XML 115 R94.htm IDEA: XBRL DOCUMENT v3.8.0.1

Net Financial Asset (Liability) Coal Trading Position Measured on a Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - Coal Trading [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Predecessor
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure		$ (0.1)
Physical Commodity Purchase Sale Contracts Fair Value Disclosure		(0.4)
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure		(0.5)
Predecessor | Fair Value, Inputs, Level 1 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure		0.0
Physical Commodity Purchase Sale Contracts Fair Value Disclosure		0.0
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure		0.0
Predecessor | Fair Value, Inputs, Level 2 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure		(0.1)
Physical Commodity Purchase Sale Contracts Fair Value Disclosure		0.7
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure		0.6
Predecessor | Fair Value, Inputs, Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure		0.0
Physical Commodity Purchase Sale Contracts Fair Value Disclosure		(1.1)
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure		$ (1.1)
Successor
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure	$ (7.2)
Physical Commodity Purchase Sale Contracts Fair Value Disclosure	(1.9)
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure	(9.1)
Successor | Fair Value, Inputs, Level 1 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure	(3.0)
Physical Commodity Purchase Sale Contracts Fair Value Disclosure	0.0
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure	(3.0)
Successor | Fair Value, Inputs, Level 2 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure	(4.2)
Physical Commodity Purchase Sale Contracts Fair Value Disclosure	(1.9)
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure	(6.1)
Successor | Fair Value, Inputs, Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Commodity Swaps And Options Fair Value Disclosure	0.0
Physical Commodity Purchase Sale Contracts Fair Value Disclosure	0.0
Coal Trading Assets and Liabilities, Net, Fair Value Disclosure	$ 0.0

X

- Definition

Coal Trading Assets and Liabilities, Net, Fair Value Disclosure

+ References

No definition available.

+ Details

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

X

- Definition

Commodity swaps and options fair value disclosure.

+ References

No definition available.

+ Details

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

X

- Definition

Physical commodity purchase sale contracts fair value disclosure.

+ References

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

Name:	us-gaap_TradingActivityByTypeAxis=btu_CoalTradingMember
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_StatementScenarioAxis=us-gaap_SuccessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: