Financial Instruments and Other Guarantees	3 Months Ended
Mar. 31, 2018
Financial Instruments And Guarantees With Off Balance Sheet Risk Disclosure [Abstract]
Financial Instruments and Other Guarantees	Financial Instruments and Other Guarantees In the normal course of business, the Company is a party to guarantees and financial instruments, some of which carry off-balance-sheet risk and are not reflected in the accompanying condensed consolidated balance sheets. Such financial instruments are valued based on the amount of exposure under the instrument and the likelihood of required performance. Reclamation Bonding The Company is required to provide various forms of financial assurance in support of its mining reclamation obligations in the jurisdictions in which it operates. Such requirements are typically established by statute or under mining permits. Historically, such assurances have taken the form of third-party instruments such as surety bonds, bank guarantees, letters of credit, collateral held in restricted accounts, and self-bonding arrangements in the U.S. In connection with its emergence from the Chapter 11 Cases, the Company elected to utilize primarily a portfolio of surety bonds to support its U.S. obligations. At March 31, 2018, the Company’s asset retirement obligations for its U.S. operations of $469.0 million were supported by surety bonds of $1,074.3 million, as well as letters of credit issued under the Company’s receivables securitization program and Revolver amounting to $174.1 million. At March 31, 2018, the Company’s asset retirement obligations for its Australia operations of $230.2 million were supported by a combination of $270.1 million of surety bonds and bank guarantees, $99.7 million of collateral arrangements, and $14.4 million of similarly issued letters of credit. Accounts Receivable Securitization As described in Note 2. “Emergence from the Chapter 11 Cases and Fresh Start Reporting” in the Company's Annual Report on Form 10-K for the year ended December 31, 2017, the Company entered into the Sixth Amended and Restated Receivables Purchase Agreement, as amended, dated as of April 3, 2017 (the Receivables Purchase Agreement) to extend the Company’s receivables securitization facility previously in place and expand that facility to include certain receivables from the Company’s Australian operations. The term of the receivables securitization program (Securitization Program) ends on April 3, 2020, subject to certain liquidity requirements and other customary events of default set forth in the Receivables Purchase Agreement. The Securitization Program provides for up to $250.0 million in funding accounted for as a secured borrowing, limited to the availability of eligible receivables, and may be secured by a combination of collateral and the trade receivables underlying the program, from time to time. Funding capacity under the Securitization Program may also be drawn upon for letters of credit in support of other obligations. During 2017, the Company entered into amendments to the Securitization Program to include the receivables of additional Australian operations, reduce the restrictions on the availability of certain eligible receivables, add an additional servicer and reduce program fees. Under the terms of the Securitization Program, the Company contributes the trade receivables of its participating subsidiaries on a revolving basis to P&L Receivables, its wholly-owned, bankruptcy-remote subsidiary, which then sells the receivables to unaffiliated banks. P&L Receivables retains the ability to repurchase the receivables in certain circumstances. The assets and liabilities of P&L Receivables are consolidated with Peabody, and the Securitization Program is treated as a secured borrowing for accounting purposes, but the assets of P&L Receivables will be used first to satisfy the creditors of P&L Receivables, not Peabody’s creditors. The borrowings under the Securitization Program remain outstanding throughout the term of the agreement, subject to the Company maintaining sufficient eligible receivables, by continuing to contribute trade receivables to P&L Receivables, unless an event of default occurs. At March 31, 2018, the Company had no outstanding borrowings and $176.3 million of letters of credit drawn under the Securitization Program. The letters of credit were primarily in support of portions of the Company’s obligations for reclamation, workers’ compensation and postretirement benefits. The Company had no collateral requirement under the Securitization Program at March 31, 2018 and December 31, 2017. The Company incurred fees associated with the Securitization Program of $1.3 million during the three months ended March 31, 2018, which have been recorded as interest expense in the accompanying unaudited condensed consolidated statements of operations. As it relates to the former receivables securitization facility in place prior to the Effective Date, the Company incurred interest expense of $2.0 million during the three months ended March 31, 2017. Collateral Arrangements and Restricted Cash The Company remits cash to certain regulatory authorities and other third parties as collateral for financial assurances associated with a variety of long-term obligations and commitments surrounding the mining, reclamation and shipping of its production. The Company had $109.1 million and $323.1 million held by third parties related to such obligations at March 31, 2018 and December 31, 2017, respectively. During the three months ended March 31, 2018, $214.0 million of such collateral was returned to the Company, and the remainder is expected to be returned within the next twelve months, largely as the result of replacing collateral balances with third-party surety bonding in Australia, which was unavailable to the Company prior to 2018. As such, the collateral balance at March 31, 2018 has been classified as current in the accompanying condensed consolidated balance sheets. The Company also had $40.1 million of restricted cash at December 31, 2017 related to a class of pending unsecured creditors’ claims in connection with the Chapter 11 Cases. The restriction was released on March 22, 2018 after the Debtors satisfied all such claims. Other The Company is the lessee under numerous equipment and property leases. It is common in such commercial lease transactions for the Company, as the lessee, to agree to indemnify the lessor for the value of the property or equipment leased, should the property be damaged or lost during the course of the Company’s operations. The Company expects that losses with respect to leased property, if any, would be covered by insurance (subject to deductibles). The Company and certain of its subsidiaries have guaranteed other subsidiaries’ performance under various lease obligations. Aside from indemnification of the lessor for the value of the property leased, the Company’s maximum potential obligations under its leases are equal to the respective future minimum lease payments, and the Company assumes that no amounts could be recovered from third parties. The Company has provided financial guarantees under certain long-term debt agreements entered into by its subsidiaries and substantially all of the Company’s U.S. subsidiaries provide financial guarantees under long-term debt agreements entered into by the Company. The maximum amounts payable under the Company’s debt agreements are equal to the respective principal and interest payments

Financial Instruments and Other Guarantees

In the normal course of business, the Company is a party to guarantees and financial instruments, some of which carry off-balance-sheet risk and are not reflected in the accompanying condensed consolidated balance sheets. Such financial instruments are valued based on the amount of exposure under the instrument and the likelihood of required performance.

Reclamation Bonding

The Company is required to provide various forms of financial assurance in support of its mining reclamation obligations in the jurisdictions in which it operates. Such requirements are typically established by statute or under mining permits. Historically, such assurances have taken the form of third-party instruments such as surety bonds, bank guarantees, letters of credit, collateral held in restricted accounts, and self-bonding arrangements in the U.S. In connection with its emergence from the Chapter 11 Cases, the Company elected to utilize primarily a portfolio of surety bonds to support its U.S. obligations.

At March 31, 2018, the Company’s asset retirement obligations for its U.S. operations of $469.0 million were supported by surety bonds of $1,074.3 million, as well as letters of credit issued under the Company’s receivables securitization program and Revolver amounting to $174.1 million. At March 31, 2018, the Company’s asset retirement obligations for its Australia operations of $230.2 million were supported by a combination of $270.1 million of surety bonds and bank guarantees, $99.7 million of collateral arrangements, and $14.4 million of similarly issued letters of credit.

Accounts Receivable Securitization

As described in Note 2. “Emergence from the Chapter 11 Cases and Fresh Start Reporting” in the Company's Annual Report on Form 10-K for the year ended December 31, 2017, the Company entered into the Sixth Amended and Restated Receivables Purchase Agreement, as amended, dated as of April 3, 2017 (the Receivables Purchase Agreement) to extend the Company’s receivables securitization facility previously in place and expand that facility to include certain receivables from the Company’s Australian operations. The term of the receivables securitization program (Securitization Program) ends on April 3, 2020, subject to certain liquidity requirements and other customary events of default set forth in the Receivables Purchase Agreement. The Securitization Program provides for up to $250.0 million in funding accounted for as a secured borrowing, limited to the availability of eligible receivables, and may be secured by a combination of collateral and the trade receivables underlying the program, from time to time. Funding capacity under the Securitization Program may also be drawn upon for letters of credit in support of other obligations. During 2017, the Company entered into amendments to the Securitization Program to include the receivables of additional Australian operations, reduce the restrictions on the availability of certain eligible receivables, add an additional servicer and reduce program fees.

Under the terms of the Securitization Program, the Company contributes the trade receivables of its participating subsidiaries on a revolving basis to P&L Receivables, its wholly-owned, bankruptcy-remote subsidiary, which then sells the receivables to unaffiliated banks. P&L Receivables retains the ability to repurchase the receivables in certain circumstances. The assets and liabilities of P&L Receivables are consolidated with Peabody, and the Securitization Program is treated as a secured borrowing for accounting purposes, but the assets of P&L Receivables will be used first to satisfy the creditors of P&L Receivables, not Peabody’s creditors. The borrowings under the Securitization Program remain outstanding throughout the term of the agreement, subject to the Company maintaining sufficient eligible receivables, by continuing to contribute trade receivables to P&L Receivables, unless an event of default occurs.

At March 31, 2018, the Company had no outstanding borrowings and $176.3 million of letters of credit drawn under the Securitization Program. The letters of credit were primarily in support of portions of the Company’s obligations for reclamation, workers’ compensation and postretirement benefits. The Company had no collateral requirement under the Securitization Program at March 31, 2018 and December 31, 2017. The Company incurred fees associated with the Securitization Program of $1.3 million during the three months ended March 31, 2018, which have been recorded as interest expense in the accompanying unaudited condensed consolidated statements of operations. As it relates to the former receivables securitization facility in place prior to the Effective Date, the Company incurred interest expense of $2.0 million during the three months ended March 31, 2017.

Collateral Arrangements and Restricted Cash

The Company remits cash to certain regulatory authorities and other third parties as collateral for financial assurances associated with a variety of long-term obligations and commitments surrounding the mining, reclamation and shipping of its production. The Company had $109.1 million and $323.1 million held by third parties related to such obligations at March 31, 2018 and December 31, 2017, respectively. During the three months ended March 31, 2018, $214.0 million of such collateral was returned to the Company, and the remainder is expected to be returned within the next twelve months, largely as the result of replacing collateral balances with third-party surety bonding in Australia, which was unavailable to the Company prior to 2018. As such, the collateral balance at March 31, 2018 has been classified as current in the accompanying condensed consolidated balance sheets.

The Company also had $40.1 million of restricted cash at December 31, 2017 related to a class of pending unsecured creditors’ claims in connection with the Chapter 11 Cases. The restriction was released on March 22, 2018 after the Debtors satisfied all such claims.

Other

The Company is the lessee under numerous equipment and property leases. It is common in such commercial lease transactions for the Company, as the lessee, to agree to indemnify the lessor for the value of the property or equipment leased, should the property be damaged or lost during the course of the Company’s operations. The Company expects that losses with respect to leased property, if any, would be covered by insurance (subject to deductibles). The Company and certain of its subsidiaries have guaranteed other subsidiaries’ performance under various lease obligations. Aside from indemnification of the lessor for the value of the property leased, the Company’s maximum potential obligations under its leases are equal to the respective future minimum lease payments, and the Company assumes that no amounts could be recovered from third parties.

The Company has provided financial guarantees under certain long-term debt agreements entered into by its subsidiaries and substantially all of the Company’s U.S. subsidiaries provide financial guarantees under long-term debt agreements entered into by the Company. The maximum amounts payable under the Company’s debt agreements are equal to the respective principal and interest payments