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Derivatives - Open Commodity Derivative Contracts - Crude Oil (Details) - Crude Oil bbl in Thousands	3 Months Ended
	Mar. 31, 2017 bbl
Exchange Traded
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	80.00%
Derivative contract expiration date	Jun. 30, 2017
Exchange Traded | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	59,205	[1]
Exchange Traded | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	56,633	[1]
Over the Counter | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	52
[1] of the exchange-traded contracts expire in the second quarter of 2017.

X

- Definition

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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- Definition

Percentage Of Derivative Contracts Expiring in the following quarter.

+ References

No definition available.

+ 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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- Definition

Date the derivative contract matures, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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- Details

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