Investments (Marketable Equity and Debt Securities and Cash Equivalents (Classified as Available-for-sale) and Cost Method Investments in Decommissioning Trust Funds) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Investment Holdings [Line Items]
Total amortized cost basis	$ 2,669		$ 2,511
Total Unrealized Gains	1,252	[1]	821	[1]
Total Unrealized Losses	(18)	[1],[2]	(2)	[1],[2]
Fair Value	3,903		3,330
Net assets related to pending sales and purchases of securities	11		6
Fair value of securities in an unrealized loss position	604		195
Virginia Electric and Power Company
Investment Holdings [Line Items]
Total amortized cost basis	1,236		1,179
Total Unrealized Gains	538	[1]	337	[1]
Total Unrealized Losses	(9)	[1],[3]	(1)	[1],[3]
Fair Value	1,765		1,515
Net assets related to pending sales and purchases of securities	6		6
Fair value of securities in an unrealized loss position	299		104
Cost method investments
Investment Holdings [Line Items]
Other investments and securities, at cost	106		117
Total Unrealized Gains	0	[1]	0	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	106		117
Cost method investments | Virginia Electric and Power Company
Investment Holdings [Line Items]
Other investments and securities, at cost	106		117
Total Unrealized Gains	0	[1]	0	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	106		117
Cash equivalents and other
Investment Holdings [Line Items]
Other investments and securities, at cost	110	[4]	72	[4]
Total Unrealized Gains	0	[1],[4]	0	[1],[4]
Total Unrealized Losses	0	[1],[4]	0	[1],[4]
Fair Value	110	[4]	72	[4]
Cash equivalents and other | Virginia Electric and Power Company
Investment Holdings [Line Items]
Other investments and securities, at cost	37	[5]	44	[5]
Total Unrealized Gains	0	[1],[5]	0	[1],[5]
Total Unrealized Losses	0	[1],[5]	0	[1],[5]
Fair Value	37	[5]	44	[5]
Corporate debt instruments
Investment Holdings [Line Items]
Amortized Cost	332		295
Total Unrealized Gains	16	[1]	30	[1]
Total Unrealized Losses	(3)	[1]	0	[1]
Fair Value	345		325
Corporate debt instruments | Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost	185		179
Total Unrealized Gains	8	[1]	17	[1]
Total Unrealized Losses	(2)	[1]	0	[1]
Fair Value	191		196
U.S. Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost	589		523
Total Unrealized Gains	8	[1]	19	[1]
Total Unrealized Losses	(10)	[1]	(2)	[1]
Fair Value	587		540
U.S. Treasury securities and agency debentures | Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost	214		231
Total Unrealized Gains	1	[1]	4	[1]
Total Unrealized Losses	(3)	[1]	(1)	[1]
Fair Value	212		234
State and municipal
Investment Holdings [Line Items]
Amortized Cost	297		248
Total Unrealized Gains	11	[1]	26	[1]
Total Unrealized Losses	(5)	[1]	0	[1]
Fair Value	303		274
State and municipal | Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost	163		106
Total Unrealized Gains	4	[1]	11	[1]
Total Unrealized Losses	(4)	[1]	0	[1]
Fair Value	163		117
Other
Investment Holdings [Line Items]
Amortized Cost	3		6
Total Unrealized Gains	0	[1]	1	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	3		7
Other | Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost			1
Total Unrealized Gains			0	[1]
Total Unrealized Losses			0	[1]
Fair Value			1
U.S.: | Equity securities: | Large Cap
Investment Holdings [Line Items]
Amortized Cost	1,183		1,210
Total Unrealized Gains	1,194	[1]	732	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	2,377		1,942
U.S.: | Equity securities: | Large Cap | Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost	506		481
Total Unrealized Gains	514	[1]	298	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	1,020		779
U.S.: | Equity securities: | Other
Investment Holdings [Line Items]
Amortized Cost	49		40
Total Unrealized Gains	23	[1]	13	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	72		53
U.S.: | Equity securities: | Other | Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost	25		20
Total Unrealized Gains	11	[1]	7	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	$ 36		$ 27

[1] Included in AOCI and the decommissioning trust regulatory liability as discussed in Note 2.

[2] The fair value of securities in an unrealized loss position was $604 million and $195 million at December 31, 2013 and 2012, respectively.

[3] The fair value of securities in an unrealized loss position was $299 million and $104 million at December 31, 2013 and 2012, respectively.

[4] Includes pending sales of securities of $11 million and pending purchases of securities of $6 million at December 31, 2013 and 2012, respectively.

[5] Includes pending sales of securities of $6 million at December 31, 2013 and 2012.