XML 103 R83.htm IDEA: XBRL DOCUMENT v3.8.0.1
Credit Risk (Narrative) (Details)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2017
USD ($)
counterparty
Jun. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
counterparty
Sep. 30, 2016
USD ($)
Dec. 31, 2016
USD ($)
Concentration Risk and Guarantor Obligations [Line Items]            
Gross credit exposure       $ 70    
Operating Revenue $ 3,179   $ 3,132 9,376 $ 8,651  
Additional collateral to be posted if the credit related contingent features were triggered 6     6   $ 3
Aggregate fair value of all derivative instruments with credit contingent provisions that are in a liability position $ 9     $ 9   $ 9
Credit Concentration Risk            
Concentration Risk and Guarantor Obligations [Line Items]            
Number of counterparties | counterparty 0     0    
Amount of exposure for single counterparty       $ 7    
Credit Concentration Risk | Investment Grade | Investment Grade Counterparty            
Concentration Risk and Guarantor Obligations [Line Items]            
Concentration risk, percentage (percentage)       49.00%    
Virginia Electric and Power Company            
Concentration Risk and Guarantor Obligations [Line Items]            
Electric distribution poles renting space, settlement charge   $ 16        
Electric distribution poles renting space, settlement charge, net of tax   $ 10        
Operating Revenue [1] $ 2,154   $ 2,211 $ 5,732 $ 5,877  
Virginia Electric and Power Company | Credit Concentration Risk | Wholesale Customers | Sales to wholesale customers            
Concentration Risk and Guarantor Obligations [Line Items]            
Number of counterparties | counterparty 0     0    
Operating Revenue       $ 23    
Amount of exposure related to sales to wholesale customers for single counterparty       $ 6    
Virginia Electric and Power Company | Credit Concentration Risk | Investment Grade | Investment Grade Counterparty            
Concentration Risk and Guarantor Obligations [Line Items]            
Concentration risk, percentage (percentage)       52.00%    
[1] See Note 17 for amounts attributable to affiliates.