Derivative Instruments and Hedging Activities (Fair Value Of Derivatives Not Designated As Hedging Instruments) (Details) - Not Designated As Hedging Instrument [Member] - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
FX Contracts Assets	$ 283	$ 125
Commodity Contracts Assets	2,764	478
Total fair value of derivative assets not designated as hedging instruments	3,047	603
FX Contracts Liabilities	270	120
Commodity Contracts Liabilities	2,034	574
Embedded Derivative, Fair Value of Embedded Derivative Liability	34	0
Embedded Derivative, Fair Value of Embedded Derivative Asset	0	0
Total fair value of derivative liabilities not designated as hedging instruments.	$ 2,338	$ 694

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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