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Affiliated and Related Party Transactions (Narrative) (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Related Party Transaction [Line Items]          
Purchases from affiliates, fuel used in electric generation $ 0 $ 35 $ 43 $ 95  
Canadys Refined Coal [Member]          
Related Party Transaction [Line Items]          
Ownership percentage 40.00%   40.00%    
Purchases from affiliates $ 38 $ 45 $ 100 $ 123  
Accounts payable to affiliates 13   13   $ 7
Solar Affiliates [Member]          
Related Party Transaction [Line Items]          
Purchases from affiliates 3   7    
Solar Affiliates [Member] | Maximum [Member]          
Related Party Transaction [Line Items]          
Accounts payable to affiliates 1   1    
Dominion Energy Carolina Gas Transmission LLC [Member]          
Related Party Transaction [Line Items]          
Purchases from affiliates 16   48    
Accounts payable to affiliates 6   6    
Purchases from affiliates, fuel used in electric generation 6   15    
Purchases from affiliates, gas purchased for resale $ 10   $ 33