|**Stock-Based and Other Compensation Plans (Tables)**                         | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                    
|----------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Disclosure of Compensation Related Costs, Share-based Payments [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Stock-based compensation expense                                              | We recognized total stock-based compensation expense as follows:Year Ended December 31,(millions)201820172016Stock-Based Compensation Expense Included in:General and Administrative Expense$54$56$62Exploration Expense and Other84815Total Stock-Based Compensation Expense$62$104$77Tax Benefit Recognized$(13)$(36)$(27)                                                                                                                       
|                                                                             
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|(millions)                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Stock-Based Compensation Expense Included in:                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|General and Administrative Expense                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Exploration Expense and Other                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Total Stock-Based Compensation Expense                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Tax Benefit Recognized                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Valuation Assumptions, Options                                                | The assumptions used in valuing stock options granted were as follows:Year Ended December 31,(weighted averages)201820172016Expected Term (in Years)6.76.46.3Expected Volatility33.4%33.2%32.4%Risk-Free Rate2.6%2.2%1.6%Expected Dividend Yield1.2%0.9%0.7%Weighted Average Grant-Date Fair Value$10.47$13.26$10.10                                                                                                                               
|                                                                             
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|(weighted averages)                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Expected Term (in Years)                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Expected Volatility                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Risk-Free Rate                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Expected Dividend Yield                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Weighted Average Grant-Date Fair Value                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Award Activity, Options                                                       | Stock option activity was as follows:OptionsWeightedAverageExercisePriceWeightedAverageRemainingContractual TermAggregateIntrinsic Value(per share)(in years)(in millions)Outstanding at December 31, 201715,549,222$43.42Granted551,88830.20Exercised(576,617)34.55Forfeited(1,672,473)40.04Outstanding at December 31, 201813,852,020$44.045.0$—Exercisable at December 31, 201811,866,188$45.584.0$—                                            
|                                                                             
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Outstanding at December 31, 2017                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Granted                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Exercised                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Forfeited                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Outstanding at December 31, 2018                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Exercisable at December 31, 2018                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Valuation Assumptions, Restricted Stock                                       | The assumptions used in valuing market based restricted stock awards granted were as follows:Year Ended December 31,201820172016Number of Simulations10,000,000500,000500,000Expected Volatility35%35%38%Risk-Free Rate2.3%1.5%1.0%                                                                                                                                                                                                                
|                                                                             
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              | Year Ended December 31,                                                                                                                                                                                                                                                                                                                                                                                                                            
|                                                                              | 2018                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Number of Simulations                                                         | 10,000,000                                                                                                                                                                                                                                                                                                                                                                                                                                         
|Expected Volatility                                                           | 35                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Risk-Free Rate                                                                | 2.3                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Award Activity, Restricted Stock                                              | Restricted stock activity was as follows:Subject to Time VestingSubject to Market ConditionsNumber of SharesWeightedAverageAward DateFair ValueNumber of SharesWeighted Average Award Date Fair Value(per share)(per share)Outstanding at December 31, 20171,839,737$37.211,212,705$25.55Awarded2,702,42630.68874,96019.56Vested(982,280)35.28——Forfeited(386,992)32.65(702,031)25.52Outstanding at December 31, 20183,172,891$32.721,385,634$21.74
|                                                                             
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Outstanding at December 31, 2017                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Awarded                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Vested                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Forfeited                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Outstanding at December 31, 2018                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Award Activity, Phantom Units                                                 | Phantom unit activity was as follows:Subject to Time VestingSubject to Market ConditionsNumber of UnitsWeightedAverageAward Date Fair ValueNumber of UnitsWeighted Average Award Date Fair Value(per share)(per share)Outstanding at December 31, 2017610,159$31.65167,483$6.82Vested(83,276)31.65——Forfeited(59,518)31.65(17,187)6.82Outstanding at December 31, 2018467,365$31.65150,296$6.82                                                    
|                                                                             
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Outstanding at December 31, 2017                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Vested                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Forfeited                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Outstanding at December 31, 2018                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Schedule of components for Rabbi Trust                                        | Components of that rabbi trust are as follows:December 31,(millions, except share amounts)20182017Mutual Fund Investments$38$57Noble Energy Common Stock (at Fair Value)514Total Rabbi Trust Assets$43$71Liability Under Related Deferred Compensation Plan$43$71Number of Shares of Noble Energy Common Stock Held by Rabbi Trust267,792470,030                                                                                                   
|                                                                             
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|(millions, except share amounts)                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Mutual Fund Investments                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Noble Energy Common Stock (at Fair Value)                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Total Rabbi Trust Assets                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Liability Under Related Deferred Compensation Plan                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Number of Shares of Noble Energy Common Stock Held by Rabbi Trust             |                                                                                                                                                                                                                                                                                                                                                                                                                                                    

X- DefinitionSchedule of Share-based Payment Award, Equity Instruments Other than Options, Valuation Assumptions [Table Text Block]
+ ReferencesNo definition available.
+ Details**Name:**
nbl_ScheduleofSharebasedPaymentAwardEquityInstrumentsOtherthanOptionsValuationAssumptionsTableTextBlock**Namespace Prefix:**
nbl_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure of pension and other postretirement benefit arrangements with individual employees, which are generally based on employment contracts between the entity and one or more selected officers or key employees, and which contain a promise by the employer to pay certain amounts at designated future dates, usually including a period after retirement, upon compliance with stipulated requirements. This type of arrangement is distinguished from broader based employee benefit plans as it is usually tailored to the employee. Disclosure also typically includes the amount of related compensation expense recognized during the reporting period and the carrying amount as of the balance sheet date of the related liability.
+ ReferencesReference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 30 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6409875&loc=d3e20015-108363Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 25 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=6409733&loc=d3e19512-108361Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6409961&loc=d3e20487-108367
+ Details**Name:**
us-gaap_DeferredCompensationArrangementWithIndividualDisclosurePostretirementBenefitsTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- ReferencesNo definition available.
+ Details**Name:**
us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract**Namespace Prefix:**
us-gaap_**Data Type:**
xbrli:stringItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure of the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed.
+ ReferencesReference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901
+ Details**Name:**
us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure of the changes in other outstanding share-based compensation awards other than stock options or nonvested awards.
+ ReferencesReference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901
+ Details**Name:**
us-gaap_ScheduleOfOtherShareBasedCompensationActivityTableTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value.
+ ReferencesReference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901
+ Details**Name:**
us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.
+ ReferencesReference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901
+ Details**Name:**
us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionDisclosure of the number and weighted-average grant date fair value for restricted stock and restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock and restricted stock units that were granted, vested, or forfeited during the year.
+ ReferencesNo definition available.
+ Details**Name:**
us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration