EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year, Description		no
Defined Benefit Plan, Accumulated Benefit Obligation		$ 905.8	$ 874.3
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation		$ 1.6	0.8
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation		$ 1.4	$ 0.7
Defined Benefit Plan Health Care Cost Trend Rate, Assumed		7.00%
Defined Benefit Plan, Target Allocation, Equity Securities		58.00%	57.00%
Defined Benefit Plan, Target Plan Asset Allocations		31.00%	32.00%
Defined Benefit Plan, Target Plan Asset Allocation, Hedge Funds		11.00%	11.00%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Benefits Paid			$ 11.1
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		$ 1.3	1.7
Defined Benefit Plan, Benefit Obligation		289.2	274.7	$ 253.6
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, Actuarial Net (Gains) Losses		$ (9.7)	$ (14.0)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.74%	4.30%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		3.00%	3.00%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%	5.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets		$ 0.0	$ 0.0
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(289.2)	(274.7)
Liability, Defined Benefit Plan, Current		(13.5)	(12.6)
Liability, Other Postretirement Defined Benefit Plan, Noncurrent		(275.7)	(262.1)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		3.5	2.5
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		0.0	0.0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		3.5	2.5
pension and other postretirement benefit plans, regulated assets, net gains, before tax		43.3	34.7
Pension and other postretirement benefit plans, regulatory assets, net prior service costs (credit), before tax		0.0	0.0
Pension and other postretirement benefit plans, regulatory assets, before tax		43.3	34.7
Defined Benefit Plan, Shared Costs Deferred		14.7	15.8
Regulatory assets, pension and other postretirement benefit plans, net unamortized gain (loss) arising during the period, net of tax		9.4	11.1	$ (18.0)
Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax		(0.8)	(0.4)	(1.8)
Regulatory assets, amortization of prior service cost, pension and other postretirement benefit plans, net of tax		0.0	(0.3)	(0.3)
Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax		$ 8.6	$ 10.4	$ (20.1)
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, Benefit Obligation, Benefits Paid		$ 12.5
Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Benefits Paid		72.4
Defined Benefit Plan, Benefit Obligation		933.2	$ 904.3	$ 855.4
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, Actuarial Net (Gains) Losses		$ (42.2)	$ (45.0)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.71%	4.22%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		3.00%	3.00%
Defined Benefit Plan, Fair Value of Plan Assets		$ 849.6	$ 793.6	781.7
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		128.4	68.1
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(83.6)	(110.7)
Liability, Defined Benefit Pension Plan, Noncurrent		(83.6)	(110.7)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		8.8	10.4
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		0.1	0.1
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		8.9	10.5
pension and other postretirement benefit plans, regulated assets, net gains, before tax		194.8	236.1
Pension and other postretirement benefit plans, regulatory assets, net prior service costs (credit), before tax		1.2	2.5
Pension and other postretirement benefit plans, regulatory assets, before tax		196.0	238.6
Defined Benefit Plan, Shared Costs Deferred		21.4	23.4
Regulatory assets, pension and other postretirement benefit plans, net unamortized gain (loss) arising during the period, net of tax		(27.1)	29.4	9.2
Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax		(14.1)	(12.7)	(11.9)
Regulatory assets, amortization of prior service cost, pension and other postretirement benefit plans, net of tax		(1.4)	(3.4)	(3.7)
Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax		$ (42.6)	$ 13.3	$ (6.4)
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, Discount Rate		4.22%	4.68%	4.20%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.00%	3.00%	3.00%
Defined Benefit Plan, Benefit Obligation, Benefits Paid		$ 72.4	$ 56.2
SCE&G
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year, Description		no
Defined Benefit Plan, Period for which Annual Base Earnings are Considered Under Average Pay Formula		3
Defined Benefit Plan, Accumulated Benefit Obligation		$ 769.7	742.9
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation		$ 1.3	0.6
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation		$ 1.1	$ 0.6
Defined Benefit Plan Health Care Cost Trend Rate, Assumed		7.00%
Defined Benefit Plan, Target Allocation, Equity Securities		58.00%	57.00%
Defined Benefit Plan, Target Plan Asset Allocations		31.00%	32.00%
Defined Benefit Plan, Target Plan Asset Allocation, Hedge Funds		11.00%	11.00%
SCE&G | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Benefits Paid		$ 10.3	$ 9.1
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		1.1	1.3
Defined Benefit Plan, Benefit Obligation		216.6	207.2	$ 191.7
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, Actuarial Net (Gains) Losses		(6.8)	(11.5)
Defined Benefit Plan, Amounts Funded to Parent		$ (1.4)	$ (1.7)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.74%	4.30%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		3.00%	3.00%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%	5.00%	5.00%
Defined Benefit Plan, Fair Value of Plan Assets		$ 0.0	$ 0.0
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(216.6)	(207.2)
Liability, Defined Benefit Plan, Current		(10.8)	(10.4)
Liability, Other Postretirement Defined Benefit Plan, Noncurrent		(205.8)	(196.8)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		1.5	1.0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		0.0	0.0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		1.5	1.0
pension and other postretirement benefit plans, regulated assets, net gains, before tax		35.9	29.3
Pension and other postretirement benefit plans, regulatory assets, net prior service costs (credit), before tax		0.0	0.0
Pension and other postretirement benefit plans, regulatory assets, before tax		35.9	29.3
Regulatory assets, pension and other postretirement benefit plans, net unamortized gain (loss) arising during the period, net of tax		7.3	9.2	$ (14.0)
Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax		(0.7)	(0.3)	1.5
Regulatory assets, amortization of prior service cost, pension and other postretirement benefit plans, net of tax		0.0	(0.2)	(0.3)
Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax		$ 6.6	$ 8.7	$ (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%
SCE&G | Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Benefits Paid		$ 62.0	$ 47.7
Defined Benefit Plan, Benefit Obligation		793.0	768.4	$ 724.0
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, Actuarial Net (Gains) Losses		(36.6)	(41.8)
Defined Benefit Plan, Amounts Funded to Parent		$ 0.0	$ 0.0
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.71%	4.22%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		3.00%	3.00%
Defined Benefit Plan, Fair Value of Plan Assets		$ 781.3	$ 732.9	720.1
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		110.4	60.5
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(11.7)	(35.5)
Liability, Defined Benefit Pension Plan, Noncurrent		(11.7)	(35.5)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		2.1	1.9
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		0.0	0.0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		2.1	1.9
pension and other postretirement benefit plans, regulated assets, net gains, before tax		171.4	208.8
Pension and other postretirement benefit plans, regulatory assets, net prior service costs (credit), before tax		1.0	2.2
Pension and other postretirement benefit plans, regulatory assets, before tax		172.4	211.0
Regulatory assets, pension and other postretirement benefit plans, net unamortized gain (loss) arising during the period, net of tax		(24.8)	26.3	12.2
Regulatory assets, amortization of actuarial losses, pension and other postretirement benefit plans, net of tax		(12.5)	(11.2)	(10.4)
Regulatory assets, amortization of prior service cost, pension and other postretirement benefit plans, net of tax		(1.3)	(3.0)	(3.1)
Regulatory assets, total recognized in regulatory assets, pension and other postretirement benefit plans, net of tax		$ (38.6)	$ 12.1	$ (1.3)
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, Discount Rate		4.22%	4.68%	4.20%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.00%	3.00%	3.00%
Pension Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority		$ 1.0
Pension Costs [Member] | SCE&G
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Deferred Debit Attributable to Share of Regulatory Authority		$ 2.0
Regulatory assets, expected recovery period (in years)		11 years
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%
Defined Benefit Plan, Target Allocation, Equity Securities	58.00%
Defined Benefit Plan, Target Plan Asset Allocations	33.00%
Defined Benefit Plan, Target Plan Asset Allocation, Hedge Funds	9.00%
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%
Defined Benefit Plan, Target Allocation, Equity Securities	58.00%
Defined Benefit Plan, Target Plan Asset Allocations	33.00%
Defined Benefit Plan, Target Plan Asset Allocation, Hedge Funds	9.00%