XML 43 R156.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Short-Term Debt and Credit Agreements (Narrative) (Detail) - USD ($)
1 Months Ended 12 Months Ended
Nov. 30, 2019
Sep. 30, 2019
Dec. 31, 2019
Apr. 30, 2019
Mar. 31, 2019
Feb. 28, 2019
Dec. 31, 2018
Debt Instrument [Line Items]              
Debt maximum borrowing capacity [1]     $ 6,000,000,000       $ 6,000,000,000
Questar Gas              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity     250,000,000        
Dominion Energy Midstream Partners, LP              
Debt Instrument [Line Items]              
Credit facility, outstanding amount           $ 73,000,000  
Dominion Energy South Carolina Inc              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity       $ 2,200,000,000      
South Carolina Generating Company Inc              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity       $ 200,000,000      
Six Billion Joint Revolving Credit Facility | Dominion Energy Midstream Partners, LP              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity           500,000,000  
Credit Facilities, Maturing in December 2017 with 1 year Automatic Renewals through 2023 | SBL Holdco              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity     30,000,000        
Credit Facilities Maturing In May 2018 With 1 Year Automatic Renewals Through 2024 [Member] | Dominion Solar Projects III, Inc              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity     25,000,000        
Term Loan Credit Agreement [Member]              
Debt Instrument [Line Items]              
Credit facility, outstanding amount   $ 3,000,000,000.0         $ 3,000,000,000.0
Weighted average useful life   364 days          
Term Loan Due in 2021 | Dominion Energy Questar Corporation              
Debt Instrument [Line Items]              
Repayments of principal $ 1,000,000,000.0   2,000,000,000.0        
Term Loan Due in 2021 | Cove Point              
Debt Instrument [Line Items]              
Repayments of principal     3,000,000,000.0        
Letter of Credit              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity           $ 21,000,000  
Credit facility, outstanding amount     $ 21,000,000        
Revolving Credit Facility              
Debt Instrument [Line Items]              
Debt maximum borrowing capacity         $ 700,000,000    
[1] This credit facility matures in March 2023 and can be used by the borrowers under the credit facility to support bank borrowings and the issuance of commercial paper, as well as to support up to a combined $2.0 billion of letters of credit.