v3.10.0.1
LONG-TERM AND SHORT-TERM DEBT (Details 2)
 12 Months Ended
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Sep. 30, 2018
Debt Instrument, Redemption [Line Items]      
Medium-term Notes $ 800,000,000 $ 800,000,000  
Interest Income, Related Party 4,000,000    
Related Party Transaction, Due from (to) Related Party, Current $ 282,000,000 28,000,000  
Bond Ratio 4.01    
Line of Credit Facility, Maximum Borrowing Capacity $ 1,800,000,000 2,000,000,000  
Long-term Line of Credit $ 40,000,000    
Line of Credit Facility, Interest Rate at Period End 3.87%    
Commercial Paper $ 172,900,000 350,300,000  
commercial paper available to be borrowed   600,000,000  
Letters of Credit Outstanding, Amount 37,600,000 3,300,000  
Line of Credit Facility, Remaining Borrowing Capacity 1,549,500,000 1,646,400,000  
Genco [Member]      
Debt Instrument, Redemption [Line Items]      
Commercial Paper   200,000,000  
SCEG including Fuel Company [Member]      
Debt Instrument, Redemption [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity 1,200,000,000 1,400,000,000  
Commercial Paper $ 73,200,000 $ 251,600,000  
Debt, Weighted Average Interest Rate 3.82% 1.92%  
Letters of Credit Outstanding, Amount $ 300,000 $ 300,000  
Line of Credit Facility, Remaining Borrowing Capacity 1,126,500,000 1,148,100,000  
Commercial paper borrowing limit   1,600,000,000  
SCANA [Member]      
Debt Instrument, Redemption [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity 400,000,000 400,000,000  
Commercial Paper $ 2,000,000 0  
Debt, Weighted Average Interest Rate 3.65%    
Letters of Credit Outstanding, Amount $ 37,300,000 3,000,000  
Line of Credit Facility, Remaining Borrowing Capacity 320,700,000 397,000,000  
Fuel Company [Member]      
Debt Instrument, Redemption [Line Items]      
Long-Term Line of Credit - SC Fuel Co only 500,000,000 500,000,000  
SCE&G      
Debt Instrument, Redemption [Line Items]      
Medium-term Notes 300,000,000    
Related Party Transaction, Due from (to) Related Party, Current 353,000,000 37,000,000  
Line of Credit Facility, Maximum Borrowing Capacity 700,000,000 700,000,000  
Debt, Weighted Average Interest Rate     6.06%
Long-term Line of Credit - SCE&G only   200,000,000  
First Mortgage Bonds 1,200,000,000    
PSNC Energy [Member]      
Debt Instrument, Redemption [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity 200,000,000 200,000,000  
Commercial Paper $ 97,700,000 $ 98,700,000  
Debt, Weighted Average Interest Rate 3.49% 1.93%  
Line of Credit Facility, Remaining Borrowing Capacity $ 102,300,000 $ 101,300,000  
Industrial and Pollution Control Bonds [Member]      
Debt Instrument, Redemption [Line Items]      
Debt, Weighted Average Interest Rate 3.52% 3.52%  
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate 1.72% 1.85%  
Industrial and Pollution Control Bonds [Member] | SCE&G      
Debt Instrument, Redemption [Line Items]      
Debt, Weighted Average Interest Rate 3.52% 3.52%  
Wells Fargo, National Association, Bank of America & Morgan Stanley [Member]      
Debt Instrument, Redemption [Line Items]      
Line of Credit Facility, Remaining Borrowing Capacity   $ 0.095  
JP Morgan Chase, Mizuho Corp, TD Bank, Credit Suisse AG ,Cayman Islands Branch and UBS Loan Finance [Member]      
Debt Instrument, Redemption [Line Items]      
Line of Credit Facility, Remaining Borrowing Capacity   7.9  
royal bank of canada [Domain]      
Debt Instrument, Redemption [Line Items]      
Line of Credit Facility, Remaining Borrowing Capacity   0.055  
3 Year Credit [Domain]      
Debt Instrument, Redemption [Line Items]      
Long-term Line of Credit - SCE&G only   200,000,000  
five year credit [Domain]      
Debt Instrument, Redemption [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity $ 1,300,000,000 $ 1,300,000,000