Other Events (Notes)	9 Months Ended
Sep. 30, 2016
Other Events [Abstract]
Other Events [Text Block]	Other Events Organizational Realignment From time to time, the Company initiates restructuring activities in connection with its repositioning efforts to appropriately align its cost structure or optimize its coal production relative to prevailing global coal industry conditions. Costs associated with restructuring actions can include early mine closures, voluntary and involuntary workforce reductions, office closures and other related activities. Costs associated with restructuring activities are recognized in the period incurred. In 2016, the Company has continued to drive operational efficiencies, optimize production across its mining platform and control operational and administrative expenses. Included in the Company's unaudited condensed consolidated statements of operations were aggregate restructuring charges, primarily comprised of cash severance costs, of $0.3 million and $1.8 million for the three months ended September 30, 2016 and 2015, respectively, and $15.5 million and $23.0 million, for the nine months ended September 30, 2016 and 2015, respectively. Restricted Cash As of September 30, 2016, the Company had restricted cash representing collateral for financial assurances associated with reclamation and other obligations of $70.6 million and $1.4 million included in “Investments and other assets” and "Restricted cash", respectively. Refer to Note 18. "Financial Instruments and Other Guarantees" for details regarding the remaining $22.8 million in restricted cash. Take-or-pay Obligations During the nine months ended September 30, 2016, the Company amended contracts to reduce certain U.S. transportation and logistics costs. In connection with these amendments, the Company will realize a net reduction of approximately $45 million in estimated liquidated damage payments that otherwise would have become due with respect to these take-or-pay obligations in 2017. In connection with these amendments, the Company paid liquidated damages of $15.5 million during the nine months ended September 30, 2016. Divestitures In May 2016, the Company completed the sale of its 5.06% participation interest in the Prairie State Energy Campus to the Wabash Valley Power Association for $57.1 million. The Company recognized a gain on sale of $6.2 million related to the transaction, which was classified in "Net gain on disposal of assets" in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2016. In May 2016, the Company entered into sale and purchase agreements with Australia-based Pembroke Resources to sell its interest in undeveloped metallurgical reserve tenements in Queensland's Bowen Basin for $64.1 million in cash plus a royalty stream. The transaction included Olive Downs South, Olive Downs South Extended and Willunga tenements. The Company recognized a gain on sale of $2.8 million related to the transaction, which was classified in "Net gain on disposal of assets" in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2016. In November 2015, the Company entered into a definitive agreement to sell its New Mexico and Colorado assets to a subsidiary of Bowie Resource Partners, LLC (Bowie) in exchange for cash proceeds of $358 million and the assumption of certain liabilities. Bowie agreed to pay the Company $20 million if it failed to obtain financing within the time frame allotted under the agreement (Termination Fee). Bowie did not obtain the necessary financing within the time allowed under the agreement, nor the additional time Peabody agreed to provide at Bowie's request. On April 12, 2016, Peabody then requested that the Termination Fee be paid, which Bowie has not done. The Company has brought action against Bowie to recover the Termination Fee, interest and certain costs. Customer Contract Amendment During the second quarter of 2016, the Company amended its arrangements concerning its long-term supply contract with the largest customer of its Australian Thermal Mining segment as a result of the Debtors' Bankruptcy Petitions. Coal under the supply contract is sourced from the Company's Wilpinjong Mine. The Bankruptcy Petitions enabled the customer to exercise their contractual step-in rights to appoint a receiver to operate the mine within the parameters of the agreement; however, the customer has not exercised this right. Under the new arrangements, the Company's subsidiary agreed to post cash collateral of $50.0 million Australian dollars by September 15, 2016, all of which was posted as of September 30, 2016 and is included in "Investments and other assets" in the condensed consolidated balance sheet. The subsidiary also agreed to maintain compliance with additional covenants and restrictions, including achieving minimum quarterly cash flow and production volumes in relation to specific forecasted amounts. If these conditions are met, the customer will not exercise their step-in rights to appoint a receiver. The arrangements provide for remedial action where certain covenants are not met; but noncompliance could result in termination of the amended arrangements and enable the customer to exercise step-in rights to appoint a receiver to operate the Wilpinjong Mine. As of November 2, 2016, the Company was in compliance with the covenants and restrictions under the new arrangements. Impact of the Chapter 11 Cases on Certain Leases The Company leases equipment and facilities under various noncancelable lease agreements. Certain lease agreements were subject to the restrictive covenants of the 2013 Credit Facility and include cross-acceleration provisions, under which the lessor could require certain remedies including, but not limited to, immediate recovery of the present value of any remaining lease payments. In relation to the Company's non-debtor subsidiaries, the Company is in various stages of negotiating stand-still arrangements with some lessors where the lessor will not exercise those rights. The Company does not currently believe it is probable the lessors will exercise those rights for the non-debtor subsidiaries. The lessors' rights related to the Debtor subsidiaries were automatically stayed as a result of the filing of the Chapter 11 Cases. As of September 30, 2016, the Company had approximately $215 million of remaining commitments under these non-debtor lease arrangements.

Other Events

Organizational Realignment

From time to time, the Company initiates restructuring activities in connection with its repositioning efforts to appropriately align its cost structure or optimize its coal production relative to prevailing global coal industry conditions. Costs associated with restructuring actions can include early mine closures, voluntary and involuntary workforce reductions, office closures and other related activities. Costs associated with restructuring activities are recognized in the period incurred.

In 2016, the Company has continued to drive operational efficiencies, optimize production across its mining platform and control operational and administrative expenses. Included in the Company's unaudited condensed consolidated statements of operations were aggregate restructuring charges, primarily comprised of cash severance costs, of $0.3 million and $1.8 million for the three months ended September 30, 2016 and 2015, respectively, and $15.5 million and $23.0 million, for the nine months ended September 30, 2016 and 2015, respectively.

Restricted Cash

As of September 30, 2016, the Company had restricted cash representing collateral for financial assurances associated with reclamation and other obligations of $70.6 million and $1.4 million included in “Investments and other assets” and "Restricted cash", respectively. Refer to Note 18. "Financial Instruments and Other Guarantees" for details regarding the remaining $22.8 million in restricted cash.

Take-or-pay Obligations

During the nine months ended September 30, 2016, the Company amended contracts to reduce certain U.S. transportation and logistics costs. In connection with these amendments, the Company will realize a net reduction of approximately $45 million in estimated liquidated damage payments that otherwise would have become due with respect to these take-or-pay obligations in 2017. In connection with these amendments, the Company paid liquidated damages of $15.5 million during the nine months ended September 30, 2016.

Divestitures

In May 2016, the Company completed the sale of its 5.06% participation interest in the Prairie State Energy Campus to the Wabash Valley Power Association for $57.1 million. The Company recognized a gain on sale of $6.2 million related to the transaction, which was classified in "Net gain on disposal of assets" in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2016.

In May 2016, the Company entered into sale and purchase agreements with Australia-based Pembroke Resources to sell its interest in undeveloped metallurgical reserve tenements in Queensland's Bowen Basin for $64.1 million in cash plus a royalty stream. The transaction included Olive Downs South, Olive Downs South Extended and Willunga tenements. The Company recognized a gain on sale of $2.8 million related to the transaction, which was classified in "Net gain on disposal of assets" in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2016.

In November 2015, the Company entered into a definitive agreement to sell its New Mexico and Colorado assets to a subsidiary of Bowie Resource Partners, LLC (Bowie) in exchange for cash proceeds of $358 million and the assumption of certain liabilities. Bowie agreed to pay the Company $20 million if it failed to obtain financing within the time frame allotted under the agreement (Termination Fee). Bowie did not obtain the necessary financing within the time allowed under the agreement, nor the additional time Peabody agreed to provide at Bowie's request. On April 12, 2016, Peabody then requested that the Termination Fee be paid, which Bowie has not done. The Company has brought action against Bowie to recover the Termination Fee, interest and certain costs.

Customer Contract Amendment

During the second quarter of 2016, the Company amended its arrangements concerning its long-term supply contract with the largest customer of its Australian Thermal Mining segment as a result of the Debtors' Bankruptcy Petitions. Coal under the supply contract is sourced from the Company's Wilpinjong Mine. The Bankruptcy Petitions enabled the customer to exercise their contractual step-in rights to appoint a receiver to operate the mine within the parameters of the agreement; however, the customer has not exercised this right. Under the new arrangements, the Company's subsidiary agreed to post cash collateral of $50.0 million Australian dollars by September 15, 2016, all of which was posted as of September 30, 2016 and is included in "Investments and other assets" in the condensed consolidated balance sheet. The subsidiary also agreed to maintain compliance with additional covenants and restrictions, including achieving minimum quarterly cash flow and production volumes in relation to specific forecasted amounts. If these conditions are met, the customer will not exercise their step-in rights to appoint a receiver. The arrangements provide for remedial action where certain covenants are not met; but noncompliance could result in termination of the amended arrangements and enable the customer to exercise step-in rights to appoint a receiver to operate the Wilpinjong Mine. As of November 2, 2016, the Company was in compliance with the covenants and restrictions under the new arrangements.

Impact of the Chapter 11 Cases on Certain Leases

The Company leases equipment and facilities under various noncancelable lease agreements. Certain lease agreements were subject to the restrictive covenants of the 2013 Credit Facility and include cross-acceleration provisions, under which the lessor could require certain remedies including, but not limited to, immediate recovery of the present value of any remaining lease payments. In relation to the Company's non-debtor subsidiaries, the Company is in various stages of negotiating stand-still arrangements with some lessors where the lessor will not exercise those rights. The Company does not currently believe it is probable the lessors will exercise those rights for the non-debtor subsidiaries. The lessors' rights related to the Debtor subsidiaries were automatically stayed as a result of the filing of the Chapter 11 Cases. As of September 30, 2016, the Company had approximately $215 million of remaining commitments under these non-debtor lease arrangements.