Investments (Marketable Equity and Debt Securities and Cash Equivalents (Classified as Available-for-sale) and Cost Method Investments in Decommissioning Trust Funds) (Details) - USD ($)		Mar. 31, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Amortized Cost, Total		$ 2,953,000,000	$ 2,936,000,000
Total Unrealized Gains	[1]	1,289,000,000	1,258,000,000
Total Unrealized Losses	[1],[2]	(3,000,000)	(11,000,000)
Fair Value		4,239,000,000	4,183,000,000	[3]
Net assets related to pending sales and purchases of securities		2,000,000	12,000,000
Fair value of securities in an unrealized loss position		151,000,000	592,000,000
Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		70,000,000	70,000,000
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		70,000,000	70,000,000
Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[4]	4,000,000	14,000,000
Total Unrealized Gains	[1],[4]	0	0
Total Unrealized Losses	[1],[4]	0	0
Fair Value	[4]	4,000,000	14,000,000
Equity securities | Large cap | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		1,317,000,000	1,295,000,000
Total Unrealized Gains	[1]	1,218,000,000	1,213,000,000
Total Unrealized Losses	[1]	0	0
Fair Value		2,535,000,000	2,508,000,000
Equity securities | REIT | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		60,000,000	59,000,000
Total Unrealized Gains	[1]	7,000,000	4,000,000
Total Unrealized Losses	[1]	0	0
Fair Value		67,000,000	63,000,000
Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		448,000,000	433,000,000
Total Unrealized Gains	[1]	19,000,000	11,000,000
Total Unrealized Losses	[1]	(3,000,000)	(7,000,000)
Fair Value		464,000,000	437,000,000
U.S. Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		650,000,000	654,000,000
Total Unrealized Gains	[1]	20,000,000	8,000,000
Total Unrealized Losses	[1]	0	(4,000,000)
Fair Value		670,000,000	658,000,000
State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		308,000,000	312,000,000
Total Unrealized Gains	[1]	25,000,000	22,000,000
Total Unrealized Losses	[1]	0	0
Fair Value		333,000,000	334,000,000
Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		96,000,000	99,000,000
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		96,000,000	99,000,000
Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost, Total		1,417,000,000	1,404,000,000
Total Unrealized Gains	[5]	564,000,000	548,000,000
Total Unrealized Losses	[5],[6]	(1,000,000)	(7,000,000)
Fair Value		1,980,000,000	1,945,000,000	[7]
Net assets related to pending sales and purchases of securities		0	8,000,000
Fair value of securities in an unrealized loss position		91,000,000	281,000,000
Virginia Electric and Power Company | Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		70,000,000	70,000,000
Total Unrealized Gains	[5]	0	0
Total Unrealized Losses	[5]	0	0
Fair Value		70,000,000	70,000,000
Virginia Electric and Power Company | Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[8]		8,000,000
Total Unrealized Gains	[5],[8]		0
Total Unrealized Losses	[5],[8]		0
Fair Value	[8]		8,000,000
Virginia Electric and Power Company | Equity securities | Large cap | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		583,000,000	574,000,000
Total Unrealized Gains	[5]	529,000,000	525,000,000
Total Unrealized Losses	[5]	0	0
Fair Value		1,112,000,000	1,099,000,000
Virginia Electric and Power Company | Equity securities | REIT | U.S.:
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		60,000,000	59,000,000
Total Unrealized Gains	[5]	7,000,000	4,000,000
Total Unrealized Losses	[5]	0	0
Fair Value		67,000,000	63,000,000
Virginia Electric and Power Company | Corporate bonds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		242,000,000	237,000,000
Total Unrealized Gains	[5]	9,000,000	5,000,000
Total Unrealized Losses	[5]	(1,000,000)	(4,000,000)
Fair Value		250,000,000	238,000,000
Virginia Electric and Power Company | U.S. Treasury securities and agency debentures
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		257,000,000	260,000,000
Total Unrealized Gains	[5]	6,000,000	1,000,000
Total Unrealized Losses	[5]	0	(2,000,000)
Fair Value		263,000,000	259,000,000
Virginia Electric and Power Company | State and municipal
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		159,000,000	162,000,000
Total Unrealized Gains	[5]	13,000,000	13,000,000
Total Unrealized Losses	[5]	0	(1,000,000)
Fair Value		172,000,000	174,000,000
Virginia Electric and Power Company | Other
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		46,000,000	34,000,000
Total Unrealized Gains	[5]	0	0
Total Unrealized Losses	[5]	0	0
Fair Value		$ 46,000,000	$ 34,000,000

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

[2] The fair value of securities in an unrealized loss position was $151 million and $592 million at March 31, 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 sales of securities of $2 million and $12 million at March 31, 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 $91 million and $281 million at March 31, 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 sales of securities of $8 million at December 31, 2015. There were no pending sales of securities at March 31, 2016.