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	Sep. 30, 2013		Dec. 31, 2012
Investment Holdings [Line Items]
Amortized Cost, Total	$ 2,629		$ 2,511
Total Unrealized Gains	1,059	[1]	821	[1]
Total Unrealized Losses	(15)	[1],[2]	(2)	[1],[2]
Fair Value	3,673		3,330	[3]
Net assets related to pending sales and purchases of securities	6		6
Fair Value of securities in an unrealized loss position	487		195
Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments	103		117
Total Unrealized Gains	0	[1]	0	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	103		117
Cash Equivalents and Other Investment
Investment Holdings [Line Items]
Amortized Cost, Other Investments	89	[4]	72	[4]
Total Unrealized Gains	0	[1],[4]	0	[1],[4]
Total Unrealized Losses	0	[1],[4]	0	[1],[4]
Fair Value	89	[4]	72	[4]
Equity Securities | Large Cap | United States
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	1,176		1,210
Total Unrealized Gains	999	[1]	732	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	2,175		1,942
Equity Securities | Other | United States
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	48		40
Total Unrealized Gains	20	[1]	13	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	68		53
Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	339		295
Total Unrealized Gains	17	[1]	30	[1]
Total Unrealized Losses	(4)	[1]	0	[1]
Fair Value	352		325
U.S. Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	571		523
Total Unrealized Gains	10	[1]	19	[1]
Total Unrealized Losses	(7)	[1]	(2)	[1]
Fair Value	574		540
State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	299		248
Total Unrealized Gains	13	[1]	26	[1]
Total Unrealized Losses	(4)	[1]	0	[1]
Fair Value	308		274
Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	4		6
Total Unrealized Gains	0	[1]	1	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	4		7
Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost, Total	1,216		1,179
Total Unrealized Gains	460	[1]	337	[1]
Total Unrealized Losses	(8)	[1],[5]	(1)	[1],[5]
Fair Value	1,668		1,515	[6]
Net assets related to pending sales and purchases of securities	4		6
Fair Value of securities in an unrealized loss position	247		104
Virginia Electric and Power Company | Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments	103		117
Total Unrealized Gains	0	[1]	0	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	103		117
Virginia Electric and Power Company | Cash Equivalents and Other Investment
Investment Holdings [Line Items]
Amortized Cost, Other Investments	28	[7]	44	[7]
Total Unrealized Gains	0	[1],[7]	0	[1],[7]
Total Unrealized Losses	0	[1],[7]	0	[1],[7]
Fair Value	28	[7]	44	[7]
Virginia Electric and Power Company | Equity Securities | Large Cap | United States
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	505		481
Total Unrealized Gains	433	[1]	298	[1]
Total Unrealized Losses	0	[1]
Fair Value	938		779
Virginia Electric and Power Company | Equity Securities | Other | United States
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	23		20
Total Unrealized Gains	10	[1]	7	[1]
Total Unrealized Losses	0	[1]	0	[1]
Fair Value	33		27
Virginia Electric and Power Company | Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	191		179
Total Unrealized Gains	9	[1]	17	[1]
Total Unrealized Losses	(3)	[1]	0	[1]
Fair Value	197		196
Virginia Electric and Power Company | U.S. Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	209		231
Total Unrealized Gains	2	[1]	4	[1]
Total Unrealized Losses	(2)	[1]	(1)	[1]
Fair Value	209		234
Virginia Electric and Power Company | State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities	157		106
Total Unrealized Gains	6	[1]	11	[1]
Total Unrealized Losses	(3)	[1]	0	[1]
Fair Value	160		117
Virginia Electric and Power Company | Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities			1
Total Unrealized Gains			0	[1]
Total Unrealized Losses			0	[1]
Fair Value			$ 1

[1] Included in AOCI and the decommissioning trust regulatory liability.

[2] The fair value of securities in an unrealized loss position was $487 million and $195 million at September 30, 2013 and December 31, 2012, respectively.

[3] Dominion’s Consolidated Balance Sheet at December 31, 2012 has been derived from the audited Consolidated Financial Statements at that date.

[4] Includes pending sales of securities of $6 million and pending purchases of securities of $6 million at September 30, 2013 and December 31, 2012, respectively.

[5] The fair value of securities in an unrealized loss position was $247 million and $104 million at September 30, 2013 and December 31, 2012, respectively.

[6] Virginia Power’s Consolidated Balance Sheet at December 31, 2012 has been derived from the audited Consolidated Financial Statements at that date.

[7] Includes pending sales of securities of $4 million and $6 million at September 30, 2013 and December 31, 2012, respectively.