Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) (Notes)	9 Months Ended
Sep. 30, 2015
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Abstract]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Table Text Block]	Matters Related to the Patriot Bankruptcy In 2012, Patriot and certain of its wholly owned subsidiaries filed voluntary petitions for relief under Chapter 11 of Title 11 of the U.S. Code. In 2013, the Company entered into a definitive settlement agreement with Patriot and the UMWA, on behalf of itself, its represented Patriot employees and its represented Patriot retirees, to resolve all then disputed issues related to Patriot’s bankruptcy. In May 2015, Patriot again filed voluntary petitions for relief under Chapter 11 of Title 11 of the U.S. Code in the Eastern District of Virginia and subsequently initiated a process to sell some or all of its assets to qualified bidders. On October 9, 2015, Patriot's bankruptcy court entered an order confirming Patriot's plan of reorganization, which provides, among other things, for the sale of substantially all of Patriot's assets to two different buyers. Credit Support As part of the 2013 definitive settlement agreement with Patriot and the UMWA, the Company has provided $121.5 million of credit support to Patriot, with $81.0 million in the form of surety bonds issued for the benefit of Patriot beneficiaries; $22.4 million in the form of letters of credit issued for the benefit of Patriot beneficiaries; and $18.1 million in the form of corporate guarantees to Patriot beneficiaries. Those surety bonds, corporate guarantees and letters of credit are excluded in the financial instruments with off-balance sheet risk table presented in Note 17. " Financial Instruments, Guarantees with Off-Balance Sheet Risk and Other Guarantees". A total of $35.3 million of the credit support relates to certain of Patriot’s Coal Act obligations that a subsidiary of the Company agreed to fund at the time of the Patriot spin-off pursuant to the Coal Act Liabilities Assumption Agreement. During the three months ended September 30, 2015, $22.4 million of cash drawdowns were made by the beneficiaries of the letters of credit, leaving $99.1 million remaining as a liability on our condensed consolidated balance sheet as of September 30, 2015. Due to Patriot’s May 2015 bankruptcy filing, the Company recorded a net charge of $34.7 million to increase its liability related to the credit support to the estimated fair value of the portion of the credit support exposed to nonperformance by Patriot. That net charge included a $16.6 million correction of an error reflected in the nine months ended September 30, 2015 to derecognize a liability that had been previously recorded to the Company’s historical financial statements in 2014 and 2013. The Company reflected the correction as an out-of-period adjustment because it considers the impact of the error to be immaterial quantitatively and qualitatively to the total mix of information available in the Company’s 2015 and historical financial statements. Black Lung Occupational Disease Liabilities Patriot has federal and state black lung occupational disease liabilities related to workers employed in periods prior to Patriot’s spin-off from the Company in 2007. Upon spin-off, Patriot indemnified the Company against any claim relating to these liabilities, which amounted to approximately $150 million at that time. The indemnification included any claim made by the U.S. Department of Labor (DOL) against the Company with respect to these obligations as a potentially liable operator under the Federal Coal Mine Health and Safety Act of 1969. The definitive settlement agreement reached in 2013 included Patriot’s affirmance of all indemnities provided in the spin-off agreements, including the indemnity relating to such black lung liabilities. By statute, the Company remains secondarily liable for the black lung liabilities related to Patriot’s workers employed by former subsidiaries of the Company. Whether the Company will ultimately be required to fund certain of those obligations in the future as a result of Patriot’s May 2015 bankruptcy remains uncertain. The Company does believe that it is probable that it will be required to fund a portion of these obligations in the future and recorded a charge to "(Loss) income from discontinued operations, net of income taxes" of $126.0 million, net of $15.0 million previously accrued credit support related to Patriot's federal black lung obligations, during the three and nine months ended September 30, 2015. The liability recorded for black lung occupational disease liability is based on information provided by Patriot which the Company continues to evaluate. As a result of the complexity of this estimate and the limited amount of time the Company has had to evaluate the underlying data, this estimate may change in future periods. The amount of the Company's recorded liability reflects only Patriot workers employed by former subsidiaries of the Company that are presently retired, disabled or otherwise not actively employed, which the Company believes reflects the low end of the range of potential loss. The Company cannot reliably estimate the potential liabilities for Patriot's workers employed by former subsidiaries of the Company that are presently active in the workforce because of the potential for such workers to continue to work for another coal operator that is a going concern, including a potential buyer of Patriot's former operations. The Company estimates that the annual cash cost to fund these potential Black Lung liabilities will range between $10 million and $15 million. Combined Benefit Fund (Combined Fund) The Combined Fund was created by the Coal Act in 1992 as a multi-employer plan to provide health care benefits to a closed group of retirees who last worked prior to 1976, as well as orphaned beneficiaries of bankrupt companies who were receiving benefits as orphans prior to the passage of the Coal Act. No new retirees will be added to this group, which includes retirees formerly employed by certain Patriot subsidiaries and their predecessors. Former employers are required to contribute to the Combined Fund according to a formula. Under the terms of the Patriot spin-off, Patriot was primarily liable for the obligations of its subsidiaries to the Combined Fund, which obligations were actuarially estimated to be approximately $40 million at that time. To the extent that Patriot ceases to meet its obligations, we may be held responsible for these costs. The Company believes it is probable that it will be required to fund these obligations in the future and recorded a "(Loss) income from discontinued operations, net of income taxes" charge of $29.1 million during the three and nine months ended September 30, 2015 utilizing the best available actuarial information received prior to the issuance of these financial statements. The Company estimates that the annual cash cost to fund these potential Combined Fund liabilities will range between $2 million and $3 million in the near-term, with those premiums expected to decline over time because the fund is closed to new participants. VEBA Payments In connection with the 2013 definitive settlement agreement, the Company was required to provide total payments of $310.0 million, payable over four years through 2017, to partially fund the newly established voluntary employee beneficiary association (VEBA) and settle all Patriot and UMWA claims involving the Patriot bankruptcy. Those payments included an initial payment of $90.0 million made in January 2014, comprised of $70.0 million paid to Patriot and $20.0 million paid to the VEBA, and a payment of $75.0 million made in January 2015 to the VEBA. The settlement agreement also contemplates subsequent payments to be made to the VEBA of $75.0 million in 2016 and $70.0 million in 2017. As a result of Patriot’s failure to reimburse the Company for the draws on the credit support that the Company provided under the 2013 Settlement Agreement, Patriot has materially breached the 2013 Settlement Agreement. The Company and the UMWA disagree about the impact Patriot's breaches have on the Company's future obligations under the 2013 Settlement Agreement, including the payment of the two remaining VEBA payments. Accordingly, on August 28, 2015, the Company sought to-reopen Patriot’s first bankruptcy cases that were pending in the United States Bankruptcy Court for the Eastern District of Missouri (the “Missouri Bankruptcy Court”) for the limited purpose of having the Missouri Bankruptcy Court decide this issue. On October 9, 2015, the Missouri Bankruptcy Court granted the Company’s motion and ordered the Company to file its declaratory judgment action within 30 days. On October 9, 2015, the Company filed in the Missouri Bankruptcy Court a declaratory judgment action against the UMWA seeking a declaration that the Company’s obligations to make the final two VEBA payments are excused as a result of Patriot’s breaches of the agreement (the “Missouri Declaratory Judgment Action”). Patriot's appeal of the Missouri Bankruptcy Court's order was dismissed on October 26, 2015. On October 16, the UMWA filed a motion to withdraw the reference with respect to the Missouri Declaratory Judgment Action to the United States District Court for the Eastern District of Missouri, with the stated intent of thereafter seeking a transfer of the case ultimately to the United States Bankruptcy Court for the Eastern District of Virginia (the “Virginia Bankruptcy Court”) where Patriot’s second bankruptcy cases are pending. On October 23, 2015, the Company filed an objection to this motion. On October 19, 2015, Patriot and the UMWA filed a declaratory judgment action in the Virginia Bankruptcy Court (the "Virginia Declaratory Judgment Action") against the Company and one of its subsidiaries seeking, among other things, a declaration that the Company must make the remaining two VEBA payments notwithstanding Patriot’s breach of the 2013 Settlement Agreement. On November 3, 2015, Patriot and the UMWA filed a motion for a preliminary and permanent injunction to prevent the Company from proceeding with the Missouri Declaratory Judgment Action (the "Injunction Motion"). On November 4, 2015, the Company filed a motion to dismiss the Virginia Declaratory Judgment Action for lack of subject matter jurisdiction or, in the alternative, to transfer it to the Missouri Bankruptcy Court; the Company intends to vigorously oppose the Injunction Motion. Retiree Health Care Obligations for Certain Salaried Patriot Personnel In connection with the 2007 spin-off of Patriot from the Company, the Company and one of its subsidiaries entered into a Salaried Employee Liabilities Assumption Agreement (“SELAA”) pursuant to which its subsidiary agreed fund the healthcare benefits that Patriot was obligated to provide for a group of Patriot’s salaried retirees. On October 9, 2015, Patriot’s bankruptcy court entered an order approving a stipulation and settlement among the Company and its subsidiary, Patriot and its affiliates and the Official Committee of Retirees in Patriot’s chapter 11 cases (on behalf of itself and the retirees that it represents), pursuant to which, among other things, (i) the SELAA is terminated as of October 31, 2015; (ii) the Company and its subsidiary have agreed to pay a total of $16.1 million in five annual installments to a VEBA to be established by the Official Committee of Retirees; (iii) the Company agreed to pay $100,000 to the VEBA for its start-up and administrative costs; and (iv) the parties exchanged mutual releases. At September 30, 2015, the Company had $33.6 million accrued in relation to these obligations. UMWA 1974 Pension Plan (Plan) Litigation On July 16, 2015, a lawsuit was filed by the Plan, the UMWA 1974 Pension Trust (Trust) and the Trustees of the Plan and Trust (Trustees) in the United States District Court for the District of Columbia, against the Company, PHC, a subsidiary of the Company, and Arch Coal, Inc. (Arch). The plaintiffs are seeking, pursuant to ERISA and the Multiemployer Pension Plan Amendments Act of 1980 (MPPAA), a declaratory judgment that the defendants are obligated to arbitrate any opposition to the Trustees’ determination that the defendants have statutory withdrawal liability as a result of the 2015 Patriot bankruptcy. The plaintiffs' July lawsuit claimed that the defendants' withdrawal liability will result in at least $767 million owed to the Plan. On October 29, 2015, the plaintiffs filed an amended complaint, alleging that the plaintiffs had determined that Peabody has $644.2 million and Arch has $299.8 million in withdrawal liabilities to the 1974 Pension Plan. Also on October 29, 2015, the Trustees issued a withdrawal liability assessment against the Company in the amount of $644.2 million (“October 29 Assessment”). The Trustees claim that a principal purpose of the Company’s 2007 spin-off of Patriot was to “evade or avoid” withdrawal liability to the Plan, and they assert that the Company is therefore liable for Patriot's withdrawal from the Plan due to Patriot terminating certain collective bargaining agreements with the UMWA eight years later, during its current bankruptcy proceeding. The October 29 Assessment does not contain the payment schedule required by ERISA. Instead, the Trustees assert that the Company was in default on the $644.2 million liability assessment as of the moment it was assessed. The Company and PHC dispute this withdrawal liability claim -- including the notion that the Company could be in default on the withdrawal liability assessment prior to being given an opportunity to make any payments on the assessment -- and are vigorously defending their positions. ERISA provides a process to adjudicate withdrawal liability disputes, which consists of administrative review by the Plan followed by arbitration, after which either side can appeal to the appropriate United States district court. The Company anticipates it will not have to make payments on the October 29 Assessment until an arbitrator issues a final decision in favor of the Trustees on the "evade or avoid" theory of liability. The Company also anticipates that during arbitration it will receive a decision on the legality of the Fund's determination that the Company was in default. The Company anticipates that as a consequence of such decision, the Fund will be required to issue it a payment schedule setting forth the annual payments required to pay the alleged withdrawal liability over time. If a payment schedule is issued, yet the underlying evade or avoid claim is not finally arbitrated to decision at least 15 months following the October 29 Assessment, the Company anticipates it would then have to post a bond or place into escrow an amount equal to one year's payment (up to $22.5 million) toward the liability. The bond would remain in place until an arbitration decision is reached on the underlying withdrawal liability issue. If it is decided in the Company's favor, the Company will not owe any amounts to the Plan.

Matters Related to the Patriot Bankruptcy

In 2012, Patriot and certain of its wholly owned subsidiaries filed voluntary petitions for relief under Chapter 11 of Title 11 of the U.S. Code. In 2013, the Company entered into a definitive settlement agreement with Patriot and the UMWA, on behalf of itself, its represented Patriot employees and its represented Patriot retirees, to resolve all then disputed issues related to Patriot’s bankruptcy. In May 2015, Patriot again filed voluntary petitions for relief under Chapter 11 of Title 11 of the U.S. Code in the Eastern District of Virginia and subsequently initiated a process to sell some or all of its assets to qualified bidders. On October 9, 2015, Patriot's bankruptcy court entered an order confirming Patriot's plan of reorganization, which provides, among other things, for the sale of substantially all of Patriot's assets to two different buyers.

Credit Support

As part of the 2013 definitive settlement agreement with Patriot and the UMWA, the Company has provided $121.5 million of credit support to Patriot, with $81.0 million in the form of surety bonds issued for the benefit of Patriot beneficiaries; $22.4 million in the form of letters of credit issued for the benefit of Patriot beneficiaries; and $18.1 million in the form of corporate guarantees to Patriot beneficiaries. Those surety bonds, corporate guarantees and letters of credit are excluded in the financial instruments with off-balance sheet risk table presented in Note 17. " Financial Instruments, Guarantees with Off-Balance Sheet Risk and Other Guarantees". A total of $35.3 million of the credit support relates to certain of Patriot’s Coal Act obligations that a subsidiary of the Company agreed to fund at the time of the Patriot spin-off pursuant to the Coal Act Liabilities Assumption Agreement. During the three months ended September 30, 2015, $22.4 million of cash drawdowns were made by the beneficiaries of the letters of credit, leaving $99.1 million remaining as a liability on our condensed consolidated balance sheet as of September 30, 2015.

Due to Patriot’s May 2015 bankruptcy filing, the Company recorded a net charge of $34.7 million to increase its liability related to the credit support to the estimated fair value of the portion of the credit support exposed to nonperformance by Patriot. That net charge included a $16.6 million correction of an error reflected in the nine months ended September 30, 2015 to derecognize a liability that had been previously recorded to the Company’s historical financial statements in 2014 and 2013. The Company reflected the correction as an out-of-period adjustment because it considers the impact of the error to be immaterial quantitatively and qualitatively to the total mix of information available in the Company’s 2015 and historical financial statements.

Black Lung Occupational Disease Liabilities

Patriot has federal and state black lung occupational disease liabilities related to workers employed in periods prior to Patriot’s spin-off from the Company in 2007. Upon spin-off, Patriot indemnified the Company against any claim relating to these liabilities, which amounted to approximately $150 million at that time. The indemnification included any claim made by the U.S. Department of Labor (DOL) against the Company with respect to these obligations as a potentially liable operator under the Federal Coal Mine Health and Safety Act of 1969. The definitive settlement agreement reached in 2013 included Patriot’s affirmance of all indemnities provided in the spin-off agreements, including the indemnity relating to such black lung liabilities.

By statute, the Company remains secondarily liable for the black lung liabilities related to Patriot’s workers employed by former subsidiaries of the Company. Whether the Company will ultimately be required to fund certain of those obligations in the future as a result of Patriot’s May 2015 bankruptcy remains uncertain. The Company does believe that it is probable that it will be required to fund a portion of these obligations in the future and recorded a charge to "(Loss) income from discontinued operations, net of income taxes" of $126.0 million, net of $15.0 million previously accrued credit support related to Patriot's federal black lung obligations, during the three and nine months ended September 30, 2015. The liability recorded for black lung occupational disease liability is based on information provided by Patriot which the Company continues to evaluate. As a result of the complexity of this estimate and the limited amount of time the Company has had to evaluate the underlying data, this estimate may change in future periods. The amount of the Company's recorded liability reflects only Patriot workers employed by former subsidiaries of the Company that are presently retired, disabled or otherwise not actively employed, which the Company believes reflects the low end of the range of potential loss. The Company cannot reliably estimate the potential liabilities for Patriot's workers employed by former subsidiaries of the Company that are presently active in the workforce because of the potential for such workers to continue to work for another coal operator that is a going concern, including a potential buyer of Patriot's former operations. The Company estimates that the annual cash cost to fund these potential Black Lung liabilities will range between $10 million and $15 million.

Combined Benefit Fund (Combined Fund)

The Combined Fund was created by the Coal Act in 1992 as a multi-employer plan to provide health care benefits to a closed group of retirees who last worked prior to 1976, as well as orphaned beneficiaries of bankrupt companies who were receiving benefits as orphans prior to the passage of the Coal Act. No new retirees will be added to this group, which includes retirees formerly employed by certain Patriot subsidiaries and their predecessors. Former employers are required to contribute to the Combined Fund according to a formula.

Under the terms of the Patriot spin-off, Patriot was primarily liable for the obligations of its subsidiaries to the Combined Fund, which obligations were actuarially estimated to be approximately $40 million at that time. To the extent that Patriot ceases to meet its obligations, we may be held responsible for these costs. The Company believes it is probable that it will be required to fund these obligations in the future and recorded a "(Loss) income from discontinued operations, net of income taxes" charge of $29.1 million during the three and nine months ended September 30, 2015 utilizing the best available actuarial information received prior to the issuance of these financial statements. The Company estimates that the annual cash cost to fund these potential Combined Fund liabilities will range between $2 million and $3 million in the near-term, with those premiums expected to decline over time because the fund is closed to new participants.

VEBA Payments

In connection with the 2013 definitive settlement agreement, the Company was required to provide total payments of $310.0 million, payable over four years through 2017, to partially fund the newly established voluntary employee beneficiary association (VEBA) and settle all Patriot and UMWA claims involving the Patriot bankruptcy. Those payments included an initial payment of $90.0 million made in January 2014, comprised of $70.0 million paid to Patriot and $20.0 million paid to the VEBA, and a payment of $75.0 million made in January 2015 to the VEBA. The settlement agreement also contemplates subsequent payments to be made to the VEBA of $75.0 million in 2016 and $70.0 million in 2017.

As a result of Patriot’s failure to reimburse the Company for the draws on the credit support that the Company provided under the 2013 Settlement Agreement, Patriot has materially breached the 2013 Settlement Agreement. The Company and the UMWA disagree about the impact Patriot's breaches have on the Company's future obligations under the 2013 Settlement Agreement, including the payment of the two remaining VEBA payments. Accordingly, on August 28, 2015, the Company sought to-reopen Patriot’s first bankruptcy cases that were pending in the United States Bankruptcy Court for the Eastern District of Missouri (the “Missouri Bankruptcy Court”) for the limited purpose of having the Missouri Bankruptcy Court decide this issue. On October 9, 2015, the Missouri Bankruptcy Court granted the Company’s motion and ordered the Company to file its declaratory judgment action within 30 days. On October 9, 2015, the Company filed in the Missouri Bankruptcy Court a declaratory judgment action against the UMWA seeking a declaration that the Company’s obligations to make the final two VEBA payments are excused as a result of Patriot’s breaches of the agreement (the “Missouri Declaratory Judgment Action”). Patriot's appeal of the Missouri Bankruptcy Court's order was dismissed on October 26, 2015.

On October 16, the UMWA filed a motion to withdraw the reference with respect to the Missouri Declaratory Judgment Action to the United States District Court for the Eastern District of Missouri, with the stated intent of thereafter seeking a transfer of the case ultimately to the United States Bankruptcy Court for the Eastern District of Virginia (the “Virginia Bankruptcy Court”) where Patriot’s second bankruptcy cases are pending. On October 23, 2015, the Company filed an objection to this motion.

On October 19, 2015, Patriot and the UMWA filed a declaratory judgment action in the Virginia Bankruptcy Court (the "Virginia Declaratory Judgment Action") against the Company and one of its subsidiaries seeking, among other things, a declaration that the Company must make the remaining two VEBA payments notwithstanding Patriot’s breach of the 2013 Settlement Agreement. On November 3, 2015, Patriot and the UMWA filed a motion for a preliminary and permanent injunction to prevent the Company from proceeding with the Missouri Declaratory Judgment Action (the "Injunction Motion"). On November 4, 2015, the Company filed a motion to dismiss the Virginia Declaratory Judgment Action for lack of subject matter jurisdiction or, in the alternative, to transfer it to the Missouri Bankruptcy Court; the Company intends to vigorously oppose the Injunction Motion.

Retiree Health Care Obligations for Certain Salaried Patriot Personnel

In connection with the 2007 spin-off of Patriot from the Company, the Company and one of its subsidiaries entered into a Salaried Employee Liabilities Assumption Agreement (“SELAA”) pursuant to which its subsidiary agreed fund the healthcare benefits that Patriot was obligated to provide for a group of Patriot’s salaried retirees. On October 9, 2015, Patriot’s bankruptcy court entered an order approving a stipulation and settlement among the Company and its subsidiary, Patriot and its affiliates and the Official Committee of Retirees in Patriot’s chapter 11 cases (on behalf of itself and the retirees that it represents), pursuant to which, among other things, (i) the SELAA is terminated as of October 31, 2015; (ii) the Company and its subsidiary have agreed to pay a total of $16.1 million in five annual installments to a VEBA to be established by the Official Committee of Retirees; (iii) the Company agreed to pay $100,000 to the VEBA for its start-up and administrative costs; and (iv) the parties exchanged mutual releases. At September 30, 2015, the Company had $33.6 million accrued in relation to these obligations.

UMWA 1974 Pension Plan (Plan) Litigation

On July 16, 2015, a lawsuit was filed by the Plan, the UMWA 1974 Pension Trust (Trust) and the Trustees of the Plan and Trust (Trustees) in the United States District Court for the District of Columbia, against the Company, PHC, a subsidiary of the Company, and Arch Coal, Inc. (Arch). The plaintiffs are seeking, pursuant to ERISA and the Multiemployer Pension Plan Amendments Act of 1980 (MPPAA), a declaratory judgment that the defendants are obligated to arbitrate any opposition to the Trustees’ determination that the defendants have statutory withdrawal liability as a result of the 2015 Patriot bankruptcy. The plaintiffs' July lawsuit claimed that the defendants' withdrawal liability will result in at least $767 million owed to the Plan. On October 29, 2015, the plaintiffs filed an amended complaint, alleging that the plaintiffs had determined that Peabody has $644.2 million and Arch has $299.8 million in withdrawal liabilities to the 1974 Pension Plan.

Also on October 29, 2015, the Trustees issued a withdrawal liability assessment against the Company in the amount of $644.2 million (“October 29 Assessment”). The Trustees claim that a principal purpose of the Company’s 2007 spin-off of Patriot was to “evade or avoid” withdrawal liability to the Plan, and they assert that the Company is therefore liable for Patriot's withdrawal from the Plan due to Patriot terminating certain collective bargaining agreements with the UMWA eight years later, during its current bankruptcy proceeding. The October 29 Assessment does not contain the payment schedule required by ERISA. Instead, the Trustees assert that the Company was in default on the $644.2 million liability assessment as of the moment it was assessed. The Company and PHC dispute this withdrawal liability claim -- including the notion that the Company could be in default on the withdrawal liability assessment prior to being given an opportunity to make any payments on the assessment -- and are vigorously defending their positions.

ERISA provides a process to adjudicate withdrawal liability disputes, which consists of administrative review by the Plan followed by arbitration, after which either side can appeal to the appropriate United States district court. The Company anticipates it will not have to make payments on the October 29 Assessment until an arbitrator issues a final decision in favor of the Trustees on the "evade or avoid" theory of liability. The Company also anticipates that during arbitration it will receive a decision on the legality of the Fund's determination that the Company was in default. The Company anticipates that as a consequence of such decision, the Fund will be required to issue it a payment schedule setting forth the annual payments required to pay the alleged withdrawal liability over time. If a payment schedule is issued, yet the underlying evade or avoid claim is not finally arbitrated to decision at least 15 months following the October 29 Assessment, the Company anticipates it would then have to post a bond or place into escrow an amount equal to one year's payment (up to $22.5 million) toward the liability. The bond would remain in place until an arbitration decision is reached on the underlying withdrawal liability issue. If it is decided in the Company's favor, the Company will not owe any amounts to the Plan.