| **Property Transactions - Discontinued Operations (Details) (USD $)In Millions, unless otherwise specified**                                                           | 12 Months Ended                                         |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------|
||
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]**                                      |                                                    |   |  |   |  |
| Discontinued Operations, Net of Tax                                                                                                                                    | $ 0us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | $ 71us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax |  | $ 62us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax |  |
| North Sea Assets [Member]                                                                                                                                              |                                                    |   |  |   |  |
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]**                                      |                                                    |   |  |   |  |
| Oil and Gas Sales                                                                                                                                                      |                                                    | 37us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  | 208us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  |
| Income Before Income Taxes                                                                                                                                             |                                                    | 12us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember | [1] | 101us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember | [1] |
| Income Tax Expense                                                                                                                                                     |                                                    | 6us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  | 55us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  |
| Operating Income, Net of Tax                                                                                                                                           |                                                    | 6us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  | 46us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  |
| Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax                                                                                  |                                                    | $ 65us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  | $ 16us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis= nbl_NorthSeaAssetsMember |  |
|                                                                                                                                                                        |
| [1]Income before income taxes for 2012 includes exploration expense of $27 million related to the Selkirk field which was determined uneconomic for joint development. |

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| - Definition
Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Overall income (loss) from a disposal group that is classified as a component of the entity, before income tax, reported as a separate component of income before extraordinary items. Includes the following (before income tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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| - Definition
Amount of sales or other form of revenues attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.
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Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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Amount of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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