Derivative Instruments and Hedging Activities (Fair Value Of Derivatives Not Designated As Hedging Instruments) (Details) - Not Designated As Hedging Instrument [Member] - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
FX Contracts Assets	$ 328	$ 283
Embedded Derivative, Fair Value of Embedded Derivative Asset	0	0
Commodity Contracts Assets	1,448	2,764
Total fair value of derivative assets not designated as hedging instruments	1,776	3,047
FX Contracts Liabilities	139	270
Commodity Contracts Liabilities	1,607	2,034
Embedded Derivative, Fair Value of Embedded Derivative Liability	17	34
Total fair value of derivative liabilities not designated as hedging instruments.	$ 1,763	$ 2,338

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as an asset.

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Fair value as of the balance sheet date of all price risk derivative assets not designated as hedging instruments.

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