Represents the estimated contractual cash spend in the next twelve months after the balance sheet date related to various short term take or pay arrangements in the U.S. and Australia associated with rail and port commitments for the delivery of coal including amounts relating to export facilities.

No definition available.

+ Details

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

- Definition

Represents the total projected cash contractual obligation spend associated with various long and short term take or pay arrangements in the U.S. and Australia for rail and port commitments for the delivery of coal including amounts relating to export facilities.

+ References

No definition available.

+ Details

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

- 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

Name:	us-gaap_LongTermPurchaseCommitmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308

+ Details

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

- Details

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Namespace Prefix:
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- Details

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Commitments and Contingencies - Commitments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Mar. 31, 2020
Long-term Purchase Commitment [Line Items]
Take Or Pay Obligations Total		$ 945.0
Capital Addition Purchase Commitments
Long-term Purchase Commitment [Line Items]
Unrecorded Unconditional Purchase Obligation		$ 42.7
Scenario, Forecast
Long-term Purchase Commitment [Line Items]
Take Or Pay Obligations Due In One Year	$ 105.0
Scenario, Forecast \| Capital Addition Purchase Commitments
Long-term Purchase Commitment [Line Items]
Unrecorded Unconditional Purchase Obligation	$ 35.6