Derivatives and Fair Value of Financial Instruments-Derivatives Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Commodities
Fair value of each type of derivative and its location in the Consolidated Balance Sheets
Margin account	$ 23	$ 20
Commodities \| Other current assets
Fair value of each type of derivative and its location in the Consolidated Balance Sheets
Asset Derivatives	5	4
Derivative assets and liabilities, net basis	17	18
Commodities \| Other current liabilities
Fair value of each type of derivative and its location in the Consolidated Balance Sheets
Liability Derivatives	11	6
Foreign currencies \| Other current assets
Fair value of each type of derivative and its location in the Consolidated Balance Sheets
Asset Derivatives		3
Foreign currencies \| Other current liabilities
Fair value of each type of derivative and its location in the Consolidated Balance Sheets
Liability Derivatives	1	$ 6
Equity \| Short term investments
Fair value of each type of derivative and its location in the Consolidated Balance Sheets
Liability Derivatives	$ 1

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.

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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-Publisher FASB
-Name Accounting Standards Codification
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Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ 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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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+ References

No definition available.

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The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

+ References

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