Coal Trading Assets and Liabilities, Net, Fair Value Disclosure

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- Definition

Coal Trading.

+ References

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- Definition

Commodity swaps and options fair value disclosure.

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Physical commodity purchase sale contracts fair value disclosure.

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- Definition

Fair value of all asset derivatives designated as cash flow 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 4B

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624163-113959

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The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

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Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

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Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

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Coal Trading (Details 1) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Coal Trading (Details 1) - USD ($) $ in Millions	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Coal Trading (Textuals) [Abstract]
Fair value hierarchy transfers from Level 1 to Level 2		$ 0.0		$ 0.0
Fair value hierarchy transfers from Level 2 to Level 1		0.0		$ 0.0
Coal Trading [Member]
Coal Trading (Textuals) [Abstract]
Cash flow hedge derivative instrument assets at fair value		16.2	$ 44.3
Fair value hierarchy transfers from Level 1 to Level 2		0.0	0.0
Fair value hierarchy transfers from Level 2 to Level 1		0.0	0.0
Fair value hierarchy transfers into (out of) Level 3		0.0	0.0
Fair Value, Measurements, Recurring [Member] \| Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis:
Commodity futures, swaps and options		12.0	32.4
Physical commodity purchase/sale contracts		2.2	(7.5)
Total net financial (liabilities) assets		14.2	24.9
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis:
Commodity futures, swaps and options		(7.0)	(0.2)
Physical commodity purchase/sale contracts		0.0	0.0
Total net financial (liabilities) assets		(7.0)	(0.2)
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis:
Commodity futures, swaps and options		19.0	32.6
Physical commodity purchase/sale contracts		0.9	(9.6)
Total net financial (liabilities) assets		19.9	23.0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis:
Commodity futures, swaps and options		0.0	0.0
Physical commodity purchase/sale contracts		1.3	2.1
Total net financial (liabilities) assets		$ 1.3	$ 2.1
Scenario, Forecast [Member] \| Coal Trading [Member]
Coal Trading (Textuals) [Abstract]
Expected amount of gains to be realized over the next 12 months in accumulated other comprehensive loss	$ 16.0