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		Sep. 30, 2015	Dec. 31, 2014
Investment Holdings [Line Items]
Amortized Cost, Total		$ 2,889	$ 2,794
Total Unrealized Gains	[1]	1,154	1,408
Total Unrealized Losses	[1],[2]	(10)	(6)
Fair Value		4,033	4,196	[3]
Net assets related to pending sales and purchases of securities		5	3
Fair value of securities in an unrealized loss position		411	379
Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		72	86
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		72	86
Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[4]	9	16
Total Unrealized Gains	[1],[4]	0	0
Total Unrealized Losses	[1],[4]	0	0
Fair Value	[4]	9	16
Equity securities | Large cap | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		1,260	1,273
Total Unrealized Gains	[1]	1,106	1,353
Total Unrealized Losses	[1]	0	0
Fair Value		2,366	2,626
Equity securities | REIT | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		59
Total Unrealized Gains	[1]	0
Total Unrealized Losses	[1]	0
Fair Value		59
Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		454	424
Total Unrealized Gains	[1]	15	19
Total Unrealized Losses	[1]	(6)	(2)
Fair Value		463	441
U.S. Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		602	597
Total Unrealized Gains	[1]	13	13
Total Unrealized Losses	[1]	(3)	(4)
Fair Value		612	606
State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		338	332
Total Unrealized Gains	[1]	20	23
Total Unrealized Losses	[1]	(1)	0
Fair Value		357	355
Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		95	66
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		95	66
Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost, Total		1,382	1,314
Total Unrealized Gains	[5]	498	619
Total Unrealized Losses	[5],[6]	(5)	(3)
Fair Value		1,875	1,930	[7]
Net assets related to pending sales and purchases of securities		3	6
Fair value of securities in an unrealized loss position		209	170
Virginia Electric and Power Company | Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		72	86
Total Unrealized Gains	[5]	0	0
Total Unrealized Losses	[5]	0	0
Fair Value		72	86
Virginia Electric and Power Company | Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[8]	3	6
Total Unrealized Gains	[5],[8]	0	0
Total Unrealized Losses	[5],[8]	0	0
Fair Value	[8]	3	6
Virginia Electric and Power Company | Equity securities | Large cap | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		558	563
Total Unrealized Gains	[5]	478	594
Total Unrealized Losses	[5]	0	0
Fair Value		1,036	1,157
Virginia Electric and Power Company | Equity securities | REIT | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		59
Total Unrealized Gains	[1]	0
Total Unrealized Losses	[1]	0
Fair Value		59
Virginia Electric and Power Company | Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		249	242
Total Unrealized Gains	[5]	7	9
Total Unrealized Losses	[5]	(4)	(1)
Fair Value		252	250
Virginia Electric and Power Company | U.S. Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		224	197
Total Unrealized Gains	[5]	2	3
Total Unrealized Losses	[5]	(1)	(2)
Fair Value		225	198
Virginia Electric and Power Company | State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		187	197
Total Unrealized Gains	[5]	11	13
Total Unrealized Losses	[5]	0	0
Fair Value		198	210
Virginia Electric and Power Company | Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		30	23
Total Unrealized Gains	[5]	0	0
Total Unrealized Losses	[5]	0	0
Fair Value		$ 30	$ 23

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

[2] The fair value of securities in an unrealized loss position was $411 million and $379 million at September 30, 2015 and December 31, 2014, respectively.

[3] Dominion’s Consolidated Balance Sheet at December 31, 2014 has been derived from the audited Consolidated Financial Statements at that date.

[4] Includes pending sales of securities of $5 million and $3 million at September 30, 2015 and December 31, 2014, respectively.

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

[6] The fair value of securities in an unrealized loss position was $209 million and $170 million at September 30, 2015 and December 31, 2014, respectively.

[7] Virginia Power’s Consolidated Balance Sheet at December 31, 2014 has been derived from the audited Consolidated Financial Statements at that date.

[8] Includes pending sales of securities of $3 million at September 30, 2015 and $6 million at December 31, 2014.