2.4.0.82416402 - Disclosure - Revision (Details)truefalsefalse1false USDfalsefalse$D2013Q2http://www.sec.gov/CIK0000073020duration2013-04-01T00:00:002013-06-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$D2012Q4http://www.sec.gov/CIK0000073020duration2012-10-01T00:00:002012-12-31T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$D2012Q3http://www.sec.gov/CIK0000073020duration2012-07-01T00:00:002012-09-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDfalsefalse$D2012Q2http://www.sec.gov/CIK0000073020duration2012-04-01T00:00:002012-06-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$5false USDfalsefalse$D2012Q1http://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-03-31T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$6false USDfalsefalse$D2011Q4http://www.sec.gov/CIK0000073020duration2011-10-01T00:00:002011-12-31T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$7false USDfalsefalse$D2011Q3http://www.sec.gov/CIK0000073020duration2011-07-01T00:00:002011-09-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$8false USDfalsefalse$D2011Q2http://www.sec.gov/CIK0000073020duration2011-04-01T00:00:002011-06-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$9false USDfalsefalse$D2011Q1http://www.sec.gov/CIK0000073020duration2011-01-01T00:00:002011-03-31T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$10false USDfalsefalse$D2013Q2YTDhttp://www.sec.gov/CIK0000073020duration2013-01-01T00:00:002013-06-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$11false USDfalsefalse$D2012Q2YTDhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-06-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$12false USDfalsefalse$D2012Q3YTDhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-09-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$13false USDfalsefalse$D2012Q4YTDhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-12-31T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$14false USDfalsefalse$D2011Q4YTDhttp://www.sec.gov/CIK0000073020duration2011-01-01T00:00:002011-12-31T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$15false USDfalsefalse$D2010Q4YTDhttp://www.sec.gov/CIK0000073020duration2010-01-01T00:00:002010-12-31T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$16false USDtruefalse$D2012Q4_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2012-10-01T00:00:002012-12-31T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$17false USDtruefalse$D2012Q3_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2012-07-01T00:00:002012-09-30T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$18false USDtruefalse$D2012Q2_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2012-04-01T00:00:002012-06-30T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$19false USDtruefalse$D2012Q1_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-03-31T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$20false USDtruefalse$D2011Q4_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2011-10-01T00:00:002011-12-31T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$21false USDtruefalse$D2011Q3_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2011-07-01T00:00:002011-09-30T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$22false USDtruefalse$D2011Q2_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2011-04-01T00:00:002011-06-30T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$23false USDtruefalse$D2011Q1_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2011-01-01T00:00:002011-03-31T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$24false USDtruefalse$D2012Q2YTD_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-06-30T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$25false USDtruefalse$D2012Q3YTD_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-09-30T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$26false USDtruefalse$D2012Q4YTD_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-12-31T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$27false USDtruefalse$D2011Q4YTD_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2011-01-01T00:00:002011-12-31T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$28false USDtruefalse$D2010Q4YTD_us-gaap_StatementScenarioAxis_us-gaap_ScenarioPreviouslyReportedMemberhttp://www.sec.gov/CIK0000073020duration2010-01-01T00:00:002010-12-31T00:00:00falsefalseScenario, Previously Reportedus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ScenarioPreviouslyReportedMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$29false USDtruefalse$D2012Q4YTD_us-gaap_StatementScenarioAxis_us-gaap_RestatementAdjustmentMemberhttp://www.sec.gov/CIK0000073020duration2012-01-01T00:00:002012-12-31T00:00:00falsefalseRestatement Adjustmentus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RestatementAdjustmentMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$30false USDtruefalse$D2011Q4YTD_us-gaap_StatementScenarioAxis_us-gaap_RestatementAdjustmentMemberhttp://www.sec.gov/CIK0000073020duration2011-01-01T00:00:002011-12-31T00:00:00falsefalseRestatement Adjustmentus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RestatementAdjustmentMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$31false USDtruefalse$D2010Q4YTD_us-gaap_StatementScenarioAxis_us-gaap_RestatementAdjustmentMemberhttp://www.sec.gov/CIK0000073020duration2010-01-01T00:00:002010-12-31T00:00:00falsefalseRestatement Adjustmentus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RestatementAdjustmentMemberus-gaap_StatementScenarioAxisexplicitMemberusdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$32false USDtruefalse$D2012Q4Jan2003toDec2012_us-gaap_StatementScenarioAxis_us-gaap_RestatementAdjustmentMemberhttp://www.sec.gov/CIK0000073020duration2003-01-01T00:00:002012-12-31T00:00:00falsefalseRestatement Adjustmentus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RestatementAdjustmentMemberus-gaap_StatementScenarioAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$33false USDtruefalse$I2009Q4_us-gaap_StatementScenarioAxis_us-gaap_RestatementAdjustmentMemberhttp://www.sec.gov/CIK0000073020instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseRestatement Adjustmentus-gaap_StatementScenarioAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RestatementAdjustmentMemberus-gaap_StatementScenarioAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1false 4nwn_RestatementAdjustmentPreTaxDecreaseToRegulatoryAssetsAndOtherIncomeAndExpensenwn_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14falsefalsefalse00falsefalsefalse15falsefalsefalse00falsefalsefalse16falsefalsefalse00falsefalsefalse17falsefalsefalse00falsefalsefalse18falsefalsefalse00falsefalsefalse19falsefalsefalse00falsefalsefalse20falsefalsefalse00falsefalsefalse21falsefalsefalse00falsefalsefalse22falsefalsefalse00falsefalsefalse23falsefalsefalse00falsefalsefalse24falsefalsefalse00falsefalsefalse25falsefalsefalse00falsefalsefalse26falsefalsefalse00falsefalsefalse27falsefalsefalse00falsefalsefalse28falsefalsefalse00falsefalsefalse29falsefalsefalse00falsefalsefalse30falsefalsefalse00falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse56000005600000USD$falsetruefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryRestatement Adjustment, Pre-Tax Decrease to Regulatory Assets and Other Income and ExpenseNo definition available.false2Pre-tax decrease to regulatory assets and other income and expense2true 4us-gaap_IncomeStatementAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14falsefalsefalse00falsefalsefalse15falsefalsefalse00falsefalsefalse16falsefalsefalse00falsefalsefalse17falsefalsefalse00falsefalsefalse18falsefalsefalse00falsefalsefalse19falsefalsefalse00falsefalsefalse20falsefalsefalse00falsefalsefalse21falsefalsefalse00falsefalsefalse22falsefalsefalse00falsefalsefalse23falsefalsefalse00falsefalsefalse24falsefalsefalse00falsefalsefalse25falsefalsefalse00falsefalsefalse26falsefalsefalse00falsefalsefalse27falsefalsefalse00falsefalsefalse28falsefalsefalse00falsefalsefalse29falsefalsefalse00falsefalsefalse30falsefalsefalse00falsefalsefalse31falsefalsefalse00falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Income Statement [Abstract]3false 5us-gaap_OtherNonoperatingIncomeExpenseus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse14500001450000falsefalsefalse2truefalsefalse887000887000falsefalsefalse3truefalsefalse11800001180000falsefalsefalse4truefalsefalse620000620000falsefalsefalse5truefalsefalse472000472000falsefalsefalse6truefalsefalse-384000-384000falsefalsefalse7truefalsefalse14260001426000falsefalsefalse8truefalsefalse779000779000falsefalsefalse9truefalsefalse12910001291000falsefalsefalse10truefalsefalse19700001970000falsefalsefalse11truefalsefalse10920001092000falsefalsefalse12truefalsefalse22720002272000falsefalsefalse13truefalsefalse31590003159000falsefalsefalse14truefalsefalse31120003112000falsefalsefalse15truefalsefalse60190006019000falsefalsefalse16truefalsefalse13000001300000falsefalsefalse17truefalsefalse17100001710000falsefalsefalse18truefalsefalse921000921000falsefalsefalse19truefalsefalse10050001005000falsefalsefalse20truefalsefalse406000406000falsefalsefalse21truefalsefalse17810001781000falsefalsefalse22truefalsefalse11220001122000falsefalsefalse23truefalsefalse12140001214000falsefalsefalse24truefalsefalse19260001926000falsefalsefalse25truefalsefalse36360003636000falsefalsefalse26truefalsefalse49360004936000falsefalsefalse27truefalsefalse45230004523000falsefalsefalse28truefalsefalse71020007102000falsefalsefalse29truefalsefalse-1777000-1777000falsefalsefalse30truefalsefalse-1411000-1411000falsefalsefalse31truefalsefalse-1083000-1083000falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe net amount of other income and expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income (expense) recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) net gains or losses on securities, (d) unusual costs, (e) gains or losses on foreign exchange transactions, and (f) miscellaneous other income and expense items.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.9) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 false2Other income and expense, net4false 5us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse34640003464000falsefalsefalse2truefalsefalse4636400046364000falsefalsefalse3truefalsefalse-14124000-14124000falsefalsefalse4truefalsefalse19950001995000falsefalsefalse5truefalsefalse6794700067947000falsefalsefalse6truefalsefalse4836600048366000falsefalsefalse7truefalsefalse-14367000-14367000falsefalsefalse8truefalsefalse31660003166000falsefalsefalse9truefalsefalse6870400068704000falsefalsefalse10truefalsefalse6706300067063000falsefalsefalse11truefalsefalse6994200069942000falsefalsefalse12truefalsefalse5581800055818000falsefalsefalse13truefalsefalse102182000102182000falsefalsefalse14truefalsefalse105869000105869000falsefalsefalse15truefalsefalse121046000121046000falsefalsefalse16truefalsefalse4677700046777000falsefalsefalse17truefalsefalse-13594000-13594000falsefalsefalse18truefalsefalse22960002296000falsefalsefalse19truefalsefalse6848000068480000falsefalsefalse20truefalsefalse4915600049156000falsefalsefalse21truefalsefalse-14012000-14012000falsefalsefalse22truefalsefalse35090003509000falsefalsefalse23truefalsefalse6862700068627000falsefalsefalse24truefalsefalse7077600070776000falsefalsefalse25truefalsefalse5718200057182000falsefalsefalse26truefalsefalse103959000103959000falsefalsefalse27truefalsefalse107280000107280000falsefalsefalse28truefalsefalse122129000122129000falsefalsefalse29truefalsefalse-1777000-1777000falsefalsefalse30truefalsefalse-1411000-1411000falsefalsefalse31truefalsefalse-1083000-1083000falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetarySum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)(1)(i)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 false2Income before income taxes5false 5us-gaap_IncomeTaxExpenseBenefitus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse13380001338000falsefalsefalse2truefalsefalse1821700018217000falsefalsefalse3truefalsefalse-3245000-3245000falsefalsefalse4truefalsefalse768000768000falsefalsefalse5truefalsefalse2766300027663000falsefalsefalse6truefalsefalse1960000019600000falsefalsefalse7truefalsefalse-5840000-5840000falsefalsefalse8truefalsefalse11810001181000falsefalsefalse9truefalsefalse2788400027884000falsefalsefalse10truefalsefalse2729800027298000falsefalsefalse11truefalsefalse2843100028431000falsefalsefalse12truefalsefalse2518600025186000falsefalsefalse13truefalsefalse4340300043403000falsefalsefalse14truefalsefalse4282500042825000falsefalsefalse15truefalsefalse4903300049033000falsefalsefalse16truefalsefalse1838000018380000falsefalsefalse17truefalsefalse-3036000-3036000falsefalsefalse18truefalsefalse887000887000falsefalsefalse19truefalsefalse2787300027873000falsefalsefalse20truefalsefalse1991200019912000falsefalsefalse21truefalsefalse-5700000-5700000falsefalsefalse22truefalsefalse13160001316000falsefalsefalse23truefalsefalse2785400027854000falsefalsefalse24truefalsefalse2876000028760000falsefalsefalse25truefalsefalse2572400025724000falsefalsefalse26truefalsefalse4410400044104000falsefalsefalse27truefalsefalse4338200043382000falsefalsefalse28truefalsefalse4946200049462000falsefalsefalse29truefalsefalse-701000-701000falsefalsefalse30truefalsefalse-557000-557000falsefalsefalse31truefalsefalse-429000-429000falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Income Tax Expense (or Benefit) -URI http://asc.fasb.org/extlink&oid=6515339 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319 false2Income tax expense6false 5us-gaap_NetIncomeLossus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse21260002126000falsefalsefalse2truefalsefalse2814700028147000falsefalsefalse3truefalsefalse-10879000-10879000falsefalsefalse4truefalsefalse12270001227000falsefalsefalse5truefalsefalse4028400040284000falsefalsefalse6truefalsefalse2876600028766000falsefalsefalse7truefalsefalse-8527000-8527000falsefalsefalse8truefalsefalse19850001985000falsefalsefalse9truefalsefalse4082000040820000falsefalsefalse10truefalsefalse3976500039765000falsefalsefalse11truefalsefalse4151100041511000falsefalsefalse12truefalsefalse3063200030632000falsefalsefalse13truefalsefalse5877900058779000falsefalsefalse14truefalsefalse6304400063044000falsefalsefalse15truefalsefalse7201300072013000falsefalsefalse16truefalsefalse2839700028397000falsefalsefalse17truefalsefalse-10558000-10558000falsefalsefalse18truefalsefalse14090001409000falsefalsefalse19truefalsefalse4060700040607000falsefalsefalse20truefalsefalse2924400029244000falsefalsefalse21truefalsefalse-8312000-8312000falsefalsefalse22truefalsefalse21930002193000falsefalsefalse23truefalsefalse4077300040773000falsefalsefalse24truefalsefalse4201600042016000falsefalsefalse25truefalsefalse3145800031458000falsefalsefalse26truefalsefalse5985500059855000falsefalsefalse27truefalsefalse6389800063898000falsefalsefalse28truefalsefalse7266700072667000falsefalsefalse29truefalsefalse-1076000-1076000falsefalsefalse30truefalsefalse-854000-854000falsefalsefalse31truefalsefalse-654000-654000falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe portion of profit or loss for the period, net of income taxes, which is attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 20 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Other Comprehensive Income -URI http://asc.fasb.org/extlink&oid=6519514 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Net Income -URI http://asc.fasb.org/extlink&oid=6518256 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.19) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.18) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.22) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580 Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 5 false2Net income7false 5us-gaap_OtherComprehensiveIncomeLossNetOfTaxus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse23580002358000falsefalsefalse2truefalsefalse2615700026157000falsefalsefalse3truefalsefalse-10712000-10712000falsefalsefalse4truefalsefalse13930001393000falsefalsefalse5truefalsefalse4045000040450000falsefalsefalse6truefalsefalse2713200027132000falsefalsefalse7truefalsefalse-8381000-8381000falsefalsefalse8truefalsefalse21310002131000falsefalsefalse9truefalsefalse4096600040966000falsefalsefalse10truefalsefalse4023000040230000falsefalsefalse11truefalsefalse4184300041843000falsefalsefalse12truefalsefalse3113100031131000falsefalsefalse13truefalsefalse5728800057288000falsefalsefalse14truefalsefalse6184800061848000falsefalsefalse15truefalsefalse7137700071377000falsefalsefalse16truefalsefalse2640700026407000falsefalsefalse17truefalsefalse-10391000-10391000falsefalsefalse18truefalsefalse15750001575000falsefalsefalse19truefalsefalse4077300040773000falsefalsefalse20truefalsefalse2761000027610000falsefalsefalse21truefalsefalse-8166000-8166000falsefalsefalse22truefalsefalse23390002339000falsefalsefalse23truefalsefalse4091900040919000falsefalsefalse24truefalsefalse4234800042348000falsefalsefalse25truefalsefalse3195700031957000falsefalsefalse26truefalsefalse5836400058364000falsefalsefalse27truefalsefalse6270200062702000falsefalsefalse28truefalsefalse7203100072031000falsefalsefalse29truefalsefalse-1076000-1076000falsefalsefalse30truefalsefalse-854000-854000falsefalsefalse31truefalsefalse-654000-654000falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount after tax and reclassification adjustments of other comprehensive income (loss).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=28358780&loc=SL7669619-108580 false2Comprehensive income8false 5us-gaap_EarningsPerShareBasicus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse0.080.08USD$falsetruefalse2truefalsefalse1.051.05USD$falsetruefalse3truefalsefalse-0.41-0.41USD$falsetruefalse4truefalsefalse0.050.05USD$falsetruefalse5truefalsefalse1.501.50USD$falsetruefalse6truefalsefalse1.081.08USD$falsetruefalse7truefalsefalse-0.32-0.32USD$falsetruefalse8truefalsefalse0.070.07USD$falsetruefalse9truefalsefalse1.531.53USD$falsetruefalse10truefalsefalse1.481.48USD$falsetruefalse11truefalsefalse1.551.55USD$falsetruefalse12truefalsefalse1.141.14USD$falsetruefalse13truefalsefalse2.192.19USD$falsetruefalse14truefalsefalse2.362.36USD$falsetruefalse15truefalsefalse2.712.71USD$falsetruefalse16truefalsefalse1.061.06USD$falsetruefalse17truefalsefalse-0.39-0.39USD$falsetruefalse18truefalsefalse0.050.05USD$falsetruefalse19truefalsefalse1.521.52USD$falsetruefalse20truefalsefalse1.091.09USD$falsetruefalse21truefalsefalse-0.31-0.31USD$falsetruefalse22truefalsefalse0.080.08USD$falsetruefalse23truefalsefalse1.531.53USD$falsetruefalse24truefalsefalse1.571.57USD$falsetruefalse25truefalsefalse1.171.17USD$falsetruefalse26truefalsefalse2.232.23USD$falsetruefalse27truefalsefalse2.392.39USD$falsetruefalse28truefalsefalse2.732.73USD$falsetruefalse29truefalsefalse-0.04-0.04USD$falsetruefalse30truefalsefalse-0.03-0.03USD$falsetruefalse31truefalsefalse-0.02-0.02USD$falsetruefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsenum:perShareItemTypedecimalThe amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1252-109256 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 55 -Paragraph 52 -URI http://asc.fasb.org/extlink&oid=32703322&loc=d3e4984-109258 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.21) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.19) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.23) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 false3Earnings per share of common stock - basic9false 5us-gaap_EarningsPerShareDilutedus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse0.080.08USD$falsetruefalse2truefalsefalse1.041.04USD$falsetruefalse3truefalsefalse-0.41-0.41USD$falsetruefalse4truefalsefalse0.050.05USD$falsetruefalse5truefalsefalse1.501.50USD$falsetruefalse6truefalsefalse1.071.07USD$falsetruefalse7truefalsefalse-0.32-0.32USD$falsetruefalse8truefalsefalse0.070.07USD$falsetruefalse9truefalsefalse1.531.53USD$falsetruefalse10truefalsefalse1.471.47USD$falsetruefalse11truefalsefalse1.541.54USD$falsetruefalse12truefalsefalse1.141.14USD$falsetruefalse13truefalsefalse2.182.18USD$falsetruefalse14truefalsefalse2.362.36USD$falsetruefalse15truefalsefalse2.702.70USD$falsetruefalse16truefalsefalse1.051.05USD$falsetruefalse17truefalsefalse-0.39-0.39USD$falsetruefalse18truefalsefalse0.050.05USD$falsetruefalse19truefalsefalse1.511.51USD$falsetruefalse20truefalsefalse1.091.09USD$falsetruefalse21truefalsefalse-0.31-0.31USD$falsetruefalse22truefalsefalse0.080.08USD$falsetruefalse23truefalsefalse1.531.53USD$falsetruefalse24truefalsefalse1.561.56USD$falsetruefalse25truefalsefalse1.171.17USD$falsetruefalse26truefalsefalse2.222.22USD$falsetruefalse27truefalsefalse2.392.39USD$falsetruefalse28truefalsefalse2.732.73USD$falsetruefalse29truefalsefalse-0.04-0.04USD$falsetruefalse30truefalsefalse-0.03-0.03USD$falsetruefalse31truefalsefalse-0.03-0.03USD$falsetruefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsenum:perShareItemTypedecimalThe amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1252-109256 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.21) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 false3Earnings per share of common stock - diluted10true 5us-gaap_AssetsNoncurrentAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14falsefalsefalse00falsefalsefalse15falsefalsefalse00falsefalsefalse16falsefalsefalse00falsefalsefalse17falsefalsefalse00falsefalsefalse18falsefalsefalse00falsefalsefalse19falsefalsefalse00falsefalsefalse20falsefalsefalse00falsefalsefalse21falsefalsefalse00falsefalsefalse22falsefalsefalse00falsefalsefalse23falsefalsefalse00falsefalsefalse24falsefalsefalse00falsefalsefalse25falsefalsefalse00falsefalsefalse26falsefalsefalse00falsefalsefalse27falsefalsefalse00falsefalsefalse28falsefalsefalse00falsefalsefalse29falsefalsefalse00falsefalsefalse30falsefalsefalse00falsefalsefalse31falsefalsefalse00falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Assets, Noncurrent [Abstract]11false 6us-gaap_RegulatoryAssetsNoncurrentus-gaap_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-5633000-5633000falsefalsefalse30truefalsefalse-3856000-3856000falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-5633000-5633000falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 false2Regulatory assets12false 6us-gaap_AssetsNoncurrentus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse25934220002593422000falsefalsefalse2truefalsefalse25294210002529421000falsefalsefalse3truefalsefalse24872470002487247000falsefalsefalse4truefalsefalse24436680002443668000falsefalsefalse5truefalsefalse24119830002411983000falsefalsefalse6truefalsefalse23940290002394029000falsefalsefalse7truefalsefalse23142280002314228000falsefalsefalse8truefalsefalse22913900002291390000falsefalsefalse9truefalsefalse22884810002288481000falsefalsefalse10truefalsefalse25934220002593422000falsefalsefalse11truefalsefalse24436680002443668000falsefalsefalse12truefalsefalse24872470002487247000falsefalsefalse13truefalsefalse25294210002529421000falsefalsefalse14truefalsefalse23940290002394029000falsefalsefalse15falsefalsefalse00falsefalsefalse16truefalsefalse25350540002535054000falsefalsefalse17truefalsefalse24924670002492467000falsefalsefalse18truefalsefalse24483590002448359000falsefalsefalse19truefalsefalse24163720002416372000falsefalsefalse20truefalsefalse23978850002397885000falsefalsefalse21truefalsefalse23172930002317293000falsefalsefalse22truefalsefalse22941000002294100000falsefalsefalse23truefalsefalse22908480002290848000falsefalsefalse24truefalsefalse24483590002448359000falsefalsefalse25truefalsefalse24924670002492467000falsefalsefalse26truefalsefalse25350540002535054000falsefalsefalse27truefalsefalse23978850002397885000falsefalsefalse28falsefalsefalse00falsefalsefalse29truefalsefalse-5633000-5633000falsefalsefalse30truefalsefalse-3856000-3856000falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-5633000-5633000falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetarySum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.10-17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 false2Total non-current assets13false 6us-gaap_Assetsus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse27725890002772589000falsefalsefalse2truefalsefalse28131200002813120000falsefalsefalse3truefalsefalse26851480002685148000falsefalsefalse4truefalsefalse26304500002630450000falsefalsefalse5truefalsefalse27228730002722873000falsefalsefalse6truefalsefalse27427180002742718000falsefalsefalse7truefalsefalse25647750002564775000falsefalsefalse8truefalsefalse25192840002519284000falsefalsefalse9truefalsefalse25691860002569186000falsefalsefalse10truefalsefalse27725890002772589000falsefalsefalse11truefalsefalse26304500002630450000falsefalsefalse12truefalsefalse26851480002685148000falsefalsefalse13truefalsefalse28131200002813120000falsefalsefalse14truefalsefalse27427180002742718000falsefalsefalse15falsefalsefalse00falsefalsefalse16truefalsefalse28187530002818753000falsefalsefalse17truefalsefalse26903680002690368000falsefalsefalse18truefalsefalse26351410002635141000falsefalsefalse19truefalsefalse27272620002727262000falsefalsefalse20truefalsefalse27465740002746574000falsefalsefalse21truefalsefalse25678400002567840000falsefalsefalse22truefalsefalse25219940002521994000falsefalsefalse23truefalsefalse25715530002571553000falsefalsefalse24truefalsefalse26351410002635141000falsefalsefalse25truefalsefalse26903680002690368000falsefalsefalse26truefalsefalse28187530002818753000falsefalsefalse27truefalsefalse27465740002746574000falsefalsefalse28falsefalsefalse00falsefalsefalse29truefalsefalse-5633000-5633000falsefalsefalse30truefalsefalse-3856000-3856000falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-5633000-5633000falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetarySum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.18) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5 false2Total assets14true 6us-gaap_LiabilitiesNoncurrentAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14falsefalsefalse00falsefalsefalse15falsefalsefalse00falsefalsefalse16falsefalsefalse00falsefalsefalse17falsefalsefalse00falsefalsefalse18falsefalsefalse00falsefalsefalse19falsefalsefalse00falsefalsefalse20falsefalsefalse00falsefalsefalse21falsefalsefalse00falsefalsefalse22falsefalsefalse00falsefalsefalse23falsefalsefalse00falsefalsefalse24falsefalsefalse00falsefalsefalse25falsefalsefalse00falsefalsefalse26falsefalsefalse00falsefalsefalse27falsefalsefalse00falsefalsefalse28falsefalsefalse00falsefalsefalse29falsefalsefalse00falsefalsefalse30falsefalsefalse00falsefalsefalse31falsefalsefalse00falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Liabilities, Noncurrent [Abstract]15false 7us-gaap_DeferredTaxLiabilitiesNoncurrentus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse469964000469964000falsefalsefalse2truefalsefalse444377000444377000falsefalsefalse3truefalsefalse428821000428821000falsefalsefalse4truefalsefalse438217000438217000falsefalsefalse5truefalsefalse436750000436750000falsefalsefalse6truefalsefalse411683000411683000falsefalsefalse7truefalsefalse393003000393003000falsefalsefalse8truefalsefalse397751000397751000falsefalsefalse9truefalsefalse395419000395419000falsefalsefalse10truefalsefalse469964000469964000falsefalsefalse11truefalsefalse438217000438217000falsefalsefalse12truefalsefalse428821000428821000falsefalsefalse13truefalsefalse444377000444377000falsefalsefalse14truefalsefalse411683000411683000falsefalsefalse15falsefalsefalse00falsefalsefalse16truefalsefalse446604000446604000falsefalsefalse17truefalsefalse430885000430885000falsefalsefalse18truefalsefalse440073000440073000falsefalsefalse19truefalsefalse438486000438486000falsefalsefalse20truefalsefalse413209000413209000falsefalsefalse21truefalsefalse394217000394217000falsefalsefalse22truefalsefalse398825000398825000falsefalsefalse23truefalsefalse396357000396357000falsefalsefalse24truefalsefalse440073000440073000falsefalsefalse25truefalsefalse430885000430885000falsefalsefalse26truefalsefalse446604000446604000falsefalsefalse27truefalsefalse413209000413209000falsefalsefalse28falsefalsefalse00falsefalsefalse29truefalsefalse-2227000-2227000falsefalsefalse30truefalsefalse-1526000-1526000falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-2227000-2227000falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of deferred tax liability attributable to taxable temporary differences, net of deferred tax asset attributable to deductible temporary differences and carryforwards net of valuation allowances expected to be realized or consumed after one year (or the normal operating cycle, if longer).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=21917399&loc=d3e31917-109318 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=21917399&loc=d3e31931-109318 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=21917399&loc=d3e31958-109318 false2Deferred tax liabilities16false 7us-gaap_DeferredCreditsAndOtherLiabilitiesNoncurrentus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse10591900001059190000falsefalsefalse2truefalsefalse10233570001023357000falsefalsefalse3truefalsefalse983665000983665000falsefalsefalse4truefalsefalse989151000989151000falsefalsefalse5truefalsefalse997292000997292000falsefalsefalse6truefalsefalse974396000974396000falsefalsefalse7truefalsefalse865713000865713000falsefalsefalse8truefalsefalse873768000873768000falsefalsefalse9truefalsefalse872776000872776000falsefalsefalse10truefalsefalse10591900001059190000falsefalsefalse11truefalsefalse989151000989151000falsefalsefalse12truefalsefalse983665000983665000falsefalsefalse13truefalsefalse10233570001023357000falsefalsefalse14truefalsefalse974396000974396000falsefalsefalse15falsefalsefalse00falsefalsefalse16truefalsefalse10255840001025584000falsefalsefalse17truefalsefalse985729000985729000falsefalsefalse18truefalsefalse991007000991007000falsefalsefalse19truefalsefalse999028000999028000falsefalsefalse20truefalsefalse975922000975922000falsefalsefalse21truefalsefalse866927000866927000falsefalsefalse22truefalsefalse874842000874842000falsefalsefalse23truefalsefalse873714000873714000falsefalsefalse24truefalsefalse991007000991007000falsefalsefalse25truefalsefalse985729000985729000falsefalsefalse26truefalsefalse10255840001025584000falsefalsefalse27truefalsefalse975922000975922000falsefalsefalse28falsefalsefalse00falsefalsefalse29truefalsefalse-2227000-2227000falsefalsefalse30truefalsefalse-1526000-1526000falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-2227000-2227000falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount as of the balance sheet date of unearned revenue or income, not otherwise specified in the taxonomy, which is expected to be taken into income after one year or beyond the normal operating cycle, if longer and noncurrent obligations not separately disclosed in the balance sheet (other liabilities, noncurrent).No definition available.false2Total deferred credits and other non-current liabilities17true 6us-gaap_EquityAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14falsefalsefalse00falsefalsefalse15falsefalsefalse00falsefalsefalse16falsefalsefalse00falsefalsefalse17falsefalsefalse00falsefalsefalse18falsefalsefalse00falsefalsefalse19falsefalsefalse00falsefalsefalse20falsefalsefalse00falsefalsefalse21falsefalsefalse00falsefalsefalse22falsefalsefalse00falsefalsefalse23falsefalsefalse00falsefalsefalse24falsefalsefalse00falsefalsefalse25falsefalsefalse00falsefalsefalse26falsefalsefalse00falsefalsefalse27falsefalsefalse00falsefalsefalse28falsefalsefalse00falsefalsefalse29falsefalsefalse00falsefalsefalse30falsefalsefalse00falsefalsefalse31falsefalsefalse00falsefalsefalse32falsefalsefalse00falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Equity [Abstract]18false 7us-gaap_RetainedEarningsAccumulatedDeficitus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse397603000397603000falsefalsefalse2truefalsefalse382347000382347000falsefalsefalse3truefalsefalse366428000366428000falsefalsefalse4truefalsefalse389247000389247000falsefalsefalse5truefalsefalse399946000399946000falsefalsefalse6truefalsefalse371575000371575000falsefalsefalse7truefalsefalse354723000354723000falsefalsefalse8truefalsefalse374853000374853000falsefalsefalse9truefalsefalse384470000384470000falsefalsefalse10truefalsefalse397603000397603000falsefalsefalse11truefalsefalse389247000389247000falsefalsefalse12truefalsefalse366428000366428000falsefalsefalse13truefalsefalse382347000382347000falsefalsefalse14truefalsefalse371575000371575000falsefalsefalse15falsefalsefalse00falsefalsefalse16truefalsefalse385753000385753000falsefalsefalse17truefalsefalse369584000369584000falsefalsefalse18truefalsefalse392082000392082000falsefalsefalse19truefalsefalse402599000402599000falsefalsefalse20truefalsefalse373905000373905000falsefalsefalse21truefalsefalse356574000356574000falsefalsefalse22truefalsefalse376489000376489000falsefalsefalse23truefalsefalse385899000385899000falsefalsefalse24truefalsefalse392082000392082000falsefalsefalse25truefalsefalse369584000369584000falsefalsefalse26truefalsefalse385753000385753000falsefalsefalse27truefalsefalse373905000373905000falsefalsefalse28falsefalsefalse00falsefalsefalse29truefalsefalse-3406000-3406000falsefalsefalse30truefalsefalse-2330000-2330000falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-3406000-3406000falsefalsefalse33truefalsefalse700000700000falsefalsefalsexbrli:monetaryItemTypemonetaryThe cumulative amount of the reporting entity's undistributed earnings or deficit.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 31 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.31(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 false2Retained earnings19false 7us-gaap_StockholdersEquityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse748549000748549000falsefalsefalse2truefalsefalse729627000729627000falsefalsefalse3truefalsefalse714403000714403000falsefalsefalse4truefalsefalse734735000734735000falsefalsefalse5truefalsefalse743318000743318000falsefalsefalse6truefalsefalse712158000712158000falsefalsefalse7truefalsefalse694754000694754000falsefalsefalse8truefalsefalse712992000712992000falsefalsefalse9truefalsefalse721799000721799000falsefalsefalse10truefalsefalse748549000748549000falsefalsefalse11truefalsefalse734735000734735000falsefalsefalse12truefalsefalse714403000714403000falsefalsefalse13truefalsefalse729627000729627000falsefalsefalse14truefalsefalse712158000712158000falsefalsefalse15falsefalsefalse00falsefalsefalse16truefalsefalse733033000733033000falsefalsefalse17truefalsefalse717559000717559000falsefalsefalse18truefalsefalse737570000737570000falsefalsefalse19truefalsefalse745971000745971000falsefalsefalse20truefalsefalse714488000714488000falsefalsefalse21truefalsefalse696605000696605000falsefalsefalse22truefalsefalse714628000714628000falsefalsefalse23truefalsefalse723228000723228000falsefalsefalse24truefalsefalse737570000737570000falsefalsefalse25truefalsefalse717559000717559000falsefalsefalse26truefalsefalse733033000733033000falsefalsefalse27truefalsefalse714488000714488000falsefalsefalse28falsefalsefalse00falsefalsefalse29truefalsefalse-3406000-3406000falsefalsefalse30truefalsefalse-2330000-2330000falsefalsefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-3406000-3406000falsefalsefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryTotal of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 4.E) -URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 4 -Section E Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29-31) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30, 31 -Article 5 false2Total equity20false 6us-gaap_LiabilitiesAndStockholdersEquityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse27725890002772589000USD$falsetruefalse2truefalsefalse28131200002813120000USD$falsetruefalse3truefalsefalse26851480002685148000USD$falsetruefalse4truefalsefalse26304500002630450000USD$falsetruefalse5truefalsefalse27228730002722873000USD$falsetruefalse6truefalsefalse27427180002742718000USD$falsetruefalse7truefalsefalse25647750002564775000USD$falsetruefalse8truefalsefalse25192840002519284000USD$falsetruefalse9truefalsefalse25691860002569186000USD$falsetruefalse10truefalsefalse27725890002772589000USD$falsetruefalse11truefalsefalse26304500002630450000USD$falsetruefalse12truefalsefalse26851480002685148000USD$falsetruefalse13truefalsefalse28131200002813120000USD$falsetruefalse14truefalsefalse27427180002742718000USD$falsetruefalse15falsefalsefalse00falsefalsefalse16truefalsefalse28187530002818753000USD$falsetruefalse17truefalsefalse26903680002690368000USD$falsetruefalse18truefalsefalse26351410002635141000USD$falsetruefalse19truefalsefalse27272620002727262000USD$falsetruefalse20truefalsefalse27465740002746574000USD$falsetruefalse21truefalsefalse25678400002567840000USD$falsetruefalse22truefalsefalse25219940002521994000USD$falsetruefalse23truefalsefalse25715530002571553000USD$falsetruefalse24truefalsefalse26351410002635141000USD$falsetruefalse25truefalsefalse26903680002690368000USD$falsetruefalse26truefalsefalse28187530002818753000USD$falsetruefalse27truefalsefalse27465740002746574000USD$falsetruefalse28falsefalsefalse00falsefalsefalse29truefalsefalse-5633000-5633000USD$falsetruefalse30truefalsefalse-3856000-3856000USD$falsetruefalse31falsefalsefalse00falsefalsefalse32truefalsefalse-5633000-5633000USD$falsetruefalse33falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.32) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 25 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 32 -Article 5 false2Total liabilities and equityfalseRevision (Details) (USD $)NoRoundingUnKnownNoRoundingUnKnowntruefalsefalseSheethttp://www.nwnatural.com/role/RevisionDetails3320