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Price Risk Management Activities, Gain (Loss) by Income Statement Location (Details) - Cost of Materials and Other [Member] - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017
Economic Hedges [Member] | Commodity Contracts [Member] |  |  |  |
Effect of Derivative Instruments on Income |  |  |  |
Gain (loss) recognized in income on derivatives | $ (108) | $ (86) | $ (222) | $ (158)
Economic Hedges [Member] | Foreign Currency Contracts [Member] |  |  |  |
Effect of Derivative Instruments on Income |  |  |  |
Gain (loss) recognized in income on derivatives | (7) | (16) | 7 | (42)
Trading Derivatives [Member] | Commodity Contracts [Member] |  |  |  |
Effect of Derivative Instruments on Income |  |  |  |
Gain (loss) recognized in income on derivatives | $ 10 | $ 31 | $ 97 | $ 29

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
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