v3.19.3.a.u2
Assets Held for Sale, Sold or Acquired Textuals (Details) - USD ($)
$ / shares in Units, shares in Millions
 1 Months Ended 3 Months Ended 5 Months Ended 7 Months Ended 12 Months Ended
Jan. 31, 2020
Oct. 31, 2019
Sep. 30, 2019
Apr. 30, 2019
Oct. 31, 2018
Sep. 30, 2017
Dec. 31, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
May 17, 2017
Jul. 31, 2017
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 02, 2019
Jan. 31, 2019
Dec. 18, 2018
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               $ 779,000,000 $ 1,074,000,000 $ 772,000,000      
Exploration Expense                               743,000,000 369,000,000 [1] 934,000,000 [1]      
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Other income                               1,358,000,000 173,000,000 529,000,000      
Equity Method Investments             $ 8,234,000,000     $ 9,005,000,000           8,234,000,000 9,005,000,000        
Operating Segments [Member]                                          
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               779,000,000 1,074,000,000 772,000,000      
Corporate, Non-Segment [Member]                                          
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               0 0 0      
Alaska Segment [Member] | Operating Segments [Member]                                          
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               7,000,000 6,000,000 7,000,000      
Lower 48 Segment [Member] | Operating Segments [Member]                                          
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               (159,000,000) 1,000,000 5,000,000      
Canada Segment [Member] | Operating Segments [Member]                                          
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               0 0 197,000,000      
Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               915,000,000 1,051,000,000 553,000,000      
Europe and North Africa Segment [Member] | Operating Segments [Member]                                          
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                               16,000,000 16,000,000 10,000,000      
Australia West Assets [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value   $ 600,000,000                                      
Amount of PP&E in carrying value of asset   1,200,000,000         1,200,000,000                 1,200,000,000          
Working Capital and cash in net carrying value   (300,000,000)                                      
Amount of deferred taxes in carrying value of asset   (200,000,000)                                      
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                               372,000,000 364,000,000 317,000,000      
Australia West Assets [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member] | Scenario Plan [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions   1,390,000,000                                      
Australia West Sale Contingent Proceeds upon Final Investment Decision   75,000,000                                      
Australia West Assets [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset Retirement Obligation of held for sale or sold   $ 700,000,000         $ 700,000,000                 $ 700,000,000          
Barossa project [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership Percent             37.50%                 37.50%          
Caldita Field [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership Percent             37.50%                 37.50%          
Darwin LNG Facility [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership Percent             56.90%                 56.90%          
Bayu-Undan Field [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership Percent             56.90%                 56.90%          
Poseidon Field [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership Percent             40.00%                 40.00%          
Athena Field [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership Percent             50.00%                 50.00%          
Niobrara [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value                                     $ 390,000,000    
Amount of PP&E in carrying value of asset             $ 426,000,000                 $ 426,000,000     426,000,000    
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                               (372,000,000) 35,000,000 (12,000,000)      
Impairment of assets in exchange             379,000,000                            
Exploration Expense             7,000,000                            
Niobrara [Member] | Lower 48 Segment [Member] | Operating Segments [Member] | Scenario Plan [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions             380,000,000                            
Niobrara [Member] | Lower 48 Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset Retirement Obligation of held for sale or sold             34,000,000                 34,000,000     $ 34,000,000    
Golden Pass [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership percentage in equity investment                                       12.40%  
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                 $ (60,000,000)                        
U.K. Subsidiaries [Member] | Europe and North Africa Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions     $ 2,200,000,000                                    
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value     500,000,000                                    
Amount of PP&E in carrying value of asset     1,600,000,000                                    
Working Capital and cash in net carrying value     (100,000,000)                                    
Amount of deferred taxes in carrying value of asset     300,000,000                                    
Cumulative foreign currency translation adjustments     500,000,000                                    
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                               400,000,000 900,000,000 300,000,000      
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition                               1,700,000,000          
After-tax gain (loss) on disposition             2,100,000,000                 2,100,000,000          
U.K. Subsidiaries [Member] | Europe and North Africa Segment [Member] | Operating Segments [Member] | Scenario Plan [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions       $ 2,675,000,000                                  
U.K. Subsidiaries [Member] | Europe and North Africa Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset Retirement Obligation of held for sale or sold     1,800,000,000                                    
Greater Sunrise Fields [Member] | Asia Pacific and Middle East Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions               $ 350,000,000                          
Ownership Percent               30.00%                          
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
After-tax gain (loss) on disposition               $ 52,000,000                          
Magnolia Field And Platform [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions             16,000,000                            
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Amount of PP&E in carrying value of asset             4,000,000                 4,000,000          
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition             82,000,000                            
Magnolia Field And Platform [Member] | Lower 48 Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset retirement obligation at disposal             $ 70,000,000                 70,000,000          
Other properties [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions                         $ 112,000,000                
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition                         $ 0                
Other properties [Member] | Lower 48 Segment [Member] | Operating Segments [Member] | Scenario Plan [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions $ 186,000,000                                        
Undeveloped Leasehold Assets [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions                   162,000,000 $ 56,000,000 $ 105,000,000                  
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition                   140,000,000   0                  
Barnett [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions         $ 196,000,000                                
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value         201,000,000                                
Amount of PP&E in carrying value of asset         250,000,000                                
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                                 (59,000,000) (566,000,000)      
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition         5,000,000                                
Impaired Assets to be Disposed of by Method Other than Sale, Carrying Value of Asset                   87,000,000             87,000,000 572,000,000      
Barnett [Member] | Lower 48 Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset retirement obligation at disposal         $ 49,000,000                                
U.K. subsidiary holding Clair field | Europe and North Africa Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions                   253,000,000                      
Ownership Percent                                         16.50%
Ownership percentage retained                                         7.50%
Fair Value Assets Disposed Of                                         $ 1,743,000,000
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value                                         1,028,000,000
Amount of PP&E in carrying value of asset                                         1,553,000,000
Amount of deferred taxes in carrying value of asset                                         (485,000,000)
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                                 748,000,000 (400,000)      
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition                   $ 715,000,000                      
U.K. subsidiary holding Clair field | Europe and North Africa Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset Retirement Obligation of held for sale or sold                                         $ 59,000,000
Foster Creek Christina Lake (FCCL) and western Canada gas properties [Member] | Canada Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions                           $ 11,000,000,000.0              
Shares Exchanged for Assets Held for Sale                           208              
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition                               $ 114,000,000 95,000,000 2,100,000,000      
Business Combination, Contingent Consideration Arrangements [Abstract]                                          
Assets Held for Sale, Contingent Consideration Term                               The contingent payment, calculated and paid on a quarterly basis, is $6 million CAD for every $1 CAD by which the WCS quarterly average crude price exceeds $52 CAD per barrel.          
Cenovus Energy common share price                           $ 9.41              
Cenovus Energy Investment at Cost                           $ 1,960,000,000              
Foster Creek Christina Lake (FCCL) [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Ownership percentage in equity investment                           50.00%              
Foster Creek Christina Lake (FCCL) [Member] | Canada Segment [Member] | Operating Segments [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Carrying Value of Equity Investment Sold                           $ 8,900,000,000              
Income related items for assets held for sale [Abstract]                                          
Income (Loss) From Equity Method Investments                                   197,000,000      
Western Canada Gas Properties [Member] | Canada Segment [Member] | Operating Segments [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value                           1,900,000,000              
Amount of PP&E in carrying value of asset                           2,600,000,000              
Total current liabilities of assets held for sale                           100,000,000              
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                                   (26,000,000)      
Western Canada Gas Properties [Member] | Canada Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset Retirement Obligation of held for sale or sold                           $ 585,000,000              
San Juan Basin [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions                             $ 2,500,000,000            
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value                             2,500,000,000            
Amount of PP&E in carrying value of asset                             2,900,000,000            
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                                   (3,200,000,000)      
Impairment of asset held for sale                       $ 3,300,000,000                  
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition                             $ (22,000,000) $ 0 $ 28,000,000        
Business Combination, Contingent Consideration Arrangements [Abstract]                                          
Assets Held for Sale, Contingent Consideration Term                             The transaction includes a contingent payment of up to $300 million. The six-year contingent payment, effective beginning January 1, 2018, is due annually for the periods in which the monthly U.S. Henry Hub price is at or above $3.20 per MMBTU.            
San Juan Basin [Member] | Lower 48 Segment [Member] | Operating Segments [Member] | Scenario Plan [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset Retirement Obligation of held for sale or sold                             $ 406,000,000            
Panhandle [Member] | Lower 48 Segment [Member] | Operating Segments [Member]                                          
Asset Held For Sale Transaction Detail [Abstract]                                          
Proceeds from asset dispositions           $ 178,000,000                              
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Net carrying value           206,000,000                              
Amount of PP&E in carrying value of asset           279,000,000                              
Income related items for assets held for sale [Abstract]                                          
Results Of Operations Income Before Income Taxes                                   $ (14,000,000)      
Gain (Loss) on Disposition of Oil and Gas Property [Abstract]                                          
Before-tax gain (loss) on disposition           $ (28,000,000)                              
Panhandle [Member] | Lower 48 Segment [Member] | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]                                          
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]                                          
Asset Retirement Obligation of held for sale or sold     $ 72,000,000                                    
[1]
See Notes to Consolidated Financial Statements.