v3.10.0.1
EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Details 3) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount $ 727.3 $ 849.6 $ 793.6
Compensation and Benefits Trust $ 400.0 $ 498.0  
Transfers of fair value amounts into or out of Levels 1, 2 or 3 no no  
Alternative Investment $ 727.0 $ 850.0  
Noncontrolling Interest in Joint Ventures 83.0 92.0  
Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 244.0 260.0  
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 107.0 120.0  
Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 20.0 17.0  
Fair Value, Inputs, Level 2 [Member] | Agency Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 7.0 15.0  
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 92.0 91.0  
Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 18.0 17.0  
SCE&G      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 676.7 781.3 $ 732.9
Compensation and Benefits Trust $ 373.0 $ 458.0  
Transfers of fair value amounts into or out of Levels 1, 2 or 3 no no  
Alternative Investment $ 677.0 $ 781.0  
Noncontrolling Interest in Joint Ventures 77.0 84.0  
SCE&G | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 227.0 239.0  
SCE&G | Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 99.0 110.0  
SCE&G | Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 19.0 16.0  
SCE&G | Fair Value, Inputs, Level 2 [Member] | Agency Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 7.0 14.0  
SCE&G | Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount 86.0 84.0  
SCE&G | Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Plan Assets, Amount $ 16.0 $ 15.0