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, 2017	Dec. 31, 2016
Investment Holdings [Line Items]
Amortized Cost, Total		$ 3,147	$ 3,053
Total Unrealized Gains	[1]	1,593	1,443
Total Unrealized Losses	[1],[2]	(5)	(12)
Fair Value		4,735	4,484	[3]
Net assets related to pending sales and purchases of securities		7	9
Fair value of securities in an unrealized loss position		457	576
Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		71	69
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		71	69
Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[4]	10	12
Total Unrealized Gains	[1],[4]	0	0
Total Unrealized Losses	[1],[4]	0	0
Fair Value	[4]	10	12
Common/collective trust funds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		46	67
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		46	67
Corporate debt instruments
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		465	478
Total Unrealized Gains	[1]	17	13
Total Unrealized Losses	[1]	(1)	(4)
Fair Value		481	487
Government securities
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		1,007	978
Total Unrealized Gains	[1]	28	22
Total Unrealized Losses	[1]	(4)	(8)
Fair Value		1,031	992
Virginia Electric and Power Company
Investment Holdings [Line Items]
Amortized Cost, Total		1,516	1,473
Total Unrealized Gains	[1]	710	639
Total Unrealized Losses	[1],[5]	(3)	(6)
Fair Value		2,223	2,106	[6]
Net assets related to pending sales and purchases of securities		7	7
Fair value of securities in an unrealized loss position		219	287
Virginia Electric and Power Company | Cost method investments
Investment Holdings [Line Items]
Amortized Cost, Other Investments		70	69
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		70	69
Virginia Electric and Power Company | Cash equivalents and other
Investment Holdings [Line Items]
Amortized Cost, Other Investments	[7]	7	7
Total Unrealized Gains	[1],[7]	0	0
Total Unrealized Losses	[1],[7]	0	0
Fair Value	[7]	7	7
Virginia Electric and Power Company | Common/collective trust funds
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		16	26
Total Unrealized Gains	[1]	0	0
Total Unrealized Losses	[1]	0	0
Fair Value		16	26
Virginia Electric and Power Company | Corporate debt instruments
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		252	274
Total Unrealized Gains	[1]	8	6
Total Unrealized Losses	[1]	(1)	(4)
Fair Value		259	276
Virginia Electric and Power Company | Government securities
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		447	420
Total Unrealized Gains	[1]	14	9
Total Unrealized Losses	[1]	(2)	(2)
Fair Value		459	427
U.S. | Equity securities
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		1,548	1,449
Total Unrealized Gains	[1]	1,548	1,408
Total Unrealized Losses	[1]	0	0
Fair Value		3,096	2,857
U.S. | Virginia Electric and Power Company | Equity securities
Investment Holdings [Line Items]
Amortized Cost, Marketable Securities		724	677
Total Unrealized Gains	[1]	688	624
Total Unrealized Losses	[1]	0	0
Fair Value		$ 1,412	$ 1,301

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

[2] The fair value of securities in an unrealized loss position was $457 million and $576 million at June 30, 2017 and December 31, 2016, respectively.

[3] Dominion Energy’s Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.

[4] Includes net pending sales of securities of $7 million and $9 million at June 30, 2017 and December 31, 2016, respectively.

[5] The fair value of securities in an unrealized loss position was $219 million and $287 million at June 30, 2017 and December 31, 2016, respectively.

[6] Virginia Power’s Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.

[7] Includes pending sales of securities of $7 million at both June 30, 2017 and December 31, 2016.