Investments (Selected Information Regarding Marketable Equity and Debt Securities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Available-for-sale securities:
Proceeds from sales	$ 1,476		$ 1,356		$ 1,757
Realized gains	157	[1]	98	[1]	79	[1]
Realized losses	33	[1]	33	[1]	92	[1]
Virginia Electric and Power Company
Available-for-sale securities:
Proceeds from sales	572		626		1,030
Realized gains	52	[1]	42	[1]	34	[1]
Realized losses	$ 14	[1]	$ 11	[1]	$ 34	[1]

[1] Includes realized gains and losses recorded to the decommissioning trust regulatory liability as discussed in Note 2.