Nature of Operations	3 Months Ended
Nature of Operations	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Nature of Operations Questar Gas is a wholly-owned subsidiary of Dominion Questar which, effective September 2016, is a wholly-owned subsidiary of Dominion. Questar Gas distributes natural gas as a public utility in Utah, southwestern Wyoming and a small portion of southeastern Idaho. The Utah, Wyoming and Idaho Commissions have granted Questar Gas the necessary regulatory approvals to serve these areas. Questar Gas also has long-term franchises granted by communities and counties within its service area. Revenue generated by Questar Gas is based primarily on rates established by the Utah and Wyoming Commissions. The Idaho Commission has contracted with the Utah Commission for rate oversight of Questar Gas operations in Idaho. Wexpro, an affiliate, provides the majority of Questar Gas' natural gas supply and Questar Pipeline, an affiliate, provides the majority of Questar Gas' transportation and storage services.

QUESTAR GAS CO 10-Q