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Derivatives Financial Instruments - Derivative Income Statement Location (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017
Derivative [Line Items] |  |
Total gain (loss) | $ 4 | $ 13
Product sales |  |
Derivative [Line Items] |  |
Realized gain (loss) | 0 | (1)
Unrealized gain (loss) | 1 | 7
Total gain (loss) | 1 | 6
Purchased product costs |  |
Derivative [Line Items] |  |
Realized gain (loss) | (3) | (2)
Unrealized gain (loss) | 6 | 9
Total gain (loss) | 3 | 7
Cost of revenues |  |
Derivative [Line Items] |  |
Realized gain (loss) | 0 | 0
Unrealized gain (loss) | 0 | 0
Total gain (loss) | $ 0 | $ 0

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- Definition Amount of realized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References No definition available. + Details
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- Definition Amount of unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References No definition available. + Details
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- Definition Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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- Definition 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. + References No definition available. + Details
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