Derivative and Financial Instruments (Financial Instruments - Debt Securities Carried at Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	$ 5,028	$ 2,991
Short-term Investments	446	3,609
Investments and long-term receivables	7,113	8,017
Remaining Maturities within One Year [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	10	13
Short-term Investments	221	289
Remaining Maturities Greater than One Year Through Eight Years [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Investments and long-term receivables	248	216
Corporate Bonds [Member] \| Remaining Maturities within One Year [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	3	0
Short-term Investments	128	130
Corporate Bonds [Member] \| Remaining Maturities Greater than One Year Through Eight Years [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Investments and long-term receivables	173	143
Commercial Paper [Member] \| Remaining Maturities within One Year [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	7	13
Short-term Investments	82	155
U.S. Government Obligations [Member] \| Remaining Maturities within One Year [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	0	0
Short-term Investments	0	4
U.S. Government Obligations [Member] \| Remaining Maturities Greater than One Year Through Eight Years [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Investments and long-term receivables	2	13
U.S. Government Agency Obligations [Member] \| Remaining Maturities within One Year [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments	2	0
U.S. Government Agency Obligations [Member] \| Remaining Maturities Greater than One Year Through Eight Years [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Investments and long-term receivables	8	17
Foreign Government Obligations [Member] \| Remaining Maturities within One Year [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments	7	0
Foreign Government Obligations [Member] \| Remaining Maturities Greater than One Year Through Eight Years [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Investments and long-term receivables	2	2
Asset-backed Securities [Member] \| Remaining Maturities within One Year [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments	2	0
Asset-backed Securities [Member] \| Remaining Maturities Greater than One Year Through Eight Years [Member] \| Carrying Amount [Member]
Schedule Of Available For Sale Securities [Line Items]
Investments and long-term receivables	$ 63	$ 41

Amount of investments including trading securities, held-to-maturity securities, and short-term investments classified as other and current but excluding investement in Cenovus Energy Common Shares.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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