XML 136 R91.htm IDEA: XBRL DOCUMENT v3.20.4
Impairment Charges and Reversals - Additional Information (Detail)
 3 Months Ended 12 Months Ended
Dec. 31, 2020
CAD ($)
Sep. 30, 2020
CAD ($)
$ / bbl
Mar. 31, 2020
CAD ($)
Dec. 31, 2020
CAD ($)
Mar. 31, 2020
CAD ($)
Dec. 31, 2018
CAD ($)
Dec. 31, 2020
CAD ($)
Dec. 31, 2019
CAD ($)
Dec. 31, 2018
CAD ($)
Dec. 31, 2017
CAD ($)
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Goodwill impairments         $ 0   $ 0 $ 0    
Exploration Expense             91,000,000 82,000,000 $ 2,123,000,000  
E&E Asset [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Exploration Expense             $ 91,000,000 82,000,000    
PP&E [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments               52,000,000    
Discounted Cash Flow [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Discounted future cash flows, discount rate 10.00%     10.00%     10.00%      
Discounted future cash flows, inflation rate 2.00%     2.00%     2.00%      
Refining Commodity Price Assumptions [Member] | 2035 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Annual Increase Thereafter   2.00%                
Bottom of Range [Member] | Discounted Cash Flow [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Discounted future cash flows, discount rate 10.00%     10.00%     10.00%      
Top of Range [Member] | Discounted Cash Flow [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Discounted future cash flows, discount rate 15.00%     15.00%     15.00%      
CGUs [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments               0 0  
Borger Cash Generating Unit [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Recoverable amount   $ 692,000,000                
Wood River Cash Generating Units                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments $ 0 $ 0                
WTI to West Texas Sour [Member] | Bottom of Range [Member] | Refining Commodity Price Assumptions [Member] | 2021 to 2022 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   36.36                
WTI to West Texas Sour [Member] | Bottom of Range [Member] | Refining Commodity Price Assumptions [Member] | 2023 to 2025 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   49.66                
WTI to West Texas Sour [Member] | Top of Range [Member] | Refining Commodity Price Assumptions [Member] | 2021 to 2022 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   50.84                
WTI to West Texas Sour [Member] | Top of Range [Member] | Refining Commodity Price Assumptions [Member] | 2023 to 2025 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   58.74                
WTI to West Texas Sour DIFFERENTIAL [Member] | Bottom of Range [Member] | Refining Commodity Price Assumptions [Member] | 2021 to 2022 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   0.37                
WTI to West Texas Sour DIFFERENTIAL [Member] | Bottom of Range [Member] | Refining Commodity Price Assumptions [Member] | 2023 to 2025 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   1.21                
WTI to West Texas Sour DIFFERENTIAL [Member] | Top of Range [Member] | Refining Commodity Price Assumptions [Member] | 2021 to 2022 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   1.73                
WTI to West Texas Sour DIFFERENTIAL [Member] | Top of Range [Member] | Refining Commodity Price Assumptions [Member] | 2023 to 2025 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   1.81                
Group 3 Forward Market Crack Spread [Member] | Bottom of Range [Member] | Refining Commodity Price Assumptions [Member] | 2021 to 2022 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   11.56                
Group 3 Forward Market Crack Spread [Member] | Bottom of Range [Member] | Refining Commodity Price Assumptions [Member] | 2023 to 2025 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   11.79                
Group 3 Forward Market Crack Spread [Member] | Top of Range [Member] | Refining Commodity Price Assumptions [Member] | 2021 to 2022 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   13.23                
Group 3 Forward Market Crack Spread [Member] | Top of Range [Member] | Refining Commodity Price Assumptions [Member] | 2023 to 2025 [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Average Price | $ / bbl   16.58                
Railcar CGUs [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments     $ 3,000,000              
Conventional [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Exploration Expense             $ 82,000,000 64,000,000 2,117,000,000  
Conventional [Member] | E&E Asset [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Exploration Expense             82,000,000 64,000,000 2,100,000,000  
Conventional [Member] | PP&E [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments             4,000,000      
Conventional [Member] | Clearwater CGU [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments                 100,000,000 $ 56,000,000
Recoverable amount           $ 761,000,000     761,000,000  
Reversed of impairment loss           $ 132,000,000        
Conventional [Member] | CGUs [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments       $ 240,000,000 $ 315,000,000          
Refining and Marketing [Member] | Borger Cash Generating Unit [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments   $ 450,000,000                
Oil Sands [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Exploration Expense             9,000,000 18,000,000 $ 6,000,000  
Oil Sands [Member] | E&E Asset [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
Exploration Expense             9,000,000 $ 18,000,000    
Oil Sands [Member] | PP&E [Member]                    
Disclosure Of Information For Each Material Impairment Loss Recognised Or Reversed For Individual Asset Or Cashgenerating Unit [Line Items]                    
CGU Impairments             $ 48,000,000