v3.21.2
Fair Value Measurement - FV Hierarchy (Details) - USD ($)
$ in Millions
Jun. 30, 2021
Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in CVE shares $ 1,802 $ 1,256
Investments in debt securities 535 518
Commodity derivative asset, gross 774 255
Fair Value, Measurements, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in CVE shares 1,802 1,256
Investments in debt securities 535 518
Commodity derivative asset, gross 774 255
Total assets 3,111 2,029
Commodity derivative liability, gross 752 220
Total liabilities 752 220
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in CVE shares 1,802 1,256
Investments in debt securities 10 17
Commodity derivative asset, gross 402 142
Total assets 2,214 1,415
Commodity derivative liability, gross 399 120
Total liabilities 399 120
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in CVE shares 0 0
Investments in debt securities 525 501
Commodity derivative asset, gross 349 101
Total assets 874 602
Commodity derivative liability, gross 287 91
Total liabilities 287 91
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in CVE shares 0 0
Investments in debt securities 0 0
Commodity derivative asset, gross 23 12
Total assets 23 12
Commodity derivative liability, gross 66 9
Total liabilities $ 66 $ 9