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For example, the basis on the underlying for a natural gas futures contract might be the NYMEX price per million British thermal units (MMBtu).No authoritative reference available.falsefalseIndex8false0nbl_IndexLessDifferentialnblfalsenadurationReference to the index or unit of measurement for the underlying which establishes the pricing terms of the derivative...falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00NYMEX HHNYMEX HHfalsefalsefalsetruefalse23falsefalsefalse00NYMEX HHNYMEX HHfalsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:stringItemTypestringReference to the index or unit of measurement for the underlying which establishes the pricing terms of the derivative instrument. For example, the basis on the underlying for a natural gas futures contract might be the NYMEX price per million British thermal units (MMBtu).No authoritative reference available.falsefalseIndex Less Differential9false0invest_DerivativeNonmonetaryNotionalAmountinvestfalsenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4truefalsefalse50005000falsefalsefalsetruefalse5truefalsefalse1300013000falsefalsefalsetruefalse6truefalsefalse1200012000falsefalsefalsetruefalse7truefalsefalse50005000falsefalsefalsetruefalse8truefalsefalse80008000falsefalsefalsetruefalse9truefalsefalse2300023000falsefalsefalsetruefalse10truefalsefalse30003000falsefalsefalsetruefalse11truefalsefalse30003000falsefalsefalsetruefalse12truefalsefalse50005000falsefalsefalsetruefalse13truefalsefalse1200012000falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15truefalsefalse3000030000falsefalsefalsetruefalse16truefalsefalse110000110000falsefalsefalsetruefalse17truefalsefalse3000030000falsefalsefalsetruefalse18truefalsefalse5000050000falsefalsefalsetruefalse19truefalsefalse5000050000falsefalsefalsetruefalse20truefalsefalse2500025000falsefalsefalsetruefalse21truefalsefalse140000140000falsefalsefalsetruefalse22truefalsefalse140000140000falsefalsefalsetruefalse23truefalsefalse150000150000falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:decimalItemTypedecimalAggregate notional amount of derivative expressed in nonmonetary units. For example the number of barrels specified in a fuel oil forward purchase contract.No authoritative reference available.falsefalseVolume Per Day10false0us-gaap_DerivativeSwapTypeAverageFixedPriceus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4truefalsefalse85.5285.52falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7truefalsefalse91.8491.84falsefalsefalsetruefalse8truefalsefalse89.0689.06falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11truefalsefalse98.0398.03falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15truefalsefalse5.105.10falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17truefalsefalse5.255.25falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20truefalsefalse6.416.41falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:decimalItemTypedecimalAverage fixed price related to the group of price risk swap derivatives.No authoritative reference available.falsefalseWeighted Average Fixed Price11false0us-gaap_DerivativeAveragePriceRiskOptionStrikePriceus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse58.3358.33falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9truefalsefalse61.0961.09falsefalsefalsetruefalse10truefalsefalse70.0070.00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12truefalsefalse65.0065.00falsefalsefalsetruefalse13truefalsefalse75.8375.83falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16truefalsefalse4.444.44falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18truefalsefalse4.004.00falsefalsefalsetruefalse19truefalsefalse4.004.00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:decimalItemTypedecimalThe average strike price on the group of price risk option contracts such as put options or call options.No authoritative reference available.falsefalseWeighted Average Short Put Price12false0us-gaap_DerivativeAverageFloorPriceus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse80.1580.15falsefalsefalsetruefalse6truefalsefalse78.3378.33falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9truefalsefalse83.0483.04falsefalsefalsetruefalse10truefalsefalse95.8395.83falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12truefalsefalse85.0085.00falsefalsefalsetruefalse13truefalsefalse97.5097.50falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16truefalsefalse5.255.25falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18truefalsefalse5.255.25falsefalsefalsetruefalse19truefalsefalse5.005.00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21truefalsefalse5.955.95falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:decimalItemTypedecimalThe average floor rate on a group of price risk derivatives such as floors or collars. A payment (receipt) is triggered if the market rate falls below the floor rate on the contract.No authoritative reference available.falsefalseWeighted Average Floor Price13false0us-gaap_DerivativeAverageCapPriceus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse94.6394.63falsefalsefalsetruefalse6truefalsefalse100.71100.71falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9truefalsefalse101.66101.66falsefalsefalsetruefalse10truefalsefalse105.00105.00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12truefalsefalse113.63113.63falsefalsefalsetruefalse13truefalsefalse125.93125.93falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16truefalsefalse6.666.66falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18truefalsefalse5.595.59falsefalsefalsetruefalse19truefalsefalse6.706.70falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21truefalsefalse6.826.82falsefalsefalsetruefalse22truefalsefalse-0.70-0.70falsefalsefalsetruefalse23truefalsefalse-0.52-0.52falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:decimalItemTypedecimalThe average cap rate on a group of price risk derivatives such as caps or collars. A payment (receipt) is triggered if the market rate exceeds the cap rate on the contract.No authoritative reference available.falsefalseWeighted Average Ceiling Price14false0us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35truefalsefalse-23000000-23falsefalsefalsetruefalse36truefalsefalse1100000011falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryThe effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph b -Clause 2 falsefalseAmount of (Gain) Loss on Derivative Instruments Recognized in Other Comprehensive (Income) Loss15false0us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14truefalsefalse50000005[4]falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24truefalsefalse10000001[4]falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryThe income statement location of the effective portion of net gain or loss reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph b -Clause 3 falsefalseAmount of (Gain) Loss on Derivative Instruments Recognized in Accumulated Other Comprehensive Loss16true0nbl_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeLineItemsnblfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseFair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Line Items]17false0us-gaap_DerivativeAssetNotDesignatedAsHedgingInstrumentFairValueus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27truefalsefalse20000002falsefalsefalsetruefalse28truefalsefalse6200000062falsefalsefalsetruefalse29truefalsefalse00falsefalsefalsetruefalse30truefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryFair value of a derivative asset that is not designated or qualifying as a hedging instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph a -Clause 1 falsefalseDerivative Asset Not Designated as Hedging Instrument, Fair Value18false0nbl_DerivativeInstrumentsDesignatedAsHedgingInstrumentsAssetAtFairValuenblfalsedebitinstantFair value as of the balance sheet date of derivative instrument designated as hedging instrument and classified as an asset.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37truefalsefalse00falsefalsefalsetruefalse38truefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryFair value as of the balance sheet date of derivative instrument designated as hedging instrument and classified as an asset.No authoritative reference available.falsefalseDerivative Asset Designated as Hedging Instrument, Fair Value19false0us-gaap_DerivativeFairValueOfDerivativeAssetus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27truefalsefalse20000002falsefalsefalsetruefalse28truefalsefalse6200000062falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryFair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph a -Clause 1 falsefalseDerivative Asset, Fair Value20false0us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValueus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31truefalsefalse119000000119falsefalsefalsetruefalse32truefalsefalse2400000024falsefalsefalsetruefalse33truefalsefalse200000000200falsefalsefalsetruefalse34truefalsefalse5100000051falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryFair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as a liability.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 107 -Paragraph 10 falsefalseDerivative Liability Not Designated as Hedging Instrument, Fair Value21false0nbl_DerivativeInstrumentsDesignatedAsHedgingInstrumentsLiabilityAtFairValuenblfalsecreditinstantFair value as of the balance sheet date of derivative instrument designated as hedging instrument and classified as a...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37truefalsefalse6300000063falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39truefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryFair value as of the balance sheet date of derivative instrument designated as hedging instrument and classified as a liability.No authoritative reference available.falsefalseDerivative Liability Designated as Hedging Instrument, Fair Value22false0us-gaap_DerivativeFairValueOfDerivativeLiabilityus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31truefalsefalse319000000319falsefalsefalsetruefalse32truefalsefalse138000000138falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryFair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph a -Clause 1 falsefalseDerivative Liability, Fair Value23true0nbl_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskLineItemsnblfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseDerivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Line Items]24false0us-gaap_GainLossOnSaleOfDerivativesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25truefalsefalse-17000000-17falsefalsefalsetruefalse26truefalsefalse20000002falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryThe difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings .Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseRealized Mark-to-Market (Gain) Loss25false0us-gaap_UnrealizedGainLossOnDerivativesAndCommodityContractsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse303000000303falsefalsefalsefalsefalse2truefalsefalse-147000000-147falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25truefalsefalse303000000303falsefalsefalsetruefalse26truefalsefalse-147000000-147falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate increase (decrease) in the market value of open derivatives, commodity, or energy contracts. These gains (losses) are included in earnings.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseUnrealized Mark-to-Market (Gain) Loss26false0us-gaap_GainLossOnDerivativeInstrumentsNetPretaxus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse286000000286falsefalsefalsefalsefalse2truefalsefalse-145000000-145falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25truefalsefalse286000000286falsefalsefalsetruefalse26truefalsefalse-145000000-145falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryAggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.No authoritative reference available.truefalseTotal (Gain) Loss on Commodity Derivative Instruments27false0us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35truefalsefalse-23000000-23falsefalsefalsetruefalse36truefalsefalse1100000011falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryThe effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph b -Clause 2 falsefalseAmount of (gain) loss on derivative instruments recognized in other comprehensive (income) loss28false0us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14truefalsefalse50000005[4]falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24truefalsefalse10000001[4]falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryThe income statement location of the effective portion of net gain or loss reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph b -Clause 3 falsefalseAmount of (Gain) Loss on Derivative Instruments Reclassified from Accumulated Other Comprehensive Loss29false0nbl_AccumulatedOtherComprehensiveIncomeLossRemainingCumulativeChangesInNetGainLossFromInterestRateCashFlowHedgesEffectNetOfTaxnblfalsedebitinstantAccumulated change, net of tax, in accumulated gains and losses from interest rate derivative instruments designated and...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2800000028falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryAccumulated change, net of tax, in accumulated gains and losses from interest rate derivative instruments designated and qualifying as the effective portion of cash flow hedges, remaining in accumulated other comprehensive loss until fixed-rate debt is issued.No authoritative reference available.falsefalseAmount of Deferred Losses Related to Interest Rate Derivative Instruments to be Amortized to Interest Expense Over the Life of the Related Debt Issuance30false0nbl_AmountOfDeferredLossesRelatedToInterestRateDerivativeInstrumentsCurrentlyBeingReclassifiedIntoEarningsnblfalsecreditinstantThe amount of net gains (losses) on interest rate cash flow hedges expected to be reclassified over the term of the hedged...falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse20000002falsetruefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00falsefalsefalsetruefalse8falsefalsefalse00falsefalsefalsetruefalse9falsefalsefalse00falsefalsefalsetruefalse10falsefalsefalse00falsefalsefalsetruefalse11falsefalsefalse00falsefalsefalsetruefalse12falsefalsefalse00falsefalsefalsetruefalse13falsefalsefalse00falsefalsefalsetruefalse14falsefalsefalse00falsefalsefalsetruefalse15falsefalsefalse00falsefalsefalsetruefalse16falsefalsefalse00falsefalsefalsetruefalse17falsefalsefalse00falsefalsefalsetruefalse18falsefalsefalse00falsefalsefalsetruefalse19falsefalsefalse00falsefalsefalsetruefalse20falsefalsefalse00falsefalsefalsetruefalse21falsefalsefalse00falsefalsefalsetruefalse22falsefalsefalse00falsefalsefalsetruefalse23falsefalsefalse00falsefalsefalsetruefalse24falsefalsefalse00falsefalsefalsetruefalse25falsefalsefalse00falsefalsefalsetruefalse26falsefalsefalse00falsefalsefalsetruefalse27falsefalsefalse00falsefalsefalsetruefalse28falsefalsefalse00falsefalsefalsetruefalse29falsefalsefalse00falsefalsefalsetruefalse30falsefalsefalse00falsefalsefalsetruefalse31falsefalsefalse00falsefalsefalsetruefalse32falsefalsefalse00falsefalsefalsetruefalse33falsefalsefalse00falsefalsefalsetruefalse34falsefalsefalse00falsefalsefalsetruefalse35falsefalsefalse00falsefalsefalsetruefalse36falsefalsefalse00falsefalsefalsetruefalse37falsefalsefalse00falsefalsefalsetruefalse38falsefalsefalse00falsefalsefalsetruefalse39falsefalsefalse00falsefalsefalsetruefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of net gains (losses) on interest rate cash flow hedges expected to be reclassified over the term of the hedged item to earnings from accumulated other comprehensive income.No authoritative reference available.falsefalseAmount of Deferred Losses Related to Interest Rate Derivative Instruments Currently Being Reclassified Into Earnings1West Texas Intermediate2Henry Hub3Colorado Interstate Gas - Northern System4Includes effect of commodity derivative instruments previously accounted for as cash flow hedges. All net derivative gains and losses that were deferred in AOCL as of January 1, 2008, as a result of previous cash flow hedge accounting, had been reclassified to earnings by December 31, 2010.3929Derivative Instruments and Hedging Activities (Details) (USD $)MillionsUnKnownUnKnownUnKnowntruetrue