0.0	(0.1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax		0.2	(0.1)	0.0
Defined Benefit Plan, Service Cost		18.1	16.9	19.3
Defined Benefit Plan, Interest Cost		31.9	33.4	32.2
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		(46.7)	(47.4)	(52.2)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)		1.4	3.4	3.4
Defined Benefit Plan, Amortization of Gain (Loss)		13.9	12.5	11.4
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ 18.6	$ 18.8	$ 14.1
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate		4.22%	4.68%	4.20%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		7.25%	7.50%	7.50%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.00%	3.00%	3.00%
SCE&G | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		$ 0.5	$ 0.3	$ (0.3)
Amortization of deferred employee benefit plan costs reclassified to net income, net of tax		0.0	0.0	0.0
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Net of Tax		0.0	0.0	0.0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax		0.5	0.3	(0.3)
Defined Benefit Plan, Service Cost		3.7	3.6	4.4
Defined Benefit Plan, Interest Cost		9.5	9.9	9.4
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)		0.0	0.3	0.3
Defined Benefit Plan, Amortization of Gain (Loss)		0.8	0.4	1.7
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ 14.0	$ 14.2	$ 15.8
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate		4.30%	4.78%	4.30%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.00%	3.00%	3.00%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		6.60%	7.00%	7.00%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%	5.00%	5.00%
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	7.00%
Scenario, Forecast [Member] | Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Amortization of Net Gains (Losses)	$ 0.5
Defined benefit plan, future amortization of gain or loss from regulatory assets	10.2
Defined benefit plan, future amortization of prior service cost (credit) from regulatory assets	0.4
Defined benefit plan, amount to be amortized from regulatory assets next year	10.6
Scenario, Forecast [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Amortization of Net Gains (Losses)	0.1
Defined benefit plan, future amortization of gain or loss from regulatory assets	1.8
Defined benefit plan, future amortization of prior service cost (credit) from regulatory assets	0.0
Defined benefit plan, amount to be amortized from regulatory assets next year	$ 1.8
Scenario, Forecast [Member] | SCE&G
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	7.00%
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	insignificant
Scenario, Forecast [Member] | SCE&G | Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, future amortization of gain or loss from regulatory assets	$ 9.0
Defined benefit plan, future amortization of prior service cost (credit) from regulatory assets	0.4
Defined benefit plan, amount to be amortized from regulatory assets next year	9.4
Scenario, Forecast [Member] | SCE&G | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, future amortization of gain or loss from regulatory assets	1.5
Defined benefit plan, future amortization of prior service cost (credit) from regulatory assets	0.0
Defined benefit plan, amount to be amortized from regulatory assets next year	$ 1.5