1.0.0.3 false Comprehensive Income false 1 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 2 Notes To Financial Statements [Abstract] 0 str_NotesToFinancialStatementsAbstract str false na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false No definition available. false 3 Comprehensive Income 1 us-gaap_ComprehensiveIncomeNoteTextBlock us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 Note 13 - Comprehensive Income Comprehensive income is the sum of net income attributable to Questar as reported in the Consolidated Statements of Income and other comprehensive income (loss). Other comprehensive income (loss) includes changes in the market value of commodity-based derivative instruments and recognition of the under-funded position of pension and other postretirement benefit plans. Comprehensive income (loss) attributable to Questar is shown below: 3 Months Ended Sept. 30, 9 Months Ended Sept. 30, 2009 2008 2009 2008 (in millions)Net income $ 98.8 $ 206.6 $245.0 $569.5 Other comprehensive income (loss) Net unrealized income (loss) on derivatives (252.5) 1,024.4 (392.5) 211.9 Income taxes 93.9 (388.1) 145.9 (80.2) Net other comprehensive income (loss) (158.6) 636.3 (246.6) 131.7 Comprehensive income (loss) (59.8) 842.9 (1.6) 701.2 Comprehensive income attributable to noncontrolling interest (0.6) (2.4) (1.7) (6.9) Total comprehensive income (loss) attributable to Questar ($ 60.4) $840.5 ($ 3.3) $694.3 The components of AOCI, net of income taxes, shown on the condensed Consolidated Balance Sheets are as follows: Sept. 30, Dec. 31, 2009 2008 Change (in millions) Net unrealized income on derivatives $ 95.0 $ 341.6 ($246.6)Pension liability (129.5) (129.5) Postretirement benefits liability (17.4) (17.4) Accumulated other comprehensive income (loss) ($ 51.9) $ 194.7 ($246.6) Note 13 - Comprehensive Income Comprehensive income is the sum of net income attributable to Questar as reported in the Consolidated Statements of Income and false false No definition available. No authoritative reference available. false false 1 2 false UnKnown UnKnown UnKnown false true