Fair Value Measurements (Assets and Liabilities that are Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		$ 388	$ 719
Derivative liabilities		343	794
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		114
Derivative liabilities		19
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		4,589	4,938
Total liabilities		343	794
Fair Value, Measurements, Recurring | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		364	695
Derivative liabilities		160	592
Fair Value, Measurements, Recurring | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		24	24
Derivative liabilities		183	202
Fair Value, Measurements, Recurring | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	2,547	2,669
Fair Value, Measurements, Recurring | Equity securities: | Large Cap | Non-U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	10	12
Fair Value, Measurements, Recurring | Equity securities: | Other | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	5	6
Fair Value, Measurements, Recurring | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	63
Fair Value, Measurements, Recurring | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	437	441
Fair Value, Measurements, Recurring | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	659	609
Fair Value, Measurements, Recurring | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	376	395
Fair Value, Measurements, Recurring | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	100	74
Fair Value, Measurements, Recurring | Cash equivalents and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	4	13
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		3,086	3,112
Total liabilities		0	3
Fair Value, Measurements, Recurring | Level 1 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		1	3
Derivative liabilities		0	3
Fair Value, Measurements, Recurring | Level 1 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Derivative liabilities		0	0
Fair Value, Measurements, Recurring | Level 1 | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	2,547	2,669
Fair Value, Measurements, Recurring | Level 1 | Equity securities: | Large Cap | Non-U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	10	12
Fair Value, Measurements, Recurring | Level 1 | Equity securities: | Other | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	5	6
Fair Value, Measurements, Recurring | Level 1 | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	63
Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	458	419
Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 1 | Cash equivalents and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	2	3
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		1,389	1,701
Total liabilities		324	773
Fair Value, Measurements, Recurring | Level 2 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		249	567
Derivative liabilities		141	571
Fair Value, Measurements, Recurring | Level 2 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		24	24
Derivative liabilities		183	202
Fair Value, Measurements, Recurring | Level 2 | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 2 | Equity securities: | Large Cap | Non-U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 2 | Equity securities: | Other | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 2 | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0
Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	437	441
Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	201	190
Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	376	395
Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	100	74
Fair Value, Measurements, Recurring | Level 2 | Cash equivalents and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	2	10
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		114	125
Total liabilities		19	18
Fair Value, Measurements, Recurring | Level 3 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		114	125
Derivative liabilities		19	18
Fair Value, Measurements, Recurring | Level 3 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Derivative liabilities		0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities: | Large Cap | Non-U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities: | Other | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0
Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Fair Value, Measurements, Recurring | Level 3 | Cash equivalents and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[1]	0	0
Virginia Electric and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		127	113
Derivative liabilities		86	87
Virginia Electric and Power Company | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		101
Derivative liabilities		8
Virginia Electric and Power Company | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		1,996	1,952
Total liabilities		86	87
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		114	113
Derivative liabilities		27	15
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		13
Derivative liabilities		59	72
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	1,100	1,157
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	63
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	238	250
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	259	198
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	175	211
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	34	23
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		1,343	1,294
Total liabilities		0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Derivative liabilities		0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Derivative liabilities		0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	1,100	1,157
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	63
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	180	137
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 1 | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		552	552
Total liabilities		78	83
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		13	7
Derivative liabilities		19	11
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		13
Derivative liabilities		59	72
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	238	250
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	79	61
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	175	211
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 2 | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	34	23
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		101	106
Total liabilities		8	4
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		101	106
Derivative liabilities		8	4
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Derivative liabilities		0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Equity securities: | Large Cap | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Equity securities: | REIT | U.S.:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | U.S. Treasury securities and agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Virginia Electric and Power Company | Fair Value, Measurements, Recurring | Level 3 | Fixed Income: | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	[2]	0	0
Dominion Gas Holdings, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		11	2
Derivative liabilities		14	9
Dominion Gas Holdings, LLC | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		6
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		11	2
Total liabilities		14	9
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		11	2
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		14	9
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		0	0
Total liabilities		0	0
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 1 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 1 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		0	0
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		5	0
Total liabilities		14	9
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 2 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		5	0
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 2 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		14	9
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		6	2
Total liabilities		0	0
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 3 | Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		6	2
Dominion Gas Holdings, LLC | Fair Value, Measurements, Recurring | Level 3 | Interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities		$ 0	$ 0

[1] Includes investments held in the nuclear decommissioning and rabbi trusts.

[2] Includes investments held in the nuclear decommissioning and rabbi trusts.