Fair Value Measurement (Net Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financial Assets [Abstract]
Investment in CVE shares	$ 1,117	$ 1,256
Carrying Amount [Member]
Financial Assets [Abstract]
Investment in CVE shares	1,117	1,256
Commodity derivatives	593	88
Investments in debt securities	479	518
Loans and advances - related parties	114	220
Financial Liabilities [Abstract]
Total debt, excluding finance leases	18,673	14,478
Carrying Amount [Member] \| Commodity Contract [Member]
Financial Liabilities [Abstract]
Commodity derivatives	537	59
Fair Value [Member]
Financial Assets [Abstract]
Investment in CVE shares	1,117	1,256
Commodity derivatives	593	88
Investments in debt securities	479	518
Loans and advances - related parties	114	220
Financial Liabilities [Abstract]
Total debt, excluding finance leases	22,451	19,106
Fair Value [Member] \| Commodity Contract [Member]
Financial Liabilities [Abstract]
Commodity derivatives	$ 537	$ 59

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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