Other Events	12 Months Ended
Dec. 31, 2020
Other Events [Abstract]
Other Events	Other Events Cost Repositioning Program As part of its cost repositioning program, the Company idled nine individual mines for periods ranging from one week to multiple months throughout the year ended December 31, 2020. Included in the count was the Shoal Creek Mine in Alabama, which was idled in October 2020 to reset the cost structure of the mine amid weak pricing and demand, and the Metropolitan Mine in New South Wales, Australia, which was idled in late December 2020. United Wambo Joint Venture with Glencore In December 2019, after receiving the requisite regulatory and permitting approvals, the Company formed an unincorporated joint venture with Glencore plc (Glencore), in which the Company holds a 50% interest, to combine the existing operations of the Company’s Wambo Open-Cut Mine in Australia with the adjacent coal reserves of Glencore’s United Mine. The Company proportionally consolidates the entity based upon its economic interest. Both parties contributed mining tenements upon formation of the joint venture (United Wambo Joint Venture), and combined operations commenced in December 2020. During the year ended December 31, 2020, the Company contributed approximately $72 million towards construction and development, which is reflected as “Additions to property, plant, equipment and mine development” in the accompanying consolidated statements of cash flows. As per the joint venture agreement, the Company fully owned and operated the Wambo Open-Cut Mine through the date that combined operations commenced. At that date, the parties contributed mining equipment and other assets, and certain additional construction and development activities are ongoing. Glencore is responsible for managing the mining operations of the joint venture. The Company accounted for its interest in the United Wambo Joint Venture at fair value and recognized a gain of $48.1 million, which was classified in “Gain on formation of United Wambo Joint Venture” in the accompanying consolidated statements of operations during the year ended December 31, 2019. The gain represented the difference between the fair value of the Company’s interest in the joint venture, $63.7 million, and the carrying value of the Company’s net assets contributed upon formation, $15.6 million. The fair value of the Company’s interest in the joint venture was based on applying the income and cost valuation methods to the combined mining tenements and included a provision for the estimated fair value of related asset retirement obligations. PRB Colorado Joint Venture with Arch On June 18, 2019, the Company entered into a definitive implementation agreement with Arch, to establish a joint venture that would have combined their respective Powder River Basin (PRB) and Colorado operations. On February 26, 2020, the U.S. Federal Trade Commission (FTC) sought a preliminary injunction to challenge the Company’s proposed joint venture. On September 29, 2020, the United States District Court for the Eastern District of Missouri (the District Court) granted the FTC’s request for a preliminary injunction. Effective September 30, 2020, Peabody and Arch terminated their agreement to establish the joint venture. Acquisition of Shoal Creek Mine On December 3, 2018, the Company completed the acquisition of the Shoal Creek metallurgical coal mine, preparation plant and supporting assets located in Alabama (Shoal Creek Mine) from Drummond Company, Inc. for a purchase price of $389.8 million after customary purchase price adjustments, which was funded with available cash on hand. The acquisition expanded the Company’s seaborne metallurgical mining platform. The acquisition excluded all liabilities other than reclamation and the Company is not responsible for other liabilities relating to the operation of the Shoal Creek Mine prior to the acquisition date, including employee benefit plans and post-employment benefits. In connection with completing the acquisition, a new collective bargaining agreement was reached with the union-represented workforce that eliminates participation in the multi-employer pension plan and replaces it with a 401(k) retirement plan. The purchase accounting allocations were recorded in the accompanying consolidated financial statements as of, and for the period subsequent to the acquisition date. The Company finalized the valuation of the net assets acquired and related purchase price allocation during the year ended December 31, 2019. The total purchase price was allocated as follows: $365.3 million to property, plant, equipment and mine development; $39.9 million to inventories; $11.3 million to asset retirement obligations; and $4.1 million to various current liabilities. Determining the fair value of assets acquired and liabilities assumed required judgment and the utilization of independent valuation experts, and included the use of significant estimates and assumptions, including assumptions with respect to future cash inflows and outflows, discount rates and asset lives, among other items. Due to the unobservable inputs to the valuation, the fair value would be considered Level 3 in the fair value hierarchy. The results of Shoal Creek Mine subsequent to the acquisition date are included in the accompanying consolidated statements of operations and are reported in the Seaborne Metallurgical Mining segment. The Shoal Creek Mine contributed revenues of $12.8 million and less than $0.1 million of net income from December 4, 2018 through December 31, 2018. This excludes acquisition costs recorded during the year ended December 31, 2018 of $7.4 million, which primarily consisted of professional fees. These acquisition costs are recorded in the “Transaction costs related to business combinations and joint ventures” line item in the consolidated statements of operations. The following unaudited pro forma financial information provides the estimated combined results of operations of the Company and Shoal Creek Mine for the year ended December 31, 2018, on a pro forma basis, as though the operations of the Shoal Creek Mine had been combined with the Company’s operations as of January 1, 2018: revenues of $6,008.4 million; income from continuing operations, net of income taxes of $826.6 million; basic earnings per share from continuing operations of $5.84; and diluted earnings per share from continuing operations of $5.75. The pro forma income from continuing operations, net of income taxes includes adjustments to operating costs to reflect the additional expense for the estimated impact of the fair value adjustment for coal inventory, a reduction in postretirement benefit costs resulting from the new collective bargaining agreement described above, and the estimated impact on depreciation, depletion and amortization for the fair value adjustment for property, plant and equipment (including coal reserve assets). On a pro forma basis, the acquisition would have had no impact on taxable income due to the Company’s federal NOLs, as further described in Note 10. “Income Taxes.” Pro forma information is not provided for the years ended December 31, 2020 or 2019 because the operations of the Shoal Creek Mine are reflected in the Company’s actual consolidated results for the entire year. The unaudited pro forma financial information does not necessarily reflect the results of operations that would have occurred had the operations of the Company and Shoal Creek Mine been combined during those periods or that may be attained in the future. North Goonyella The Company’s North Goonyella Mine in Queensland, Australia experienced a fire in a portion of the mine during September 2018 and mining operations have been suspended since then. During the years ended December 31, 2019 and 2018, the Company recorded provisions for equipment losses of $83.2 million and $66.4 million, respectively, related to the fire, representing the best estimate of losses to date. No additional provisions for equipment losses were recorded during the year ended December 31, 2020. The Company has also incurred containment and idling costs subsequent to the mine’s suspension which amounted to $32.3 million, $111.5 million and $58.0 million during the years ended December 31, 2020, 2019 and 2018, respectively. In March 2019, the Company entered into an insurance claim settlement agreement with its insurers and various re-insurers under a combined property damage and business interruption policy and recorded a $125 million insurance recovery, the maximum amount available under the policy above a $50 million deductible. The Company has collected the full amount of the recovery. The Company is currently evaluating various alternatives regarding the future utility of the mine. In the event that no future mining occurs at the North Goonyella Mine or the Company is unable to find a commercial alternative, the Company may record additional charges for the remaining carrying value of the North Goonyella Mine of up to approximately $300 million, which is included in the at-risk value described in Note 3. “Asset Impairment.” Incremental exposures above the aforementioned include take-or-pay obligations and other costs associated with idling or closing the mine. Divestitures and Other Transactions The Company’s Kayenta Mine closed during August 2019 upon termination of its coal supply agreement with the Navajo Generating Station (NGS) in Arizona. The NGS was the sole customer of the Kayenta Mine and the coal supply agreement provided for consideration to the Company related to its post-mining obligations for retiree healthcare and reclamation costs. A cumulative portion of such consideration, $53.5 million, was held in trust and released to the Company upon termination. During the fourth quarter of 2019, the parties entered into a settlement agreement to finalize such consideration for an additional $78.5 million payable to the Company. Of this amount, $35.4 million was receivable at December 31, 2019, all of which was collected during the year ended December 31, 2020. In June 2018, Peabody entered into an agreement to sell approximately 23 million tonnes of metallurgical coal resources adjacent to its Millennium Mine to Stanmore Coal Limited for approximately $22 million. The sale was completed in July 2018 and the Company recorded a gain of $20.5 million which is included within “Net gain on disposals” in the accompanying consolidated statements of operations for the year ended December 31, 2018. On February 6, 2018, the Company sold its 50% interest in the Red Mountain Joint Venture (RMJV) with BHP Billiton Mitsui Coal Pty Ltd (BMC) for $20.0 million and recorded a gain of $7.1 million, which is included within “Net gain on disposals” in the accompanying consolidated statements of operations for the year ended December 31, 2018. RMJV operated the coal handling and preparation plant utilized by the Company’s Millennium Mine. BMC assumed the reclamation obligations and other commitments associated with the assets of RMJV. The Millennium Mine had continued usage of the coal handling and preparation plant and the associated rail loading facility until the end of 2019 via a coal washing take-or-pay agreement with BMC. In January 2018, Peabody entered into an agreement to sell its share in certain surplus land assets in Queensland’s Bowen Basin to Pembroke Resources South Pty Ltd for approximately $37 million Australian dollars, net of transaction costs. The necessary approval of the Australian Foreign Investment Review Board to complete the transaction was received on March 29, 2018, satisfying all the conditions precedent to the sale, and the Company recorded a gain of $20.6 million, which is included within “Net gain on disposals” in the accompanying consolidated statements of operations for the year ended December 31, 2018.

As part of its cost repositioning program, the Company idled nine individual mines for periods ranging from one week to multiple months throughout the year ended December 31, 2020. Included in the count was the Shoal Creek Mine in Alabama, which was idled in October 2020 to reset the cost structure of the mine amid weak pricing and demand, and the Metropolitan Mine in New South Wales, Australia, which was idled in late December 2020.

In December 2019, after receiving the requisite regulatory and permitting approvals, the Company formed an unincorporated joint venture with Glencore plc (Glencore), in which the Company holds a 50% interest, to combine the existing operations of the Company’s Wambo Open-Cut Mine in Australia with the adjacent coal reserves of Glencore’s United Mine. The Company proportionally consolidates the entity based upon its economic interest.

Both parties contributed mining tenements upon formation of the joint venture (United Wambo Joint Venture), and combined operations commenced in December 2020. During the year ended December 31, 2020, the Company contributed approximately $72 million towards construction and development, which is reflected as “Additions to property, plant, equipment and mine development” in the accompanying consolidated statements of cash flows. As per the joint venture agreement, the Company fully owned and operated the Wambo Open-Cut Mine through the date that combined operations commenced. At that date, the parties contributed mining equipment and other assets, and certain additional construction and development activities are ongoing. Glencore is responsible for managing the mining operations of the joint venture.

The Company accounted for its interest in the United Wambo Joint Venture at fair value and recognized a gain of $48.1 million, which was classified in “Gain on formation of United Wambo Joint Venture” in the accompanying consolidated statements of operations during the year ended December 31, 2019. The gain represented the difference between the fair value of the Company’s interest in the joint venture, $63.7 million, and the carrying value of the Company’s net assets contributed upon formation, $15.6 million. The fair value of the Company’s interest in the joint venture was based on applying the income and cost valuation methods to the combined mining tenements and included a provision for the estimated fair value of related asset retirement obligations.

On June 18, 2019, the Company entered into a definitive implementation agreement with Arch, to establish a joint venture that would have combined their respective Powder River Basin (PRB) and Colorado operations. On February 26, 2020, the U.S. Federal Trade Commission (FTC) sought a preliminary injunction to challenge the Company’s proposed joint venture. On September 29, 2020, the United States District Court for the Eastern District of Missouri (the District Court) granted the FTC’s request for a preliminary injunction. Effective September 30, 2020, Peabody and Arch terminated their agreement to establish the joint venture.

On December 3, 2018, the Company completed the acquisition of the Shoal Creek metallurgical coal mine, preparation plant and supporting assets located in Alabama (Shoal Creek Mine) from Drummond Company, Inc. for a purchase price of $389.8 million after customary purchase price adjustments, which was funded with available cash on hand. The acquisition expanded the Company’s seaborne metallurgical mining platform.

The acquisition excluded all liabilities other than reclamation and the Company is not responsible for other liabilities relating to the operation of the Shoal Creek Mine prior to the acquisition date, including employee benefit plans and post-employment benefits. In connection with completing the acquisition, a new collective bargaining agreement was reached with the union-represented workforce that eliminates participation in the multi-employer pension plan and replaces it with a 401(k) retirement plan.

The purchase accounting allocations were recorded in the accompanying consolidated financial statements as of, and for the period subsequent to the acquisition date. The Company finalized the valuation of the net assets acquired and related purchase price allocation during the year ended December 31, 2019. The total purchase price was allocated as follows: $365.3 million to property, plant, equipment and mine development; $39.9 million to inventories; $11.3 million to asset retirement obligations; and $4.1 million to various current liabilities.

Determining the fair value of assets acquired and liabilities assumed required judgment and the utilization of independent valuation experts, and included the use of significant estimates and assumptions, including assumptions with respect to future cash inflows and outflows, discount rates and asset lives, among other items. Due to the unobservable inputs to the valuation, the fair value would be considered Level 3 in the fair value hierarchy.

The results of Shoal Creek Mine subsequent to the acquisition date are included in the accompanying consolidated statements of operations and are reported in the Seaborne Metallurgical Mining segment. The Shoal Creek Mine contributed revenues of $12.8 million and less than $0.1 million of net income from December 4, 2018 through December 31, 2018. This excludes acquisition costs recorded during the year ended December 31, 2018 of $7.4 million, which primarily consisted of professional fees. These acquisition costs are recorded in the “Transaction costs related to business combinations and joint ventures” line item in the consolidated statements of operations.

The following unaudited pro forma financial information provides the estimated combined results of operations of the Company and Shoal Creek Mine for the year ended December 31, 2018, on a pro forma basis, as though the operations of the Shoal Creek Mine had been combined with the Company’s operations as of January 1, 2018: revenues of $6,008.4 million; income from continuing operations, net of income taxes of $826.6 million; basic earnings per share from continuing operations of $5.84; and diluted earnings per share from continuing operations of $5.75.

The pro forma income from continuing operations, net of income taxes includes adjustments to operating costs to reflect the additional expense for the estimated impact of the fair value adjustment for coal inventory, a reduction in postretirement benefit costs resulting from the new collective bargaining agreement described above, and the estimated impact on depreciation, depletion and amortization for the fair value adjustment for property, plant and equipment (including coal reserve assets). On a pro forma basis, the acquisition would have had no impact on taxable income due to the Company’s federal NOLs, as further described in Note 10. “Income Taxes.”

Pro forma information is not provided for the years ended December 31, 2020 or 2019 because the operations of the Shoal Creek Mine are reflected in the Company’s actual consolidated results for the entire year. The unaudited pro forma financial information does not necessarily reflect the results of operations that would have occurred had the operations of the Company and Shoal Creek Mine been combined during those periods or that may be attained in the future.

The Company’s North Goonyella Mine in Queensland, Australia experienced a fire in a portion of the mine during September 2018 and mining operations have been suspended since then. During the years ended December 31, 2019 and 2018, the Company recorded provisions for equipment losses of $83.2 million and $66.4 million, respectively, related to the fire, representing the best estimate of losses to date. No additional provisions for equipment losses were recorded during the year ended December 31, 2020. The Company has also incurred containment and idling costs subsequent to the mine’s suspension which amounted to $32.3 million, $111.5 million and $58.0 million during the years ended December 31, 2020, 2019 and 2018, respectively.

In March 2019, the Company entered into an insurance claim settlement agreement with its insurers and various re-insurers under a combined property damage and business interruption policy and recorded a $125 million insurance recovery, the maximum amount available under the policy above a $50 million deductible. The Company has collected the full amount of the recovery.

The Company is currently evaluating various alternatives regarding the future utility of the mine. In the event that no future mining occurs at the North Goonyella Mine or the Company is unable to find a commercial alternative, the Company may record additional charges for the remaining carrying value of the North Goonyella Mine of up to approximately $300 million, which is included in the at-risk value described in Note 3. “Asset Impairment.” Incremental exposures above the aforementioned include take-or-pay obligations and other costs associated with idling or closing the mine.

The Company’s Kayenta Mine closed during August 2019 upon termination of its coal supply agreement with the Navajo Generating Station (NGS) in Arizona. The NGS was the sole customer of the Kayenta Mine and the coal supply agreement provided for consideration to the Company related to its post-mining obligations for retiree healthcare and reclamation costs. A cumulative portion of such consideration, $53.5 million, was held in trust and released to the Company upon termination. During the fourth quarter of 2019, the parties entered into a settlement agreement to finalize such consideration for an additional $78.5 million payable to the Company. Of this amount, $35.4 million was receivable at December 31, 2019, all of which was collected during the year ended December 31, 2020.

In June 2018, Peabody entered into an agreement to sell approximately 23 million tonnes of metallurgical coal resources adjacent to its Millennium Mine to Stanmore Coal Limited for approximately $22 million. The sale was completed in July 2018 and the Company recorded a gain of $20.5 million which is included within “Net gain on disposals” in the accompanying consolidated statements of operations for the year ended December 31, 2018.

On February 6, 2018, the Company sold its 50% interest in the Red Mountain Joint Venture (RMJV) with BHP Billiton Mitsui Coal Pty Ltd (BMC) for $20.0 million and recorded a gain of $7.1 million, which is included within “Net gain on disposals” in the accompanying consolidated statements of operations for the year ended December 31, 2018. RMJV operated the coal handling and preparation plant utilized by the Company’s Millennium Mine. BMC assumed the reclamation obligations and other commitments associated with the assets of RMJV. The Millennium Mine had continued usage of the coal handling and preparation plant and the associated rail loading facility until the end of 2019 via a coal washing take-or-pay agreement with BMC.