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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
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Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
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The average strike price on the group of price risk option contracts such as put options or call options.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of price risk derivatives not designated as hedging instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Paragraph 4C
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Nominal or face amount used to calculate payments on a nonderivative instrument.

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Amount, after tax, of cumulative translation adjustment attributable to gain (loss) on foreign currency derivatives that are designated as, and are effective as, economic hedges of a net investment in a foreign entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 30
-Section 45
-Paragraph 20
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Pre-tax cumulative adjustment resulting from gains and losses on foreign currency derivatives that are designated as, and are effective as, hedges of a net investment in a foreign entity, commencing as of the designation date. Adjustment reported in equity as part of accumulated other comprehensive income.

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Derivative Financial Instruments (Textuals) (Details) € in Millions, ¥ in Millions, $ in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2018 EUR (€) MBbls $ / bbl	Sep. 30, 2018 JPY (¥)	Sep. 30, 2018 USD ($)	Sep. 30, 2018 SGD ($) MBbls $ / bbl	Sep. 30, 2018 JPY (¥) MBbls $ / bbl	Sep. 30, 2018 USD ($) MBbls $ / bbl	Apr. 24, 2018 MBbls	Dec. 31, 2017 EUR (€) MBbls	Dec. 31, 2017 SGD ($) MBbls	Dec. 31, 2017 USD ($) MBbls
Debt EUR Denominated [Member]
Derivative [Line Items]
Notional amount, nonderivative instruments		€ 21.0		$ 24.3
Cumulative foreign currency translation loss							$ 0.5
Cumulative foreign currency translation loss, net of tax							0.4
Debt Yen Denominated [Member]
Derivative [Line Items]
Notional amount, nonderivative instruments			¥ 500.0	4.4
Cumulative foreign currency translation loss							0.2
Cumulative foreign currency translation loss, net of tax							$ 0.2
Options Held [Member]
Derivative [Line Items]
Derivative, nonmonetary notional amount \| MBbls		72,699			72,699	72,699	72,699	30,612	125,166	125,166	125,166
Gain (Loss) related to call options	$ 0.1			$ 0.5
Derivative, Average Price Risk Option Strike Price \| $ / bbl		74.21			74.21	74.21	74.21
Euro Member Countries, Euro \| Forward Contracts [Member]
Derivative [Line Items]
Notional amount \| €		€ 10.0							€ 12.0
Singapore, Dollars \| Forward Contracts [Member]
Derivative [Line Items]
Notional amount					$ 601.5					$ 171.0
United States of America, Dollars \| Forward Contracts [Member]
Derivative [Line Items]
Notional amount							$ 13.4				$ 13.4
Long [Member] \| Designated as Hedging Instrument [Member] \| Singapore, Dollars \| Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount					$ 21.5
Long [Member] \| Designated as Hedging Instrument [Member] \| United States of America, Dollars \| Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount							19.9
Long [Member] \| Designated as Hedging Instrument [Member] \| Japan, Yen \| Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount \| ¥						¥ 3,601.4
Short [Member] \| Designated as Hedging Instrument [Member] \| Singapore, Dollars \| Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount		4.5					10.7
Short [Member] \| Designated as Hedging Instrument [Member] \| United States of America, Dollars \| Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount		16.3					0.0
Short [Member] \| Designated as Hedging Instrument [Member] \| Japan, Yen \| Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount		€ 12.0					$ 18.9