Additional cash upon collection of underlying receivables.

No definition available.

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount available under securitization program.

+ References

No definition available.

+ Details

Name:	btu_AmountAvailableUnderSecuritizationProgram
Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount in letters of credit and surety bonds related to collateral for surety companies, road maintenance, performance guarantees and other operations.

+ References

No definition available.

+ Details

Name:	btu_AmountInLettersOfCreditAndSuretyBondsRelatedToCollateralForSuretyCompaniesRoadMaintenancePerformanceGuaranteesAndOtherOperations
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Cash up front from sale of receivables.

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of investments in debt securities placed into a trust as collateral for letter of credit related to workers comp

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Consideration Received By Company Related To Securitization Program.

+ References

No definition available.

+ Details

Name:	btu_ConsiderationReceivedByCompanyRelatedToSecuritizationProgram
Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Credit support (all in the form of surety bonds) related to Patriot’s Coal Act obligations that the Company agreed to fund at the time of the Patriot spin-off pursuant to the Coal Act Liabilities Assumption Agreement and to Patriot’s Federal Black Lung obligations for which the Company could be held responsible if Patriot fails to fund such obligations when they become due.

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Credit support to Patriot

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Credit support to Patriot ending after five years

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The Company is required to make special contributions to two of the Company's defined benefit pension plans.

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Term of lease held by Dominion Terminal Associates, an equity method investee, for a coal export terminal in Newport News, Virginia.

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
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Period Type:	instant

- Definition

Guarantee In Place From Affiliate.

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Letter of Credit Arrangement for Workers Compensation

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Letter Of Credit maintained.

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum capacity of the securitization program.

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maximum Reimbursement Obligation.

+ References

No definition available.

+ Details

Name:	btu_MaximumReimbursementObligation
Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Non collected receivables

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of Letters of Credit Supporting Reimbursement Obligation

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Potential exposure from Patriot bankruptcy related to certain federal and state black lung occupational disease liabilities

+ References

No definition available.

+ Details

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Namespace Prefix:	btu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

A gain (loss) realized on a transfer, accounted for as a sale, of all or a portion of financial assets in which the transferor surrenders control and receives consideration other than a beneficial interest in the assets transferred. Reflects the amount of sales proceeds in excess of, or deficient from, the sum of the carrying amounts of transferred financial assets plus transaction costs.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7,9)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Details

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Period Type:	duration

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This includes only the derecognized portion of the total principal amount of financial assets which have been either securitized, used in an asset-backed financing arrangement, or similar transfers which are accounted for as sales and in which the transferor has continuing involvement with the assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- Details

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- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=btu_SelfBondingMember
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- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=btu_SuretyBondsMember
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- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_PerformanceGuaranteeMember
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- Details

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- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_SuretyBondMember
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- Details

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Data Type:	na
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- Details

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- Details

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- Details

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- Details

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- Details

Name:	us-gaap_UnderlyingAssetClassAxis=us-gaap_GuaranteeTypeOtherMember
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- Details

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