XML 102 R84.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Coal Trading (Details 2) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Concentration Risk [Line Items] |  |  |
Number of major credit rating agencies that adjusted corporate credit rating |  | 3 |
Coal Trading [Member] |  |  |
Concentration Risk [Line Items] |  |  |
Potential collateralization that may be requested by counterparties related to material adverse event |  | $ 2.0 | $ 21.0
Margin posted to counterparties related to material adverse event |  | 1.0 | 0.0
Additional potential collateral requirements for a credit downgrade |  | 0.0 | 0.0
Margin posted to counterparties related to credit rating |  | 0.0 | 0.0
Net variation margin held | [1] | (57.4) | (10.7)
Initial margin posted |  | 16.2 | 9.2
Margin in excess of the exchange-required variation and initial margin |  | $ 2.0 | $ 0.7
External Credit Rating, Investment Grade [Member] | Credit Concentration Risk [Member] | Coal Trading Positions [Member] | Coal Trading [Member] |  |  |
Concentration Risk [Line Items] |  |  |
Credit concentration risk percentage |  | 22.00% |
External Credit Rating, Non Investment Grade [Member] | Credit Concentration Risk [Member] | Coal Trading Positions [Member] | Coal Trading [Member] |  |  |
Concentration Risk [Line Items] |  |  |
Credit concentration risk percentage |  | 7.00% |
Non Rated [Member] | Credit Concentration Risk [Member] | Coal Trading Positions [Member] | Coal Trading [Member] |  |  |
Concentration Risk [Line Items] |  |  |
Credit concentration risk percentage |  | 71.00% |
[1] | None of the net variation margin (held) posted at December 31, 2016 and 2015, respectively, related to cash flow hedges.

X
- Definition Additional potential collateral requirements for a credit downgrade. + References No definition available. + Details
Name: | btu_AdditionalPotentialCollateralRequirementsForCreditDowngrade
Namespace Prefix: | btu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Margin posted to counterparties related to credit rating + References No definition available. + Details
Name: | btu_MarginPostedToCounterpartiesRelatedToCreditRating
Namespace Prefix: | btu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Margin posted to counterparties related to material adverse event. + References No definition available. + Details
Name: | btu_MarginPostedToCounterpartiesRelatedToMaterialAdverseEvent
Namespace Prefix: | btu_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of major credit rating agencies that adjusted the Company's corporate credit rating during the period. + References No definition available. + Details
Name: | btu_Numberofmajorcreditratingagenciesthatadjustedcorporatecreditrating
Namespace Prefix: | btu_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Potential collateralization that may be requested by counterparties due to a material adverse event. + References No definition available. + Details
Name: | btu_PotentialCollateralizationThatMayBeRequestedByCounterpartiesDueToMaterialAdverseEvent
Namespace Prefix: | btu_
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_ConcentrationRiskLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226016-175313 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56946850&loc=d3e41678-113959 + Details
Name: | us-gaap_DerivativeCollateralRightToReclaimCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The net amount as of the balance sheet date of the fair value of derivative assets and derivative liabilities that in accordance with the entity's accounting policy were offset against collateral under a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=56946850&loc=d3e41678-113959 + Details
Name: | us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount receivable from broker-dealers and clearing organizations, including, but not limited to, securities failed-to-deliver, certain deposits for securities borrowed, open transactions, good faith and margin deposits, commissions and floor brokerage receivables. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=35710130&loc=d3e41645-110958 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 + Details
Name: | us-gaap_ReceivablesFromBrokersDealersAndClearingOrganizations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_TradingActivityByTypeAxis=btu_CoalTradingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=btu_CoalTradingPositionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=btu_NonRatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |