XML 75 R62.htm IDEA: XBRL DOCUMENT
v3.19.2

Derivatives and Fair Value Measurements - Financial Instruments Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions | Jun. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | $ 15.2 | $ 11.8
Level 1 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Level 2 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 5.2 | 1.8
Level 3 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 10.0 | 10.0
Foreign currency option contracts |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 1.2 | 1.2
Foreign currency option contracts | Level 1 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Foreign currency option contracts | Level 2 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 1.2 | 1.2
Foreign currency option contracts | Level 3 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Coal contracts related to forecasted sales |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 41.3 | (21.2)
Coal contracts related to forecasted sales | Level 1 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Coal contracts related to forecasted sales | Level 2 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 41.3 | (21.2)
Coal contracts related to forecasted sales | Level 3 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Coal trading contracts |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | (37.3) | 21.8
Coal trading contracts | Level 1 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Coal trading contracts | Level 2 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | (37.3) | 21.8
Coal trading contracts | Level 3 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Equity securities |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 10.0 | 10.0
Equity securities | Level 1 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Equity securities | Level 2 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | 0.0 | 0.0
Equity securities | Level 3 |  |
Derivative [Line Items] |  |
Derivative Assets (Liabilities), at Fair Value, Net | $ 10.0 | $ 10.0

X
- Definition Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958 + Details
Name: | us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=btu_PhysicalCommodityPurchaseSaleContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CoalContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |