Preferred Stock (Narrative) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Preferred stock shares authorized		20,000,000
Preferred stock shares issued		0	0
Preferred stock shares outstanding		0	0
Virginia Electric and Power Company
Class of Stock [Line Items]
Preferred stock shares authorized		10,000,000
Preferred stock shares issued		0	0
Preferred stock shares outstanding		0	0
Liquidation preference (in dollars per share)		$ 100
Virginia Electric and Power Company | Redeemable Preferred Stock
Class of Stock [Line Items]
Number of shares redeemed	2,590,000