Leases (Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Detail) - USD ($) $ in Millions		Dec. 31, 2019		Jan. 01, 2019	Dec. 31, 2018
Lessee Lease Disclosure [Line Items]
Operating lease assets		$ 499	[1]	$ 504
Finance lease assets	[2]	140
Total lease assets		639
Operating lease liabilities	[3]	59
Finance lease liabilities	[4]	29
Total lease liabilities - current		88
Operating lease liabilities	[5]	442
Finance lease liabilities		105			$ 35
Total lease liabilities - noncurrent		547
Total lease liabilities		635
Virginia Electric and Power Company
Lessee Lease Disclosure [Line Items]
Operating lease assets		212	[1]	209
Finance lease assets	[2]	19
Total lease assets		231
Operating lease liabilities	[3]	30
Finance lease liabilities	[4]	3
Total lease liabilities - current		33
Operating lease liabilities	[5]	180
Finance lease liabilities		16			1
Total lease liabilities - noncurrent		196
Total lease liabilities		229
Dominion Energy Gas Holdings, LLC
Lessee Lease Disclosure [Line Items]
Operating lease assets		37	[1]	$ 64
Finance lease assets	[2]	6
Total lease assets		43
Operating lease liabilities	[3]	6
Finance lease liabilities	[4]	1
Total lease liabilities - current		7
Operating lease liabilities	[5]	29
Finance lease liabilities		5			$ 0
Total lease liabilities - noncurrent		34
Total lease liabilities		$ 41

[1] Included in other deferred charges and other assets in the Companies’ Consolidated Balance Sheets.

[2] Included in property, plant and equipment in the Companies’ Consolidated Balance Sheets, net of $27 million, $4 million and $1 million of accumulated amortization at Dominion Energy, Virginia Power and Dominion Energy Gas, respectively, at December 31, 2019.

[3] Included in other current liabilities in the Companies’ Consolidated Balance Sheets.

[4] Included in securities due within one year in the Companies’ Consolidated Balance Sheets.

[5] Included in other deferred credits and other liabilities in the Companies’ Consolidated Balance Sheets.