XML 108 R78.htm IDEA: XBRL DOCUMENT v3.21.2
Divestitures (Details) - CAD ($)
$ in Millions
 2 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
May 01, 2021
Aug. 31, 2021
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Disclosure of analysis of single amount of discontinued operations [line items]                  
Before-tax gain on disposal     $ 25 $ 1 $ 97 $ 0 $ 81 $ 2 $ (795)
Marten Hills, Alberta                  
Disclosure of analysis of single amount of discontinued operations [line items]                  
Proceeds from disposal of oil and gas assets $ 102                
Before-tax gain on disposal 60                
After-tax gain on disposal $ 47                
East Clearwater area and Kaybob area                  
Disclosure of analysis of single amount of discontinued operations [line items]                  
Proceeds from disposal of oil and gas assets   $ 82              
Before-tax gain on disposal     17            
After-tax gain on disposal     $ 13