|**Asset Impairments (Notes)**    | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|-------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Asset Impairments [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Asset Impairments                | Asset ImpairmentsPre-tax (non-cash) asset impairment charges were as follows:Three Months Ended June 30,Six Months EndedJune 30,(millions)2015201420152014Deepwater Gulf of Mexico$8$18$11$23Eastern Mediterranean7143214North Sea—2—94Total$15$34$43$131Impairments for 2015 were primarily related to revisions in expected field abandonment or other costs at South Raton (Deepwater Gulf of Mexico) and the Noa and Pinnacles fields (Eastern Mediterranean).Impairments for 2014 were primarily related to an increase in expected field abandonment costs and a change in the timing of abandonment activities at the North Sea MacCulloch field.See Note2. Basis of Presentation,Note8. Fair Value Measurements and DisclosuresandNote10. Asset Retirement Obligations.
|                                
|                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|                                 | Three Months Ended June 30,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|(millions)                       | 2015                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Deepwater Gulf of Mexico         | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Eastern Mediterranean            | 7                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|North Sea                        | —                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Total                            | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              

X- DefinitionAsset Impairments [Abstract]
+ ReferencesNo definition available.
+ Details**Name:**
nbl_AssetImpairmentsAbstract**Namespace Prefix:**
nbl_**Data Type:**
xbrli:stringItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionThe entire disclosure for the details of the charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value. Disclosure may also include a description of the impaired asset and facts and circumstances leading to the impairment, amount of the impairment loss and where the loss is located in the income statement, method(s) for determining fair value, and the segment in which the impaired asset is reported.
+ ReferencesNo definition available.
+ Details**Name:**
us-gaap_AssetImpairmentChargesTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration