2.4.0.82202201 - Disclosure - Basis of Presentation of Interim Financial Statements (Policies)truefalsefalse1falsefalsefalseD2013Q2YTDhttp://www.sec.gov/CIK0000751652duration2013-01-01T00:00:002013-06-30T00:00:001true1us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse02false2str_NatureOfOperationsPolicyTextBlockstr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Questar Corporation is a Rockies-based integrated natural gas company with </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">three</font><font style="font-family:inherit;font-size:10pt;"> principal complementary and wholly-owned lines of business:</font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:36px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:24px;"><font style="font-family:inherit;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Questar Gas Company (Questar Gas) provides retail natural gas distribution in Utah, Wyoming and Idaho.</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:36px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:24px;"><font style="font-family:inherit;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Wexpro Company (Wexpro) develops and produces natural gas from cost-of-service reserves for Questar Gas customers.</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:36px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:24px;"><font style="font-family:inherit;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Questar Pipeline Company (Questar Pipeline) operates interstate natural gas pipelines and storage facilities in the western United States and provides other energy services.</font></div></td></tr></table><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Questar is headquartered in Salt Lake City, Utah. Shares of Questar common stock trade on the New York Stock Exchange (NYSE:STR).</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDescribes the nature of an entity's business, the major products or services it sells or provides and its principal markets, including the locations of those markets. If the entity operates in more than one business, the disclosure also indicates the relative importance of its operations in each business and the basis for the determination (for example, assets, revenues, or earnings). Disclosures about the nature of operations need not be quantified; relative importance could be conveyed by use of terms such as "predominately", "about equally", or "major and other". This element is also referred to as "Business Description".No definition available.false03false2str_ComprehensiveIncomePolicyTextBlockstr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Comprehensive income, as reported in Questar's Condensed Consolidated Statements of Comprehensive Income, is the sum of net income as reported in the Questar Consolidated Statements of Income and other comprehensive income (loss) (OCI). OCI includes recognition of the under-funded position of pension and other postretirement benefit plans, interest rate cash flow hedges, changes in the fair value of long-term investment, and the related income taxes. These transactions are not the culmination of the earnings process but result from periodically adjusting historical balances to fair value. Income or loss is recognized when the pension or other postretirement benefit (OPRB) costs are accrued, as the Company records interest expense for hedged interest payments and when the long-term investment is sold or otherwise realized.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaComprehensive Income [Policy Text Block]No definition available.false04false2str_ComprehensiveIncomeNotePolicyQuestarPipelineTextBlockstr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Comprehensive income (loss), as reported in Questar Pipeline's Condensed Consolidated Statements of Comprehensive Income, is the sum of net income as reported in the Questar Pipeline Consolidated Statements of Income and OCI. OCI includes interest rate cash flow hedges and the related income taxes. These transactions are not the culmination of the earnings process but result from periodically adjusting historical balances to fair value. Income or loss is recognized as the company records interest expense for hedged interest payments.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaThis element may include the following: 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. Components of comprehensive income include: (1) foreign currency translation adjustments; (2) gains and losses on foreign currency transactions that are designated as, and are effective as, economic hedges of a net investment in a foreign entity; (3) gains and losses on intercompany foreign currency transactions that are of a long-term-investment nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; (4) change in the market value of a futures contract that qualifies as a hedge of an asset reported at fair value; (5) unrealized holding gains and losses on available-for-sale securities and that resulting from transfers of debt securities from the held-to-maturity category to the available-for-sale category; (6) a net loss recognized as an additional pension liability not yet recognized as net periodic pension cost; and (7) the net gain or loss and net prior service cost or credit for pension plans and other postretirement benefit plans.No definition available.false05false2us-gaap_EquityMethodInvestmentsPolicyus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Questar uses the equity method to account for its investment in an unconsolidated affiliate where it does not have control, but has significant influence. White River Hub, LLC is a limited liability company and FERC-regulated transporter of natural gas. Questar Pipeline owns </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">50%</font><font style="font-family:inherit;font-size:10pt;"> of White River Hub, LLC and is the operator. Generally, the investment in White River Hub, LLC on the Company's balance sheets equals the Company's proportionate share of equity reported by White River Hub, LLC. The investment is assessed for possible impairment when events indicate that the fair value of the investment may be below the Company's carrying value. When such a condition is deemed to be other-than-temporary, the carrying value of the investment is written down to its fair value, and the amount of the write-down is included in the determination of net income.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for the equity method of accounting for investments in common stock or other interests including unconsolidated subsidiaries, corporate joint ventures, noncontrolling interests in real estate ventures, limited partnerships, and limited liability companies. The accounting policy may include information such as: (1) initially recording an investment in the stock of an investee at cost; (2) adjusting the carrying amount of the investment to recognize the investor's share of the earnings or losses of the investee after the date of acquisition; and (3) adjustments to reflect the investor's share of changes in the investee's capital (dividends). This disclosure may also include a detailed description of the policy for determining the amount of equity method losses recognized after an investment has been reduced to zero as a result of previous losses, reasons for not using the equity method when the investor company owns 20 percent or more of the voting stock of the investee's company (including identification of the significant investee), reasons for using the equity method when the ownership percentage is less than 20 percent, and discussion of recognition of equity method losses when an investor's total investment in an investee includes, in addition to an investment in common stock, other investments such as preferred stock and loans to the investee. An entity also may describe how such investments are assessed for impairment.Reference 1: http://www.xbrl.org/2003/role/presentationRef
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false06false2us-gaap_EarningsPerSharePolicyTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Basic earnings per share (EPS) is computed by dividing net income by the weighted-average number of common shares outstanding during the reporting period. Diluted EPS includes the potential increase in the number of outstanding shares that could result from the exercise of in-the-money stock options, the vesting of restricted stock units (RSUs) with forfeitable dividends and the distribution of performance shares that are part of the Company's Long-Term Stock Incentive Plan (LTSIP), less shares repurchased under the treasury stock method. Restricted shares and RSUs with nonforfeitable dividends are participating securities for the computation of basic earnings per share. The application of the two-class method had an insignificant impact on the calculation of both basic and diluted EPS.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.Reference 1: http://www.xbrl.org/2003/role/presentationRef
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false07false2str_AssetRetirementObligationsPolicyTextBlockstr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Questar records an asset retirement obligation (ARO) along with an increase to the carrying value of the related property, plant and equipment when there is a legal obligation associated with the retirement of a tangible long-lived asset. Questar's AROs apply primarily to abandonment costs associated with gas and oil wells, production facilities and certain other properties. The Company has not recorded AROs on a majority of its long-lived transportation and distribution assets because the Company does not have a legal obligation to restore the area surrounding abandoned assets. The fair value of retirement costs is estimated by Company personnel based on abandonment costs of similar properties available to field operations and depreciated over the life of the related assets. Revisions to estimates result from material changes in the expected timing or amount of cash flows associated with AROs. Income or expense resulting from the settlement of ARO liabilities is included in net gain (loss) from asset sales in the Consolidated Statements of Income. The ARO liability is adjusted to present value each period through an accretion calculation using a credit-adjusted risk-free interest rate.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDescribes an entity's accounting policy for determining amounts to accrue and charge against earnings so as to satisfy legal obligations associated with the retirement (through sale, abandonment, recycling, or disposal in some other manner) of a tangible long-lived asset that result from the acquisition, construction, or development and (or) the normal operation of a long-lived asset. This accounting policy disclosure excludes obligations arising 1) in connection with leased property, whether imposed by a lease agreement or by a party other than the lessor, that meet the definition of either minimum lease payments or contingent rentals; 2) solely from a plan to sell or otherwise dispose of a long-lived asset and 3) from certain environmental remediation liabilities.No definition available.false08false2str_SegmentReportingPolicyTextBlockstr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Line-of-business information is presented according to senior management's basis for evaluating performance and considering differences in the nature of products, services and regulation, among other factors.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaThis element may be used to describe the disclosure of reporting segments. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10% or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.No definition available.false0falseBasis of Presentation of Interim Financial Statements (Policies)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.questar.com/role/BasisOfPresentationOfInterimFinancialStatementsPolicies18