LONG-TERM AND SHORT-TERM DEBT (Details 2) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Borrowings under credit agreement	$ 100.0
Related Party Transaction, Due from (to) Related Party, Current	187.0	$ 28.0
Line of Credit Facility, Maximum Borrowing Capacity	2,000.0	2,000.0
Borrowings under LOC	$ 100.0
Weighted Average interest rate on LOC borrowing	3.31%
Commercial Paper	$ 517.4	350.3
Letters of Credit Outstanding, Amount	33.7	3.3
Line of Credit Facility, Remaining Borrowing Capacity	$ 1,348.9	1,646.4
Line of Credit Facility, Interest Rate During Period	3.31%
Commercial paper borrowing limit	$ 600.0
five year credit [Domain]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,300.0	1,300.0
SCANA [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	400.0	400.0
Commercial Paper	$ 29.0	$ 0.0
Debt, Weighted Average Interest Rate	2.99%	0.00%
Letters of Credit Outstanding, Amount	$ 33.4	$ 3.0
Line of Credit Facility, Remaining Borrowing Capacity	337.6	397.0
SCEG including Fuel Company [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,400.0	1,400.0
Borrowings under LOC	100.0
Commercial Paper	$ 457.5	$ 251.6
Debt, Weighted Average Interest Rate	2.96%	1.92%
Letters of Credit Outstanding, Amount	$ 0.3	$ 0.3
Line of Credit Facility, Remaining Borrowing Capacity	842.2	1,148.1
Commercial paper borrowing limit	1,600.0
Genco
Debt Instrument [Line Items]
Commercial paper borrowing limit	200.0
Fuel Company [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	500.0	500.0
Long-Term Line of Credit - SC Fuel Co only	500.0	500.0
SCEG
Debt Instrument [Line Items]
Related Party Transaction, Due from (to) Related Party, Current	144.0	37.0
Line of Credit Facility, Maximum Borrowing Capacity	700.0	700.0
Long-term Line of Credit - SCE&G only	200.0	200.0
PSNC Energy [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	200.0	200.0
Commercial Paper	$ 30.9	$ 98.7
Debt, Weighted Average Interest Rate	2.61%	1.93%
Line of Credit Facility, Remaining Borrowing Capacity	$ 169.1	$ 101.3