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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

X

- 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

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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

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