Operating Revenue (Operating Revenue) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Electric sales:
Regulated									$ 7,348		$ 7,482		$ 7,460
Nonregulated									1,519		1,488		1,839
Gas sales:
Regulated									500		218		334
Nonregulated									354		471		751
Gas transportation and storage									1,636		1,616		1,543
Other									380		408		509
Total operating revenue	$ 3,086	$ 3,132	$ 2,598	$ 2,921	$ 2,556	$ 2,971	$ 2,747	$ 3,409	11,737		11,683		12,436
Virginia Electric and Power Company
Electric sales:
Regulated									7,348		7,482		7,460
Gas sales:
Other									240		140		119
Total operating revenue	1,711	2,211	1,776	1,890	1,614	2,058	1,813	2,137	7,588	[1]	7,622	[1]	7,579	[1]
Dominion Gas Holdings, LLC
Gas sales:
Regulated									119		122		209
Nonregulated									13		10		26
Gas transportation and storage									1,307		1,366		1,353
NGL revenue									62		93		212
Other									137		125		98
Total operating revenue	$ 457	$ 382	$ 368	$ 431	$ 425	$ 365	$ 395	$ 531	$ 1,638	[2]	$ 1,716	[2]	$ 1,898	[2]

[1] See Note 24 for amounts attributable to affiliates.

[2] See Note 24 for amounts attributable to related parties.