|**Divestitures (Tables)**                                                                 | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|----------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Acquisitions and Dispositions [Abstract]**                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Discontinued Operations Balance Sheet and Income Statement Disclosures [Table Text Block] | Summarized results of discontinued operations are as follows:Three Months EndedMarch 31,20132012(millions)Oil and Gas Sales$10$75Income (Loss) Before Income Taxes(1)39Income Tax Expense725Operating Income (Loss), Net of Tax(8)14Gain on Sale, Net of Tax37—Discontinued Operations, Net of Tax$29$14                                                                                                                                                                                                                                                                                                                      
|                                                                                         
|                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|                                                                                          | Three Months EndedMarch 31,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|                                                                                          | 2013                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
|(millions)                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Oil and Gas Sales                                                                         | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
|Income (Loss) Before Income Taxes                                                         | (1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Income Tax Expense                                                                        | 7                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
|Operating Income (Loss), Net of Tax                                                       | (8                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Gain on Sale, Net of Tax                                                                  | 37                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Discontinued Operations, Net of Tax                                                       | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
|Schedule of Disposal Groups, Gain on Asset Onshore Divestitures [Table Text Block]        | Sale of Onshore US PropertiesDuring thefirstquarter of2013, we closed the sales of certain crude oil and natural gas properties in the Gulf Coast area with an effective date ofNovember 1, 2012.  The information regarding the assets sold is as follows:Three Months EndedMarch 31,2013(millions)Sale Proceeds$55LessNet Book Value of Assets Sold(28)Goodwill Allocated to Assets Sold(3)Asset Retirement Obligations Associated with Assets Sold5Other Closing Adjustments(1)(14)Gain on Divestitures$15(1)Other closing adjustments also include adjustments related to onshore US property sales completed during 2012.
|                                                                                         
|                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|                                                                                          | Three Months EndedMarch 31,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|                                                                                          | 2013                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
|(millions)                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Sale Proceeds                                                                             | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
|Less                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Net Book Value of Assets Sold                                                             | (28                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Goodwill Allocated to Assets Sold                                                         | (3                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Asset Retirement Obligations Associated with Assets Sold                                  | 5                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
|Other Closing Adjustments(1)                                                              | (14                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Gain on Divestitures                                                                      | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             

X- Details**Name:**
                    nbl_AcquisitionsAndDispositionsAbstract**Namespace Prefix:**
                    nbl_**Data Type:**
                    xbrli:stringItemType**Balance Type:**
                    na**Period Type:**
                    duration X- DefinitionTabular disclosure of disposal groups, which may include the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the classification and carrying value of the assets and liabilities comprising the disposal group, and the segment in which the disposal group was reported. Also may include the amount of adjustments to amounts previously reported in discontinued operations such as resolution of contingencies arising from the disposal transaction or the operations of the component prior to disposal.+ ReferencesNo definition available.+ Details**Name:**
                    nbl_ScheduleOfDisposalGroupsGainOnAssetSaleMidConIllinoisBasinTableTextBlock**Namespace Prefix:**
                    nbl_**Data Type:**
                    nonnum:textBlockItemType**Balance Type:**
                    na**Period Type:**
                    duration X- DefinitionTabular disclosure of disposal groups, which may include the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the classification and carrying value of the assets and liabilities comprising the disposal group, and the segment in which the disposal group was reported. Also may include the amount of adjustments to amounts previously reported in discontinued operations such as resolution of contingencies arising from the disposal transaction or the operations of the component prior to disposal.+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1474-107760Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2443-110228Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 43, 44, 45, 47, 48 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1510-107760+ Details**Name:**
                    us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock**Namespace Prefix:**
                    us-gaap_**Data Type:**
                    nonnum:textBlockItemType**Balance Type:**
                    na**Period Type:**
                    duration