|**Loss Per Share**                                                                                                                          | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
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|**Earnings Per Share [Abstract]**                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Loss Per Share                                                                                                                              | Loss Per ShareBasic loss per share of common stock is computed using the weighted average number of shares of common stock outstanding during each period. The following table summarizes the calculation of basic and diluted loss per share:Three Months EndedJune 30,Six Months EndedJune 30,(millions, except per share amounts)2016201520162015Net Loss$(315)$(109)$(602)$(131)Weighted Average Number of Shares Outstanding, Basic(1)430387429378Weighted Average Number of Shares Outstanding, Diluted(2)430387429378Loss Per Share, Basic$(0.73)$(0.28)$(1.40)$(0.35)Loss Per Share, Diluted(0.73)(0.28)(1.40)(0.35)Number of Antidilutive Stock Options, Shares of Restricted Stock, and Shares of Common Stock in Rabbi Trust Excluded from Calculation Above1510159(1)The weighted average number of shares outstanding includes the weighted average shares of common stock issued in connection with the underwritten public offering of24.15 millionshares of Noble Energy common stock in first quarter 2015 and issued in connection with the exchange of approximately41 millionshares for all outstanding shares of Rosetta common stock on July 20, 2015.(2)For all periods, all outstanding options and non-vested restricted shares have been excluded from the calculation of diluted loss per share as Noble Energy incurred a net loss. Therefore, inclusion of outstanding options and non-vested restricted shares in the calculation of diluted loss per share would be anti-dilutive.
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|                                                                                                                                            | Three Months EndedJune 30,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|(millions, except per share amounts)                                                                                                        | 2016                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
|Net Loss                                                                                                                                    | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
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|Weighted Average Number of Shares Outstanding, Basic(1)                                                                                     | 430                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Weighted Average Number of Shares Outstanding, Diluted(2)                                                                                   | 430                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Loss Per Share, Basic                                                                                                                       | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Loss Per Share, Diluted                                                                                                                     | (0.73                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Number of Antidilutive Stock Options, Shares of Restricted Stock, and Shares of Common Stock in Rabbi Trust Excluded from Calculation Above | 15                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
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|(1)                                                                                                                                         | The weighted average number of shares outstanding includes the weighted average shares of common stock issued in connection with the underwritten public offering of24.15 millionshares of Noble Energy common stock in first quarter 2015 and issued in connection with the exchange of approximately41 millionshares for all outstanding shares of Rosetta common stock on July 20, 2015.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
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|(2)                                                                                                                                         | For all periods, all outstanding options and non-vested restricted shares have been excluded from the calculation of diluted loss per share as Noble Energy incurred a net loss. Therefore, inclusion of outstanding options and non-vested restricted shares in the calculation of diluted loss per share would be anti-dilutive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

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