Acquisitions and Dispositions (Narrative) (Details) $ / shares in Units, $ in Millions			1 Months Ended						3 Months Ended		24 Months Ended
	Sep. 30, 2015 USD ($) a Field	Apr. 01, 2015 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) a Field Project mi MW shares	Jun. 30, 2015 USD ($) Project MW	Mar. 31, 2015 USD ($) a Field	Jan. 31, 2015 USD ($) mi	Mar. 31, 2014 USD ($)	Dec. 31, 2013 USD ($) a Field	Mar. 31, 2016 USD ($) Project MW	Dec. 31, 2015 USD ($) MW	Dec. 31, 2014 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expected cost of projects				$ 66
Goodwill	$ 3,294		$ 3,294								$ 3,044	[1]
Electric Retail Energy Marketing Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale							$ 187
Gain on sale							100
After tax gain on sale							57
Write off of goodwill							$ 31
Iroquois | Partnership Interest | NG
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of common units issued | shares			6,800,000
Percentage of equity interests in DCGT contributed in Dominion Midstream			20.40%
Iroquois | Partnership Interest | NJNR
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of common units issued | shares			1,800,000
Percentage of equity interests in DCGT contributed in Dominion Midstream			5.53%
Scenario, Forecast
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interests acquired										100.00%
Acquisition price										$ 65
Expected generation capacity of facilities (mw) | MW										20
Scenario, Forecast | Merchant Solar Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expected generation capacity of facilities (mw) | MW									425
Percentage of equity interest sold to noncontrolling interest owners									33.00%
Sales price of equity interest to noncontrolling interest owners									$ 300
Total number of solar projects related to potential sale | Project									24
Four Brothers and Three Cedars
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage ownership in total units	50.00%		50.00%
Four Brothers
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interests acquired				50.00%
Acquisition price				$ 64
Expected cost of projects				$ 730
Expected generation capacity of facilities (mw) | MW				320
Acquisition price in cash				$ 2
Number of solar development projects | Project				4
Net property, plant and equipment acquired				$ 89
Non-controlling interest				25
Acquired equity				64
Four Brothers | Four Brothers | Obligation to Contribute Capital to Fund Construction of Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount obligated to contribute to fund construction of projects				445
Contributions to fund projects	$ 38		$ 38
Four Brothers | Federal | Investment Tax Credits
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of expected federal investment tax credits on projects to be claimed	99.00%		99.00%
Four Brothers | Other Current Liabilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities incurred	$ 56			$ 62
Three Cedars
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interests acquired	50.00%		50.00%
Acquisition price			$ 43
Expected cost of projects	$ 425		$ 425
Expected generation capacity of facilities (mw) | MW			210
Acquisition price in cash			$ 6
Number of solar development projects | Project			3
Net property, plant and equipment acquired	65		$ 65
Non-controlling interest	22		22
Acquired equity	43		43
Three Cedars | Three Cedars | Obligation to Contribute Capital to Fund Construction of Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount obligated to contribute to fund construction of projects	$ 276		276
Three Cedars | Other Current Liabilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities incurred			$ 37
Acquisition of DCGT
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interests acquired						100.00%
Acquisition price						$ 497
Net property, plant and equipment acquired						$ 277
Length of natural gas pipeline | mi						1,500
Goodwill						$ 250
Goodwill expected to be deductible for income tax purposes						225
Regulatory liabilities assumed						$ 38
Dominion Midstream Partners, LP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage ownership in total units	63.10%		63.10%
Dominion Midstream Partners, LP | Iroquois | Partnership Interest
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership%	25.93%		25.93%
Length of natural gas pipeline | mi			416
Number of common units issued | shares			8,600,000
Value of common units issued			$ 216
Dominion Midstream Partners, LP | Acquisition of DCGT | Three Cedars
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Acquisition price		$ 501
Percentage of equity interests in DCGT contributed in Dominion Midstream		100.00%
Dominion Midstream Partners, LP | Acquisition of DCGT | Three Cedars | Partnership Interest
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received, common units of Dominion Midstream | shares		5,112,139
Consideration received, value of common units of Dominion Midstream		$ 200
Number of trading days used to determine weighted average trading price		10 days
Price per unit | $ / shares		$ 39.12
Dominion Midstream Partners, LP | Acquisition of DCGT | Three Cedars | Senior unsecured promissory note payable
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities incurred		$ 301
Term of senior unsecured promissory note payable		2 years
Annual interest rate for senior unsecured promissory note payable		0.60%
Dominion Gas Holdings, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill	$ 542		542								542	[2]
Dominion Gas Holdings, LLC | Marcellus Shale | Shale development rights
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Acres of rights conveyed | a					11,000			79,000
Number of natural gas storage fields | Field					1			1
Amount per agreement					$ 27			$ 200
Duration of conveyance of rights								9 years
Cash proceeds from sale of assets											98
Deferred revenue											$ 85
Gain on sale of assets					27
After tax gain on sale of assets					$ 16
Dominion Gas Holdings, LLC | Marcellus Shale | Shale development rights | Amended Agreement to Extend Conveyance of Development Rights
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Acres of rights conveyed | a					9,000
Duration of conveyance of rights					2 years
Deferred revenue	$ 38		$ 38
Deferred revenue recognized from conveyance of rights					$ 43
Deferred revenue recognized from conveyance of rights, after tax					$ 27
Dominion Gas Holdings, LLC | Utica and Point Pleasant Shale | Shale development rights
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Acres of rights conveyed | a	16,000		16,000
Number of natural gas storage fields | Field	1		1
Amount per agreement	$ 52		$ 52
Cash proceeds from sale of assets			52
Gain on sale of assets			52
After tax gain on sale of assets			$ 29
Dominion Gas Holdings, LLC | Iroquois | Partnership Interest
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership%	24.72%		24.72%
Virginia Electric and Power Company | Morgans Corner Solar Energy, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interests acquired	100.00%		100.00%
Acquisition price			$ 47
Expected cost of projects	$ 50		$ 50
Expected generation capacity of facilities (mw) | MW			20
Virginia Electric and Power Company | Morgans Corner Solar Energy, LLC | Supply Agreement with US Navy
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Duration of supply agreement with Navy			10 years

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

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