Derivatives and Risk Management (Narrative) (Details) $ in Millions	Mar. 31, 2020 USD ($)
Derivative [Line Items]
Fair value of net derivative asset position	$ (1)
Commodities
Derivative [Line Items]
Derivative asset	402
Interest rate swaps
Derivative [Line Items]
Derivative liabilities	(1)
Not Designated as Hedging Instrument \| Interest rate swaps
Derivative [Line Items]
Derivative notional amount	$ 170

Derivative Assets, Increase (Decrease), Impact, Non Performing Risk

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Fair value, after the 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 not subject to a master netting arrangement and not elected to be offset.

+ References

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Fair value, after the 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 not subject to a master netting arrangement and not elected to be offset.

+ References

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Nominal or face amount used to calculate payment on derivative.

+ References

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