v3.10.0.1
FAIR VALUE MEASUREMENTS, INCLUDING DERIVATIVES (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset $ 14 $ 59
Derivative Liability $ 38 $ 37
Liabilities, Fair Value Disclosure [Abstract]    
Transfers of fair value amounts into or out of Levels 1, 2 or 3 no no
Level 3 Fair Value Measurements no no
Available-for-sale Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure $ 0 $ 119
Held-to-maturity Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 6 6
Interest Rate Contract [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset 0 54
Derivative Liability 24 32
Interest Rate Contract [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 0 54
Financial and Nonfinancial Liabilities, Fair Value Disclosure 24 32
Commodity Contract [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset 1 1
Derivative Liability 1 3
Commodity Contract [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 1 1
Financial and Nonfinancial Liabilities, Fair Value Disclosure 1 2
Commodity Contract [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 0 0
Financial and Nonfinancial Liabilities, Fair Value Disclosure 0 1
Other Energy Management Contract [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset 2 4
Derivative Liability 2 2
Other Energy Management Contract [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 11 0
Financial and Nonfinancial Liabilities, Fair Value Disclosure 12 1
Other Energy Management Contract [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 2 4
Financial and Nonfinancial Liabilities, Fair Value Disclosure 3 4
SCE&G    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset 0 54
Derivative Liability $ 11 $ 15
Liabilities, Fair Value Disclosure [Abstract]    
Transfers of fair value amounts into or out of Levels 1, 2 or 3 no no
Level 3 Fair Value Measurements no no
SCE&G | Available-for-sale Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure $ 0 $ 100
SCE&G | Interest Rate Contract [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset 0 54
Derivative Liability 11 15
SCE&G | Interest Rate Contract [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 0 54
Financial and Nonfinancial Liabilities, Fair Value Disclosure $ 11 $ 15