Significant Accounting Policies (Policies)	6 Months Ended
Significant Accounting Policies (Policies)	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Accounting	As permitted by the rules and regulations of the SEC, the Companies' accompanying unaudited Consolidated Financial Statements contain certain condensed financial information and exclude certain footnote disclosures normally included in annual audited consolidated financial statements prepared in accordance with GAAP. These unaudited Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes in the Companies' Annual Report on Form 10-K for the year ended December 31, 2016.
Estimates	The Companies make certain estimates and assumptions in preparing their Consolidated Financial Statements in accordance with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses for the periods presented. Actual results may differ from those estimates.
Consolidation	The Companies' accompanying unaudited Consolidated Financial Statements include, after eliminating intercompany transactions and balances, their accounts, those of their respective majority-owned subsidiaries and non-wholly-owned entities in which they have a controlling financial interest.
Consolidation, consolidated entities and noncontrolling interest	For certain partnership structures, income is allocated based on the liquidation value of the underlying contractual arrangements. At June 30, 2017, Dominion Energy owns the general partner, 50.9% of the common and subordinated units and 37.5% of the convertible preferred interests in Dominion Energy Midstream. The public’s ownership interest in Dominion Energy Midstream is reflected as noncontrolling interest in Dominion Energy’s Consolidated Financial Statements. Also, at June 30, 2017, Dominion Energy owns 50% of the units in and consolidates Four Brothers and Three Cedars. NRG's ownership interest in Four Brothers and Three Cedars, as well as Terra Nova Renewable Partners' 33% interest in certain Dominion Energy merchant solar projects, is reflected as noncontrolling interest in Dominion Energy’s Consolidated Financial Statements.
Reclassifications	Certain amounts in the Companies' 2016 Consolidated Financial Statements and Notes have been reclassified to conform to the 2017 presentation for comparative purposes. The reclassifications did not affect the Companies’ net income, total assets, liabilities, equity or cash flows.
New Accounting Standards	New Accounting Standards In March 2017, the Financial Accounting Standards Board issued revised accounting guidance for the presentation of net periodic pension and other postretirement benefit costs. The update requires that the service cost component of net periodic pension and other postretirement benefit costs be classified in the same line item as other compensation costs arising from services rendered by employees, while all other components of net periodic pension and other postretirement benefit costs would be classified outside of income from operations. In addition, only the service cost component will be eligible for capitalization during construction. The standard also recognized that in the event that a regulator continues to require capitalization of all net periodic benefit costs prospectively, the difference would result in recognition of a regulatory asset or liability. The guidance is effective for the Companies’ interim and annual reporting periods beginning January 1, 2018, although it can be early adopted, with a retrospective approach for income statement presentation and a prospective approach for capitalization. The Companies are currently evaluating the impact the adoption of the standard will have on their consolidated financial statements and disclosures. The Companies are also evaluating industry issues that could potentially create a regulatory accounting difference in the event that FERC or any of our state commissions do not adopt the change in capitalization requirements for regulatory reporting.