Fair Value Measurements (Financial Instruments' Carrying Amounts and Fair Values) (Details) - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Junior subordinated notes		$ 1,370	$ 1,374	[1]
Valuation of certain fair value hedges		19	19
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Long-term Debt	[2],[3]	21,318	19,723
Junior subordinated notes	[3]	1,370	1,374
Remarketable subordinated notes	[3]	2,085	2,083
Estimate of Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Long-term Debt	[2],[3],[4]	22,923	21,881
Junior subordinated notes	[3],[4]	1,290	1,396
Remarketable subordinated notes	[3],[4]	2,214	2,362
Virginia Electric and Power Company | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Long-term Debt	[3]	9,629	8,937
Virginia Electric and Power Company | Estimate of Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Long-term Debt	[3],[4]	10,764	10,293
Dominion Gas Holdings, LLC | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Long-term Debt	[3]	2,595	2,594
Dominion Gas Holdings, LLC | Estimate of Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Long-term Debt	[3],[4]	$ 2,618	$ 2,672

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

[2] At both September 30, 2015 and December 31, 2014, includes the valuation of certain fair value hedges associated with fixed rate debt of approximately $19 million

[3] Carrying amount includes amounts which represent the unamortized discount and/or premium.

[4] Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issues with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.