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		Jun. 30, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Amortized Cost, Total		$ 2,988	$ 2,936
Total Unrealized Gains	[1]	1,344	1,258
Total Unrealized Losses	[1],[2]	(1)	(11)
Fair Value		4,331	4,183	[3]
Net assets related to pending sales and purchases of securities		(16)	12
Fair value of securities in an unrealized loss position		90	592
Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		69	70
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		69	70
Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[4]	(12)	14
Total Unrealized Gains	[1],[4]	0	0
Total Unrealized Losses	[1],[4]	0	0
Fair Value	[4]	(12)	14
Equity securities | Large cap | United States:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		1,326	1,295
Total Unrealized Gains	[1]	1,251	1,213
Total Unrealized Losses	[1]	0	0
Fair Value		2,577	2,508
Equity securities | REIT
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		61	59
Total Unrealized Gains	[1]	11	4
Total Unrealized Losses	[1]	0	0
Fair Value		72	63
Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		474	433
Total Unrealized Gains	[1]	25	11
Total Unrealized Losses	[1]	(1)	(7)
Fair Value		498	437
United States Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		672	654
Total Unrealized Gains	[1]	26	8
Total Unrealized Losses	[1]	0	(4)
Fair Value		698	658
State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		290	312
Total Unrealized Gains	[1]	31	22
Total Unrealized Losses	[1]	0	0
Fair Value		321	334
Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		108	99
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		108	99
Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost, Total		1,437	1,404
Total Unrealized Gains	[5]	594	548
Total Unrealized Losses	[5],[6]	(1)	(7)
Fair Value		2,030	1,945	[7]
Net assets related to pending sales and purchases of securities		(13)	8
Fair value of securities in an unrealized loss position		66	281
Virginia Electric and Power Company | Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		69	70
Total Unrealized Gains	[5]	0	0
Total Unrealized Losses	[5]	0	0
Fair Value		69	70
Virginia Electric and Power Company | Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[8]	(13)	8
Total Unrealized Gains	[5],[8]	0	0
Total Unrealized Losses	[5],[8]	0	0
Fair Value	[8]	(13)	8
Virginia Electric and Power Company | Equity securities | Large cap | United States:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		590	574
Total Unrealized Gains	[5]	546	525
Total Unrealized Losses	[5]	0	0
Fair Value		1,136	1,099
Virginia Electric and Power Company | Equity securities | REIT
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		61	59
Total Unrealized Gains	[5]	11	4
Total Unrealized Losses	[5]	0	0
Fair Value		72	63
Virginia Electric and Power Company | Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		271	237
Total Unrealized Gains	[5]	13	5
Total Unrealized Losses	[5]	(1)	(4)
Fair Value		283	238
Virginia Electric and Power Company | United States Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		270	260
Total Unrealized Gains	[5]	7	1
Total Unrealized Losses	[5]	0	(2)
Fair Value		277	259
Virginia Electric and Power Company | State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		141	162
Total Unrealized Gains	[5]	17	13
Total Unrealized Losses	[5]	0	(1)
Fair Value		158	174
Virginia Electric and Power Company | Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		48	34
Total Unrealized Gains	[5]	0	0
Total Unrealized Losses	[5]	0	0
Fair Value		$ 48	$ 34

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

[2] The fair value of securities in an unrealized loss position was $90 million and $592 million at June 30, 2016 and December 31, 2015, respectively.

[3] Dominion’s Consolidated Balance Sheet at December 31, 2015 has been derived from the audited Consolidated Financial Statements at that date.

[4] Includes pending purchases of securities of $16 million and pending sales of securities of $12 million at June 30, 2016 and December 31, 2015, respectively.

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

[6] The fair value of securities in an unrealized loss position was $66 million and $281 million at June 30, 2016 and December 31, 2015, respectively.

[7] Virginia Power’s Consolidated Balance Sheet at December 31, 2015 has been derived from the audited Consolidated Financial Statements at that date.

[8] Includes pending purchases of securities of $13 million and pending sales of securities of $8 million at June 30, 2016 and December 31, 2015, respectively.