Peabody Energy (BTU) 10-K 22 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document Document - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Mar. 15, 2017	Jun. 30, 2016
Document Information [Line Items]
Entity Registrant Name	PEABODY ENERGY CORP
Entity Central Index Key	1,064,728
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		18,491,188
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 25.3

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	$ (57.6)	$ (182.2)	$ (23.8)
Revenues
Sales	4,117.9	5,138.3	6,132.7
Other revenues	597.4	470.9	659.5
Total revenues	4,715.3	5,609.2	6,792.2
Costs and expenses
Operating costs and expenses (exclusive of items shown separately below)	4,107.6	5,007.7	5,716.9
Depreciation, depletion and amortization	465.4	572.2	655.7
Asset retirement obligation expenses	41.8	45.5	81
Selling and administrative expenses	153.4	176.4	227.1
Restructuring and pension settlement charges	15.5	23.5	26
Other operating (income) loss:
Net gain on disposal of assets	(23.2)	(45)	(41.4)
Asset impairment	247.9	1,277.8	154.4
(Gain) loss from equity affiliates	(16.2)	15.9	107.6
Operating loss	(276.9)	(1,464.8)	(135.1)
Interest Expense	298.6	465.4	426.6
Loss on early debt extinguishment	29.5	67.8	1.6
Interest income	(5.7)	(7.7)	(15.4)
Reorganization Items	159	0	0
Loss from continuing operations before income taxes	(758.3)	(1,990.3)	(547.9)
Income tax (benefit) provision	(84)	(176.4)	201.2
Loss from continuing operations, net of income taxes	(674.3)	(1,813.9)	(749.1)
Loss from discontinued operations, net of income taxes	(57.6)	(175)	(28.2)
Net loss	(731.9)	(1,988.9)	(777.3)
Less: Net income attributable to noncontrolling interests	7.9	7.1	9.7
Net loss attributable to common stockholders	$ (739.8)	$ (1,996)	$ (787)
Loss From Continuing Operations
Basic loss per share	$ (37.30)	$ (100.34)	$ (42.52)
Diluted loss per share	(37.30)	(100.34)	(42.52)
Net Loss Attributable to Common Stockholders
Basic loss per share	(40.45)	(109.98)	(44.09)
Diluted loss per share	(40.45)	(109.98)	(44.09)
Dividends declared per share	$ 0	$ 0.075	$ 5.100

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net loss	$ (199.3)	$ (133.7)	$ (233.8)	$ (165.1)	$ (470.2)	$ (301.9)	$ (1,043.5)	$ (173.3)	$ (493.7)	$ (731.9)	$ (1,988.9)	$ (777.3)
Net change in unrealized (losses) gains on available-for-sale securities (net of respective tax benefit of ($0.0), ($0.1) and $(0.5)
Unrealized holding losses on available-for-sale securities										0	0	(3.7)
Reclassification for realized losses included in net loss										0	0	2.9
Net change in unrealized losses on available-for-sale securities										0	0	(0.8)
Net unrealized gains (losses) on cash flow hedges (net of respective tax provision (benefit) of $85.9, $72.2 and ($54.6))
Decrease in fair value of cash flow hedges										0	(131.3)	(195)
Reclassification for realized losses (gains) included in net loss										146.3	251.7	(10.2)
Net unrealized gains (losses) on cash flow hedges										146.3	120.4	(205.2)
Postretirement plans and workers' compensation obligations (net of respective tax (benefit) provision of ($1.5), $36.2 and ($10.3))
Prior service (cost) credit for the period										(4.5)	10.4	11.4
Net actuarial (loss) gain for the period										(13.5)	18.1	(142.7)
Amortization of actuarial loss and prior service cost included in net loss										15.4	31.9	32.7
Postretirement plans and workers' compensation obligations										(2.6)	60.4	(98.6)
Foreign currency translation adjustment										(1.8)	(34.9)	(41)
Other comprehensive income (loss), net of income taxes										141.9	145.9	(345.6)
Comprehensive loss										(590)	(1,843)	(1,122.9)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										7.9	7.1	9.7
Comprehensive loss attributable to common stockholders										$ (597.9)	$ (1,850.1)	$ (1,132.6)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Allowance for Doubtful Accounts Receivable, Current	$ 13.1	$ 6.6
Current assets
Cash and cash equivalents	872.3	261.3
Restricted Cash and Investments, Current	54.3	0
Accounts receivable, net of allowance for doubtful accounts of $13.1 at December 31, 2016 and $6.6 at December 31, 2015	473	228.8
Inventories	203.7	307.8
Assets from coal trading activities, net	0.7	23.5
Deferred income taxes	0	53.5
Other current assets	486.6	447.6
Total current assets	2,090.6	1,322.5
Property, plant, equipment and mine development, net	8,776.7	9,258.5
Deferred income taxes	0	2.2
Investments and other assets	910.4	363.7
Total assets	11,777.7	10,946.9
Current liabilities
Current portion of long-term debt	20.2	5,874.9
Liabilities from coal trading activities, net	1.2	15.6
Accounts payable and accrued expenses	990.4	1,446.3
Total current liabilities	1,011.8	7,336.8
Long-term debt, less current portion	0	366.3
Deferred income taxes	17.6	69.1
Asset retirement obligations	717.8	686.6
Accrued postretirement benefit costs	756.3	722.9
Other noncurrent liabilities	496.2	846.7
Total liabilities	11,439.9	10,028.4
Total liabilities not subject to compromise	2,999.7	10,028.4
Liabilities Subject to Compromise	8,440.2	0
Stockholders' equity
Additional paid-in capital	2,422	2,410.7
Treasury stock, at cost - 0.8 shares as of December 31, 2016 and December 31, 2015	(371.8)	(371.7)
(Accumulated deficit) retained earnings	(1,243.2)	(503.4)
Accumulated other comprehensive loss	(477)	(618.9)
Peabody Energy Corporation's stockholders' equity	330.2	916.9
Noncontrolling interests	7.6	1.6
Total stockholders' equity	337.8	918.5
Total liabilities and stockholders' equity	11,777.7	10,946.9
Preferred Stock [Member]
Stockholders' equity
Preferred Stock	0	0
Perpetual Preferred Stock [Member]
Stockholders' equity
Preferred Stock	0	0
Series Common Stock [Member]
Stockholders' equity
Common Stock	0	0
Common Stock [Member]
Stockholders' equity
Common Stock	$ 0.2	$ 0.2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows From Operating Activities
Net loss	$ (731.9)	$ (1,988.9)	$ (777.3)
Loss from discontinued operations, net of income taxes	57.6	175	28.2
Loss from continuing operations, net of income taxes	(674.3)	(1,813.9)	(749.1)
Adjustments to reconcile loss from continuing operations, net of income taxes to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	465.4	572.2	655.7
Noncash interest expense	61.3	30.6	23.6
Deferred income taxes	(86.5)	(107.6)	231.9
Share-based Compensation, Total	12.8	28.2	46.8
Asset impairment	247.9	1,277.8	154.4
Net gain on disposal of assets	(23.2)	(45)	(41.4)
(Gain) loss from equity affiliates	(16.2)	15.9	107.6
Gain on VEBA settlement	(68.1)	0	0
Monetization of foreign currency hedge positions	(25)	(14.9)	(136.9)
Gains on previously monetized foreign currency hedge positions	125.2	0	0
Debtor Reorganization Items, Other Expense (Income)	90.9	0	0
Changes in current assets and liabilities:
Accounts receivable	(101.3)	188	55.4
Change in receivable from accounts receivable securitization program	(168.5)	138.5	(70)
Inventories	104	96.2	104.9
Net assets from coal trading activities	8.5	(27.3)	(10.1)
Other current assets	(24.4)	14.8	7.7
Accounts payable and accrued expenses	156.5	(381.7)	(29.2)
Decrease in Restricted Cash for Operating Activities	(125.7)	0	0
Asset retirement obligations	13.1	23.9	60.3
Workers' compensation obligations	(0.4)	(4.2)	2.2
Accrued postretirement benefit costs	6.3	18.7	9.6
Accrued pension costs	21.7	29.6	28.3
Take or pay obligation settlement	(15.5)	0	0
Other, net	(7.4)	(20.9)	(10.7)
Net cash provided by continuing operations	(22.9)	18.9	441
Net cash used in discontinued operations	(29.9)	(33.3)	(104.4)
Net cash provided by operating activities	(52.8)	(14.4)	336.6
Cash Flows From Investing Activities
Additions to property, plant, equipment and mine development	(126.6)	(126.8)	(194.4)
Changes in accrued expenses related to capital expenditures	(6.1)	(9.2)	(16.6)
Federal coal lease expenditures	(249)	277.2	276.7
Proceeds from disposal of assets, net of notes receivable	144.4	70.4	203.7
Purchases of debt and equity securities	0	(28.8)	(15.1)
Proceeds from sales and maturities of debt and equity securities	0	90.3	13.5
Contributions to joint ventures	(309.5)	(425.4)	(529.8)
Distributions from joint ventures	312.4	422.6	534.2
Advances to related parties	(40.4)	(3.7)	(33.7)
Repayment of loans from related parties	40.6	0.9	5.4
Other, net	(9.9)	(3.1)	(5)
Net cash used in investing activities	(244.1)	(290)	(314.5)
Net cash used in investing activities	(244.1)	(290)	(314.5)
Cash Flows From Financing Activities
Proceeds from long-term debt	1,458.4	975.7	1.1
Repayments of long-term debt	(513.7)	(671.3)	(21)
Payment of deferred financing costs	(31)	(28.7)	(10.1)
Dividends paid	0	(1.4)	(92.3)
Restricted cash for distributions to noncontrolling interests	0	0	(42.5)
Other, net	(5.8)	(6.6)	(3.3)
Net cash used in financing activities	907.9	267.7	(168.1)
Net change in cash and cash equivalents	611	(36.7)	(146)
Cash and cash equivalents at beginning of year	261.3	298	444
Cash and cash equivalents at end of year	$ 872.3	$ 261.3	$ 298

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Noncontrolling Interests [Member]	Equity Award
Beginning Balance at Dec. 31, 2013	$ 3,947.9	$ 0.2	$ 2,342.6	$ (464.7)	$ 2,449.8	$ (419.2)	$ 39.2
Net loss	(777.3)
Net loss attributable to common stockholders	(787)				(787)
Less: Net income attributable to noncontrolling interests	9.7						9.7
Net change in unrealized gains (losses) on available-for-sale securities, net of tax	(0.8)					(0.8)
Net unrealized gains (losses) on cash flow hedges	(205.2)					(205.2)
Foreign currency translation adjustment	(41)					(41)
Dividends paid	(92.3)				(92.3)
Share-based Compensation for equity-classified awards	46.1		46.1					$ 46.1
Excess (write-off) tax benefits related to share-based compensation	(8.3)		(8.3)
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options	5.5
Defined contribution plan share contribution	0.5		0.5
Postretirement plans and workers' compensation obligations	(98.6)					(98.6)
Employee stock purchases	5.1		5.1
Repurchase of employee common stock relinquished for tax withholding	(2.4)		0	(2.4)
Distributions to Non controlling interest	4.7						(4.7)
Dividend payable to noncontrolling interests	(42.5)						(42.5)
Ending Balance at Dec. 31, 2014	2,726.5	0.2	2,386	(467.1)	1,570.5	(764.8)	1.7
Net loss	(1,988.9)
Net loss attributable to common stockholders	(1,996)				(1,996)
Less: Net income attributable to noncontrolling interests	7.1						7.1
Net change in unrealized gains (losses) on available-for-sale securities, net of tax	0
Net unrealized gains (losses) on cash flow hedges	120.4					120.4
Foreign currency translation adjustment	(34.9)					(34.9)
Dividends paid	(1.4)				(1.4)
Share-based Compensation for equity-classified awards	26.2		26.2					26.2
Excess (write-off) tax benefits related to share-based compensation	0	0	(3.5)	0	0	0	0
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options	3.4
Defined contribution plan share contribution	19.6		(1.4)	97.5	(76.5)
Postretirement plans and workers' compensation obligations	60.4					60.4
Employee stock purchases	(4)		3.4				(0.5)
Repurchase of employee common stock relinquished for tax withholding	(2.1)			(2.1)
Consolidation of noncontrolling interests	1.6	0	0	0	0	0	1.6
Dividend payable to noncontrolling interests	(6.3)						(6.3)
Dividend payable to noncontrolling interests	(2)						(2)
Ending Balance at Dec. 31, 2015	918.5	0.2	2,410.7	(371.7)	(503.4)	(618.9)	1.6
Net loss	(731.9)
Net loss attributable to common stockholders	(739.8)				(739.8)
Less: Net income attributable to noncontrolling interests	7.9						7.9
Net unrealized gains (losses) on cash flow hedges	146.3					146.3
Foreign currency translation adjustment	(1.8)					(1.8)
Share-based Compensation for equity-classified awards			11.3					$ 11.3
Excess (write-off) tax benefits related to share-based compensation	0
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options	0
Postretirement plans and workers' compensation obligations	(2.6)					(2.6)
Repurchase of employee common stock relinquished for tax withholding	(0.1)			(0.1)
Dividend payable to noncontrolling interests	(1.9)	0	0	0	0	0	(1.9)
Dividend payable to noncontrolling interests		0	0	0	0	0
Ending Balance at Dec. 31, 2016	$ 337.8	$ 0.2	$ 2,422	$ (371.8)	$ (1,243.2)	$ (477)	$ 7.6

Comprehensive Income Parentheti

Comprehensive Income Parenthetical (Parentheticals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net change in unrealized (losses) gains on available-for-sale securities, tax (benefit) provision	$ 0	$ (0.1)	$ (0.5)
Net unrealized gains (losses) on cash flow hedges, tax benefit	85.9	72.2	(54.6)
Postretirement plans and workers' compensation obligations, tax (benefit) provision	$ (1.5)	$ 36.2	$ (10.3)

Balance Sheet Parenthetical (Pa

Balance Sheet Parenthetical (Parentheticals) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current assets
Allowance for Doubtful Accounts Receivable, Current	$ 13.1	$ 6.6
Stockholders' equity
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Common Stock, par or Stated Value Per Share	$ 0.01
Common Stock, Shares Authorized	53.3
Common Stock, shares outstanding	18.5	18.5
Treasury Stock, shares	0.8	0.8
Preferred Stock [Member]
Stockholders' equity
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, shares authorized	10	10
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Perpetual Preferred Stock Member
Stockholders' equity
Preferred Stock, shares authorized	0.8	0.8
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Series Common Stock Member
Stockholders' equity
Common Stock, par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	40	40
Common Stock, shares issued	0	0
Common Stock, shares outstanding	0	0
Common Stock [Member]
Stockholders' equity
Common Stock, par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	53.3	53.3
Common Stock, shares issued	19.3	19.3
Common Stock, shares outstanding	18.5	18.5

Stockholders' Equity Parentheti

Stockholders' Equity Parenthetical (Parentheticals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders' Equity Parenthetical [Abstract]
Net change in unrealized (losses) gains on available-for-sale securities, tax (benefit) provision	$ 0	$ (0.1)	$ (0.5)
Net unrealized gains (losses) on cash flow hedges, tax benefit	85.9	72.2	(54.6)
Postretirement plans and workers' compensation obligations, tax (benefit) provision	$ (1.5)	$ 36.2	$ (10.3)

Summary of Significant Accounti

Summary of Significant Accounting Policies Discussion	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies Discussion	Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements include the accounts of Peabody Energy Corporation and its affiliates. The Company, or Peabody, are used interchangeably to refer to Peabody Energy Corporation, to Peabody Energy Corporation and its subsidiaries, or to such subsidiaries, as appropriate to the context. Interests in subsidiaries controlled by the Company are consolidated with any outside stockholder interests reflected as noncontrolling interests, except when the Company has an undivided interest in an unincorporated joint venture. In those cases, the Company includes its proportionate share in the assets, liabilities, revenues and expenses of the jointly controlled entities within each applicable line item of the consolidated financial statements. All intercompany transactions, profits and balances have been eliminated in consolidation. As discussed below in "Newly Adopted Accounting Standards," prior year amounts of deferred financing costs have been reclassified to conform with the new standard. Pursuant to the authorization provided at a special meeting of the Company's stockholders held on September 16, 2015, the Company completed a 1-for-15 reverse stock split of the shares of the Company’s common stock on September 30, 2015 (the Reverse Stock Split). As a result of the Reverse Stock Split, every 15 shares of issued and outstanding common stock were combined into one issued and outstanding share of Common Stock, without any change in the par value per share. No fractional shares were issued as a result of the Reverse Stock Split and any fractional shares that would otherwise have resulted from the Reverse Stock Split were paid in cash. The Reverse Stock Split reduced the number of shares of common stock outstanding from approximately 278 million shares to approximately 19 million shares. The number of authorized shares of common stock was also decreased from 800 million shares to 53.3 million shares. The Company's common stock began trading on a reverse stock split-adjusted basis on October 1, 2015. All share and per share data included in this report has been retroactively restated to reflect the Reverse Stock Split. Since the par value of the common stock remained at $0.01 per share, the value for "Common stock" recorded to the Company's consolidated balance sheets has been retroactively reduced to reflect the par value of restated outstanding shares, with a corresponding increase to "Additional paid-in capital." The Company has classified items within discontinued operations in the audited consolidated financial statements for disposals (by sale or otherwise) that have occurred prior to January 1, 2015 when the operations and cash flows of a disposed component of the Company were eliminated from the ongoing operations of the Company as a result of the disposal and the Company no longer had any significant continuing involvement in the operation of that component. Description of Business The Company is engaged in the mining of thermal coal for sale primarily to electric utilities and metallurgical coal for sale to industrial customers. The Company’s mining operations are located in the United States (U.S.) and Australia, including an equity-affiliate mining operation in Australia. The Company also markets and brokers coal from other coal producers, both as principal and agent, and trades coal and freight-related contracts through trading and business offices in Australia, China, Germany, the United Kingdom and the U.S. (listed alphabetically). The Company’s other energy-related commercial activities include managing its coal reserve and real estate holdings and supporting the development of clean coal technologies. Filing Under Chapter 11 of the United States Bankruptcy Code On April 13, 2016 (the Petition Date), Peabody and a majority of its wholly owned domestic subsidiaries as well as one international subsidiary in Gibraltar (the Filing Subsidiaries, and together with Peabody, the Debtors) filed voluntary petitions for reorganization (the petitions collectively, the Bankruptcy Petitions) under Chapter 11 of Title 11 of the U.S. Code (the Bankruptcy Code) in the United States Bankruptcy Court for the Eastern District of Missouri (the Bankruptcy Court). The Company’s Australian operations and other international subsidiaries are not included in the filings. The Debtors' Chapter 11 cases (collectively, the Chapter 11 Cases) are being jointly administered under the caption In re Peabody Energy Corporation, et al. , Case No. 16-42529 (Bankr. E.D. Mo.). The Debtors continue to operate their business as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of the Bankruptcy Code and orders of the Bankruptcy Court. In general, as debtors-in-possession, the Debtors are authorized under Chapter 11 to continue to operate as an ongoing business, but may not engage in transactions outside the ordinary course of business without the prior approval of the Bankruptcy Court. The filings of the Bankruptcy Petitions constituted an event of default under the Company’s prepretition credit agreement as well as the indentures governing certain of the Company’s debt instruments, as further described in Note 14. "Current and Long-term Debt" to the consolidated financial statements, and all unpaid principal and accrued and unpaid interest due thereunder became immediately due and payable. Any efforts to enforce such payment obligations are automatically stayed as a result of the Bankruptcy Petitions and the creditors' rights of enforcement are subject to the applicable provisions of the Bankruptcy Code. Additionally, on the Petition Date, the New York Stock Exchange (NYSE) determined that Peabody’s common stock was no longer suitable for listing pursuant to NYSE regulations, and trading in the Company’s common stock was suspended. The Company's common stock began trading on the OTC Pink Sheets marketplace under the symbol BTUUQ on April 14, 2016. Following the Petition Date, the NYSE formally de-listed the Company's common stock. In August 2016, the Company outlined a business plan intended to form the basis for its plan of reorganization, as further described below. As a result of its reorganization, the Company expects to emerge from its Chapter 11 Cases with the competitive cost structure necessary to improve its financial position and provide long-term stability for its stakeholders in the face of potentially volatile supply and demand conditions. Important aspects of the Company’s emergence business strategy include (i) a continued focus on safe, cost-disciplined mining operations and reclamation activities, (ii) maximization of the most profitable elements of its asset base and potential divesture of non-strategic assets, (iii) investment return-driven capital discipline, and (iv) a reduction of overall debt and fixed charges. Filing of Plan of Reorganization with the Bankruptcy Court. In order to successfully emerge from the Chapter 11 Cases, the Debtors must propose and obtain confirmation from the Bankruptcy Court of a plan of reorganization that satisfies the requirements of the Bankruptcy Code. The Debtors retain the exclusive right to file a plan of reorganization until May 1, 2017, and have the exclusive right until June 30, 2017 to obtain the necessary acceptances to a plan. These periods may be extended by the Bankruptcy Court for cause. If the Debtors’ exclusivity period were to lapse, any party in interest may file a plan of reorganization for any of the Debtors. On January 27, 2017, the Debtors filed with the Bankruptcy Court their Second Amended Joint Plan of Reorganization of Debtors and Debtors in Possession (as further modified, the Plan) and a related Second Amended Disclosure Statement with Respect to Second Amended Joint Plan of Reorganization of Debtors and Debtors in Possession (Disclosure Statement). The Plan provides for, among other things, (1) classification and treatment of various claims and equity interests, (2) a reduction of the Company’s debt upon emergence, and (3) the recapitalization of the Company through a rights offering and private placement for equity securities of the Company. The Bankruptcy Court approved the Disclosure Statement by order entered on January 27, 2017. The reorganization contemplated by the Plan will reduce the Debtors' debt burden by over $6.6 billion , but does not compromise existing coal mining reclamation obligations. The Plan will provide creditors with recoveries, funded in large part by a $1.95 billion first lien exit facility, a $750 million rights offering available to holders of second lien and general unsecured claims, and a $750 million private placement offering of new mandatory convertible preferred stock of the Company. Under the Plan, current holders of the Company’s equity interests will not receive any distributions, and their equity interests will be canceled once the Plan becomes effective. The Company and various creditor constituencies entered into an agreement which serves as the cornerstone of the Plan (the Global Settlement). The Global Settlement is premised upon a consensual resolution of a number of complex issues that have been the subject of extensive and vigorous negotiations post-petition among the Debtors and holders of certain second lien notes. Under the Global Settlement, certain lenders will backstop the first lien exit facility by agreeing to take up to $1.5 billion in take-back paper in the event the Debtors are unable to raise the exit facility, subject to certain restrictions as set forth in the Plan. Similarly, holders of certain second lien notes have agreed that, at the Company's sole discretion, in partial satisfaction of their claims, they may receive $450 million in cash, $450 million of first lien debt on the same terms as the exit facility or $450 million of new second lien notes at terms and conditions set forth in the Plan. A third group of lenders and other parties have agreed to backstop the $750 million rights offering and invest through the $750 million private placement offering in order to ensure that the Company raises the $1.5 billion equity investment that will be necessary to consummate the Plan. On January 11, 2017, the Debtors obtained an exit facility commitment letter (Exit Facility Commitment Letter) from a consortium of lenders (Lenders), pursuant to which, in connection with the consummation of the Plan, the Lenders have agreed to provide a senior secured term loan facility (Term Loan Facility) in an aggregate amount of (a) $1.5 billion , less (b) the aggregate principal amount of privately placed debt securities (Notes) of the Company, or special purpose escrow issuer, issued on or prior to the closing date of the Term Loan Facility (Closing Date), plus (c) any amount of additional senior secured term loans funded on the Closing Date at the sole discretion of the Term Loan Facility's arranging Lenders and the Company. The commitments of the Lenders to provide the Term Loan Facility are subject to the occurrence or waiver of all conditions precedent to the effectiveness of the Plan, other than the closing and funding of the Term Loan Facility (and the Notes issued in lieu thereof, if any). The Lenders’ commitments to provide and arrange the Term Loan Facility will terminate on a dollar-for-dollar basis to the extent of the issuance of the Notes. On February 8, 2017, the Company announced the pricing of a $950.0 million senior secured term loan. The term loan will mature in 2022 and bears interest at a fluctuating rate of LIBOR plus 4.50% per annum, with a 1.00% LIBOR floor. The closing of the term loan is expected to occur in early April 2017, concurrently with the anticipated effective date of the Plan and subject to customary closing conditions and final documentation. The proceeds from the term loan will be used to fund a portion of the distributions to creditors provided for under the Plan. Also on February 8, 2017, the Company announced that a special purpose wholly owned subsidiary of the Company priced an offering of $500.0 million aggregate principal amount of 6.000% senior secured notes due 2022 and $500.0 million aggregate principal amount of 6.375% senior secured notes due 2025, each exempt from the registration requirements of the Securities Act of 1933, as amended. The offering of the notes closed on February 15, 2017 at which time the net proceeds of the offering were funded into an escrow account pending the Plan Effective Date. The notes are being offered by a special purpose wholly owned subsidiary of the Company. If certain conditions are satisfied on or before August 1, 2017, the net proceeds from the offering will be released from escrow to fund a portion of the distributions to creditors provided for under the Plan, and the Company will become the obligor under the notes. Pursuant to the Plan, the Company will use reasonable best efforts to cause the Company's common stock (Reorganized PEC Common Stock) and Preferred Equity (as defined below) to be listed on the New York Stock Exchange as soon as practicable after the Plan Effective Date. The Plan also provides for a long-term incentive plan (the LTIP) for directors, management and other employees of the Company, including reservation of an amount of Reorganized PEC Common Stock for the LTIP. In addition, in accordance with the Plan, a nine member Board of Directors of the Company was established (the Reorganized PEC Board). The Reorganized PEC Board is comprised of the Company’s Chief Executive Officer and eight independent directors. On January 26, 2017, the Bankruptcy Court approved the amended Disclosure Statement, and authorized the Debtors to begin soliciting votes from creditors to approve the Plan. Subsequently, the Debtors solicited votes on the Plan. On March 15, 2017, the Debtors filed a revised version of the Plan. On March 16, 2017, the Bankruptcy Court held a hearing to determine whether the Plan should be confirmed. On March 17, 2017, the Bankruptcy Court entered an order confirming the Plan. Although the Bankruptcy Court has confirmed the Plan, the Debtors have not yet consummated all of the transactions that are contemplated by the Plan. Rather, the Debtors intend to consummate these transactions in the near future, on or before the Plan Effective Date. As set forth in Section V.B of the Plan, there are certain conditions precedent to the occurrence of the Plan Effective Date, which must be satisfied or waived in accordance with the Plan in order for the Plan to become effective and the Debtors to emerge from the Chapter 11 Cases. The Debtors anticipate that each of these conditions will be either satisfied or waived by early April 2017, which is the target for the Debtors' emergence from the Chapter 11 Cases. On the Plan Effective Date, the Debtors will, generally, no longer be governed by the Bankruptcy Court's oversight. Under the provisions set forth in Section 1129(b) of the Bankruptcy Code, the Bankruptcy Court confirmed the Plan even though the Plan was not accepted by all impaired classes of claims and equity interests. The classes of claims or equity interests that will not receive or retain any property under the Plan on account of such claims or interests were deemed to have voted to reject the Plan. The precise requirements and evidentiary showing for confirming a plan notwithstanding its rejection by one or more impaired classes of claims or equity interests depends upon a number of factors, including the status and seniority of the claims or equity interests in the rejecting class (e.g., secured claims or unsecured claims, subordinated or senior claims, preferred or common stock). Generally, the Bankruptcy Court confirmed the Plan and allowed it to be “crammed down” on owners of the Company's common stock, even though the shareowners will receive no recovery under the Plan, because the Debtors demonstrated that (1) no class junior to the common stock is receiving or retaining property under the Plan and (2) no class of claims or interests senior to the common stock is being paid more than in full. Notices to Creditors; Effect of Automatic Stay. Shortly after the Petition Date, the Debtors began notifying all known current or potential creditors of the Chapter 11 filing. Pursuant to Section 362 of the Bankruptcy Code, the filing of the Bankruptcy Petitions automatically stayed most actions against the Debtors, including actions to collect indebtedness incurred prior to the Petition Date or to exercise control over the Debtors’ property. Subject to certain exceptions under the Bankruptcy Code, the filing of the Debtors’ Chapter 11 Cases also automatically stayed the continuation of most legal proceedings, including certain of the third party litigation matters described in Note 26. "Commitments and Contingencies" and Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" of this report or the filing of other actions against or on behalf of the Debtors or their property to recover on, collect or secure a claim arising prior to the Petition Date or to exercise control over property of the Debtors’ bankruptcy estates, unless and until the Bankruptcy Court modifies or lifts the automatic stay as to any such claim. Notwithstanding the general application of the automatic stay described above, governmental authorities may determine to continue actions brought under their police and regulatory powers. The automatic stay remains in place pending the occurrence of the Plan Effective Date. After the Plan Effective Date, subject to certain limited exceptions, holders of claims against the Debtors and interests in the Debtors will be bound by the discharge, release and exculpation provisions set forth in Sections V.E.2, V.E.4 and V.E.5 of the Plan and will be enjoined from taking any action against the reorganized Debtors pursuant to the injunction provisions set forth in Section V.E.3 of the Plan and paragraphs 16 through 31 of the order confirming the Plan. Appointment of Creditors' Committee. As required by the Bankruptcy Code, the United States Trustee for the Eastern District of Missouri appointed an official committee of unsecured creditors (the Creditors' Committee) on April 29, 2016. On January 4, 2017, the United States Trustee for the Eastern District of Missouri filed a document with the Bankruptcy Court indicating that additional members had been added to the Creditors' Committee. The Creditors' Committee represents all unsecured creditors of the Debtors and has a right to be heard on all matters that come before the Bankruptcy Court. The Creditors' Committee has been generally supportive of the Debtors’ positions on various matters. After negotiations between the Creditors' Committee and the Debtors, the Debtors agreed to include the following provisions in the Plan in exchange for the Creditors' Committee's support for the Plan: (a) holders of Class 5B Claims (as defined in the Plan) will have the option to elect to receive, in lieu of receiving other distributions on such claims, their pro rata share of $75 million in cash (with recoveries capped at 50%) and (b) the cash distributable to Class 5A Claims (as defined in the Plan) will be set at $5 million . In exchange for these, and certain other, provisions, the Creditors' Committee agreed to support the Plan. Rejection of Executory Contracts. Under Section 365 and other relevant sections of the Bankruptcy Code, the Debtors may assume, assume and assign, or reject certain executory contracts and unexpired leases, including leases of real property and mining equipment, subject to the approval of the Bankruptcy Court and certain other conditions. In general, rejection of an executory contract or unexpired lease is treated as a prepetition breach of the executory contract or unexpired lease in question and, subject to certain exceptions, relieves the Debtors of performing their future obligations under such executory contract or unexpired lease but entitles the contract counterparty or lessor to a prepetition general unsecured claim for damages caused by such deemed breach. Counterparties to such rejected contracts or leases can file claims against the Debtors for such damages. Generally, the assumption of an executory contract or unexpired lease requires the Debtors to cure existing defaults under such executory contract or unexpired lease. Under the terms of the Plan, the Debtors will reject all of their executory contracts and unexpired leases unless the Debtors expressly provide for the assumption of any such executory contract or unexpired lease, or any such executory contract or unexpired lease is otherwise assumed pursuant to the terms of the Plan. With limited exceptions, the assumptions and rejections of the executory contracts and unexpired leases pursuant to the Plan will occur as of the Plan Effective Date. Liabilities subject to compromise and resolution in the Chapter 11 proceedings will likely arise in the future as a result of damage claims created by the Debtors’ rejection of various executory contracts and unexpired leases. Such claims may be material (see “Magnitude of Potential Claims” below). 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 confirming 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 December 31, 2016, the Company had approximately $189 million of remaining commitments under these non-debtor lease arrangements. Adequate Protection. The Debtors were required to make adequate protection payments subsequent to the Petition Date to certain secured lenders and other parties in accordance with Section 502(b)(2) of the Bankruptcy Code in order to continue using the assets comprising collateral under the Debtors’ first lien debt and because of the priming liens granted to the DIP Lenders, as defined in Note 14. "Current and Long-term Debt". Such payments are included in interest expense in the accompanying consolidated statements of operations. Magnitude of Potential Claims. The Debtors filed with the Bankruptcy Court schedules and statements of financial affairs setting forth, among other things, the assets and liabilities of the Debtors, subject to the assumptions filed in connection therewith. The schedules were not prepared in accordance with generally accepted accounting principles and are subject to amendment or modification. Bankruptcy Rule 3003(c)(3) requires the Bankruptcy Court to set the time within which proofs of claim must be filed in a Chapter 11 case. The Bankruptcy Court established August 19, 2016 (the Bar Date) as the last date and time for each person or entity to file a proof of claim against the Debtors. The Bankruptcy Court also established October 11, 2016, as the last date for governmental units to file a proof of claim against the Debtors. Subject to certain exceptions, the Bar Date applies to all claims against the Debtors that arose prior to the Petition Date. As of March 20, 2017, nearly 7,000 claims had been filed with the Bankruptcy Court against the Debtors, and new and amended claims are expected to be filed in the future, including claims amended to assign values to claims originally filed with no designated value. Management has identified, and expects to continue to identify, many claims that it believes should be disallowed by the Bankruptcy Court because they are duplicative, have been later amended or superseded, are without merit, are overstated or for other reasons. The Bankruptcy Court has disallowed certain claims and has not yet ruled on other objections to claims. Management expects to continue to file objections in the future. Because the process of analyzing and objecting to claims will be ongoing, the number of disallowed claims may increase significantly in the future. Through the claims resolution process, differences in amounts scheduled by the Debtors and claims filed by creditors will be investigated and resolved, including through the filing of objections with the Bankruptcy Court where appropriate. In light of the substantial number and amount of claims filed, the claims resolution process may take considerable time to complete, and management expects that it will continue after emergence from Chapter 11. Accordingly, the ultimate number and amount of allowed claims is not presently known, nor is the exact recovery with respect to allowed claims presently known. Costs of Reorganization. The Company has incurred and will continue to incur significant costs associated with reorganization. The amount of these costs, which are being expensed as incurred, are expected to significantly affect the Company’s results of operations. For additional information, see Note 2. “Reorganization Items, Net". Effect of Filing on Creditors and Equity Holders. Under the priority structure established by the Bankruptcy Code, unless creditors agree otherwise, prepetition claims and post-petition claims must be satisfied in full before equity holders are entitled to receive any distribution or retain any property under a plan of reorganization. Under the Plan, current holders of Peabody common stock will not retain or receive any property, and the common stock, and other Peabody equity interests, will be canceled upon the Plan Effective Date. As discussed above (see “Filing of Plan of Reorganization with the Bankruptcy Court”), because the Plan satisfied the requirements of Section 1129(b) of the Bankruptcy Code, the Plan was confirmed notwithstanding its rejection by the holders of Peabody common stock and notwithstanding the fact that such holders do not receive or retain any property on account of their equity interests under the plan. Newly Adopted Accounting Standards Going Concern. In August 2014, the Financial Accounting Standards Board (FASB) issued disclosure guidance that requires management to evaluate, at each annual and interim reporting period, whether substantial doubt exists about an entity's ability to continue as a going concern and, if applicable, to provide related disclosures. As outlined by that guidance, substantial doubt about an entity's ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that an entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued (or are available to be issued). The new guidance is effective for annual reporting periods ending after December 15, 2016 (the year ending December 31, 2016 for the Company) and interim periods thereafter, with early adoption permitted. The Company is currently operating its business as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court, has incurred net losses for the years ended 2016, 2015 and 2014, and had an accumulated deficit as of December 31, 2016 and 2015. These conditions raise substantial doubt about the Company's ability to continue for one year from the date these financial statements are issued. However, the Bankruptcy Court entered an order confirming the Plan on March 17, 2017 and the Company's current projections, based on the confirmed Plan, indicate that it is probable the Company will have sufficient liquidity to meet its obligations as they become due within one year after the date of this report. The confirmed Plan provides for the elimination of the Company's existing debt outstanding at December 31, 2016, which is discussed in Note 14. "Current and Long-term Debt." The Company's projections include the debt issued and planned equity issuance as part of its restructuring which are discussed above in “Filing of Plan of Reorganization with the Bankruptcy Court." Given the Plan confirmation on March 17, 2017, management believes it is probable the Plan will become effective and consummated in early April 2017, and emergence from the Chapter 11 Cases will occur at that time. There are certain substantial conditions precedent for the confirmed Plan to become effective and legally binding. Management believes it is probable these conditions precedent to the Plan effective date will be satisfied or waived by the Company’s targeted emergence date in early April 2017. Based on the confirmation of the Plan and the Company's financial projections, management believes it is probable the conditions that raise substantial doubt about its ability to continue as a going concern have been alleviated. The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern and contemplate the realization of assets and the satisfaction of liabilities in the normal course of business, the likelihood of which has been increased by the Bankruptcy Court’s confirmation of the Company’s Plan and the Company's ability to obtain exit financing, but is contingent on the Company’s ability to successfully consummate the Plan and maintain sufficient liquidity, among other factors. As a result of the Bankruptcy Petitions, the realization of assets and the satisfaction of liabilities are subject to uncertainty. If the Plan were not to become effective and the Company continued to operate as debtors-in-possession under Chapter 11, the Company may sell or otherwise dispose of or liquidate assets or settle liabilities, subject to the approval of the Bankruptcy Court or as otherwise permitted in the ordinary course of business for amounts other than those reflected in the accompanying consolidated financial statements. Further, the Plan is expected to materially change the amounts and classifications of assets and liabilities reported in the consolidated financial statements. The accompanying consolidated financial statements do not include any adjustments related to the recoverability and classification of assets or the amounts and classification of liabilities or any other adjustments that might be necessary should the Company be unable to continue as a going concern or as a consequence of the Bankruptcy Petitions. Deferred Financing Costs. On April 7, 2015, the FASB issued accounting guidance that requires deferred financing costs to be presented as a direct reduction from the related debt liability in the financial statements rather than as a separately recognized asset. Under the new guidance, amortization of such costs will continue to be reported as interest expense. In August 2015, an update was issued that clarified that debt issuance costs associated with line-of-credit arrangements may continue to be reported as an asset. The new guidance became effective retrospectively for interim and annual periods beginning after December 15, 2015 (January 1, 2016 for the Company). There was no material impact to the Company's results of operations or cash flows in connection with the adoption of the guidance. The impact to the Company's consolidated balance sheets as of December 31, 2015 was as follows: Before Application of Accounting Guidance Adjustment After Application of Accounting Guidance (Dollars in millions) Other current assets $ 503.1 $ (55.5 ) $ 447.6 Investments and other assets 382.6 (18.9 ) 363.7 Total assets 11,021.3 (74.4 ) 10,946.9 Current portion of long-term debt 5,930.4 (55.5 ) 5,874.9 Long-term debt, less current portion 385.2 (18.9 ) 366.3 Total liabilities 10,102.8 (74.4 ) 10,028.4 Income Taxes. In November 2015, the FASB issued accounting guidance that requires entities to classify all deferred tax assets and liabilities, along with any related valuation allowance as noncurrent on the balance sheet. Under the new guidance, each jurisdiction will now only have one net noncurrent deferred tax asset or liability. The new guidance does not change the existing requirement that only permits offsetting within a jurisdiction. The new guidance will be effective prospect

Asset Impairment and Mine Closu

Asset Impairment and Mine Closure Costs	12 Months Ended
	Dec. 31, 2016
Asset Impairment and Mine Closure Costs [Abstract]
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Asset Impairment Year Ended December 31, 2016 The following costs are reflected in "Asset impairment" in the consolidated statement of operations for the year ended December 31, 2016: Reportable Segment Australian Metallurgical Mining Corporate and Other Consolidated (Dollars in millions) Asset impairment charges $ 193.2 $ 54.7 $ 247.9 Australian Metallurgical Mining On November 3, 2016, Peabody Australia Mining Pty Ltd, one of the Company’s Australian subsidiaries, entered into a definitive share sale and purchase agreement (SPA) for the sale of all of its equity interest in Metropolitan Collieries Pty Ltd, the entity that owns the Metropolitan mine in New South Wales, Australia and the associated interest in the Port Kembla Coal Terminal, to a subsidiary of South32 Limited (South32). Pursuant to the SPA, the Company will receive cash consideration of $200 million , subject to a customary working capital adjustment. The transaction also includes contingent consideration that enables the Company to share equally with South32 in any revenue above an agreed metallurgical coal price forward curve, after taxes, royalties and appropriate discounts, on all coal sold for the 12 months following completion of the transaction, subject to extension if a minimum amount of coal is not sold during that period. The closing of the transaction is conditional on receipt of approval from the Australian Competition and Consumer Commission (the ACCC). On February 22, 2017, the ACCC issued a Statement of Issues relating to the transaction, noting that the ACCC is continuing to review the transaction. On February 24, 2017, pursuant to its right under the SPA, South32 extended the CP End Date (as defined in the SPA) from March 3, 2017 to April 17, 2017. On March 21, 2017, the ACCC notified the Company that it has extended the date on which it intends to render its decision regarding the transaction to April 27, 2017, which date extends beyond the CP End Date. As a result, the Company is assessing its options under the SPA. The Company determined that, as a result of entering into the transaction, and the approval of the Company’s Board of Directors of such a transaction in October 2016, the Metropolitan mine was deemed to meet held-for-sale accounting criteria in the fourth quarter of 2016. Accordingly, the Company recorded an after-tax impairment charge of $193.2 million to write down the assets to their estimated selling price, which is the best estimate of fair value under a held-for-sale accounting model. Corporate and Other During a 2016 review of its asset portfolio and prepetition leases, the Company identified certain non-strategic Midwestern coal reserves held under lease that were determined to be uneconomical to be mined in the future. As a result, the Company rejected certain leases and recognized an aggregate impairment charge of $37.5 million . The Company also recognized a $17.2 million impairment charge to record at fair value certain non-strategic Australian metallurgical assets classified as held for sale. For additional information regarding those divested assets, refer to Note 22. "Resource Management, Acquisitions and Other Commercial Events". Risks and Uncertainties The Company's mining and exploration assets and mining-related investments may be adversely affected by numerous uncertain factors that may cause the Company to be unable to recover all or a portion of the carrying value of those assets. The Company generally does not view short-term declines in thermal and metallurgical coal prices as an indicator of impairment. However, the Company generally views a sustained trend (for example, over periods exceeding one year) of adverse coal pricing or unfavorable changes thereto as a potential indicator of impairment. Because of the volatile and cyclical nature of coal prices and demand, it is reasonably possible that coal prices may decrease and/or fail to improve in the near term, which, absent sufficient mitigation such as an offsetting reduction in the Company's operating costs, may result in the need for future adjustments to the carrying value of the Company's long-lived mining assets and mining-related investments. The Company's assets whose recoverability and values are most sensitive to near-term pricing include certain Australian metallurgical and thermal assets and certain U.S. coal properties being leased to unrelated mining companies under agreements that require royalties to be paid as the coal is mined. These assets had an aggregate carrying value of $1,407.3 million as of December 31, 2016. The Company conducted a review of those assets for recoverability as of December 31, 2016 and determined that, other than the charges described above, no further impairment charge was necessary as of that date. Year Ended December 31, 2015 The following costs are reflected in "Asset impairment" in the consolidated statement of operations for the year ended December 31, 2015: Reportable Segment Australian Metallurgical Mining Australian Thermal Mining Midwestern U.S. Mining Corporate and Other Consolidated (Dollars in millions) Asset impairment charges: Long-lived assets $ 675.2 $ 17.5 $ 40.2 $ 268.4 $ 1,001.3 Equity method investment — — — 276.5 276.5 Total $ 675.2 $ 17.5 $ 40.2 $ 544.9 $ 1,277.8 Australian Metallurgical and Thermal Mining Due to the severity of the decline in seaborne metallurgical and thermal coal pricing observed during 2015 and other adverse supply and demand conditions noted during the year that drove an unfavorable change in the expected timing of eventual seaborne supply and demand rebalancing, the Company concluded that indicators of impairment existed surrounding its Australian mining platform as of June 30, 2015 and December 31, 2015. Accordingly, the Company reviewed its Australian mining assets for recoverability at those dates and determined that the carrying values of three of its active mines that produce metallurgical coal were not recoverable and recognized impairment charges of $230.5 million and $144.5 million during the three-month periods ended June 30, 2015 and December 31, 2015, respectively, to write those assets down to their estimated fair value. Also during 2015, the Company reviewed its portfolio of mining tenements and surface lands to identify non-strategic assets that could be monetized. In connection with that review, certain of such assets were deemed to meet held-for-sale accounting criteria or were otherwise deemed more likely to generate cash flows through divestiture rather than development, with the long-term plans for certain adjacent assets also consequently affected. Accordingly, the Company recognized an aggregate impairment charge of $317.7 million to write down the targeted divestiture assets and abandoned assets to their estimated fair value. Midwestern U.S. Mining The Company identified indicators of impairment to be present for one of its inactive surface mines due to the property no longer being part of the Company's long-term mining plan as a result of the decline in thermal coal prices and a lack of observed interest from potential buyers in acquiring the asset. Accordingly, the Company recognized an impairment charge of $30.5 million to write down the asset to its estimated fair value. Due to the severity of the decline in thermal coal pricing observed during 2015 and other adverse market conditions noted during 2015, the Company identified indicators of impairment to be present for one of its Midwestern U.S. Mining assets. Due to the adverse conditions, the Company's long-term mining plan changed and the asset was no longer part of the long-term mining plan. Accordingly, the Company recognized an impairment charge of $9.7 million to write down the asset to its estimated fair value. Corporate and Other Long-lived Assets. In connection with a similar review of the Company's asset portfolio conducted during 2015 to identify non-strategic domestic assets that could be monetized, the Company identified non-strategic, non-coal-supplying assets as held-for-sale rather than held-for-use as of December 31, 2015. Accordingly, the Company recognized an impairment charge of $182.2 million to write the assets down to estimated fair value. The Company also identified indicators of impairment to be present for several of its non-strategic undeveloped coal properties that are no longer part of the Company's long-term mining plan as a result of the decline in thermal coal prices and a lack of observed interest from potential buyers in acquiring those assets. Accordingly, the Company recognized an aggregate impairment charge of $86.2 million to write down the assets to their estimated fair value. Equity Method Investment. Due to the impairment indicators noted above surrounding the Company's Australian platform, the Company similarly reviewed its total investment in Middlemount, which owns the Middlemount Mine in Queensland, Australia, as of December 31, 2015. As a result of that review, the Company determined that the carrying value of its equity investment in Middlemount was other-than-temporarily impaired and recorded a charge of $46.6 million to write-off the investment. The Company, along with the other equity interest holder, also periodically makes loans to Middlemount pursuant to the related stockholders’ agreement for purposes of funding capital expenditures and working capital requirements. The Company reviewed the loans for impairment and recorded a charge of $229.9 million to write down the full carrying value of the Subordinated Loans. The Subordinated Loans are provided on an equal and shared basis with the other equity interest holder, and the Company's and the other equity interest holder's claims under the Subordinated Loans are on equal footing. The Company also has Priority Loans to Middlemount which have seniority over the fully impaired Subordinated Loans. The Priority Loans amounted to $84.8 million and $65.2 million at December 31, 2016 and 2015, respectively, and were not impaired as of December 31, 2016 as the Company had the intent and ability to hold the loans to payoff and Middlemount had sufficient assets to settle. The fair value estimates made during the Company's impairment assessments were determined in accordance with the methods outlined in Note 1. "Summary of Significant Accounting Policies", except in certain instances where indicative bids were received related to non-strategic assets being marketed for divestiture. In those instances, the indicative bids were also considered in estimating fair value. Year Ended December 31, 2014 The following costs are reflected in "Asset impairment" in the consolidated statement of operations for the year ended December 31, 2014: Reportable Segment Australian Metallurgical Mining Australian Thermal Mining Western U.S. Mining Corporate and Other Consolidated (Dollars in millions) Asset impairment charges: Long-lived assets $ 66.7 $ 11.9 $ 2.7 $ 68.4 $ 149.7 Marketable securities — — — 4.7 4.7 Total $ 66.7 $ 11.9 $ 2.7 $ 73.1 $ 154.4 Australian Metallurgical and Thermal Mining In 2014, the Company observed continued weakness in seaborne metallurgical and thermal coal pricing that has persisted longer than the Company previously anticipated and, accordingly, conducted a review of its Australian Metallurgical Mining and Australian Thermal Mining segment assets for recoverability. Based on that evaluation, the following Australian segments were impacted as follows: Australian Metallurgical Mining. The Company determined that the carrying value of one of its active surface mines and a non-strategic undeveloped coal property were not recoverable and correspondingly recognized an aggregate impairment charge of $66.7 million to write those assets down from their carrying value to their estimated fair value. In addition to the impairment indicators surrounding the segment, the fair value of the impaired surface mining operation was affected by a short remaining economic life compared to those of other operations and the incremental cost associated with utilizing a contractor to operate the mine. Australian Thermal Mining. The Company determined that the carrying values of a non-strategic undeveloped coal property was not recoverable and correspondingly recognized an aggregate impairment charge of $11.9 million to write those assets down from its carrying value to their estimated fair value. Corporate and Other The Company also identified indicators of impairment to be present in 2014 for certain assets in its Corporate and Other segment. Those assets were certain non-strategic undeveloped coal properties in Indiana and Colorado that were found to be impaired due to a lack of observed interest from potential buyers in acquiring those assets, properties that are no longer part of the Company's long-term mining plan and, in the case of certain of the assets, an election by the Company to terminate or allow the lapse of mining-related leases. The Company determined the carrying value of those holdings to not be recoverable and recognized an aggregate impairment charge of $68.4 million to write down the carrying value of the related properties.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Discontinued Operations Discontinued operations include certain former Australian Thermal Mining and Midwestern U.S. Mining segment assets that have ceased production and other previously divested legacy operations, including Patriot Coal Corporation and certain of its wholly-owned subsidiaries (Patriot). Summarized Results of Discontinued Operations Results from discontinued operations were as follows during the years ended December 31, 2016 , 2015 and 2014 : Year Ended December 31, 2016 2015 2014 (Dollars in millions) Loss from discontinued operations before income taxes $ (57.6 ) $ (182.2 ) $ (23.8 ) Income tax benefit (provision) — 7.2 (4.4 ) Loss from discontinued operations, net of income taxes $ (57.6 ) $ (175.0 ) $ (28.2 ) There were no significant revenues from discontinued operations during the years ended December 31, 2016 , 2015 and 2014. Assets and Liabilities of Discontinued Operations Assets and liabilities classified as discontinued operations included in the Company's consolidated balance sheets were as follows: December 31, 2016 2015 (Dollars in millions) Assets: Other current assets $ 0.2 $ 3.1 Investments and other assets 15.9 13.2 Total assets classified as discontinued operations $ 16.1 $ 16.3 Liabilities: Accounts payable and accrued expenses $ 55.9 $ 60.0 Other noncurrent liabilities 198.5 203.7 Liabilities subject to compromise 20.9 — Total liabilities classified as discontinued operations $ 275.3 $ 263.7 Patriot-Related Matters. Included in "Loss from discontinued operations, net of income taxes" for the year ended December 31, 2016, is a charge of $54.3 million for the UMWA 1974 Pension Plan related to the settlement of litigation. Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" for information surrounding charges recorded during the years ended December 31, 2016 and 2015 associated with the bankruptcy of Patriot. Wilkie Creek Mine. In December 2013, the Company ceased production and started reclamation of the Wilkie Creek Mine in Queensland, Australia. On June 30, 2014, Queensland Bulk Handling Pty Ltd (QBH) commenced litigation against Peabody (Wilkie Creek) Pty Limited, the indirect wholly-owned subsidiary of the Company that owns the Wilkie Creek Mine, alleging breach of a Coal Port Services Agreement (CPSA) between the parties. Included in "Loss from discontinued operations, net of income taxes" for the year ended December 31, 2015 is a $9.7 million charge related to the settlement of that litigation. In September 2016, a settlement was reached under which the Company agreed to pay $13.0 million Australian dollars ( $9.9 million USD) to QBH in a full and final settlement of all claims each party had against the other in relation to the CPSA litigation. Refer to Note 26. "Commitments and Contingencies" for additional information surrounding the QBH matter.
Disposal Groups, Including Discontinued Operations [Table Text Block]	Assets and liabilities classified as discontinued operations included in the Company's consolidated balance sheets were as follows: December 31, 2016 2015 (Dollars in millions) Assets: Other current assets $ 0.2 $ 3.1 Investments and other assets 15.9 13.2 Total assets classified as discontinued operations $ 16.1 $ 16.3 Liabilities: Accounts payable and accrued expenses $ 55.9 $ 60.0 Other noncurrent liabilities 198.5 203.7 Liabilities subject to compromise 20.9 — Total liabilities classified as discontinued operations $ 275.3 $ 263.7

Inventories

Inventories	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories as of December 31, 2016 and December 31, 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) Materials and supplies $ 104.5 $ 115.9 Raw coal 29.6 75.9 Saleable coal 69.6 116.0 Total $ 203.7 $ 307.8 Materials and supplies inventories presented above have been shown net of reserves of $5.6 million and $4.7 million as of December 31, 2016 and 2015 , respectively.

Investments Investments (Notes)

Investments Investments (Notes)	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	Investments Investments in Marketable Securities Investments in available-for-sale securities were liquidated prior to December 31, 2015. Proceeds from sales and maturities of available-for-sale debt securities amounted to $90.3 million and $13.5 million for the years ended December 31, 2015 and 2014, respectively. The Company realized zero net gains associated with those sales and maturities during the years ended December 31, 2015 and 2014. Equity Method Investments The Company’s equity method investments include its joint venture interest in Middlemount in addition to certain other equity method investments. The table below summarizes the book value of those investments, which is reported in “Investments and other assets” in the consolidated balance sheets, and the related (income) loss from equity affiliates: Book Value at December 31, (Income) Loss from Equity Affiliates for the Year Ended December 31, 2016 2015 2016 2015 2014 (Dollars in millions) Equity interest in Middlemount Coal Pty Ltd $ — $ — $ (22.6 ) $ 7.0 $ 98.5 Other equity method investments 0.5 1.5 6.4 8.9 9.1 Total equity method investments $ 0.5 $ 1.5 $ (16.2 ) $ 15.9 $ 107.6 During the years ended December 31, 2016 , 2015 and 2014 , Middlemount generated revenues of approximately $183 million , $160 million and $165 million (on a 50% basis). During the year ended December 31, 2015, due to sustained weakness in seaborne metallurgical coal prices that had persisted longer than the Company had previously anticipated, a history of operating losses at the mine and the magnitude of the difference between the estimated fair value and the carrying value of its equity investment, the Company determined the carrying value of its equity investment in Middlemount to be other-than-temporarily impaired. Correspondingly, the Company recorded an impairment charge of $46.6 million to write down the carrying value of its equity investment. The Company determined its Subordinated Loans to Middlemount were also fully impaired resulting in an additional impairment charge of $229.9 million . A total impairment charge related to Middlemount of $276.5 million was reflected in "Asset impairment" in the consolidated statement of operations for the year ended December 31, 2015. Refer to Note 4. "Asset Impairment" for additional background surrounding the impairment charge recognized in 2015. At December 31, 2016 , the Company had priority loans related to Middlemount with a carrying value of $84.8 million reflected in "Investments and other assets". Refer to Note 10. "Financing Receivables" for additional background on the Company's loans with Middlemount as of December 31, 2016 . In 2014, the Company recorded to "(Gain) loss from equity affiliates" its pro-rata share of a valuation allowance of $52.3 million on Middlemount's Australian net deferred tax assets. Based on a Middlemount's history of operating losses driven by sustained weakness in seaborne metallurgical coal prices, and considering available sources of taxable income, it was determined in 2014 that the net deferred tax assets are no longer considered more likely than not of being realized. There is no remaining unamortized basis difference as of December 31, 2016 between the amount at which the Company's equity investment in Middlemount is carried and the amount of underlying equity in net assets of Middlemount. Middlemount had current assets, noncurrent assets, current liabilities and noncurrent liabilities of $47.3 million , $263.4 million , $363.5 million and $50.3 million , respectively, as of December 31, 2016 and $31.7 million , $348.0 million , $362.2 million and $10.5 million , respectively, as of December 31, 2015 (on a 50% basis). In addition to its equity method investment, the Company periodically makes loans to Middlemount pursuant to the related stockholders' agreement. Refer to Note 10. "Financing Receivables" for additional details surrounding those loans.

Derivatives and Fair Value Meas

Derivatives and Fair Value Measurements (Notes)	12 Months Ended
	Dec. 31, 2016
Derivatives and Fair Value Measurements [Abstract]
Derivatives and Fair Value [Text Block]	Derivatives and Fair Value Measurements Risk Management — Corporate Hedging Activities The Company is exposed to several risks in the normal course of business, including (1) foreign currency exchange rate risk for non-U.S. dollar expenditures and balances, (2) price risk on coal produced by, and diesel fuel utilized in, the Company's mining operations and (3) interest rate risk that has been partially mitigated by fixed rates on long-term debt. The Company manages a portion of its price risk related to the sale of coal (excluding coal trading activities) using long-term coal supply agreements (those with terms longer than one year), rather than using derivative instruments. Derivative financial instruments have historically been used to manage the Company's risk exposure to foreign currency exchange rate risk, primarily on Australian dollar expenditures made in its Australian mining platform. This risk was historically managed using forward contracts and options designated as cash flow hedges, with the objective of reducing the variability of cash flows associated with forecasted foreign currency expenditures. The Company has also used derivative instruments to manage its exposure to the variability of diesel fuel prices used in production in the U.S. and Australia with swaps or options, which it has also designated as cash flow hedges, with the objective of reducing the variability of cash flows associated with forecasted diesel fuel purchases. These risk management activities are collectively referred to as "Corporate Hedging" and are actively monitored for compliance with the Company's risk management policies. During the fourth quarter of 2015, the Company performed an assessment of its risk of nonperformance with respect to derivative financial instruments designated as cash flow hedges in light of three rating agencies downgrading the Company's corporate credit rating during 2015 and declining financial results. The Company determined its hedging relationships were expected to be "highly effective" throughout 2015 based on its quarterly assessments. However, as a result of a deterioration in the Company's credit profile, the Company could no longer conclude, as of December 31, 2015, that its hedging relationships were expected to be "highly effective" at offsetting the changes in the anticipated exposure of the hedged item. Therefore, the Company discontinued the application of cash flow hedge accounting subsequent to December 31, 2015 and changes in the fair value of derivative instruments have been recorded as operating costs and expenses in the accompanying consolidated statements of operations after that date. Previous fair value adjustments recorded in "Accumulated other comprehensive loss" were frozen until the underlying transactions impact the Company's earnings. The Company's Bankruptcy Petitions constituted an event of default under the Company's derivative financial instrument contracts and the counterparties terminated the agreements shortly thereafter in accordance with contractual terms. The terminated positions are first-lien obligations under the Company's secured credit agreement dated September 24, 2013 (as amended, the 2013 Credit Facility). The resulting net settlement liability of $257.3 million was accounted for as a prepetition liability subject to compromise without credit valuation adjustments. As of December 31, 2016, the Company had no derivative financial instruments in place in relation to diesel fuel or foreign currency exchange rate. The Company is reevaluating its future Corporate Hedging activities and programs. Based on the previous fair value adjustments of the Company's foreign currency and diesel fuel hedge contracts recorded in "Accumulated other comprehensive loss", the net loss expected to be reclassified from comprehensive income to earnings over the next 12 months is approximately $93 million (which excludes the impact of fresh start reporting rules in connection with emergence from the Chapter 11 Cases). The tables below show the classification and amounts of pre-tax gains and losses related to the Company’s Corporate Hedging derivatives during the years ended December 31, 2016 , 2015 and 2014 : Year Ended December 31, 2016 Income Statement Classification Total realized loss recognized in income Loss (1) (Loss) gain recognized in income on derivatives Financial Instrument (Dollars in millions) Commodity swap contracts Operating costs and expenses $ (98.0 ) $ (86.1 ) $ (11.9 ) Commodity swap contracts Reorganization items, net (38.8 ) — (38.8 ) Foreign currency forward contracts Operating costs and expenses (142.9 ) (145.6 ) 2.7 Foreign currency forward contracts Reorganization items, net (36.4 ) — (36.4 ) Total $ (316.1 ) $ (231.7 ) $ (84.4 ) (1) Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $13.6 million and $9.0 million of previously unrecognized losses on foreign currency and fuel contracts, respectivley, monetized in first quarter of 2016. Year Ended December 31, 2015 Income Statement Classification Loss recognized in other comprehensive income on derivative (effective portion) Loss reclassified from other comprehensive income into income (effective portion) (1) Loss reclassified from other comprehensive income into income (ineffective portion) Financial Instrument (Dollars in millions) Commodity swap contracts Operating costs and expenses $ (77.0 ) $ (122.0 ) $ 1.6 Foreign currency forward contracts Operating costs and expenses (122.0 ) (316.4 ) — Total $ (199.0 ) $ (438.4 ) $ 1.6 (1) Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $14.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012. Year Ended December 31, 2014 Income Statement Classification Losses - Realized Loss recognized in other comprehensive income on derivative (effective portion) Loss reclassified from other comprehensive income into income (effective portion) (1) Loss reclassified from other comprehensive income into income (ineffective portion) Financial Instrument (Dollars in millions) Commodity swap contracts Operating costs and expenses $ (194.5 ) $ (20.6 ) $ (1.7 ) Foreign currency forward contracts Operating costs and expenses (100.9 ) (27.3 ) — Total $ (295.4 ) $ (47.9 ) $ (1.7 ) (1) Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $136.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012. Cash Flow Presentation. The Company classifies the cash effects of its Corporate Hedging derivatives within the "Cash Flows From Operating Activities" section of the consolidated statements of cash flows. Offsetting and Balance Sheet Presentation The Company's previous Corporate Hedging derivative financial instruments were transacted in over-the-counter (OTC) markets with financial institutions under International Swaps and Derivatives Association (ISDA) Master Agreements. Those agreements contain symmetrical default provisions which allow for the net settlement of amounts owed by either counterparty in the event of default or contract termination. The Company offset its Corporate Hedging asset and liability derivative positions on a counterparty-by-counterparty basis in the consolidated balance sheets, with the fair values of those respective derivatives reflected in “Other current assets,” “Investments and other assets,” “Accounts payable and accrued expenses” and “Other noncurrent liabilities." Though the symmetrical default provisions associated with the Company's Corporate Hedging derivatives existed at the overall counterparty level across its foreign currency and diesel fuel hedging strategy derivative contract portfolios, the Company's accounting policy is to apply counterparty offsetting separately within those derivative contract portfolios for presentation in the consolidated balance sheets because that application is more consistent with the fact that the Company generally net settled its Corporate Hedging derivatives with each counterparty by derivative contract portfolio on a routine basis. The classification and amount of Corporate Hedging derivative financial instruments presented on a gross and net basis as of December 31, 2015 are presented in the table that follows. Fair Value of Liabilities Presented in the Consolidated Balance Sheet as of December 31, 2015 (1) Financial Instrument (Dollars in millions) Current Liabilities: Commodity swap contracts $ 86.1 Foreign currency forward contracts 145.6 Total $ 231.7 Noncurrent Liabilities: Commodity swap contracts $ 37.6 Foreign currency forward contracts 55.1 Total $ 92.7 (1) All commodity swap contracts and foreign currency forward contracts were in a liability position as of December 31, 2015. See Note 9. "Coal Trading" for information on balance sheet offsetting related to the Company’s coal trading activities. Fair Value Measurements The Company uses a three-level fair value hierarchy that categorizes assets and liabilities measured at fair value based on the observability of the inputs utilized in the valuation. These levels include: Level 1 - inputs are quoted prices in active markets for the identical assets or liabilities; Level 2 - inputs are other than quoted prices included in Level 1 that are directly or indirectly observable through market-corroborated inputs; and Level 3 - inputs are unobservable, or observable but cannot be market-corroborated, requiring the Company to make assumptions about pricing by market participants. Financial Instruments Measured on a Recurring Basis. The following tables set forth the hierarchy of the Company’s net financial (liability) asset positions for which fair value is measured on a recurring basis: December 31, 2015 Level 1 Level 2 Level 3 Total (Dollars in millions) Investments in debt and equity securities $ — $ — $ — $ — Commodity swap contracts — — (123.7 ) (123.7 ) Foreign currency forward contracts — — (200.7 ) (200.7 ) Total net financial liabilities $ — $ — $ (324.4 ) $ (324.4 ) As of December 31, 2016, the Company no longer had any outstanding financial positions. For Level 1 and 2 financial assets and liabilities, the Company utilizes both direct and indirect observable price quotes, including interest rate yield curves, exchange indices, broker/dealer quotes, published indices, issuer spreads, benchmark securities and other market quotes. In the case of certain debt securities, fair value is provided by a third-party pricing service. Below is a summary of the Company’s valuation techniques for Level 1 and 2 financial assets and liabilities: • Commodity swap contracts: valued based on a valuation that is corroborated by the use of market-based pricing (Level 2) except when credit and non-performance risk is considered to be a significant input, then the Company classifies such contracts as Level 3. • Foreign currency forward and option contracts: valued utilizing inputs obtained in quoted public markets (Level 2) except when credit and non-performance risk is considered to be a significant input, then the Company classifies such contracts as Level 3. The following table summarizes the changes related to the Company’s Corporate Hedging derivative financial instruments recurring Level 3 financial liabilities: Year Ended December 31, 2016 Commodity Contracts Foreign Currency Contracts Total (Dollars in millions) Beginning of period $ 123.7 $ 200.7 $ 324.4 Total net losses realized/unrealized: Included in earnings 15.7 (48.0 ) (32.3 ) Settlements / terminations (139.4 ) (152.7 ) (292.1 ) End of period $ — $ — $ — The Company had no transfers between Levels 1, 2 and 3 during the years ended December 31, 2016 or 2015. Transfers into Level 3 of liabilities previously classified in Level 2 during the year ended December 31, 2015 were due to the relative value of unobservable inputs to the total fair value measurement of certain derivative contracts rising above the 10% threshold. The Company’s policy is to value all transfers between levels using the beginning of period valuation. Other Financial Instruments. The following methods and assumptions were used by the Company in estimating fair values for other financial instruments as of December 31, 2016 and 2015 : • Cash and cash equivalents, restricted cash, accounts receivable, including those within the Company’s accounts receivable securitization program, notes receivable and accounts payable have carrying values which approximate fair value due to the short maturity or the liquid nature of these instruments. • Long-term debt fair value estimates are based on observed prices for securities with an active trading market when available (Level 2), and otherwise on estimated borrowing rates to discount the cash flows to their present value (Level 3). The estimated fair value of the Company’s current and long-term debt as of December 31, 2016 is subject to compromise in connection with the Company's Plan and as such has been excluded from the table below. The carrying amount and estimated fair value of the Company's current and long-term debt as of December 31, 2015 are summarized as follows: December 31, 2015 Carrying Amount Estimated Fair Value (Dollars in millions) Current and Long-term debt $ 6,241.2 $ 1,373.7

Coal Trading

Coal Trading	12 Months Ended
	Dec. 31, 2016
Coal Trading [Abstract]
Coal Trading	Coal Trading The Company engages in the direct and brokered trading of coal and freight-related contracts (coal trading). Except those for which the Company has elected to apply a normal purchases and normal sales exception, all derivative coal trading contracts are accounted for at fair value. The Company includes instruments associated with coal trading transactions as a part of its trading book. Trading revenues from such transactions are recorded in “Other revenues” in the consolidated statements of operations and include realized and unrealized gains and losses on derivative instruments, including those that arise from coal deliveries related to contracts accounted for on an accrual basis under the normal purchases and normal sales exception. Therefore, the Company has elected the trading exemption surrounding disclosure of its coal trading activities. Trading revenues recognized during the years ended December 31, 2016 , 2015 and 2014 were as follows: Year Ended December 31, Trading Revenues by Type of Instrument 2016 2015 2014 (Dollars in millions) Commodity futures, swaps and options $ (96.5 ) $ 107.3 $ 92.3 Physical commodity purchase/sale contracts 85.6 (64.5 ) (33.9 ) Total trading revenues $ (10.9 ) $ 42.8 $ 58.4 Risk Management Hedge Ineffectiveness. In some instances prior to 2016, the Company designated an existing coal trading derivative as a hedge and, thus, the derivative has a non-zero fair value at hedge inception. The “off-market” nature of these derivatives, which is best described as an embedded financing element within the derivative, is a source of ineffectiveness. In other instances, the Company uses a coal trading derivative that settles at a different time, has different quality specifications or has a different location basis than the occurrence of the cash flow being hedged. These collectively yield ineffectiveness to the extent that the derivative hedge contract does not exactly offset changes in the fair value or expected cash flows of the hedged item. The Company had no coal trading positions designated as cash flow hedges as of December 31, 2016 and 2015 . Offsetting and Balance Sheet Presentation The Company's coal trading assets and liabilities include financial instruments, such as swaps, futures and options, cleared through various exchanges, which involve the daily net settlement of closed positions. The Company must post cash collateral, known as variation margin, on exchange-cleared positions that are in a net liability position and receives variation margin when in a net asset position. The Company also transacts in coal trading financial swaps and options through OTC markets with financial institutions and other non-financial trading entities under ISDA Master Agreements, which contain symmetrical default provisions. Certain of the Company's coal trading agreements with OTC counterparties also contain credit support provisions that may periodically require the Company to post, or entitle the Company to receive, initial and variation margin. Physical coal and freight-related purchase and sale contracts included in the Company's coal trading assets and liabilities are executed pursuant to master purchase and sale agreements that also contain symmetrical default provisions and allow for the netting and setoff of receivables and payables that arise during the same time period. The Company offsets its coal trading asset and liability derivative positions, and variation margin related to those positions, on a counterparty-by-counterparty basis in the consolidated balance sheets, with the fair values of those respective derivatives reflected in “Assets from coal trading activities, net” and “Liabilities from coal trading activities, net." The fair value of assets and liabilities from coal trading activities presented on a gross and net basis as of December 31, 2016 and 2015 is set forth below: Affected line item in the consolidated balance sheets Gross Amounts of Recognized Assets (Liabilities) Gross Amounts Offset in the Consolidated Balance Sheets Variation margin (held) posted (1) Net Amounts of Assets (Liabilities) Presented in the Consolidated Balance Sheets (Dollars in millions) Fair Value as of December 31, 2016 Assets from coal trading activities, net $ 191.2 $ (190.5 ) $ — $ 0.7 Liabilities from coal trading activities, net (249.1 ) 190.5 57.4 (1.2 ) Total, net $ (57.9 ) $ — $ 57.4 $ (0.5 ) Fair Value as of December 31, 2015 Assets from coal trading activities, net $ 128.6 $ (87.3 ) $ (17.8 ) $ 23.5 Liabilities from coal trading activities, net (110.0 ) 87.3 7.1 (15.6 ) Total, net $ 18.6 $ — $ (10.7 ) $ 7.9 (1) None of the net variation margin (held) posted at December 31, 2016 and 2015 , respectively, related to cash flow hedges. See Note 8. "Derivatives and Fair Value Measurements" for information on balance sheet offsetting related to the Company’s Corporate Hedging activities. Fair Value Measurements The following tables set forth the hierarchy of the Company’s net financial asset (liability) coal trading positions for which fair value is measured on a recurring basis as of December 31, 2016 and 2015 : December 31, 2016 Level 1 Level 2 Level 3 Total (Dollars in millions) Commodity futures, swaps and options $ — $ (0.1 ) $ — $ (0.1 ) Physical commodity purchase/sale contracts — 0.7 (1.1 ) (0.4 ) Total net financial assets (liabilities) $ — $ 0.6 $ (1.1 ) $ (0.5 ) December 31, 2015 Level 1 Level 2 Level 3 Total (Dollars in millions) Commodity futures, swaps and options $ — $ 3.3 $ — $ 3.3 Physical commodity purchase/sale contracts — 20.2 (15.6 ) 4.6 Total net financial assets (liabilities) $ — $ 23.5 $ (15.6 ) $ 7.9 For Level 1 and 2 financial assets and liabilities, the Company utilizes both direct and indirect observable price quotes, including U.S. interest rate curves; LIBOR yield curves; Chicago Mercantile Exchange (CME) Group, Intercontinental Exchange (ICE), LCH.Clearnet (formerly known as the London Clearing House), NOS Clearing ASA and Singapore Exchange (SGX) contract prices; broker quotes; published indices and other market quotes. Below is a summary of the Company’s valuation techniques for Level 1 and 2 financial assets and liabilities: • Futures, swaps and options: generally valued based on unadjusted quoted prices in active markets (Level 1) or a valuation that is corroborated by the use of market-based pricing (Level 2) except when credit and non-performance risk is considered to be a significant input (greater than 10% of fair value), then the Company classifies as Level 3. • Physical purchase/sale contracts: purchases and sales at locations with significant market activity corroborated by market-based information (Level 2) except when credit and non-performance risk is considered to be a significant input (greater than 10% of fair value), then the Company classifies as Level 3. Physical purchase/sale contracts include a credit valuation adjustment based on credit and non-performance risk (Level 3). The credit valuation adjustment has not historically had a material impact on the valuation of the contracts resulting in Level 2 classification. However, due to the Company's corporate credit rating downgrades in 2016 and 2015, the credit valuation adjustments as of December 31, 2016 and 2015 are considered to be significant unobservable inputs in the valuation of the contracts resulting in Level 3 classification. The Company's risk management function, which is independent of the Company's commercial trading function, is responsible for valuation policies and procedures, with oversight from executive management. Generally, the Company's Level 3 instruments or contracts are valued using bid/ask price quotations and other market assessments obtained from multiple, independent third-party brokers or other transactional data incorporated into internally-generated discounted cash flow models. Decreases in the number of third-party brokers or market liquidity could erode the quality of market information and therefore the valuation of the Company's market positions. The Company's valuation techniques include basis adjustments to the foregoing price inputs for quality, such as heat rate and sulfur and ash content, location differentials, expressed as port and freight costs, and credit risk. The Company's risk management function independently validates the Company's valuation inputs, including unobservable inputs, with third-party information and settlement prices from other sources where available. A daily process is performed to analyze market price changes and changes to the portfolio. Further periodic validation occurs at the time contracts are settled with the counterparty. These valuation techniques have been consistently applied in all periods presented, and the Company believes it has obtained the most accurate information available for the types of derivative contracts held. The following table summarizes the quantitative unobservable inputs utilized in the Company's internally-developed valuation models for physical purchase/sale contracts classified as Level 3 as of December 31, 2016 : Range Weighted Input Low High Average Quality adjustments 2 % 2 % 2 % Credit and non-performance risk 26 % 26 % 26 % Significant increases or decreases in the inputs in isolation could result in a significantly higher or lower fair value measurement. The unobservable inputs do not have a direct interrelationship; therefore, a change in one unobservable input would not necessarily correspond with a change in another unobservable input. The following table summarizes the changes in the Company’s recurring Level 3 net financial assets: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Beginning of period $ (15.6 ) $ 2.1 $ 2.1 Transfers into Level 3 5.3 (4.4 ) — Transfers out of Level 3 (0.4 ) — — Total gains realized/unrealized: Included in earnings (2.4 ) (10.1 ) 6.7 Purchases — (0.5 ) — Sales — (0.1 ) — Settlements 12.0 (2.6 ) (6.7 ) End of period $ (1.1 ) $ (15.6 ) $ 2.1 The Company had no transfers between Levels 1 and 2 during the years ended December 31, 2016, 2015 or 2014, Transfers of liabilities into/out of Level 3 from/to Level 2 during the years ended December 31, 2016 and 2015 were due to the relative value of unobservable inputs to the total fair value measurement of certain derivative contracts falling below, or in the case of transfers in, rising above, the 10% threshold. There were no transfers of liabilities into/out of Level 3 from/to Level 2 during the year ended December 31, 2014. The Company’s policy is to value all transfers between levels using the beginning of period valuation. The following table summarizes the changes in net unrealized (losses) gains relating to Level 3 net financial assets held both as of the beginning and the end of the period: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Changes in unrealized (losses) gains (1) $ — $ (6.2 ) $ 2.1 (1) Within the consolidated statements of operations and consolidated statements of comprehensive income for the periods presented, unrealized gains and losses from Level 3 items are combined with unrealized gains and losses on positions classified in Level 1 or 2, as well as other positions that have been realized during the applicable periods. As of December 31, 2016 , the estimated future realization of the value of the Company’s trading portfolio is expected to all be realized in 2017. Credit and Nonperformance Risk. The fair value of the Company’s coal derivative assets and liabilities reflects adjustments for credit risk. The Company’s exposure is substantially with electric utilities, energy marketers, steel producers and nonfinancial trading houses. The Company’s policy is to independently evaluate each customer’s creditworthiness prior to entering into transactions and to regularly monitor the credit extended. If the Company engages in a transaction with a counterparty that does not meet its credit standards, the Company seeks to protect its position by requiring the counterparty to provide an appropriate credit enhancement. Also, when appropriate (as determined by its credit management function), the Company has taken steps to reduce its exposure to customers or counterparties whose credit has deteriorated and who may pose a higher risk of failure to perform under their contractual obligations. These steps include obtaining letters of credit or cash collateral (margin), requiring prepayments for shipments or the creation of customer trust accounts held for the Company’s benefit to serve as collateral in the event of a failure to pay or perform. To reduce its credit exposure related to trading and brokerage activities, the Company seeks to enter into netting agreements with counterparties that permit the Company to offset asset and liability positions with such counterparties and, to the extent required, the Company will post or receive margin amounts associated with exchange-cleared and certain OTC positions. The Company also continually monitors counterparty and contract nonperformance risk, if present, on a case-by-case basis. As of December 31, 2016 , 22% of the Company’s credit exposure related to coal trading activities was with investment grade counterparties, while 7% was with non-investment grade counterparties and 71% was with counterparties that are not rated. Performance Assurances and Collateral The Company is required to post variation margin on positions that are in a net liability position and is entitled to receive and hold variation margin on positions that are in a net asset position with an exchange and certain of its OTC derivative contract counterparties. At December 31, 2016 the Company had posted $57.4 million of net variation margin. At December 31, 2015 the Company held net variation margin of $10.7 million . In addition to the requirements surrounding variation margin, the Company is required by the exchanges upon which it transacts and by certain of its OTC arrangements to post certain additional collateral, known as initial margin, which represents an estimate of potential future adverse price movements across the Company’s portfolio under normal market conditions. As of December 31, 2016 and 2015 , the Company had posted initial margin of $16.2 million and $9.2 million , respectively, which is reflected in “Other current assets” in the consolidated balance sheets. As of December 31, 2016 the Company was in receipt of $2.0 million of the required variation and initial margin, compared to December 31, 2015 when the Company had posted $0.7 million of margin in excess of the required variation and initial margin. Certain of the Company’s derivative trading instruments require the parties to provide additional performance assurances whenever a material adverse event jeopardizes one party’s ability to perform under the instrument. If the Company was to sustain a material adverse event (using commercially reasonable standards), its counterparties could request collateralization on derivative trading instruments in net liability positions which, based on an aggregate fair value at December 31, 2016 and 2015 , would have amounted to collateral postings to counterparties of approximately $2 million and $21 million , respectively. As of December 31, 2016 , the Company was required to post approximately $1 million in collateral to counterparties for such positions. No collateral was required to be posted to counterparties as of December 31, 2015 . Certain of the Company’s other derivative trading instruments require the parties to provide additional performance assurances whenever a credit downgrade occurs below a certain level, as specified in each underlying contract. The terms of such derivative trading instruments typically require additional collateralization, which is commensurate with the severity of the credit downgrade. During 2016, each of the three rating agencies downgraded the Company's corporate credit rating due to the Bankruptcy Petitions. Despite the rating agencies downgrades, the Company’s additional collateral requirement owed to its counterparties for these ratings based derivative trading instruments would have been zero at December 31, 2016 and 2015 based on the aggregate fair value of all derivative trading instruments with such features. As of December 31, 2016 and 2015 , no collateral was posted to counterparties to support such derivative trading instruments.

Financing Receivables

Financing Receivables	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Financing Receivables	Financing Receivables The Company's total financing receivables as of December 31, 2016 and 2015 consisted of the following: December 31, Balance Sheet Classification 2016 2015 (Dollars in millions) Other current assets $ — $ 20.0 Investments and other assets 84.8 65.2 Total financing receivables $ 84.8 $ 85.2 The Company periodically assesses the collectability of accounts and loans receivable by considering factors such as specific evaluation of collectability, historical collection experience, the age of the receivable and other available evidence. Below is a description of the Company's financing receivables outstanding as of December 31, 2016 and 2015 . Codrilla Mine Project. In 2011, a wholly-owned subsidiary of Peabody Energy Australia PCI Pty Ltd, then Macarthur Coal Limited, completed the sale of a portion of its 85% interest in the Codrilla Mine Project to the other participants of the Coppabella Moorvale Joint Venture, afterward retaining 73.3% ownership. The final outstanding installment payment of 40% of the sale price was due upon the earlier of the mine's first coal shipment or a specified date. The sales agreement was amended in the second quarter of 2013 to delay the specified date from March 31, 2015 to June 30, 2016 with the remaining balance being received during 2016. At December 31, 2015, the balance associated with these receivables totaled $ 20 million and was recorded in "Other current assets" in the consolidated balance sheets. Middlemount Mine. The Company periodically makes loans to Middlemount, in which the Company owns a 50% equity interest, pursuant to the related stockholders' agreement for purposes of funding capital expenditures and working capital requirements. The Priority Loans bear interest at a rate equal to the monthly average 30-day Australian Bank Bill Swap Reference Rate plus 3.5% . They were due to expire on December 31, 2016, but have been extended to June 30, 2017 in conjunction with a commercial agreement with the stockholders concerning the distribution of available cash against outstanding payables and the loans. That agreement requires the distribution of available cash at least twice each month. Available cash is defined as the amount in Middlemount’s bank accounts that will not be required to pay known bills within the next 35 days. The available cash is distributed to the stockholders in a 50/50 ratio, unless there is no marketing royalty payment overdue. In that situation, 100% of the available cash is distributed to the Company until its priority repayment loans are repaid in full. Based on the existence of letters of support from related entities of the stockholders, the expected timing of repayment of these loans is projected to extend beyond the stated expiration date and so the Company considers these loans to be of a long-term nature. As a result, (i) the foreign currency impact related to the stockholder loans is included in foreign currency translation adjustment in the consolidated balance sheets and the consolidated statements of comprehensive income and (ii) interest income on the Priority Loans is recognized when cash is received. Refer to Note 4. "Asset Impairment" for background surrounding the impairment charge recognized in 2015 related to Middlemount. The carrying value of the loans of $84.8 million and $65.2 million was reflected in "Investments and other assets" in the consolidated balance sheets as of December 31, 2016 and 2015 , respectively. On August 8, 2016, one of the Company's Australian subsidiaries and the other stockholder of Middlemount entered into an agreement to provide a revolving loan (Revolving Loans) to Middlemount not to exceed $60.0 million Australian dollars (Revolving Loan Limit). The Company’s participation in the Revolving Loans will not, at any time, exceed its 50% equity interest of the Revolving Loan Limit. The Revolving Loans bear interest at 15% per annum and expire on December 31, 2017. As of December 31, 2016, the carrying value of the Revolving Loans due to the Company's Australian subsidiary was zero .

Property, Plant, Equipment and

Property, Plant, Equipment and Mine Development (Notes)	12 Months Ended
	Dec. 31, 2016
Property, Plant, Equipment and Mine Development [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	Property, Plant, Equipment and Mine Development Property, plant, equipment and mine development, net, as of December 31, 2016 and December 31, 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) Land and coal interests $ 10,330.8 $ 10,503.7 Buildings and improvements 1,507.6 1,506.0 Machinery and equipment 2,130.2 2,280.4 Less: Accumulated depreciation, depletion and amortization (5,191.9 ) (5,031.6 ) Total, net $ 8,776.7 $ 9,258.5 The net book value of coal reserves totaled $5.5 billion as of December 31, 2016 and $5.7 billion as of December 31, 2015 , which excludes the carrying value of acquired interests in mineral rights at certain Australian exploration properties of $1.2 billion for both years, respectively. The coal reserves include mineral rights for leased coal interests and advance royalties that had a net book value of $4.4 billion as of December 31, 2016 and $4.6 billion as of December 31, 2015 . The remaining net book value of coal reserves of $1.1 billion at December 31, 2016 and December 31, 2015 relates to coal reserves held by fee ownership. Amounts attributable to coal reserves at properties where the Company was not currently engaged in mining operations or leasing to third parties and, therefore, the coal reserves were not currently being depleted, was $1.6 billion as of December 31, 2016 and $1.7 billion as of December 31, 2015 .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Loss from continuing operations before income taxes for the years ended December 31, 2016, 2015 and 2014 consisted of the following: Year Ended December 31, 2016 2015 2014 (Dollars in millions) U.S. $ (49.7 ) $ (515.9 ) $ 268.9 Non-U.S. (708.6 ) (1,474.4 ) (816.8 ) Total $ (758.3 ) $ (1,990.3 ) $ (547.9 ) Total income tax (benefit) provision for the years ended December 31, 2016, 2015 and 2014 consisted of the following: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Current: U.S. federal $ (12.4 ) $ (71.9 ) $ 27.1 Non-U.S. 14.4 3.7 (61.1 ) State 0.5 (0.6 ) 3.3 Total current 2.5 (68.8 ) (30.7 ) Deferred: U.S. federal (82.1 ) (117.4 ) 111.0 Non-U.S. (2.3 ) 15.7 122.3 State (2.1 ) (5.9 ) (1.4 ) Total deferred (86.5 ) (107.6 ) 231.9 Total income tax (benefit) provision $ (84.0 ) $ (176.4 ) $ 201.2 The following is a reconciliation of the expected statutory federal income tax benefit to the Company’s income tax (benefit) provision for the years ended December 31, 2016, 2015 and 2014: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Expected income tax benefit at U.S. federal statutory rate $ (265.4 ) $ (696.6 ) $ (191.7 ) Changes in valuation allowance, income tax 2,462.8 462.0 569.4 Worthless partnership (2,204.4 ) — — Changes in tax reserves 2.3 (21.4 ) (81.5 ) Excess depletion (37.2 ) (53.7 ) (65.3 ) Foreign earnings repatriation — — (71.4 ) Foreign earnings provision differential 27.5 146.5 28.8 General business tax credits (14.2 ) (15.7 ) (19.2 ) Minerals resource rent tax, net of federal tax — — 16.1 Remeasurement of foreign income tax accounts (0.4 ) (0.5 ) (2.7 ) State income taxes, net of federal tax benefit (90.2 ) (20.1 ) (2.3 ) Reorganization costs 29.6 — — Other, net 5.6 23.1 21.0 Total income tax (benefit) provision $ (84.0 ) $ (176.4 ) $ 201.2 Certain reconciliation items included in the above table exclude the remeasurement of foreign income tax accounts as these foreign currency effects are separately presented. The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities as of December 31, 2016 and 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) Deferred tax assets: Tax loss carryforwards and credits $ 4,284.4 $ 1,817.4 Accrued postretirement benefit obligations 364.5 372.4 Asset retirement obligations 163.6 160.9 Financial guarantees 77.9 16.9 Employee benefits 57.0 69.6 Payable to voluntary employee beneficiary association for certain Patriot retirees (1) — 52.9 Hedge activities 21.0 26.6 Workers’ compensation obligations 7.5 13.7 Other 2.1 66.7 Total gross deferred tax assets 4,978.0 2,597.1 Deferred tax liabilities: Property, plant, equipment and mine development, principally due to differences in depreciation, depletion and asset impairments 900.4 966.6 Unamortized discount on Convertible Junior Subordinated Debentures 127.7 130.3 Investments and other assets 86.3 70.1 Total gross deferred tax liabilities 1,114.4 1,167.0 Valuation allowance, income tax (3,881.2 ) (1,447.3 ) Net deferred tax liability $ (17.6 ) $ (17.2 ) Deferred taxes are classified as follows: Current deferred income taxes $ — $ 49.7 Noncurrent deferred income taxes (17.6 ) (66.9 ) Net deferred tax liability $ (17.6 ) $ (17.2 ) (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction. During 2016, the Company determined that a foreign holding company was insolvent, resulting in a worthlessness deduction which increased the Company's federal net operating losses (NOL) by $6.3 billion . The Company's tax loss carryforwards and credits included federal NOL carryforwards of $2,340.4 million , state NOL carryforwards of $127.9 million , foreign tax credits of $267.9 million , U.S. alternative minimum tax (AMT) credits of $264.3 million , tax general business credits of $119.4 million , U.S. capital losses of $60.8 million , charitable contribution carryforwards of $1.3 million and foreign NOL carryforwards of $1,102.2 million as of December 31, 2016. The AMT credits and foreign NOLs have no expiration date. The federal NOLs expire in 2036. The U.S. capital losses and state NOLs begin to expire in 2017 and 2018, respectively. The foreign tax credits and general business credits begin to expire in 2020 and 2027, respectively. In assessing the near-term use of NOLs and tax credits and corresponding valuation allowance adjustments, the Company evaluated the expected level of future taxable income, available tax planning strategies, reversals of existing taxable temporary differences and taxable income in carryback years. During the year ended December 31, 2016, the Company continued to record valuation allowance against net deferred tax asset positions in the U.S. and Australia of $2,342.9 million and $91.0 million , respectively. Recognition of those valuation allowances was driven by recent cumulative book losses, as determined by considering all sources of available income (including items classified as discontinued operations or recorded directly to "Accumulated other comprehensive loss"), which limited the Company’s ability to look to future taxable income in assessing the realizability of the related assets. The $2,342.9 million recorded in U.S. valuation allowance during the year ended December 31, 2016, was reflected in "Income tax (benefit) provision". Unrecognized Tax Benefits Net unrecognized tax benefits (excluding interest and penalties) were recorded as follows in the consolidated balance sheets as of December 31, 2016 and 2015: December 31, 2016 2015 (Dollars in millions) Deferred income taxes $ 8.9 $ 7.9 Other noncurrent liabilities 11.2 11.7 Net unrecognized tax benefits $ 20.1 $ 19.6 Gross unrecognized tax benefits $ 20.1 $ 22.9 The amount of the Company's gross unrecognized tax benefits decreased by $ 2.8 million since January 1, 2016 due to the finalization settlement of state audits, offset by additions for current positions. The amount of the net unrecognized tax benefits that, if recognized, would directly affect the effective tax rate was $20.1 million and $19.6 million at December 31, 2016 and 2015, respectively. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for the years ended December 31, 2016, 2015 and 2014 is as follows: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Balance at beginning of period $ 22.9 $ 44.5 $ 143.9 Additions for current year tax positions 1.5 2.3 12.0 Reductions for prior year tax positions (2.8 ) (23.5 ) — Reductions for settlements with tax authorities (1.5 ) (0.4 ) (111.4 ) Balance at end of period $ 20.1 $ 22.9 $ 44.5 The Company recognizes interest and penalties related to unrecognized tax benefits in its income tax provision. The Company reversed gross interest and penalties of $0.4 million , $2.1 million and $8.0 million for the years ended December 31, 2016, 2015 and 2014, respectively. The Company had $2.4 million and $0.4 million of accrued gross interest and penalties related to unrecognized tax benefits at December 31, 2016 and 2015, respectively. The Company expects that during the next twelve months there will be no changes to its net unrecognized tax benefits due to potential audit settlements and the expiration of statutes of limitations. Tax Returns Subject to Examination The Company's federal income tax returns for the 2014 and 2015 tax years are subject to potential examinations by the Internal Revenue Service (IRS). The Company's state income tax returns for the tax years 1999 and thereafter remain potentially subject to examination by various state taxing authorities due to NOL carryforwards. Australian income tax returns for tax years 2010 through 2013 continue to be subject to potential examinations by the Australian Taxation Office (ATO). Foreign Earnings As of December 31, 2016, the Company has a consolidated earnings deficit outside the U.S. but with some immaterial unremitted earnings in certain jurisdictions. The Company continues to be permanently reinvested with respect to its current and historical earnings. However, when appropriate, the Company has the ability to access foreign cash without incurring a residual tax. Tax Payments and Refunds The following table summarizes the Company’s income tax refunds, net for the years ended December 31, 2016, 2015 and 2014: Year Ended December 31, 2016 2015 2014 (Dollars in millions) U.S. — federal $ (56.5 ) $ (38.1 ) $ (7.7 ) U.S. — state and local 1.4 0.4 (6.8 ) Non-U.S. 15.0 11.9 (2.2 ) Total income tax refunds, net $ (40.1 ) $ (25.8 ) $ (16.7 )

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts Payable and Accrued Expenses	Accounts Payable and Accrued Expenses Accounts payable and accrued expenses consisted of the following: December 31, 2016 2015 (Dollars in millions) Trade accounts payable $ 288.6 $ 333.3 Accrued payroll and related benefits 201.2 191.9 Other accrued expenses 190.1 225.8 Accrued taxes other than income 119.6 135.9 Accrued royalties 62.8 41.0 Asset retirement obligations 41.0 25.5 Accrued health care insurance 16.0 15.8 Workers’ compensation obligations 7.8 8.6 Income taxes payable 6.2 6.8 Accrued interest 1.2 68.8 Accrued environmental cleanup-related costs — 23.9 Other — 2.3 Payable to voluntary employee beneficiary associated for certain Patriot retirees (1) — 75.0 Commodity and foreign currency hedge contracts — 231.7 Liabilities associated with discontinued operations 55.9 60.0 Total accounts payable and accrued expenses $ 990.4 $ 1,446.3 (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction.

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Long-term Debt The Company’s total indebtedness as of December 31, 2016 and 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) 2013 Revolver $ 1,558.1 $ — 2013 Term Loan Facility due September 2020 1,154.5 1,156.3 6.00% Senior Notes due November 2018 1,509.9 1,508.9 6.50% Senior Notes due September 2020 645.8 645.5 6.25% Senior Notes due November 2021 1,327.7 1,327.0 10.00% Senior Secured Second Lien Notes due March 2022 962.3 960.4 7.875% Senior Notes due November 2026 245.9 245.8 Convertible Junior Subordinated Debentures due December 2066 367.1 366.3 Capital lease obligations 19.7 30.3 Other 0.4 0.7 7,791.4 6,241.2 Less: Current portion of long-term debt 20.2 5,874.9 Less: Liabilities subject to compromise 7,771.2 — Long-term debt $ — $ 366.3 The carrying amounts of the 2013 Term Loan Facility due September 2020, the 6.00% Senior Notes due November 2018, the 6.50% Senior Notes due September 2020, the 6.25% Senior Notes due November 2021, the 10.00% Senior Secured Second Lien Notes due March 2022 (the Senior Secured Second Lien Notes), the 7.875% Senior Notes due December 2026 and the Convertible Junior Subordinated Debentures due December 2066 (the Debentures) have been presented above net of the respective unamortized debt issuance costs and original issue discounts, as applicable. Prior to the issuance of the Company's 2015 consolidated financial statements, the Company believed it would not comply with the financial covenants of its 2013 Credit Facility (as defined below), and as such, all of its long-term debt with the exception of the Debentures was classified as current at December 31, 2015. As of December 31, 2016 , substantially all of the Company's long-term debt was recorded in “Liabilities subject to compromise” in the consolidated balance sheets. Refer to Note 3. "Liabilities Subject to Compromise" for additional information. The filing of the Bankruptcy Petitions constituted an event of default that accelerated Peabody’s obligations under the following debt instruments (collectively, the Debt Instruments): • Indenture governing $1,000.0 million outstanding aggregate principal amount of the Company’s 10.00% Senior Secured Second Lien Notes due 2022, dated as of March 16, 2015, among the Company, U.S. Bank National Association (U.S. Bank), as trustee and collateral agent, and the guarantors named therein, as supplemented; • Indenture governing $650.0 million outstanding aggregate principal amount of the Company’s 6.50% Senior Notes due 2020, dated as of March 19, 2004, among the Company, U.S. Bank and the guarantors named therein, as supplemented; • Indenture governing $1,518.8 million outstanding aggregate principal amount of the Company’s 6.00% Senior Notes due 2018, dated as of November 15, 2011, among the Company, U.S. Bank and the guarantors named therein, as supplemented; • Indenture governing $1,339.6 million outstanding aggregate principal amount of the Company’s 6.25% Senior Notes due 2021, dated as of November 15, 2011, by and among the Company, U.S. Bank and the guarantors named therein, as supplemented; • Indenture governing $250.0 million outstanding aggregate principal amount of the Company’s 7.875% Senior Notes due 2026, dated as of March 19, 2004, among the Company, U.S. Bank and the guarantors named therein, as supplemented; • Subordinated Indenture governing $732.5 million outstanding aggregate principal amount of the Company’s Convertible Junior Subordinated Debentures due 2066, dated as of December 20, 2006, among the Company and U.S. Bank, as supplemented; and • Amended and Restated Credit Agreement, as amended and restated as of September 24, 2013 (the 2013 Credit Facility), related to $1,170.0 million outstanding aggregate principal amount of term loans under the 2013 Term Loan Facility and $1,650.0 million in the 2013 Revolver which includes approximately $675 million of posted but undrawn letters of credit and approximately $947 million in outstanding borrowings, by and among the Company, Citibank, N.A., as administrative agent, swing line lender and letter of credit (L/C) issuer, Citigroup Global Markets, Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated, BNP Paribas Securities Corp., Crédit Agricole Corporate and Investment Bank, HSBC Securities (USA) Inc., Morgan Stanley Senior Funding, Inc., PNC Capital Markets LLC and RBS Securities Inc., as joint lead arrangers and joint book managers, and the lender parties thereto, as amended by that certain Omnibus Credit Agreement, dated as of February 5, 2015. During March 2016, the Company elected to exercise the 30-day grace period with respect to a $21.1 million semi-annual interest payment due March 15, 2016 on the 6.50% Senior Notes due September 2020 and a $50.0 million semi-annual interest payment due March 15, 2016 on the Senior Secured Second Lien Notes. The Company filed the Bankruptcy Petitions before the grace period lapsed, which stayed the related interest payments. As a result of the filing of the Bankruptcy Petitions, all unpaid principal and accrued and unpaid interest related to the Company's Debt Instruments due thereunder became immediately due and payable. Any efforts to enforce such payment obligations under the Debt Instruments are automatically stayed as a result of the Bankruptcy Petitions, and the creditors’ rights of enforcement in respect of the Debt Instruments are subject to the applicable provisions of the Bankruptcy Code. The Company was also required to pay monthly adequate protection payments to the First Lien Secured Parties in accordance with the rates defined in the 2013 Credit Facility. The adequate protection payments were recorded as "Interest expense" in the consolidated statement of operations, which totaled $121.4 million for the year ended December 31, 2016. The Company has not recorded interest expense on the 6.00% Senior Notes due November 2018, the 6.50% Senior Notes due September 2020, the 6.25% Senior Notes due November 2021, the Debentures, the Senior Secured Second Lien Notes or the 7.875% Senior Notes due November 2026 since the filing of the Bankruptcy Petitions on the Petition Date. The Company's contractual interest obligation was $564.9 million for the year ended December 31, 2016; however, in accordance with Section 502(b)(2) of the Bankruptcy Code, $266.3 million of that amount was automatically stayed. Interest paid on debt was $132.3 million , $414.2 million and $404.4 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Financing costs incurred with the issuance of the Company’s debt (excluding DIP financing costs) were being amortized to interest expense over the remaining term of the associated debt prior to the Bankruptcy Petitions. The remaining balance at December 31, 2016 was $89.0 million . DIP Financing On the Petition Date, the Debtors filed a motion (the DIP Motion) seeking authorization to use cash collateral and to approve financing (the DIP Financing) under that certain Superpriority Secured Debtor-In-Possession Credit Agreement (the DIP Credit Agreement) by and among the Company as borrower, Peabody Global Funding, LLC, formerly known as the Global Center for Energy and Human Development and certain Debtors party thereto as guarantors (the Guarantors and together with the Company, the Loan Parties), the lenders party thereto (the DIP Lenders) and Citibank, N.A. as Administrative Agent (in such capacity, the DIP Agent) and L/C Issuer. The DIP Credit Agreement provided for (i) a term loan not to exceed $500 million (the DIP Term Loan Facility), of which $200 million was made available upon entry of an interim order, the remaining $300 million pending the entry of the final order approving the DIP Credit Agreement (the Final Order), secured by substantially all of the assets of the Loan Parties, subject to certain excluded assets and carve outs and guaranteed by the Loan Parties (other than the Company), which would be used for working capital and general corporate purposes, to cash collateralize letters of credit and to pay fees and expenses, (ii) a cash collateralized letter of credit facility in an amount up to $100 million (the L/C Facility), and (iii) a bonding accommodation facility in an amount up to $200 million consisting of (x) a carve-out from the collateral with superpriority claim status, subject only to the fees carve-out, entitling the authority making any bonding request to receive proceeds of collateral first in priority before distribution to any DIP Lender or other prepetition secured creditor, except for letters of credit issued under the DIP Credit Agreement and/or (y) a letter of credit facility (the Bonding L/C Facility). The aggregate face amount of all letters of credit issued under the L/C Facility and the Bonding L/C Facility could not at any time exceed $50 million without DIP Lender consent. On April 15, 2016, the Bankruptcy Court issued an order approving the DIP Motion on an interim basis and authorizing the Loan Parties to, among other things, (i) enter into the DIP Credit Agreement and initially borrow up to $200 million , (ii) obtain a cash collateralized letter of credit facility in the aggregate amount of up to $100 million , and (iii) establish an accommodation facility for bonding requests in an aggregate stated amount of up to $200 million . On April 18, 2016, the Company entered into the DIP Credit Agreement with the DIP Lenders and borrowed $200 million under the DIP Term Loan Facility. On May 17, 2016, the Bankruptcy Court approved the DIP Financing on a final basis and entered an order to that effect on May 18, 2016. On May 19, 2016, following entry of the Final Order, the Company borrowed the remaining $300 million available under the DIP Term Loan Facility. The Company paid aggregate debt issuance costs of $26.8 million during the year ended December 31, 2016 related to the DIP Term Loan Facility. On December 14, 2016, the Bankruptcy Court entered an order authorizing the repayment of the DIP Term Loan Facility prior to its scheduled maturity date and on December 15, 2016, the Company repaid the DIP Term Loan Facility in full. Upon making this payment, the Company’s obligations under the DIP Credit Agreement were satisfied in full and it was terminated. In connection with the repayment and termination, the Company incurred a loss on the early debt extinguishment of $29.5 million , consisting of a $10.0 million early-termination fee and $19.5 million related to the write-off of unamortized deferred financing costs and an original issue discount. 2013 Credit Facility On September 24, 2013, the Company entered into a secured credit agreement (as amended, the 2013 Credit Facility), which provides for a $1.65 billion revolving credit facility (the 2013 Revolver) and a $1.20 billion term loan facility (the 2013 Term Loan Facility). During the first quarter of 2016, the Company borrowed $947.0 million under the 2013 Revolver for general corporate purposes. As of the Petition Date, the Company had approximately $675 million letters of credit outstanding on the 2013 Revolver. Subsequent to the Petition Date, certain counterparties drew on a portion of those letters of credit. The letters of credit were in place to support various types of obligations, though the most significant items related to bank guarantees in place for certain reclamation bonding requirements in Australia. The draws required the recording of previously off-balance sheet liabilities, except in certain instances where the Company had previously recorded a liability, and as such have been reflected as additional borrowings under the 2013 Revolver. The total of such letters of credit was $611.1 million as of December 31, 2016 . "Investments and other assets" in the consolidated balance sheets as of December 31, 2016 includes $479.3 million of collateral in support of certain of these obligations. As a result of filing the Bankruptcy Petitions on April 13, 2016, as discussed in Note 1. "Summary of Significant Accounting Policies", the Company is in default under the 2013 Credit Facility and as such the 2013 Revolver can no longer be utilized. Senior Secured Second Lien Notes Offering On March 16, 2015, the Company completed the offering of $1.0 billion aggregate principal amount of the Senior Secured Second Lien Notes. The notes were offered to qualified institutional buyers under Rule 144A of the Securities Act, and to non-U.S. persons in transactions outside the U.S. under Regulation S of the Securities Act. The Company used the net proceeds from the sale of the notes, in part, to fund the tender offer to purchase its 7.375% Senior Notes due November 2016 (the 2016 Senior Notes) and to redeem the aggregate principal amount of the 2016 Senior Notes that was not tendered in the tender offer. The remaining proceeds were used for general corporate purposes. 2016 Senior Notes Tender Offer and Redemption Concurrently with the offering of the Senior Secured Second Lien Notes, the Company commenced a tender offer to repurchase the $650.0 million aggregate principal amount then outstanding of the 2016 Senior Notes. Consequently, the Company repurchased $566.9 million aggregate principal amount of the 2016 Senior Notes that were validly tendered and not validly withdrawn during the tender offer. The Company redeemed the remaining $83.1 million aggregate principal amount of the 2016 Senior Notes on April 15, 2015. In connection with those repurchases, the Company recognized an aggregate loss on early debt extinguishment of $67.8 million in the consolidated statement of operations for the year ended December 31, 2015 comprised of aggregate tender offer and make-whole premiums paid of $66.4 million and the non-cash write-off of associated unamortized debt issuance costs of $1.4 million . Exit Financing On February 8, 2017, the Company announced the pricing of a $950.0 million senior secured term loan. The term loan will mature in 2022 and bear interest at a fluctuating rate of LIBOR plus 4.50% per annum, with a 1.00% LIBOR floor. The closing of the term loan is expected to occur in early April 2017, concurrent with the anticipated effective date of the Plan and subject to confirmation of the Plan and customary closing conditions and final documentation. The proceeds from the term loan will be used to fund a portion of the distributions to creditors provided for under the Plan. Also on February 8, 2017, the Company announced that a special purpose wholly owned subsidiary of the Company priced an offering of $500.0 million aggregate principal amount of 6.000% senior secured notes due 2022 and $500.0 million aggregate principal amount of 6.375% senior secured notes due 2025, each exempt from the registration requirements of the Securities Act of 1933, as amended. The offering of the notes closed on February 15, 2017 at which time the net proceeds of the offering were funded into an escrow account pending the Plan Effective Date. The notes were offered by a special purpose wholly owned subsidiary of the Company and if the Plan is confirmed and certain other conditions are satisfied on or before August 1, 2017, the net proceeds from the offering will be released from escrow to fund a portion of the distributions to creditors provided for under the Plan, and the Company will become the obligor under the notes. Capital Lease Obligations Refer to Note 15. "Leases" for additional information associated with the Company's capital leases, which pertain to the financing of mining equipment used in operations.

Leases

Leases	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Leases	Leases The Company leases equipment and facilities under various noncancellable lease agreements. Certain lease agreements are subject to the restrictive covenants of the Company's credit facilities 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. Rental expense under operating leases, including expense related to short-term operating leases, was $264.7 million , $290.1 million and $306.0 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. One of the Company's operating lease agreements for underground mining equipment in Australia entered into in 2013 requires contingent rent to be paid only if and when certain coal is mined at a specified margin as defined in the agreements. There was no contingent expense related to that arrangement for the years ended December 31, 2016, 2015 and 2014. The gross value of property, plant, and equipment under capital leases was $77.9 million and $77.5 million as of December 31, 2016 and 2015, respectively, related primarily to the leasing of mining equipment. The accumulated depreciation for these items was $48.6 million and $32.2 million at December 31, 2016 and 2015 , respectively, and changes thereto have been included in "Depreciation, depletion and amortization" in the consolidated statements of operations. The Company also leases coal reserves under agreements that require royalties to be paid as the coal is mined. Certain agreements also require minimum annual royalties to be paid regardless of the amount of coal mined during the year. Total royalty expense was $389.7 million , $444.5 million and $507.8 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. A substantial amount of the coal mined by the Company is produced from mineral reserves leased from the owner. One of the major lessors is the U.S. government, from which the Company leases substantially all of the coal it mines in Wyoming under terms set by Congress and administered by the U.S. Bureau of Land Management. These leases are generally for an initial term of ten years but may be extended by diligent development and mining of the reserves until all economically recoverable reserves are depleted. The Company has met the diligent development requirements for substantially all of these federal leases either directly through production, by including the lease as a part of a logical mining unit with other leases upon which development has occurred, or by paying an advance royalty in lieu of continued operations. Annual production on these federal leases must total at least 1.0% of the leased reserve or the original amount of coal in the entire logical mining unit in which the leased reserve resides. In addition, royalties are payable monthly at a rate of 12.5% of the gross realization from the sale of the coal mined using surface mining methods and at a rate of 8.0% of the gross realization for coal produced using underground mining methods. The Company also leases coal reserves in Arizona from The Navajo Nation and the Hopi Tribe under leases that are administered by the U.S. Department of the Interior. These leases expire upon exhaustion of the leased reserves or upon the permanent ceasing of all mining activities on the related reserves as a whole. The royalty rates are also generally based upon a percentage of the gross realization from the sale of coal. These rates are subject to redetermination every ten years under the terms of the leases. The remainder of the leased coal is generally leased from state governments, land holding companies and various individuals. The duration of these leases varies greatly. Typically, the lease terms are automatically extended as long as active mining continues. Royalty payments are generally based upon a specified rate per ton or a percentage of the gross realization from the sale of the coal. Mining and exploration in Australia is generally conducted under leases, licenses or permits granted by state governments. Mining and exploration licenses and their associated environmental protection approvals contain conditions relating to such matters as minimum annual expenditures, environmental compliance, restoration and rehabilitation. Royalties are paid to the state government as a percentage of the sales price (less certain allowable deductions in some cases). Generally landowners do not own the mineral rights or have the ability to grant rights to mine those minerals. These rights are retained by state governments. Compensation is often payable to landowners, occupiers and Aboriginal traditional owners with residual native title rights and interests for the loss of access to the land from the proposed mining activities. The amount and type of compensation and the ability to proceed to grant of a mining tenement may be determined by agreement or court determination, as provided by law. Future minimum lease and royalty payments as of December 31, 2016 are as follows: Capital Leases Operating Leases Coal Lease and Royalty Obligations Year Ending December 31, (Dollars in millions) 2017 $ 7.3 $ 148.7 $ 6.1 2018 8.9 100.4 5.7 2019 0.5 60.2 5.2 2020 0.5 26.4 4.9 2021 0.5 10.6 5.3 2022 and thereafter 9.6 26.6 26.6 Total minimum lease payments 27.3 $ 372.9 $ 53.8 Less interest 7.6 Present value of minimum capital lease payments $ 19.7 As of December 31, 2016 , certain of the Company’s coal lease obligations were secured by outstanding surety bonds totaling $94.0 million .

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2016
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations Reconciliations of the Company’s asset retirement obligations are as follows: December 31, 2016 2015 (Dollars in millions) Balance at beginning of year $ 712.1 $ 752.5 Liabilities incurred or acquired — 1.3 Liabilities settled or disposed (41.5 ) (53.3 ) Accretion expense 45.7 42.7 Revisions to estimates 42.5 (31.1 ) Balance at end of year $ 758.8 $ 712.1 Less: Current portion (included in "Accounts payable and accrued expenses") 41.0 25.5 Noncurrent obligation (included in "Asset retirement obligations") $ 717.8 $ 686.6 Balance at end of year — active locations $ 651.1 $ 656.8 Balance at end of year — closed or inactive locations $ 107.7 $ 55.3 The credit-adjusted, risk-free interest rates utilized to estimate the Company's asset retirement obligations were 13.45% for its U.S. reclamation obligations and 4.92% for its Australia reclamation obligations at December 31, 2016 and 50.83% and 6.82% at December 31, 2015 and 2014 , respectively. For 2016, a distinct rate was developed for Australia due to the amount of cash collateral held in support of the related obligations as of December 31, 2016. As of December 31, 2016 and 2015 , the Company had $374.3 million and $609.4 million , respectively, in surety bonds and bank guarantees outstanding to secure reclamation obligations. The amount of reclamation self-bonding in certain U.S. states in which the Company qualifies was $1,094.2 million and $1,430.8 million as of December 31, 2016 and 2015 , respectively. Additionally, the Company had $80.0 million and $126.6 million , respectively, of letters of credit in support of reclamation obligations as of December 31, 2016 and 2015. During 2016, the Company replaced certain bank guarantees with cash collateral of $233.2 million as of December 31, 2016.

Postretirement Health Care and

Postretirement Health Care and Life Insurance Benefits	12 Months Ended
	Dec. 31, 2016
Postretirement Health Care and LIfe Insurance Benefits [Abstract]
Postretirement Health Care and Life Insurance Benefits	Postretirement Health Care and Life Insurance Benefits The Company currently provides health care and life insurance benefits to qualifying salaried and hourly retirees of its current and certain former subsidiaries and their dependents from benefit plans established by the Company. Plan coverage for health benefits is provided to future hourly and salaried retirees in accordance with the applicable plan document. Life insurance benefits are provided to future hourly retirees in accordance with the applicable labor agreement. Net periodic postretirement benefit cost included the following components: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Service cost for benefits earned $ 10.4 $ 11.2 $ 12.2 Interest cost on accumulated postretirement benefit obligation 34.5 33.8 36.4 Amortization of prior service (credit) cost (9.2 ) (6.8 ) 1.3 Amortization of actuarial loss 20.4 24.9 14.5 Special termination benefits (1) — — 1.6 Net periodic postretirement benefit cost $ 56.1 $ 63.1 $ 66.0 (1) Reflected in "Restructuring and pension settlement charges" in the consolidated statement of operations for the year ended December 31, 2014. The following includes pre-tax amounts recorded in "Accumulated other comprehensive loss": Year Ended December 31, 2016 2015 2014 (Dollars in millions) Net actuarial loss (gain) arising during year $ 32.3 $ (35.1 ) $ 115.8 Prior service credit arising during year — — (18.0 ) Amortization: Actuarial loss (20.4 ) (24.9 ) (14.5 ) Prior service credit (cost) 9.2 6.8 (1.3 ) Settlement related to the Patriot bankruptcy: (1) Prior service cost 7.2 (16.6 ) — Total recorded in "Accumulated other comprehensive loss" $ 28.3 $ (69.8 ) $ 82.0 (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction. The Company amortizes actuarial gain and loss using a 0% corridor with an amortization period that covers the average future working lifetime of active employees ( 10.31 years and 10.49 years at January 1, 2017 and 2016 , respectively). The estimated net actuarial loss and prior service credit that will be amortized from accumulated other comprehensive loss into net periodic postretirement benefit cost during the year ending December 31, 2017 are $22.0 million and $9.2 million , respectively. The following table sets forth the plans' funded status reconciled with the amounts shown in the consolidated balance sheets: December 31, 2016 2015 (Dollars in millions) Change in benefit obligation: Accumulated postretirement benefit obligation at beginning of period $ 776.1 $ 839.1 Service cost 10.4 11.2 Interest cost 34.5 33.8 Participant contributions 0.6 1.7 Plan changes (1) 7.2 (16.6 ) Benefits paid (49.0 ) (46.5 ) Actuarial loss (gain) 32.3 (35.1 ) Settlement related to the Patriot bankruptcy (1) — (15.2 ) Other — 3.7 Accumulated postretirement benefit obligation at end of period 812.1 776.1 Change in plan assets: Fair value of plan assets at beginning of period — — Employer contributions 48.4 44.8 Participant contributions 0.6 1.7 Benefits paid and administrative fees (net of Medicare Part D reimbursements) (49.0 ) (46.5 ) Fair value of plan assets at end of period — — Funded status at end of year (812.1 ) (776.1 ) Less: Current portion (included in "Accounts payable and accrued expenses") 55.8 53.2 Noncurrent obligation (included in "Accrued postretirement benefit costs") $ (756.3 ) $ (722.9 ) (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to the changes in the benefit obligation. The weighted-average assumptions used to determine the benefit obligations as of the end of each year were as follows: December 31, 2016 2015 Discount rate 4.15 % 4.50 % Measurement date December 31, 2016 December 31, 2015 The weighted-average assumptions used to determine net periodic benefit cost during each year were as follows: Year Ended December 31, 2016 2015 2014 Discount rate 4.50 % 4.10 % 4.90 % Measurement date December 31, 2015 December 31, 2014 December 31, 2013 The following presents information about the assumed health care cost trend rate: Year Ended December 31, 2016 2015 Pre-Medicare: Health care cost trend rate assumed for next year 6.20 % 6.60 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 4.75 % 4.75 % Year that the rate reaches the ultimate trend rate 2021 2021 Post-Medicare: Health care cost trend rate assumed for next year 5.60 % 5.80 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 4.75 % 4.75 % Year that the rate reaches the ultimate trend rate 2021 2021 Assumed health care cost trend rates have a significant effect on the expense and liability amounts reported for health care plans. A one-percentage-point change in the assumed health care cost trend would have the following effects: One Percentage- Point Increase One Percentage- Point Decrease (Dollars in millions) Effect on total service and interest cost components (1) $ 3.6 $ (3.2 ) Effect on total postretirement benefit obligation (1) $ 67.0 $ (61.9 ) (1) In addition to the effect on total service and interest cost components of expense, changes in trend rates would also increase or decrease the actuarial gain or loss amortization expense component. The impact on actuarial gain or loss amortization would approximate the increase or decrease in the obligation divided by 10.31 years at January 1, 2017. Plan Assets The Company’s postretirement benefit plans are unfunded. Estimated Future Benefit Payments The following benefit payments (net of retiree contributions), which reflect expected future service, as appropriate, are expected to be paid by the Company: Postretirement Benefits (Dollars in millions) 2017 $ 55.0 2018 56.2 2019 57.0 2020 57.5 2021 61.3 Years 2022-2026 290.3

Pension and Savings Plans

Pension and Savings Plans	12 Months Ended
	Dec. 31, 2016
Pension and Savings Plans [Abstract]
Pension and Savings Plans	Pension and Savings Plans One of the Company’s subsidiaries, Peabody Investments Corp. (PIC), sponsors a defined benefit pension plan covering certain U.S. salaried employees and eligible hourly employees at certain PIC subsidiaries (the Peabody Plan). A subsidiary of PIC also has a defined benefit pension plan covering eligible employees who are represented by the United Mine Workers of America (UMWA) under the Western Surface Agreement (the Western Plan). PIC also sponsors an unfunded supplemental retirement plan to provide senior management with benefits in excess of limits under the federal tax law (collectively, the Pension Plans). Effective May 31, 2008, the Peabody Plan was frozen in its entirety for both participation and benefit accrual purposes. The Company adopted an enhanced savings plan contribution structure in lieu of benefits formerly accrued under the Peabody Plan. In August 2014, the Company announced a program to offer voluntary lump-sum pension payout to eligible former salaried employees in the Peabody Plan that settled the Company’s obligation to them. The program provided participants with a one-time choice of electing to receive a lump-sum settlement of their pension benefit. As part of this voluntary lump-sum program, the Company settled $41.7 million of its pension obligations for U.S. salaried retirees and former salaried employees in the Peabody Plan with an equal amount paid from plan assets. As a result, the Company recorded a settlement charge of $8.7 million reflecting the accelerated recognition of unamortized actuarial losses in the Peabody Plan proportionate to the obligation that was settled. The settlement charge was reflected in “Restructuring and pension settlement charges” on the consolidated statement of operations with a corresponding reduction in “Accumulated other comprehensive loss” on the consolidated balance sheet. Net periodic pension cost included the following components: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Service cost for benefits earned $ 2.5 $ 2.7 $ 2.1 Interest cost on projected benefit obligation 41.5 40.4 45.4 Expected return on plan assets (45.3 ) (48.2 ) (54.3 ) Amortization of prior service cost 0.3 1.0 1.3 Amortization of net actuarial losses 24.7 39.6 30.2 Settlement charge — — 8.7 Net periodic pension cost $ 23.7 $ 35.5 $ 33.4 The following includes pre-tax amounts recorded in "Accumulated other comprehensive loss": Year Ended December 31, 2016 2015 2014 (Dollars in millions) Net actuarial loss arising during year $ 6.6 $ 30.6 $ 79.2 Amortization: Net actuarial loss (24.7 ) (39.6 ) (30.2 ) Prior service cost (0.3 ) (1.0 ) (1.3 ) Settlement charge — — (8.7 ) Total recorded in "Accumulated other comprehensive loss" $ (18.4 ) $ (10.0 ) $ 39.0 The Company amortizes actuarial gain and loss using a 5% corridor with a five -year amortization period. The estimated net actuarial loss and prior service cost that will be amortized from "Accumulated other comprehensive loss" into net periodic pension cost during the year ending December 31, 2017 are $25.4 million and $0.3 million , respectively. The following summarizes the change in benefit obligation, change in plan assets and funded status of the Pension Plans: December 31, 2016 2015 (Dollars in millions) Change in benefit obligation: Projected benefit obligation at beginning of period $ 939.3 $ 1,002.5 Service cost 2.5 2.7 Interest cost 41.5 40.4 Benefits paid (61.1 ) (62.6 ) Actuarial loss (gain) 37.1 (43.7 ) Projected benefit obligation at end of period 959.3 939.3 Change in plan assets: Fair value of plan assets at beginning of period 757.3 839.8 Actual return (loss) on plan assets 75.7 (26.1 ) Employer contributions 1.1 6.2 Benefits paid (61.1 ) (62.6 ) Fair value of plan assets at end of period 773.0 757.3 Funded status at end of year $ (186.3 ) $ (182.0 ) Amounts recognized in the consolidated balance sheets: Current obligation (included in "Accounts payable and accrued expenses") $ — $ (1.6 ) Noncurrent obligation (included in "Other noncurrent liabilities") (163.5 ) (180.4 ) Liabilities subject to compromise (22.8 ) — Net amount recognized $ (186.3 ) $ (182.0 ) The weighted-average assumptions used to determine the benefit obligations as of the end of each year were as follows: December 31, 2016 2015 Discount rate 4.15 % 4.55 % Measurement date December 31, 2016 December 31, 2015 The weighted-average assumptions used to determine net periodic benefit cost during each year were as follows: Year Ended December 31, 2016 2015 2014 Discount rate 4.55 % 4.15 % 4.95 % Expected long-term return on plan assets 6.00 % 6.25 % 6.85 % Measurement date December 31, 2015 December 31, 2014 December 31, 2013 The expected rate of return on plan assets is determined by taking into consideration expected long-term returns associated with each major asset class based on long-term historical ranges, inflation assumptions and the expected net value from active management of the assets based on actual results. Effective January 1, 2017, the Company lowered its expected rate of return on plan assets from 6.00% to 5.90% reflecting the impact of the Company's asset allocation and capital market expectations. The projected benefit obligation and the accumulated benefit obligation exceeded plan assets for all plans as of December 31, 2016 and 2015 . The accumulated benefit obligation for all plans was $959.3 million and $939.3 million as of December 31, 2016 and 2015 , respectively. Assets of the Pension Plans Assets of the PIC Master Trust (the Master Trust) are invested in accordance with investment guidelines established by the Peabody Plan Retirement Committee and the Peabody Western Plan Retirement Committee (collectively, the Retirement Committees) after consultation with outside investment advisors and actuaries. The asset allocation targets have been set with the expectation that the assets of the Master Trust will be managed with an appropriate level of risk to fund each Pension Plan's expected liabilities. To determine the appropriate target asset allocations, the Retirement Committees consider the demographics of each Pension Plan's participants, the funded status of each Pension Plan, the business and financial profile of the Company and other associated risk preferences. These allocation targets are reviewed by the Retirement Committees on a regular basis and revised as necessary. The Retirement Committees have developed and implemented a dynamic asset-liability management investment strategy (the Dynamic Investment Strategy) designed to reduce each Pension Plan's funded status volatility risk as funded status increases resulting from changes in liabilities due to discount rates and other factors, investment returns and funding contributions. The Dynamic Investment Strategy adjusts allocations between return-seeking (i.e., equities and other similar investments) and liability hedging (i.e., fixed income duration and spread exposure) portfolios in a pre-established manner, with changes triggered when the Pension Plans reach certain funded status thresholds. As of December 31, 2016 and 2015, the Master Trust investment portfolio reflected the Company's target asset mix of 31% equity securities and 69% fixed income investments. Master Trust assets also include funds invested in various real estate properties representing approximately 2% and 3% of total Master Trust assets as of December 31, 2016 and 2015, respectively. The Retirement Committees' intention is to liquidate these real estate holdings when allowable per the terms of the limited partnership agreements. Generally, dissolution and liquidation of the limited partnerships is required before the Master Trust’s real estate holdings can be liquidated and is estimated to occur at various times through 2021. Assets of the Master Trust are either under active management by third-party investment advisors or in index funds, all of which are selected and monitored by the Retirement Committees. Specific investment guidelines have been established by the Retirement Committees for each major asset class including performance benchmarks, allowable and prohibited investment types and concentration limits. In general, investment guidelines do not permit leveraging the assets held in the Master Trust. However, investment managers may employ various strategies and derivative instruments in establishing overall portfolio characteristics consistent with the guidelines and investment objectives established by the Retirement Committees for their portfolios. Equity investment guidelines do not permit entering into put or call options (except as deemed appropriate to manage currency risk), and futures contracts are permitted only to the extent necessary to facilitate liquidity management. Fixed income investment guidelines only allow for exchange-traded derivatives if the investment manager deems the derivative vehicle to be more attractive than a similar direct investment in an underlying cash market or to manage the duration of the fixed income portfolio. A financial instrument’s level within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Following is a description of the valuation techniques and inputs used for investments measured at fair value, including the general classification of such investments pursuant to the valuation hierarchy. Mutual funds. The Master Trust invests in mutual funds for growth and diversification. Investment vehicles include a fund (benchmarked against the performance of the S&P 500 Index) that invests in large-cap publicly traded common stocks (Large-Cap Fund), an institutional fund that holds a diversified portfolio of long-duration corporate fixed income investments (Corporate Bond Fund), and an institutional fund that consists of a diversified portfolio of liquid, short-term instruments of varying maturities (Short-Term Fund). The Large-Cap Fund, which is traded on a national securities exchange in an active market, is valued using daily publicly quoted net asset value (NAV) prices and accordingly classified within Level 1 of the valuation hierarchy. The Corporate Bond Fund and the Short-Term Fund are not traded on a national securities exchange and are valued at NAV, the practical expedient to estimate fair value. Corporate bonds . The Master Trust invests in corporate bonds for diversification, volatility reduction of equity securities and to provide a hedge to interest rate movements affecting liabilities. Investment vehicles include investment-grade corporate bonds. Fair value for these securities is provided by a third-party pricing service that utilizes various inputs such as benchmark yields, reported trades, broker/dealer quotes, issuer spreads and benchmark securities as well as other relevant economic measures. Corporate bonds are classified within the Level 2 valuation hierarchy since fair value inputs are derived prices in active markets and the bonds are not traded on a national securities exchange. U.S. government securities. The Master Trust invests in U.S. government securities for diversification, volatility reduction of equity securities and to provide a hedge to interest rate movements affecting liabilities. Investment vehicles include U.S. government bonds, agency securities and municipal bonds. Fair value for these securities is provided by a third-party pricing service that utilizes various inputs such as benchmark yields, reported trades, broker/dealer quotes, issuer spreads and benchmark securities as well as other relevant economic measures. If fair value is based on quoted prices in active markets and traded on a national securities exchange, U.S. government securities are classified within the Level 1 valuation hierarchy; otherwise, U.S. government securities are classified within the Level 2 valuation hierarchy. International government securities. The Master Trust invests in international government securities for diversification, volatility reduction of equity securities and to provide a hedge to interest rate movements affecting liabilities. Investment vehicles include non-U.S. government bonds. Fair value for these securities is provided by a third-party pricing service that utilizes various inputs such as benchmark yields, reported trades, broker/dealer quotes, issuer spreads and benchmark securities as well as other relevant economic measures. International government securities are classified within the Level 2 valuation hierarchy since fair value inputs are derived prices in active markets and the bonds are not traded on a national securities exchange. Common/collective trusts . The Master Trust invests in common/collective trusts (CCT) for growth and diversification. Investment vehicles include a CCT (benchmarked against the performance of the Russell 2000 Index) that invests in small-cap publicly traded common stocks (the Small-Cap CCT), a CCT that invests in publicly traded non-U.S. equity securities (the Equity CCT) and a CCT (benchmarked against the performance of the MSCI Emerging Markets Index) that primarily invests in equity index securities of companies in global emerging markets (the Equity Index CCT). The Equity CCT and the Equity Index CCT are valued using the closing price reported by their primary stock exchange and translated at each valuation date from local currency into U.S. dollars based on independently published currency exchange rates. The NAV is determined in U.S. dollars and calculated as of the last business day of each month for the Equity CCT and daily for the Equity Index CCT. All CCTs are not traded on a national securities exchange and are valued at NAV, the practical expedient to estimate fair value. Cash funds . The Master Trust invests in cash funds to manage liquidity resulting from payment of participant benefits and certain administrative fees. Investment vehicles primarily include a non-interest bearing cash fund with an earnings credit allowance feature and various exchange-traded derivative instruments consisting of futures and interest rate swap agreements used to manage the duration of certain liability-hedging investments. The non-interest bearing cash fund is classified within the Level 1 valuation hierarchy. Exchange traded derivatives, such as options and futures, for which market quotations are readily available, are valued at the last reported sale price or official closing price on the primary market or exchange on which they are traded and are classified within the Level 1 valuation hierarchy. Real estate investment trusts . The Master Trust invests in real estate interests for diversification. Investments in real estate represent interests in several limited partnerships, which invest in various real estate properties. Interests in real estate are valued using various methodologies, including independent third party appraisals; fair value measurements are not developed by the Company. For some investments, little market activity may exist and determination of fair value is then based on the best information available in the circumstances. This involves a significant degree of judgment by taking into consideration a combination of internal and external factors. Accordingly, interests in real estate are classified within the Level 3 valuation hierarchy. Some limited partnerships issue dividends to their investors in the form of cash distributions that the Pension Plans invest elsewhere within the Master Trust. The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Company believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. The inputs or methodologies used for valuing investments are not necessarily an indication of the risk associated with investing in those investments. The following tables present the fair value of assets in the Master Trust by asset category and by fair value hierarchy: December 31, 2016 Level 1 Level 2 Level 3 Total (Dollars in millions) Mutual funds $ 119.9 $ — $ — $ 119.9 Corporate bonds — 265.7 — 265.7 U.S. government securities 25.1 22.7 — 47.8 International government securities — 12.6 — 12.6 Cash funds 17.8 — — 17.8 Real estate investment trusts — — 14.1 14.1 Total assets at fair value $ 162.8 $ 301.0 $ 14.1 477.9 Assets measured at net asset value practical expedient (1) Private mutual funds 186.1 Common collective trusts 109.0 295.1 Total plan assets $ 773.0 December 31, 2015 Level 1 Level 2 Level 3 Total (Dollars in millions) Mutual funds $ 107.1 $ — $ — $ 107.1 Corporate bonds — 259.4 — 259.4 U.S. government securities 26.8 26.6 — 53.4 International government securities — 15.0 — 15.0 Cash funds 18.2 — — 18.2 Real estate investment trusts — — 23.0 23.0 Total assets at fair value $ 152.1 $ 301.0 $ 23.0 476.1 Assets measured at net asset value practical expedient (1) Private mutual funds 183.9 Common collective trusts 97.3 281.2 Total plan assets $ 757.3 (1) In accordance with Accounting Standards Update 2015-07, investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the total value of assets of the plans. The table below sets forth a summary of changes in the fair value of the Master Trust’s Level 3 investments: Year Ended December 31, 2016 2015 (Dollars in millions) Balance, beginning of year $ 23.0 $ 30.2 Realized gains 1.8 3.2 Unrealized gains relating to investments still held at the reporting date 0.2 0.2 Purchases, sales and settlements, net (10.9 ) (10.6 ) Balance, end of year $ 14.1 $ 23.0 Contributions Annual contributions to qualified plans are made in accordance with minimum funding standards and the Company's agreement with the Pension Benefit Guaranty Corporation (PBGC). Funding decisions also consider certain funded status thresholds defined by the Pension Protection Act of 2006 (generally 80% ). During the year ended December 31, 2016, the Company contributed $0.5 million and $0.6 million , respectively, to its qualified and non-qualified pension plans. As of December 31, 2016, the Company's qualified plans are expected to be at or above the Pension Protection Act thresholds. However, during the Chapter 11 Cases, certain forms of payment from the Pension Plans are restricted. On November 2, 2015, the Bipartisan Budget Act of 2015 (BBA15) was signed into law, which extends pension funding stabilization provisions that were part of the Highway and Transportation Funding Act of 2014 (HATFA) and the Moving Ahead for Progress in the 21 st Century Act of 2012 (MAP-21). Under BBA15, the pension funding stabilization provisions temporarily increased the interest rates used to determine pension liabilities for purposes of minimum funding requirements through 2020. Similar to MAP-21, BBA15 is not expected to change the Company's total required cash contributions over the long term, but is expected to reduce the Company's required cash contributions through 2020 if current interest rate levels persist. Based upon minimum funding requirements in accordance with HATFA and BBA15, the Company expects to contribute approximately $5.9 million to its pension plans to meet minimum funding requirements for its qualified plans and benefit payments for its non-qualified plans in 2017. Contributions to non-qualified plans ceased subsequent to April 12, 2016 as a result of filing the Bankruptcy Petitions. Estimated Future Benefit Payments The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid in connection with the Company's benefit obligation: Pension Benefits (Dollars in millions) 2017 $ 61.7 2018 62.3 2019 62.2 2020 64.0 2021 65.1 Years 2022-2026 312.4 Defined Contribution Plans The Company sponsors employee retirement accounts under two 401(k) plans for eligible U.S. employees. The Company matches voluntary contributions to each plan up to specified levels. The expense for these plans was $19.2 million , $22.0 million and $44.7 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. A performance contribution feature in one of the plans allows for additional contributions from the Company based upon meeting specified Company performance targets. There was no performance contribution for the year ended December 31, 2016. Performance contributions paid during the years ended December 31, 2015 and 2014 were $19.5 million and $18.3 million , respectively. The performance contribution was paid in Peabody Energy Corporation common stock for the year ended December 31, 2015 and cash for the year ended December 31, 2014.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity	Stockholders’ Equity If the Plan becomes effective, the Company's common stock will be extinguished, canceled and discharged on the Plan Effective Date. Under the Plan, holders of common stock are not entitled to receive, and will not receive or retain, any property or interest in property on account of such equity interests. In the event of cancellation of the Company's common stock, amounts invested by the holders will not be recoverable and the common stock will have no value. Common Stock Pursuant to the authorization provided at a special meeting of the Company's stockholders held on September 16, 2015, the Company completed a 1-for-15 reverse stock split of the shares of the Company’s common stock on September 30, 2015 (the Reverse Stock Split). Refer to Note 1. "Summary of Significant Accounting Policies" for additional details surrounding the Reverse Stock Split. As a result of the Reverse Stock Split, the Company has 53.3 million authorized shares of $0.01 par value common stock. Holders of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders. The holders of common stock do not have cumulative voting rights in the election of directors. Holders of common stock are entitled to receive ratably dividends if, as and when dividends are declared from time to time by the Company's Board of Directors out of funds legally available for that purpose, after payment of dividends required to be paid on outstanding preferred stock or series common stock, as described below. Upon liquidation, dissolution or winding up, any business combination or a sale or disposition of all or substantially all of the assets, the holders of common stock are entitled to receive ratably the assets available for distribution to the stockholders after payment of liabilities and accrued but unpaid dividends and liquidation preferences on any outstanding preferred stock or series common stock. The common stock has no preemptive or conversion rights and is not subject to further calls or assessment by the Company. There are no redemption or sinking fund provisions applicable to the common stock. The following table summarizes common stock activity from January 1, 2014 to December 31, 2016 : 2016 2015 2014 (In millions) Shares outstanding at the beginning of the year 18.5 18.1 18.0 Stock grants to employees — 0.2 0.1 Performance share contribution 401k — 0.2 — Shares outstanding at the end of the year 18.5 18.5 18.1 Preferred Stock and Series Common Stock The Board of Directors is authorized to issue up to 10.0 million shares of preferred stock and up to 40.0 million shares of series common stock, both with a $0.01 per share par value. The Board of Directors can determine the terms and rights of each series, whether dividends (if any) will be cumulative or non-cumulative and the dividend rate of the series, redemption or sinking fund provisions, conversion terms, prices and rates and amounts payable on shares of the series in the event of any voluntary or involuntary liquidation, dissolution or winding up of the affairs of the Company and whether the shares of the series will be convertible into shares of any other class or series, or any other security, of the Company or any other corporation. The Board of Directors may also determine restrictions on the issuance of shares of the same series or of any other class or series, and the voting rights (if any) of the holders of the series. There were no outstanding shares of preferred stock or series common stock as of December 31, 2016 . Perpetual Preferred Stock The Company had $732.5 million aggregate principal amount of the Debentures outstanding as of December 31, 2016 . Perpetual preferred stock issued upon a conversion of the Debentures will be fully paid and non-assessable, and holders will have no preemptive or preferential right to purchase any of the Company’s other securities. The perpetual preferred stock has a liquidation preference of $1,000 per share, is not convertible and is redeemable at the Company’s option at any time at a cash redemption price per share equal to the liquidation preference plus any accumulated dividends. Holders are entitled to receive cumulative dividends at an annual rate of 3.0875% if and when declared by the Company’s Board of Directors. If the Company fails to pay dividends on the perpetual preferred stock for five years, the Company generally must sell warrants or preferred stock with specified characteristics and use the funds from that sale to pay accumulated dividends after the payment in full of any deferred interest on the Debentures, subject to certain limitations. Additionally, holders of the perpetual preferred stock are entitled to elect two additional members to serve on the Company’s Board of Directors if (1) prior to any remarketing of the perpetual preferred stock, the Company fails to declare and pay dividends with respect to the perpetual preferred stock for 10 consecutive years or (2) after any successful remarketing or any final failed remarketing of the perpetual preferred stock, the Company fails to declare and pay six dividends thereon, whether or not consecutive. The perpetual preferred stock may be remarketed at the holder’s election after December 15, 2046 or earlier, upon the first occurrence of a change of control if the Company does not redeem the perpetual preferred stock. There were no outstanding shares of perpetual preferred stock as of December 31, 2016 . Treasury Stock Share repurchases. The Company has a share repurchase program for its common stock with an authorized amount of $1.0 billion in which repurchases may be made from time to time based on an evaluation of the Company’s outlook and general business conditions, as well as alternative investment and debt repayment options (Repurchase Program). The Repurchase Program does not have an expiration date and may be discontinued at any time. From October 2008 through December 2013, the Company made total repurchases of 0.5 million shares at a cost of $299.6 million ( $199.8 million in 2008 and $99.8 million in 2006), leaving $700.4 million available under the Repurchase Program. No share repurchases were made under the Repurchase Program during the years ended December 31, 2016 , 2015 and 2014 . As a result of filing the Bankruptcy Petition, the Company is currently prohibited from repurchasing shares. The payment of future cash dividends and future repurchases will depend upon the Company's earnings, economic conditions, liquidity and capital requirements, and other factors, including the Company's debt leverage. In addition, the terms of the Preferred Equity will limit the Company's ability to pay cash dividends on or purchase shares of Reorganized PEC Common Stock without the consent of holders representing at least a majority of the outstanding shares of the Preferred Equity. Shares relinquished. The Company routinely allows employees to relinquish common stock to pay estimated taxes upon the payout of performance units that are settled in common stock and the vesting of restricted stock. The number of shares of common stock relinquished was less than 0.1 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The value of the common stock tendered by employees was based upon the closing price on the dates of the respective transactions.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Share-Based Compensation	Share-Based Compensation In 2015, the Company established the 2015 Long-Term Incentive Plan (the 2015 Plan) for employees and non-employee directors that allows for the issuance of share-based compensation in various forms including stock appreciation rights, restricted stock, performance awards, incentive stock options, nonqualified stock options, deferred stock units, restricted stock units and cash incentive awards. The 2015 Plan superseded the Company’s 2011 Long-Term Equity Incentive Plan (the 2011 Plan). The 2015 Plan became effective on May 4, 2015, which was the date approval by the Company’s stockholders was obtained. Subsequent to May 4, 2015, the Company can only issue awards under the 2015 Plan. Awards previously issued under the 2011 Plan (or any other prior equity plan) will remain outstanding under their terms. Under the 2015 Plan, 1.2 million shares of the Company’s common stock were authorized for issuance. The pool of shares authorized for issuance is intended to be fungible. As a result, the number of shares available under the 2015 Plan is reduced by the number of shares underlying any stock appreciation right or stock option granted, and awards other than a stock option or stock appreciation right will reduce the number of shares available under the 2015 Plan by two shares. As of December 31, 2016, there are approximately 1.0 million shares of the Company’s common stock available for grant. The Company had two employee stock purchase plans, which provided for the purchase of up to 0.1 million shares of the Company’s common stock. Due to the low number of shares available for employee purchase, coupled with the Company’s low stock price, both employee stock purchase plans terminated in October 2015. On the Plan Effective Date, equity holders' interests will be canceled and all unrecognized share-based compensation expense will be charged to reorganization items, net. Share-Based Compensation Expense and Cash Flows The Company’s share-based compensation expense is recorded in “Selling and administrative expenses” in the consolidated statements of operations. Cash received by the Company upon the exercise of stock options and when employees purchase stock under the employee stock purchase plans is reflected as a financing activity in the consolidated statements of cash flows. Share-based compensation expense and cash flow amounts were as follows: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Share-based compensation expense - equity classified awards $ 11.3 $ 26.2 $ 46.1 Share-based compensation expense - liability classified awards 1.5 2.0 0.7 Total share-based compensation expense 12.8 28.2 46.8 Tax benefit — — 17.3 Share-based compensation expense, net of tax benefit $ 12.8 $ 28.2 $ 29.5 Cash received upon the exercise of stock options and from employee stock purchases — 3.4 5.5 Write-off tax benefits related to share-based compensation — — (8.3 ) As of December 31, 2016 , the total unrecognized compensation cost related to nonvested awards was $4.9 million , net of taxes, which is expected to be recognized over one year with a weighted-average period of 0.5 years. Deferred Stock Units In 2016 , 2015 and 2014 , the Company granted deferred stock units to each of its non-employee directors. The fair value of these units is equal to the market price of the Company’s common stock at the date of grant. These deferred stock units generally vest after one year and are settled in common stock on the specified distribution date elected by each non-employee director. Non-employee directors are also given the option to receive their total annual cash retainer in the form of additional deferred stock units (based on the fair market value of the Company's common stock on the date of grant). The additional grant of deferred stock units is subject to the same grant timing, vesting and distribution date elections as the annual equity compensation grant. Restricted Stock Awards Prior to 2016, the primary share-based compensation tool used by the Company for its employees was awards of restricted stock. The majority of restricted stock awards are granted in January of each year, with a lesser portion granted in the first month of the subsequent three quarters. Awards generally cliff vest after three years of service and only contain a service condition, with compensation cost recognized on a straight-line basis over the requisite service period, net of estimated forfeitures. For awards with service and performance conditions, the Company recognizes compensation cost using the graded-vesting method, net of estimated forfeitures. The fair value of restricted stock is equal to the market price of the Company’s common stock at the date of grant. A summary of restricted stock award activity is as follows: Year Ended December 31, 2016 Weighted Average Grant-Date Fair Value Nonvested at December 31, 2015 306,931 $ 184.09 Granted 7,847 7.75 Vested (76,663 ) 277.28 Forfeited (30,076 ) 167.68 Canceled (11,295 ) 82.49 Nonvested at December 31, 2016 196,744 $ 151.72 The total fair value at grant date of restricted stock awards granted during the year ended December 31, 2016 was less than $0.1 million . The total fair value at grant date of restricted stock awards granted during the years ended December 31, 2015 and 2014 was $26.0 million and $25.5 million , respectively. The total fair value of restricted stock awards vested during the years ended December 31, 2016 , 2015 and 2014 , was $21.3 million , $35.7 million and $24.5 million , respectively. Restricted Stock Units The Company grants restricted stock units to certain senior management and non-senior management employees. The Company grants restricted stock units to non-senior management employees who either met the Company's retirement eligibility guidelines or would meet the guidelines during the vesting period of the award. For units granted to both senior and non-senior management employees containing only service conditions, the fair value of the award is equal to the market price of the Company's common stock at the date of grant. Units granted to non-senior management retirement-eligible employees vest quarterly. Units granted to senior management employees vest at various times (none of which exceed five years) in accordance with the underlying award agreement. Compensation cost for both senior and non-senior management employees is recognized on a straight-line basis over the requisite service period. The payouts for active grants awarded in 2016 and 2014 will be settled in the Company's common stock. All awards granted in 2015 will be settled in the Company's common stock with the exception of a grant awarded in 2015 to a member of senior management which will be settled in cash instead of the Company's common stock. A summary of restricted stock unit activity is as follows: Year Ended December 31, 2016 Weighted Average Grant-Date Fair Value Nonvested at December 31, 2015 48,780 $ 170.42 Granted 342,627 7.75 Vested (23,220 ) 149.84 Forfeited (59,629 ) 22.41 Nonvested at December 31, 2016 308,558 $ 16.98 The total fair value at grant date of restricted stock units granted during the years ended December 31, 2016, 2015 and 2014 was $ 2.7 million , $ 5.5 million and $4.2 million , respectively. The total fair value of restricted stock units vested was $ 3.5 million and $ 2.1 million during the years ended December 31, 2016 and 2015, respectively. The total fair value was less than $ 0.1 million during the year ended December 31, 2014. Stock Options The Company’s stock option awards have been primarily limited to senior management personnel. All stock options are granted at an exercise price equal to the market price of the Company’s common stock at the date of grant. Stock options generally vest in one-third increments over a period of three years or cliff vest after three years, and expire after 10 years from the date of grant. Expense is recognized ratably over the service period, net of estimated forfeitures. Option grants are typically made in January of each year or upon hire for eligible plan participants. There were no stock options granted in 2016. All awards granted in 2015 will be settled in the Company's common stock with the exception of a grant awarded in 2015 to a certain senior management employee which will be settled in cash instead of the Company's common stock. All awards granted in 2014 will be settled in the Company's common stock. The Company used the Black-Scholes option pricing model to determine the fair value of stock options. The Company utilized U.S. Treasury yields as of the grant date for its risk-free interest rate assumption, matching the U.S. Treasury yield terms to the expected life of the option. The Company utilized historical company data to develop its dividend yield, expected volatility and expected option life assumptions. A summary of outstanding option activity under the plans is as follows: Year Ended December 31, 2016 Weighted Average Exercise Price Weighted Average Remaining Contractual Life Aggregate Intrinsic Value (in millions) Options Outstanding at December 31, 2015 240,428 $ 388.16 6.28 $ — Forfeited (22,182 ) 419.40 Options Outstanding at December 31, 2016 218,246 $ 379.17 5.56 $ — Vested and Exercisable 162,402 $ 451.88 4.86 $ — There were no stock options exercised during the years ended December 31, 2016 and 2015. During the year ended December 31, 2014, the total intrinsic value of options exercised, defined as the excess fair value of the underlying stock over the exercise price of the options, was $0.4 million . The weighted-average fair values of the Company’s stock options and the assumptions used in applying the Black-Scholes option pricing model were as follows: Year Ended December 31, 2015 2014 Weighted-average fair value $ 43.66 $ 110.70 Risk-free interest rate 1.7 % 1.7 % Expected option life 5 years 5 years Expected volatility 45.2 % 48.4 % Dividend yield 2.4 % 1.7 % Performance Units Performance units are typically granted annually in January and vest over a three -year measurement period and are primarily limited to senior management personnel. The performance units are usually subject to the achievement of goals based on the following conditions or any combination thereof: three-year stock price performance compared to both an industry peer group and a S&P index (market condition) and/or three-year return on capital or mining asset targets (performance condition). Generally, three performance unit grants are outstanding for any given year. There were no performance units granted in 2016. Awards granted in 2015 to certain senior management employees will be settled in cash. All other awards granted in 2015 will be settled in the Company's common stock. All awards granted in 2014 will be settled in the Company's common stock with the exception of a grant awarded in 2014 to a certain senior management employee, which was later modified to be settled in cash instead of the Company's common stock. At the date of the modification, the Company reclassified the award from an equity award to a liability award. There was no incremental cost recognized since the fair value of the modified liability award at the modification date was less than the grant-date fair value of the original equity award. To the extent that the fair value of the modified liability award may exceed the recognized compensation cost associated with the grant-date fair value of the original equity award in the future, changes in the liability award's fair value will be recognized as compensation cost prospectively. A summary of performance unit activity is as follows: Year Ended December 31, 2016 Weighted Average Remaining Contractual Life Nonvested at December 31, 2015 81,812 1.7 Forfeited (5,916 ) Vested (24,474 ) Nonvested at December 31, 2016 51,422 1.0 As of December 31, 2016 , there were 24,474 performance units vested. As a result of the Chapter 11 Cases, these units will not be paid out. The performance condition awards were valued utilizing the grant date fair values of the Company’s stock adjusted for dividends foregone during the vesting period. The market condition awards were valued utilizing a Monte Carlo simulation model which incorporates the total stockholder return hurdles set for each grant. The assumptions used in the valuations for grants were as follows: Year Ended December 31, 2015 2014 Risk-free interest rate 1.1 % 0.8 % Expected volatility 45.0 % 45.3 % Dividend yield 2.4 % 1.7 % Employee Stock Purchase Plans Prior to October 2015, the Company’s eligible full-time and part-time employees were able to contribute up to 15% of their base compensation into the employee stock purchase plans, subject to an annual limit of $25,000 per person. Employees were able to purchase Company common stock at a 15% discount to the lower of the fair market value of the Company’s common stock on the initial or final trading dates of each six-month offering period. Offering periods began on January 1 and July 1 of each year. The Company used the Black-Scholes option pricing model to determine the fair value of employee stock purchase plan share-based payments. The fair value of the six-month “look-back” option in the Company’s employee stock purchase plans was estimated by adding the fair value of 0.15 of one share of stock to the fair value of 0.85 of an option on one share of stock . The Company utilized U.S. Treasury yields as of the grant date for its risk-free interest rate assumption, matching the Treasury yield terms to the six-month offering period. The Company utilized historical company data to develop its dividend yield and expected volatility assumptions. The plans were terminated in October 2015. Shares purchased under the plans were less than 0.1 million for each of the years ended December 31, 2015 and 2014.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2016
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Loss The following table sets forth the after-tax components of comprehensive loss: Foreign Currency Translation Adjustment Net Actuarial Loss Associated with Postretirement Plans and Workers’ Compensation Obligations Prior Service Credit (Cost) Associated with Postretirement Plans Cash Flow Hedges Available-For-Sale Securities Total Accumulated Other Comprehensive Loss (Dollars in millions) December 31, 2013 $ (70.5 ) $ (205.8 ) $ 12.0 $ (155.7 ) $ 0.8 $ (419.2 ) Net change in fair value — — — (195.0 ) (3.7 ) (198.7 ) Reclassification from other comprehensive income to earnings — 31.0 1.7 (10.2 ) 2.9 25.4 Current period change (41.0 ) (142.7 ) 11.4 — — (172.3 ) December 31, 2014 (111.5 ) (317.5 ) 25.1 (360.9 ) — (764.8 ) Net change in fair value — — — (131.3 ) — (131.3 ) Reclassification from other comprehensive income to earnings — 35.6 (3.7 ) 251.7 — 283.6 Current period change (34.9 ) 18.1 10.4 — — (6.4 ) December 31, 2015 (146.4 ) (263.8 ) 31.8 (240.5 ) — (618.9 ) Net change in fair value — — — — — — Reclassification from other comprehensive income to earnings — 21.0 (5.6 ) 146.3 — 161.7 Current period change (1.8 ) (13.5 ) (4.5 ) — — (19.8 ) December 31, 2016 $ (148.2 ) $ (256.3 ) $ 21.7 $ (94.2 ) $ — $ (477.0 ) The following table provides additional information regarding items reclassified out of "Accumulated other comprehensive loss" into earnings during the years ended December 31, 2016 and 2015: Amount reclassified from accumulated other comprehensive loss (1) Year Ended December 31 Details about accumulated other comprehensive loss components 2016 2015 Affected line item in the consolidated statement of operations (Dollars in millions) Net actuarial loss associated with postretirement plans and workers' compensation obligations: Postretirement health care and life insurance benefits $ (20.4 ) $ (24.9 ) Operating costs and expenses Defined benefit pension plans (20.5 ) (32.9 ) Operating costs and expenses Defined benefit pension plans (4.2 ) (6.7 ) Selling and administrative expenses Workers' compensation amortization 11.7 8.0 Operating costs and expenses (33.4 ) (56.5 ) Total before income taxes 12.4 20.9 Income tax benefit $ (21.0 ) $ (35.6 ) Total after income taxes Prior service credit (cost) associated with postretirement plans: Postretirement health care and life insurance benefits $ 9.2 $ 6.8 Operating costs and expenses Defined benefit pension plans (0.3 ) (1.0 ) Operating costs and expenses 8.9 5.8 Total before income taxes (3.3 ) (2.1 ) Income tax benefit $ 5.6 $ 3.7 Total after income taxes Cash flow hedges: Foreign currency forward contracts $ (145.6 ) $ (316.4 ) Operating costs and expenses Fuel and explosives commodity swaps (86.1 ) (120.4 ) Operating costs and expenses Coal trading commodity futures, swaps and options — 51.8 Other revenues Insignificant items (0.5 ) (0.7 ) (232.2 ) (385.7 ) Total before income taxes 85.9 134.0 Income tax provision $ (146.3 ) $ (251.7 ) Total after income taxes (1) Presented as gains (losses) in the consolidated statements of operations. Comprehensive loss differs from net loss by the amount of unrealized gain or loss resulting from valuation changes of the Company’s cash flow hedges (see Note 8. "Derivatives and Fair Value Measurements" and Note 9. "Coal Trading" for information related to the Company’s cash flow hedges), changes in the fair value of available-for-sale securities (see Note 7. "Investments" for information related to the Company's investments in available-for-sale securities), the change in actuarial loss and prior service cost of postretirement plans and workers' compensation obligations (see Note 17. "Postretirement Health Care and Life Insurance Benefits," Note 18. "Pension and Savings Plans" and Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" for information related to the Company's postretirement and pension plans) and foreign currency translation adjustment related to the Company's investments in Middlemount, whose functional currency is the Australian dollar. The values of the Company’s cash flow hedging instruments are primarily affected by the U.S. dollar/Australian dollar exchange rate and changes in the prices of certain coal and diesel fuel products.

Resource Management, Acquisitio

Resource Management, Acquisitions and Other Commercial Events	12 Months Ended
	Dec. 31, 2016
Resource Management, Acquisitions and Other Commercial Events [Abstract]
Resource Management, Acquisitions and Other Commercial Events	Resource Management, Acquisitions and Other Commercial 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 consolidated statement of operations were aggregate restructuring charges, primarily comprised of cash severance costs, of $15.5 million for the year ended December 31, 2016. These costs were primarily incurred in the first half of 2016. Divestitures On January 30, 2017, the Bankruptcy Court issued an order authorizing certain subsidiaries of the Company to enter into a stalking horse purchase agreement and approved bidding procedures for the sale of its 37.5% interest in Dominion Terminal Associates, a partnership that operates a coal export terminal in Newport News, Virginia. Pursuant to that order, the deadline to submit qualified bids for the purchase of this interest was set for March 2, 2017 at 4:00 p.m. (Central) and the related auction was scheduled to begin on March 6, 2017 at 10:00 a.m. (Central). On February 10, 2017, Contura Terminal and Ashland Terminal, Inc., both of which are partners of the Dominion Terminal Associates partnership, filed an appeal of the January 30, 2017 order. On March 6, 2017, the Company held the auction relating to the sale of this interest. At the auction, Contura Terminal, LLC and Ashland Terminal, Inc., who bid at the auction together, were declared the successful bidder. On March 7, 2017, the Company filed a notice with the Bankruptcy Court indicating the identity of the successful bidder. On March 9, 2017, the Bankruptcy Court entered an order approving the sale of the Company's interest in Dominion Terminal Associates to Contura Terminal, LLC and Ashland Terminal, Inc. On March 14, 2017, the Bankruptcy Appellate Panel for the Eighth Circuit entered an order dismissing the appeal of Contura Terminal, LLC and Ashland Terminal, Inc. to the Bankruptcy Court's January 26, 2017 order. The sale of the Company's interest in Dominion Terminal Associates is expected to close prior to the Plan Effective Date. On November 3, 2016, Peabody Australia Mining Pty Ltd, one of the Company’s Australian subsidiaries, entered into a definitive share sale and purchase agreement for the sale of all of its equity interest in Metropolitan Collieries Pty Ltd, the entity that owns the Metropolitan mine in New South Wales, Australia and the associated interest in the Port Kembla Coal Terminal, to a subsidiary of South32 Limited (South32), which is conditional on receipt of approval from the ACCC. Refer to Note 4. "Asset Impairment" for additional details related to the transaction. 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 consolidated statement of operations for the year ended December 31, 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 consolidated statement of operations for the year ended December 31, 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 a termination fee of $20 million (Termination Fee) in the event the Company terminated the agreement because Bowie failed to obtain financing and close the transaction. On April 12, 2016, Peabody terminated the agreement and demanded payment of the Termination Fee, which Bowie has not done. The Company brought action against Bowie to recover the Termination Fee, interest and certain costs. On February 7, 2017, the United States Bankruptcy Court issued a memorandum opinion stating that it would grant summary judgment in favor of the Company and award it the Termination Fee, interest and attorney’s fees and costs incurred in collecting the Termination Fee. On March 9, 2017, after a hearing on the attorneys’ fees and costs that the Company incurred in collecting the Termination Fee, the United States Bankruptcy Court entered judgment in favor of the Company. The Company will not record income related to this judgment until collection from Bowie. The Company initiated a review of its asset portfolio during the second quarter of 2015. In connection with that review and related marketing and divestiture approval processes conducted during that period, certain assets were classified as held-for-sale. Subsequent to the related write-downs, these assets had an aggregate carrying value of approximately $125 million and were included in "Other current assets" in the Company's consolidated balance sheet as of December 31, 2015. The results of operations and cash flows of such assets were not material to the consolidated financial statements for the periods presented in this report. In December 2014, the Company sold non-strategic coal reserves located in Kentucky in exchange for cash proceeds of $29.6 million . The Company recognized a gain on sale of $13.6 million related to the transaction, which was classified in "Net gain on disposal of assets" in the consolidated statement of operations for the year ended December 31, 2014. In January 2014, the Company sold a non-strategic exploration tenement asset in Australia in exchange for cash proceeds of $62.6 million . The Company had previously recorded an impairment charge in December 2013 to write down the carrying value of that asset to its fair value. Accordingly, there was no gain or loss recognized on the disposal during the year ended December 31, 2014. Joint Venture In 2014, the Company agreed to establish an unincorporated joint venture project with Glencore plc (Glencore), in which each party will hold 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 expects the project to result in several operation synergies, including improved mining productivity, lower per-unit operating costs and an extended mine life. The joint venture operations are expected to commence in 2018, subject to substantive contingencies, including the requisite regulatory and permitting approvals. At such time as those contingencies have been resolved or are no longer considered to be substantive, the Company will account for its beneficial interest in the combined operations at fair value. 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, all of which was posted and is included in "Investments and other assets" in the consolidated balance sheet at December 31, 2016. 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 March 20, 2017, the Company was in compliance with the covenants and restrictions under the new arrangements.

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share (EPS) Basic and diluted EPS are computed using the two-class method, which is an earnings allocation that determines EPS for each class of common stock and participating securities according to dividends declared and participation rights in undistributed earnings. The Company’s restricted stock awards are considered participating securities because holders are entitled to receive non-forfeitable dividends during the vesting term. Diluted EPS includes securities that could potentially dilute basic EPS during a reporting period, for which the Company includes the Debentures and share-based compensation awards. Dilutive securities are not included in the computation of loss per share when a company reports a net loss from continuing operations as the impact would be anti-dilutive. For all but the performance units, the potentially dilutive impact of the Company’s share-based compensation awards is determined using the treasury stock method. Under the treasury stock method, awards are treated as if they had been exercised with any proceeds used to repurchase common stock at the average market price during the period. Any incremental difference between the assumed number of shares issued and purchased is included in the diluted share computation. For the Company’s performance units, their contingent features result in an assessment for any potentially dilutive common stock by using the end of the reporting period as if it were the end of the contingency period for all units granted. For further discussion of the Company’s share-based compensation awards, see Note 20. "Share-Based Compensation." A conversion of the Debentures may result in payment for any conversion value in excess of the principal amount of the Debentures in the Company’s common stock. For diluted EPS purposes, potential common stock is calculated based on whether the market price of the Company’s common stock at the end of each reporting period is in excess of the conversion price of the Debentures. The effect of the Debentures was excluded from the calculation of diluted EPS for all periods presented herein because to do so would have been anti-dilutive for those periods. The computation of diluted EPS also excluded aggregate share-based compensation awards of approximately 0.4 million , 0.6 million and 0.2 million for the years ended December 31, 2016 , 2015 and 2014 , respectively, because to do so would have been anti-dilutive for those periods. Because the potential dilutive impact of such share-based compensation awards is calculated under the treasury stock method, anti-dilution generally occurs when the exercise prices or unrecognized compensation cost per share of such awards are higher than the Company’s average stock price during the applicable period. The following illustrates the earnings allocation method utilized in the calculation of basic and diluted EPS. The number of shares and per share amounts for all period presented below have been retroactively restated to reflect the Reverse Stock Split discussed in Note 1. "Summary of Significant Accounting Policies.": Year Ended December 31, 2016 2015 2014 (In millions, except per share amounts) EPS numerator: Loss from continuing operations, net of income taxes $ (674.3 ) $ (1,813.9 ) $ (749.1 ) Less: Net income attributable to noncontrolling interests 7.9 7.1 9.7 Loss from continuing operations attributable to common stockholders, before allocation of earnings to participating securities (682.2 ) (1,821.0 ) (758.8 ) Less: Earnings allocated to participating securities — — 1.0 Loss from continuing operations attributable to common stockholders, after allocation of earnings to participating securities (682.2 ) (1,821.0 ) (759.8 ) Loss from discontinued operations attributable to common stockholders, after allocation of earnings to participating securities (57.6 ) (175.0 ) (28.2 ) Net loss attributable to common stockholders, after earnings allocated to participating securities $ (739.8 ) $ (1,996.0 ) $ (788.0 ) EPS denominator: Weighted average shares outstanding — basic and diluted 18.3 18.1 17.9 Basic and diluted EPS attributable to common stockholders: Loss from continuing operations $ (37.30 ) $ (100.34 ) $ (42.52 ) Loss from discontinued operations (3.15 ) (9.64 ) (1.57 ) Net loss attributable to common stockholders $ (40.45 ) $ (109.98 ) $ (44.09 )

Management - Labor Relations

Management - Labor Relations	12 Months Ended
	Dec. 31, 2016
Risk Management Labor Relations [Abstract]
Management - Labor Relations	Management — Labor Relations On December 31, 2016 , the Company had approximately 6,700 employees worldwide, including approximately 5,100 hourly employees; the employee amounts exclude employees that were employed at operations classified as discontinued operations. Approximately 39% of those hourly employees were represented by organized labor unions and were employed by mines that generated 22% of the Company's 2016 coal production from continuing operations. In the U.S., one surface mine is represented by an organized labor union. In Australia, the coal mining industry is unionized and the majority of hourly workers employed at the Company’s Australian Mining operations are members of trade unions. The Construction Forestry Mining and Energy Union generally represents the Company’s Australian subsidiaries’ hourly production and engineering employees, including those employed through contract mining relationships. The Company believes labor relations with its employees are good. Should that condition change, the Company could experience labor disputes, work stoppages or other disruptions in production that could negatively impact the Company’s results of operations and cash flows. The following table presents the Company's active mining operations as of December 31, 2016 in which the employees are represented by organized labor unions: Mine Current Agreement Expiration Date U. S. Kayenta (1) September 2019 Australia Owner-operated mines: Wambo Open-Cut December 2018 Wambo Underground (2) April 2017 North Goonyella December 2018 Metropolitan (3) December 2016 Millennium (4) October 2015 Wilpinjong (5) May 2016 Coppabella (6) December 2016 Moorvale (6) October 2019 (1) Hourly workers at the Company’s Kayenta Mine in Arizona are represented by the UMWA under the Western Surface Agreement, which is effective through September 16, 2019. This agreement covers approximately 8% of the Company’s U.S. subsidiaries’ hourly employees, who generated approximately 4% of the Company’s U.S. production during the year ended December 31, 2016 . (2) Employees of the Company's Wambo Underground Mine operate under a separate labor agreement. That agreement expired in April 2015. The parties agreed to an initial rollover for 12 months through April 2016 and agreed to a further rollover for another 12 months through April 2017. There were no wage increases for the two rollover periods and there have been no disruptions to the operation of the site as a result of the expiration of the agreement. Hourly employees of this mine comprise approximately 8% of the Company's Australian subsidiaries hourly employees, who generated approximately 10% of the Company's Australian production during the year ended December 31, 2016 . (3) Employees of the Company's Metropolitan mine operate under a separate labor agreement, which expired in September 2015. Negotiations progressed to a vote on the Company’s best offer in November 2015, which was rejected by the employees. The parties agreed to hold off on any further negotiations until the Company's emergence from the Chapter 11 Cases, expected to occur in early April 2017. There were no wage increases during this period and there have been no disruptions to the operation of the site as a result of the expiration of the agreement. There is also a Deputy labor agreement which expired in September 2015. The parties agreed to a rollover for 18 months through to December 2016. Negotiations resumed in January 2017 for a new labor agreement. There have been no disruptions to the operations of the site as a result of the expiration of the agreement. Hourly employees of this mine comprise approximately 11% of the Company's Australian subsidiaries hourly employees, who generated approximately 6% of the Company's Australian production during the year ended December 31, 2016 . (4) Employees of the Company's Millennium mine operate under a separate labor agreement. Negotiations have been ongoing for an extended period of time, where employees rejected the Company's offers in July 2016 and again in November 2016. After the second unsuccessful vote the Company informed employees it was in the process of applying for the agreement to be terminated. Employees requested the Company to vote again on the second rejected agreement with the intent to accept the offer, 70% of employees voted and accepted the offer late January 2017. The agreement was approved by the Fair Work Commission in early March 2017. Hourly employees of this mine comprise approximately 16% of the Company's Australian subsidiaries hourly employees, who generated approximately 11% of the Company's Australian production during the year ended December 31, 2016 . (5) Employees of the Company's Wilpinjong Mine operate under an enterprise agreement. Negotiations to replace the enterprise agreement that nominally expired in May 2016 commenced in April 2016. In January 2017 the workforce formally rejected Wilpinjong’s proposed replacement agreement and good faith negotiations are now continuing. Hourly employees of this mine comprise approximately 18% of the Company's Australian subsidiaries hourly employees, who generated approximately 42% of the Company's Australian production during the year ended December 31, 2016 . (6) Employees of the Company's Coppabella/Moorvale Coal Handling and Preparation Plant facility previously operated under a separate enterprise agreement. As a result of the latest negotiation process the Company was successful in its application to terminate the agreement. The negotiations resulted in the Coppabella employees requesting to be employed on individual salaried contracts (rather than a labor agreement) and the Moorvale employees accepted the Company's final offer. The Moorevale agreement expires in October 2019. Hourly employees of this mine comprise approximately 28% of the Company's Australian subsidiaries hourly employees, who generated approximately 13% of the Company's Australian production during the year ended December 31, 2016 .

Financial Instruments, Guarante

Financial Instruments, Guarantees with Off-Balance-Sheet Risk and Other Guarantees (Notes)	12 Months Ended
	Dec. 31, 2016
Financial Instruments And Guarantees With Off Balance Sheet Risk Disclosure [Abstract]
Financial Instruments, Guarantees with Off-Balance-Sheet Risk and Other Guarantees	Financial Instruments, Guarantees With Off-Balance-Sheet Risk and Other Guarantees In the normal course of business, the Company is a party to guarantees and financial instruments with off-balance-sheet risk, most of which are not reflected in the accompanying consolidated balance sheets. Such financial instruments are valued based on the amount of exposure under the instrument and the likelihood of required performance. As of March 21, 2017 , management does not expect any material losses to result from these guarantees or off-balance-sheet instruments in excess of liabilities provided for in the consolidated balance sheet as of December 31, 2016. Financial Instruments with Off-Balance Sheet Risk As of December 31, 2016 , the Company had the following financial instruments with off-balance-sheet risk: Reclamation Bonding Requirements Coal Lease Obligations Workers’ Compensation Obligations Other (1) Total (2) Cash Collateral in Support of Financial Instruments (Dollars in millions) Self bonding $ 1,094.2 $ — $ — $ — $ 1,094.2 $ — Surety bonds (3) 319.6 94.0 19.1 15.5 448.2 64.5 Bank guarantees 54.7 — — 24.5 79.2 83.8 Other (4) 233.2 — 42.7 118.0 393.9 233.2 Total $ 1,701.7 $ 94.0 $ 61.8 $ 158.0 $ 2,015.5 $ 381.5 (1) Other includes the $37.0 million in letters of credit related to the PBGC, as described below, and an additional $121.0 million in bank guarantees, letters of credit and surety bonds related to road maintenance, performance guarantees and other operations. (2) Letters of credit held as collateral in support of surety bonds at December 31, 2016 were $48.0 million and are not reflected in the table above. (3) A total of $72.6 million of letters of credit issued as collateral to support surety bonds related to Patriot have been excluded from above as they no longer represent off-balance sheet obligations as discussed in Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation". (4) Other under the "Reclamation Bonding Requirements" header represents the amount of reclamation bonding requirements for our Australian Mining operations that were not otherwise supported by bank guarantees. Such amounts were supported by cash collateral held by the applicable state agency. The Company owns a 37.5% interest in Dominion Terminal Associates, a partnership that operates a coal export terminal in Newport News, Virginia under a 30 -year lease that permits the partnership to purchase the terminal at the end of the lease term for a nominal amount. The partners have severally (but not jointly) agreed to make payments under various agreements which, in the aggregate, provide the partnership with sufficient funds to pay rents and to cover the principal and interest payments on the floating-rate industrial revenue bonds issued by the Peninsula Ports Authority, and which are supported by letters of credit from a commercial bank. On July 1, 2016, $39.9 million of the total $42.7 million of letters of credit supporting the reimbursement obligation to the commercial bank were drawn down to repay the outstanding bonds. As a result, the bonds were retired with the balance of the letters of credit canceled. Refer to Note 22. "Resource Management, Acquisitions and Other Commercial Events" for details related to the Company's divestiture of Dominion Terminal Associates. The Company is party to an agreement with the PBGC and TXU Europe Limited, an affiliate of the Company’s former parent corporation, under which the Company is required to make special contributions to two of the Company’s defined benefit pension plans and to maintain a $37.0 million letter of credit in favor of the PBGC. If the Company or the PBGC gives notice of an intent to terminate one or more of the covered pension plans in which liabilities are not fully funded, or if the Company fails to maintain the letter of credit, the PBGC may draw down on the letter of credit and use the proceeds to satisfy liabilities under the Employee Retirement Income Security Act of 1974, as amended. The PBGC, however, is required to first apply amounts received from a $110.0 million guarantee in place from TXU Europe Limited in favor of the PBGC before it draws on the Company’s letter of credit. On November 19, 2002, TXU Europe Limited was placed under the administration process in the U.K. (a process similar to bankruptcy proceedings in the U.S.) and continues under this process as of December 31, 2016 . As a result of these proceedings, TXU Europe Limited may be liquidated or otherwise reorganized in such a way as to relieve it of its obligations under its guarantee. Reclamation Bonding The Company bonds its reclamation requirements using three categories of bonds: surety bonds, collateral bonds or self-bonds. A surety bond is an indemnity agreement in a sum certain payable to the regulatory authority, executed by the permittee as principal and which is supported by the performance guarantee of a surety corporation. A collateral bond can take several forms, including cash, letters of credit, first lien security interest in property or other qualifying investment securities. A self-bond is an indemnity agreement in a sum certain executed by the permittee or by the permittee and any corporate guarantor made payable to the regulatory authority. Our total reclamation bonding requirements in the U.S. were $1,413.8 million as of December 31, 2016. The bond requirements represent the calculated cost to reclaim the current operations of a mine if it ceased to operate in the current period. The cost calculation for each bond must be completed according to the regulatory authority of each state. Our asset retirement obligations calculated in accordance with GAAP for our U.S. operations was $471.1 million as of December 31, 2016. The bond requirement amount for our U.S. operations significantly exceeds the financial liability for final mine reclamation because the financial liability is discounted from the end of the mine’s economic life to the balance sheet date in recognition of the economic reality that the final reclamation obligation is a number of years (and in some cases decades) away. The bond amount, in contrast with the asset retirement obligation, presumes reclamation begins immediately. In Australia, we generally used bank guarantees to satisfy our financial assurance requirements related to reclamation. Those bank guarantees allowed the issuer to request collateral, which was provided in the forms of letters of credit. Subsequent to the petition date, some of the bank guarantee issuers drew on a portion of those letters of credit and subsequently canceled the bank guarantees, which resulted in the cash collateral being transferred to the applicable state agency. The total cash collateral held in relation to the Company's Australian reclamation obligations was $233.2 million at December 31, 2016 and was included in "Investments and other assets" due to the long-term nature of the underlying obligations. The Company's asset retirement obligations calculated in accordance with GAAP for its Australian operations was $287.7 million as of December 31, 2016. During August and September 2016, the Bankruptcy Court approved four motions for Stipulations and Orders (collectively, the Stipulations) regarding settlement agreements with the states of Wyoming, New Mexico, Indiana, and Illinois. The Stipulations provide the relevant state authorities with additional financial assurance for the Company’s performance of its reclamation bonding requirements by entitling them to (i) claims in the Chapter 11 Cases that have priority over all administrative expenses of the kind specified in section 503(b) of the Bankruptcy Code for the specified values set forth in the Stipulations and (ii) in the cases of Wyoming, Indiana and Illinois, $0.8 million , $7.5 million and $3.2 million , respectively, in letters of credit or surety bonds related to closed mining operations, together not to exceed the full amount of the $200 million bonding accommodation facility provided for in the DIP Credit Agreement. Each state received financial assurances equal to approximately 17.5% of the Company's prepetition reclamation bond amount with the relevant state. In addition to providing supplemental financial assurances to these states, the Company has agreed to, among other things, quarterly reclamation activity status meetings as well as targeting reductions in the amount of bonds outstanding with these states. Pursuant to the Stipulations, the states will effectively deem the Company’s bonding requirements satisfied for the pendency of the Chapter 11 Cases. As previously disclosed, the Company's ability to self-bond reduces the Company's costs of securing reclamation bonding requirements and enhances liquidity to the extent alternate forms of bonding would require the Company to post collateral. To the extent the Company is unable to maintain its current level of self-bonding following the conclusion of the Chapter 11 Cases for any reason, the Company would be required to obtain replacement financial assurances or security. Further, self-bonding is permitted at the discretion of each state. As of December 31, 2016, the Company was self-bonded in Illinois, Indiana, New Mexico and Wyoming. As a condition precedent to the occurrence of the Effective Date of the Plan, the Company was required to put in place mutually acceptable forms of bonding for coal mine reclamation requirements in those states subsequent to the Effective Date. On March 6, 2017, the Debtors notified the Bankruptcy Court that the Company had determined to secure all of its coal mine reclamation obligations, including those in Illinois, Indiana, New Mexico and Wyoming, by arranging for approximately $1.3 billion in surety bonds. Accounts Receivable Securitization On March 25, 2016, the Company amended and restated its accounts receivable securitization program (securitization program) to, among other things, extend the term of the program by two years to March 23, 2018 and reduce the maximum availability under the facility from $275.0 million to $180.0 million . The accessible capacity of the program varies daily, dependent upon the actual amount of receivables available for contribution and various reserves and limits. As of December 31, 2016, $40.5 million was deposited in a collateral account to secure obligations under the facility. Under the securitization program, the Company contributes the trade receivables of most of its U.S. subsidiaries on a revolving basis to its wholly-owned, bankruptcy-remote subsidiary (Seller), which then sells the receivables in their entirety to unaffiliated asset-backed commercial paper conduits and banks (the Conduits). After the sale, the Company, as servicer of the assets, collects the receivables on behalf of the Conduits for a nominal servicing fee. The Seller is a separate legal entity whose assets are available first and foremost to satisfy the claims of its creditors. Of the receivables sold to the Conduits, a portion of the amount due to the Seller is deferred until the ultimate collection of the underlying receivables. During the year ended December 31, 2016 , the Company received total consideration of $2,859.9 million related to accounts receivable sold under the securitization program, including $1,541.7 million of cash up front from the sale of the receivables, an additional $1,155.3 million of cash upon the collection of the underlying receivables and $162.9 million that had not been collected at December 31, 2016 and was recorded at carrying value, which approximates fair value. There was no reduction in accounts receivable as a result of securitization activity with the Conduits at December 31, 2016 and a $168.5 million reduction at December 31, 2015. The securitization activity has been reflected in the consolidated statements of cash flows as an operating activity because both the cash received from the Conduits upon sale of receivables as well as the cash received from the Conduits upon the ultimate collection of receivables are not subject to significantly different risks given the short-term nature of the Company’s trade receivables. The Company recorded expense associated with securitization transactions of $8.2 million , $1.8 million and $1.5 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. With the approval of the Bankruptcy Court, the Company executed two additional amendments to the March 25, 2016 agreement during the second quarter of 2016. These amendments permit the continuation of the securitization program through the Company’s Chapter 11 Cases, change the maturity date to the earlier of March 23, 2018 or the emergence of the Company from the Chapter 11 Cases, revise the associated fees, and enter into an additional performance guarantee by the Company’s subsidiaries that are contributors under the securitization facility to fulfill the obligations of the other contributors. On January 27, 2017, the Company and P&L Receivables Company, LLC (P&L Receivables) obtained a commitment letter (Commitment Letter) from PNC Bank, National Association (PNC), pursuant to which, in connection with the consummation of the Plan, PNC has agreed to amend the existing securitization facility evidenced by the Fifth Amended and Restated Receivables Purchase Agreement, dated as of March 25, 2016 (as amended prior to the date hereof), among P&L Receivables, as the seller, the Company, as the servicer, the sub-servicers party thereto, the various purchasers and purchaser agents party thereto and PNC, as administrator, in order to, among other things, (i) increase the purchase limit to an amount not to exceed $250,000,000 (the Purchase Limit), (ii) extend the facility termination date, and (iii) consider adding certain Australian subsidiaries of the Company as originators (as so amended, the Sixth Amended Securitization Facility). The commitment of PNC to provide 100% of the Purchase Limit under the Sixth Amended Securitization Facility is subject to certain conditions set forth in the Commitment Letter, including but not limited to the occurrence or waiver of all conditions precedent to the effectiveness of the Plan. The Commitment Letter will terminate upon the occurrence of certain events described therein. The outside termination date for the Commitment Letter is May 1, 2017. On January 27, 2017, the Debtors filed a motion with the Bankruptcy Court seeking authorization to enter into and perform under the Commitment Letter. On February 15, 2017, the Bankruptcy Court issued an order authorizing the Company’s entry into and performance under the Commitment Letter Restricted Cash As of December 31, 2016, the Company had balance sheet-reflected restricted cash of $54.3 million , primarily related to the collateral under its securitization program and various other obligations. The company also had restricted cash held as collateral for financial assurances associated with reclamation and other obligations of $71.4 million as of December 31, 2016 included in "Investments and other assets" due to the long-term nature of the underlying obligations. 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.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments Unconditional Purchase Obligations As of December 31, 2016 , purchase commitments for capital expenditures were $7.4 million , all of which is obligated within the next year. In Australia, the Company has generally secured the ability to transport coal through rail contracts and ownership interests in five east coast coal export terminals that are primarily funded through take-or-pay arrangements with terms ranging up to 26 years. In the U.S., the Company has entered into certain long-term coal export terminal agreements to secure export capacity through the Gulf Coast. As of December 31, 2016 , these Australian and U.S. commitments under take-or-pay arrangements totaled $1.6 billion , of which approximately $210 million is obligated within the next year. Federal Coal Leases In the second quarter of 2012, the Company was named by the U.S. Department of the Interior, Bureau of Land Management (BLM) as the winning bidder for control of approximately 1.1 billion tons of federal coal reserves adjacent to its North Antelope Rochelle Mine in the Southern Powder River Basin of Wyoming, with a weighted average bid price of approximately $1.10 per mineable ton. Consequently, the Company made aggregate payments of $247.9 million during each of the years ended December 31, 2016 , 2015 and 2014 pursuant to the two associated federal coal leases. The payments for these leases are now complete. In July 2011, the Company was named by the BLM as the winning bidder for control of approximately 220 million tons of federal coal reserves adjacent to its Caballo Mine in the Powder River Basin at a bid price of $0.95 per mineable ton, with payments of $42.1 million due annually in each of the years from 2011 through 2015 pursuant to the associated federal coal lease (the Belle Ayr North Lease). Similarly, in September 2011, a subsidiary of Alpha Natural Resources, Inc. (Alpha) was named by the BLM as the winning bidder for control of approximately 130 million tons of federal coal reserves in the Powder River Basin at a bid price of $1.10 per mineable ton, with contractual payments of $28.6 million due annually in each of the years from 2011 through 2015 under the associated federal coal lease (the Caballo West Lease). In July 2012, the Company and Alpha executed a lease exchange agreement with the BLM whereby the Company agreed to sell, assign and transfer its interest in the Belle Ayr North Lease in exchange for (1) Alpha's interest in the Caballo West Lease, (2) reimbursement of $13.5 million for the difference in the related federal coal lease payments made by each party in 2011 and (3) five annual true up payments of $3.9 million for the excess of the $1.10 bid price per mineable ton assumed under the Caballo West Lease over the $0.95 price under the transferred lease. The Company received a true-up payment during the year ended December 31, 2014 and the cash receipt was classified in "Proceeds from disposal of assets, net of notes receivable" in the consolidated statement of cash flows. During 2015, Alpha filed voluntary petitions for reorganization under Chapter 11 of the U.S. Code and the final true up payment was not received. On February 19, 2016 the Company filed a claim in Alpha’s bankruptcy. Additionally, on April 15, 2016 the Company filed an objection to the potential assumption and assignment of the lease exchange agreement and to the cure amount. On October 16, 2016 the Company entered into a settlement agreement with Alpha and Contura Wyoming Land, LLC allowing the claim in the full amount of the true-up payment and resolving other issues between the parties. The settlement agreement was approved by the Bankruptcy Court on December 14, 2016. The federal coal leases executed with the BLM described above expire after a 20 -year initial term, unless at such time there is ongoing production on the subject leases or within an active logical mining unit of which they are part. Contingencies From time to time, the Company or its subsidiaries are involved in legal proceedings arising in the ordinary course of business or related to indemnities or historical operations. The Company believes it has recorded adequate reserves for these liabilities. The Company discusses its significant legal proceedings below, including ongoing proceedings and those that impacted the Company's results of operations for the periods presented. Effect of Automatic Stay . The Debtors filed voluntary petitions for relief under the Bankruptcy Code on the Petition Date in the Bankruptcy Court. Each of the Debtors continues to operate its business and manage its property as a debtor-in-possession pursuant to Sections 1107 and 1108 of the Bankruptcy Code. Subject to certain exceptions under the Bankruptcy Code, the filing of the Debtors’ Chapter 11 Cases, pursuant to Section 362(a) of the Bankruptcy Code, automatically enjoined, or stayed, among other things, the continuation of most judicial or administrative proceedings or the filing of other actions against or on behalf of the Debtors or their property to recover on, collect or secure a claim arising prior to the Petition Date or to exercise control over property of the Debtors’ bankruptcy estates, unless and until the Bankruptcy Court modifies or lifts the automatic stay as to any such claim. Notwithstanding the general application of the automatic stay described above, governmental authorities may determine to continue actions brought under their police and regulatory powers. The Debtors have filed notices of the bankruptcy filings and suggestions of stay in the applicable matters involving one or more of the Debtors as discussed below and in Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation". The Company expects that the Chapter 11 Cases will impact the liabilities of the Debtors described below and in Note 27, as well as certain other contingent liabilities the Debtors may have. For example, if a contingent litigation liability of the Debtors is ultimately allowed as a prepetition "claim" under the Bankruptcy Code, that claim would be subject to the applicable treatment set forth in the Plan and be discharged pursuant to the terms of the Plan. However, until the Plan becomes effective, there can be no certainty as to how such liabilities will be impacted. Litigation Relating to Continuing Operations Peabody Monto Coal Pty Ltd, Monto Coal 2 Pty Ltd and Peabody Energy Australia PCI Pty Ltd (PEA-PCI). In October 2007, a statement of claim was delivered to Peabody Monto Coal Pty Ltd, a wholly-owned subsidiary of PEA-PCI, then Macarthur Coal Limited, and Monto Coal 2 Pty Ltd, an equity accounted investee, from the minority interest holders in the Monto Coal Joint Venture, alleging that Monto Coal 2 Pty Ltd breached the Monto Coal Joint Venture Agreement and Peabody Monto Coal Pty Ltd breached the Monto Coal Management Agreement. Peabody Monto Coal Pty Ltd is the manager of the Monto Coal Joint Venture pursuant to the Management Agreement. Monto Coal 2 Pty Ltd holds a 51% interest in the Monto Coal Joint Venture. The plaintiffs are Sanrus Pty Ltd, Edge Developments Pty Ltd and H&J Enterprises (Qld) Pty Ltd. An additional statement of claim was delivered to PEA-PCI in November 2010 from the same minority interest holders in the Monto Coal Joint Venture, alleging that PEA-PCI induced Monto Coal 2 Pty Ltd and Peabody Monto Coal Pty Ltd to breach the Monto Coal Joint Venture Agreement and the Monto Coal Management Agreement, respectively. The plaintiffs later amended their claim to allege damages for lost opportunities to sell their joint venture interest. These actions, which are pending before the Supreme Court of Queensland, Australia, seek damages from the three defendants collectively of amounts ranging from $15.6 million Australian dollars to $1.8 billion Australian dollars, plus interest and costs. The defendants dispute the claims and are vigorously defending their positions. Based on the Company's evaluation of the issues and their potential impact, the amount of any future loss cannot be reasonably estimated. Eagle Mining, LLC Arbitration. On May 3, 2013, Eagle Mining, LLC (Eagle) filed an arbitration demand against a Company subsidiary under a contract mining agreement, asserting various claims for damages. An arbitration hearing was held in January 2014 before a single arbitrator. As a result of the damages awarded to Eagle in arbitration, the Company recorded a charge of $15.6 million in "Operating costs and expenses" in the consolidated statement of operations for the year ended December 31, 2014 to increase the associated liability accrual to $23.4 million . On April 18, 2014, the Company subsidiary filed a petition to partially vacate and modify the arbitration award in the United States District Court for the Southern District of West Virginia, Charleston Division. On July 29, 2015, the District Court issued a Memorandum Opinion and Order denying the petition to partially vacate and modify the arbitration award and granting Eagle’s motion to confirm the arbitration award. In September 2015, Eagle and the Company's subsidiary settled all claims and agreed to dismiss with prejudice all pending litigation between the parties. In connection with this settlement, the Company recorded a gain totaling $10.8 million during the year ended December 31, 2015 to reduce the accrued liability to the amount paid. The matter has concluded. Queensland Bulk Handling Pty Ltd. On June 30, 2014, QBH filed a statement of claim with the Supreme Court of Queensland, Australia, against Peabody (Wilkie Creek) Pty Limited, an indirect wholly-owned subsidiary of the Company, alleging breach of a CPSA between the parties. QBH originally sought damages of $113.1 million Australian dollars, plus interest and costs. However, it later altered its claim to seek a declaration that the Company subsidiary had exercised an option to renew the contract for a further term, and withdrew its claim for money damages. In September 2016, a settlement was reached under which the Company agreed to pay $13.0 million Australian dollars ( $9.9 million USD) to QBH in a full and final settlement of all claims each party had against the other in relation to the CPSA litigation. A deed of settlement was executed by the parties and the settlement amount was paid to QBH on September 30, 2016. This matter has concluded. Lori J. Lynn Class Action. On June 11, 2015, a former Peabody Investments Corp. (PIC) employee filed a putative class action lawsuit in the United States District Court, Eastern District of Missouri on behalf of three of the Company’s or its subsidiaries' 401(k) retirement plans and certain participants and beneficiaries of the plans. The lawsuit, which was brought against the Peabody Energy Corporation (PEC), Peabody Holding Company, LLC (PHC), PIC and a number of the Company’s and PIC’s current and former executives and employees, alleges breach of fiduciary duties and seeks monetary damages under the Employee Retirement Income Security Act of 1974 (ERISA) relating to the offering of the Peabody Energy Stock Fund as an investment option in the 401(k) retirement plans. On September 8, 2015, the plaintiffs filed an amended complaint which, among other things, named a new plaintiff and named all of the current members and two former members of the relevant boards of directors as defendants. The class period (December 2012 to present) remains unchanged. On November 9, 2015, the defendants filed a motion seeking dismissal of all claims. Plaintiffs filed a second amended complaint on March 11, 2016 that included new allegations against the Company related to the Company's disclosure to investors of risks associated with climate change and related legislation and regulations. The second amended complaint also added the three committees responsible for administering the three 401(k) retirement plans at issue and dropped several individual defendants, including current directors of PEC's board of directors. As a result of filing the Chapter 11 Cases, the plaintiffs voluntarily dismissed the three Debtor defendants (PEC, PIC and PHC) and elected to proceed against the individual defendants and the three named committees with the second amended complaint. On November 17, 2016, the parties presented arguments on the defendants’ motion to dismiss. A ruling has not yet been issued. CNTA Dispute. On May 20, 2016, the Company filed a complaint and a request for declaratory judgment in the Bankruptcy Court against Citibank, N.A. (in its capacity as Administrative Agent under the Company’s 2013 Credit Facility), among others, regarding the extent of certain collateral and secured claims of certain prepetition creditors. On June 13, 2016, Citibank, N.A. filed an answer and counter-claim for declaratory judgment. On June 14, 2016, two motions to intervene were filed, one from the Creditors' Committee and another from a group of creditors holding $1.65 billion in face value of the Company's Senior Notes (as indicated in their motion). On June 20, 2016, the Bankruptcy Court entered an order granting the Debtors' motion requesting that the Bankruptcy Court direct all parties to the proceeding to participate in non-binding mediation. The intervention motions were granted on July 7, 2016. On October 7, 2016, a group of creditors holding approximately $287.4 million in face value of the Company’s Senior Secured Second Lien Notes (as indicated in their motion) filed a motion to intervene. The Bankruptcy Court heard oral arguments related to the parties’ motions for summary judgment on September 12, 2016 and subsequently vacated the previously scheduled trial dates and deferred ruling on the matter while the parties continued with mediation. Mediation and negotiation with certain creditors resulted in a settlement of the CNTA Dispute, which is reflected in the economic terms of the Plan, including the treatment of the holders of allowed secured and unsecured claims. APS/PacifiCorp Litigation. The Arizona Public Service Company (APS) and PacifiCorp filed a motion in the Bankruptcy Court seeking authorization to allow it to terminate a coal supply agreement, which accounts for approximately half of the Company's El Segundo Mine sales volume. The Company filed a complaint for APS’s and PacifiCorp’s violation of the automatic stay applicable to the Chapter 11 Cases and breach of the coal supply agreement. In September 2016, the parties engaged in a court-ordered mediation. The parties continued to engage in mediation in December 2016 and January 2017. On January 8, 2017 the parties entered into a Settlement Term Sheet outlining a settlement in principle (Settlement Term Sheet). On January 17, 2017, the Company filed a Motion Of The Debtors And Debtors In Possession, Pursuant To Bankruptcy Rule 9019 And Section 365 Of The Bankruptcy Code, For Entry Of An Order (I) Approving A Settlement Agreement With APS and PacifiCorp, (II) Authorizing The Assumption Of The Coal Supply Agreement, As Amended and (III) Granting Related Relief . On January 27, 2017 the Bankruptcy Court entered its order approving the Settlement Term Sheet and authorizing the parties to enter into a settlement agreement and amendment to the coal supply agreement. The parties entered into a settlement agreement and an amendment to the coal supply agreement on February 3, 2017. Berenergy Corporation. The Company has been in a legal dispute with Berenergy Corporation (Berenergy) regarding Berenergy’s access to certain of its underground oil deposits beneath the Company's North Antelope Rochelle Mine and contiguous undisturbed areas. The Company believes that any claims related to this matter constitute prepetition claims. On October 13, 2016, the Sixth Judicial Court in the state of Wyoming (Wyoming Court) entered an order (Wyoming Court Decision) allowing the Company the right to mine through certain wells owned by Berenergy but required the Company to compensate Berenergy for damages of $0.9 million , which the Company has accrued as of December 31, 2016. Further, the Wyoming Court ruled that should Berenergy obtain approval from the Wyoming Oil and Gas Conservation Commission (the Commission) to recover certain secondary deposits beneath the mine’s contiguous undisturbed areas, the Company would be liable to Berenergy for the cost of certain special procedures and equipment required to access the secondary deposits remotely from outside the Company's mine area, which has been estimated as $13.1 million by Berenergy. The Company believes it is not probable that the Commission will approve access to the secondary deposits based on the Company's view of a lack of economic feasibility and certain restrictions on Berenergy's legal claim to the deposits. Based upon these factors, the Company has not accrued a liability related to the secondary deposits as of December 31, 2016. On November 22, 2016, the Bankruptcy Court entered an order granting Berenergy limited relief from the automatic stay to pursue an appeal of the Wyoming Court Decision with the Wyoming Supreme Court. On December 21, 2016, Berenergy filed a Notice of Appeal with the Wyoming Supreme Court of the Wyoming Court Decision. On January 5, 2017, Peabody filed a Notice of Cross-Appeal with the Wyoming Supreme Court of the Wyoming Court Decision. Claims, Litigation and Settlements Relating to Indemnities or Historical Operations Environmental Claims and Litigation Arising From Historical, Non-Coal Producing Operations. Gold Fields Mining, LLC (Gold Fields) is a non-coal producing entity that was previously managed and owned by Hanson plc, the Company's predecessor owner. In a February 1997 spin-off, Hanson plc transferred ownership of Gold Fields to PEC despite the fact that Gold Fields had no ongoing operations and PEC had no prior involvement in the past operations of Gold Fields. Gold Fields is currently one of PEC's subsidiaries. As part of separate transactions, both PEC and Gold Fields also agreed to indemnify Blue Tee with respect to certain claims relating to the historical operations of a predecessor of Blue Tee, which is a former affiliate of Gold Fields. Neither PEC nor Gold Fields had any involvement with the past operations of the Blue Tee predecessor. Pursuant to the indemnity, Blue Tee has tendered its environmental claims for remediation, past cost and future costs and/or natural resource damages (Blue Tee Liabilities) to Gold Fields. Although Gold Fields has paid remediation costs as a result of the indemnification obligations, Blue Tee has been identified as a potentially responsible party (PRP) at various designated national priority list (NPL) sites under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and similar statutes. Of these sites where Blue Tee has been identified as a PRP, neither Gold Fields nor PEC is a party to any cleanup orders relating to the operations of Blue Tee’s predecessor. In addition to the NPL sites, Blue Tee has been named a PRP at multiple other sites, where Gold Fields has either paid remediation costs or settled the environmental claims on behalf of Blue Tee. As a result of filing the Chapter 11 Cases, Gold Fields has now stopped paying these remediation costs. Environmental assessments for remediation, past and future costs and/or natural resource damages also have been asserted by the EPA and natural resources trustees against Gold Fields related to historical activities of Gold Fields’ predecessor. Gold Fields has been identified as a PRP at four NPL sites and has been conducting response actions or working with the EPA to resolve past cost recovery claims at these sites pursuant to cleanup orders or other negotiations. As a result of filing the Chapter 11 Cases, Gold Fields has ceased its response actions and other engagements with the EPA at these sites. Undiscounted liabilities for environmental cleanup-related costs relating to (i) the contractual indemnification obligations owed to Blue Tee and (ii) for the sites noted above for which Gold Fields has been identified as a PRP as a result of the operations of its predecessor, are collectively estimated to be $62.8 million and $66.9 million as of December 31, 2016 and 2015, respectively, in the consolidated balance sheets. The majority of these estimated costs relate to Blue Tee site liabilities. P rior to the August 19, 2016 bar date for filing claims in the Chapter 11 Cases, Blue Tee filed an unliquidated, general unsecured claim in the amount of $65.6 million against Gold Fields regarding the Blue Tee Liabilities, additional unliquidated claims in an unknown amount in excess of $150 million at known sites, and further contingent claims at known and unknown sites, including natural resources damages (NRDs) claims alleged, without explanation, to be in the range of $500 million . On November 17, 2016 Blue Tee amended its claim to increase the amount of the claim to $1.2 billion . PEC and Gold Fields believe that these claims significantly overstate any liabilities that may exist for remediation costs or potential NRDs. Prior to the October 11, 2016 government bar date for filing claims in the Chapter 11 Cases, several governmental entities including the EPA, the Department of the Interior and several states filed unliquidated, secured and general unsecured claims against PEC and Gold Fields. These claims total in excess of $2.7 billion and allege damages for past and future remediation costs as well as for alleged NRDs at several sites. As noted in the claims, many of the claims are duplicative as they overlap with each other as well as with claims made by Blue Tee. Additionally, PEC and Gold Fields believe the claims significantly overstate any liabilities that may exist for remediation costs or potential NRDs. On January 27, 2017, PEC filed objections to claims filed by the U.S. Department of Interior, the U.S. Department of Justice and the EPA (collectively the PEC Objections). The PEC Objections dispute that Peabody Energy Corporation has liability to the claimant under applicable federal environmental statutes for the Blue Tee sites listed in the claims based on the fact that Peabody Energy Corporation never owned any of the sites or disposed or arranged for the disposal of hazardous substances at any of the sites. On February 2, 2017, Gold Fields filed objections to claims filed by the State of Oklahoma, the State of Missouri, the Kansas Department of Health and Environment and the U.S. Department of Interior, the EPA, the Kansas Department of Health and Environment, the Illinois Department of Natural Resources and the Missouri Department of Natural Resources (collectively the Gold Fields Objections). The Gold Fields Objections dispute that Gold Fields has liability to the claimant under applicable federal and state environmental statutes for the Blue Tee sites listed in the claims based on the fact that Gold Fields never owned any of the sites or disposed or arranged for the disposal of hazardous substances at any of the sites. On March 16, 2017, the Debtors agreed to settle the objections to the Plan filed by Blue Tee and several government entities in the Chapter 11 Cases. Under the settlements, the Debtors will (1) not seek to recover federal tax refunds owed to Debtors in the amount of approximately $11 million; (2) transfer $12 million of insurance settlement proceeds from Century and Pacific Employers Insurance Company relating to environmental liabilities to the Gold Fields Liquidating Trust (as described in the Plan); and (3) pay $20 million to the Gold Fields Liquidating Trust on or around the Plan Effective Date. On March 16 and 17, 2017, the Bankruptcy Court entered orders approving these settlements. The Debtors and government entities intend to enter into settlement agreements to reflect the above. Other At times the Company becomes a party to other disputes, including those related to contract miner performance, claims, lawsuits, arbitration proceedings, regulatory investigations and administrative procedures in the ordinary course of business in the U.S., Australia and other countries where the Company does business. Based on current information, the Company believes that such other pending or threatened proceedings are likely to be resolved without a material adverse effect on its financial condition, results of operations or cash flows.

Matters Related to the Bankrupt

Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) (Notes)	12 Months Ended
	Dec. 31, 2016
Matters Related to the Bankruptcy of Patriot Coal Corporation [Abstract]
Matters Related to the Bankruptcy of Patriot Coal Corporation [Text Block]	Matters Related to the Bankruptcy of Patriot Coal Corporation In 2012, Patriot 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 (2013 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 their 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 Agreement, the Company provided certain credit support to Patriot. The Company has recorded $20.9 million of credit support provided to Patriot as a liability on the Company's consolidated balance sheet as of December 31, 2016 , of which $15.7 million was supported by letters of credit. Due to Patriot’s May 2015 bankruptcy filing, the Company recorded a net charge during the year ended December 31, 2015 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 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 considered 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 had 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 had secondary liability 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 amount of the liability at December 31, 2016 was $123.3 million . While the Company has recorded a liability, it intends to review each claim on a case-by-case basis and contest liability estimates as appropriate. 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. 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. The Company paid $0.7 million related to these liabilities during 2016. The Company's accounting for the black lung liabilities related to Patriot is based on an interpretation of applicable statutes. Management believes that there exist inconsistencies among the applicable statutes, regulations promulgated under those statutes and the Department of Labor’s interpretative guidance. The Company may seek clarification from the Department of Labor regarding these inconsistencies and the accounting for these liabilities could change in the future depending on the Department of Labor’s responses to inquiries. 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 to the Combined Fund for the approximately $40 million of its subsidiaries' obligations at that time. Once Patriot ceased meeting its obligations, the Company was held responsible for these costs and, as a result, recorded a "Loss from discontinued operations, net of income taxes" charge of $24.6 million during the year ended December 31, 2015 . During the year ended December 31, 2016 , the Company recorded an additional charge of $1.2 million . The Company paid $2.6 million into the fund during 2016 and 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. The liability related to the fund was $22.7 million at December 31, 2016 . VEBA Payments In connection with the 2013 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 2013 Agreement also contemplated subsequent payments to be made to the VEBA of $75.0 million in 2016 and $70.0 million in 2017. The parties agreed to a subsequent settlement of the Company’s obligations for payment of the remaining VEBA payments (2016 Settlement Agreement), which was approved by the Missouri Bankruptcy Court on January 5, 2016 and the Virginia Bankruptcy Court on January 6, 2016. Under this settlement, the Company agreed to pay $75 million to the VEBA, payable in equal monthly installments of $7.5 million beginning on January 4, 2016. The remaining monthly installments were due at the beginning of each successive month ending October 2016, and the obligations were supported in full by a letter of credit. As a result of the Company’s Chapter 11 Cases, the Company’s remaining obligations to the VEBA under the 2016 Settlement Agreement were being satisfied by monthly draws on the letter of credit by the VEBA trustees. As part of the settlement, the Company recognized a gain of $68.1 million during the year ended December 31, 2016 , which was classified in "Operating costs and expenses" in the consolidated statements of operations and is included in the Company's Corporate and Other segment results. 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 and accounts for the related liabilities within continuing operations. 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 second chapter 11 cases (on behalf of itself and the retirees that it represented), pursuant to which, among other things, (i) the SELAA terminated as of October 31, 2015; (ii) the Company and its subsidiary 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. The Company reduced its obligations to match the payments to the VEBA, with the difference accounted for as negative plan amendment and the corresponding prior service credit to be amortized over the same four-year period the payments to the VEBA will occur. UMWA 1974 Pension Plan (UMWA Plan) Litigation On July 16, 2015, a lawsuit was filed by the UMWA Plan, the UMWA 1974 Pension Trust (Trust) and the Trustees of the UMWA Plan and Trust (Trustees) in the United States District Court for the District of Columbia, against PEC, PHC, a subsidiary of the Company, and Arch Coal, Inc. (Arch). The plaintiffs sought, pursuant to ERISA and the Multiemployer Pension Plan Amendments Act of 1980 (MPPAA), a declaratory judgment that the defendants were 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' lawsuit claimed that the defendants' withdrawal liability would result in at least $767 million owed to the UMWA Plan. After a comprehensive legal and arbitration process and with the approval of the Bankruptcy Court, on January 25, 2017, the UMWA Plan and the Debtors agreed to a settlement of the claim whereby the UMWA Plan will be entitled to $75 million to be paid by the Company as follows: $5 million upon the Plan Effective Date, $10 million paid 90 days after the Plan Effective Date, $15 million paid one year after the previous payment and $15 million per year for the following 3 years. In exchange, the UMWA Plan will release PEC and all members of the PEC control group (as defined under ERISA) from any cause of action regarding withdrawal liability. In connection with the settlement, the Company recorded a liability representing the present value of the installments of $54.3 million at December 31, 2016 and recognized an equivalent charge to "Loss from discontinued operations, net of income taxes" in the consolidated statement of operations for the year ended December 31, 2016 .

Summary Quarterly Financial Inf

Summary Quarterly Financial Information	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Summary Quarterly Financial Information (Unaudited)	ummary of Quarterly Financial Information (Unaudited) A summary of the unaudited quarterly results of operations for the years ended December 31, 2016 and 2015 is presented below. Year Ended December 31, 2016 First Quarter Second Quarter Third Quarter Fourth Quarter (In millions, except per share data) Revenues $ 1,027.2 $ 1,040.2 $ 1,207.1 $ 1,440.8 Operating loss (102.7 ) (107.7 ) (21.6 ) (44.9 ) Loss from continuing operations, net of income taxes (161.7 ) (230.8 ) (95.6 ) (186.2 ) Net loss (165.1 ) (233.8 ) (133.7 ) (199.3 ) Net loss attributable to common stockholders (165.1 ) (235.5 ) (135.5 ) (203.7 ) Basic and diluted EPS — continuing operations (1) $ (8.85 ) $ (12.71 ) $ (5.32 ) $ (10.42 ) Weighted average shares used in calculating basic and diluted EPS 18.3 18.3 18.3 18.3 (1) EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis. Operating loss for the first quarter and second quarter of 2016 reflected $26.4 million and $10.3 million of debt restructuring costs, respectively. Operating loss for the first and fourth quarters of 2016 included $17.2 million and $230.7 million of asset impairment costs, respectively, primarily driven by the impairment of Metropolitan Mine to reflect estimated selling price. The operating loss for the second quarter of 2016 included net gain on disposal of assets of $13.7 million , primarily driven by net gains on sale of the Olive Downs South tenements and participation interest in Prairie State Energy Campus of $2.8 million and $6.2 million , respectively. Operating loss for the fourth quarter of 2016 included income from equity affiliates of $28.8 million , due to favorable coal pricing at Middlemount. Loss from continuing operations, net of income taxes for the first quarter included $126.2 million of interest expense, while the following three quarters experienced significant decreases in interest expense due to bankruptcy filing and stay of interest payments. Loss from continuing operations, net of income taxes for the second, third and fourth quarters of 2016 reflected $95.4 million , $29.7 million and $33.9 million of reorganization items, net due to bankruptcy filing and ongoing chapter 11 cases, respectively. Loss from continuing operations, net of income taxes for the fourth quarter of 2016 included a loss on debt extinguishment of $29.5 million resulting from the repayment of debtor-in-possession term loan. Loss from discontinued operations, net of income for the third and fourth quarters reflected $38.1 million and $13.1 million of Patriot bankruptcy related charges associated with black lung liabilities and the UMWA Combined Benefit fund, respectively. Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter (In millions, except per share data) Revenues $ 1,537.9 $ 1,339.3 $ 1,418.9 $ 1,313.1 Operating profit (loss) 2.2 (975.8 ) (20.4 ) (470.8 ) Loss from continuing operations, net of income taxes (164.4 ) (1,007.2 ) (144.4 ) (497.9 ) Net loss (173.3 ) (1,043.5 ) (301.9 ) (470.2 ) Net loss attributable to common stockholders (176.6 ) (1,045.3 ) (304.7 ) (469.4 ) Basic and diluted EPS — continuing operations (1) $ (9.31 ) $ (55.59 ) $ (8.08 ) $ (27.28 ) Weighted average shares used in calculating basic and diluted EPS 18.0 18.2 18.2 18.2 (1) EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis. Operating loss for the fourth quarter of 2015 reflected $377.0 million of asset impairment costs. Operating loss for the second quarter of 2015 included $900.8 million of asset impairment costs and $21.2 million of restructuring and pension settlement charges. Loss from continuing operations for the first and second quarter of 2015 included losses on early debt extinguishment of $59.5 million and $8.3 million , respectively. Loss from continuing operations, net of income taxes for the first, third, and fourth quarters of 2015 included benefits (expenses) related to the remeasurement of foreign income tax accounts of $0.2 million , $0.8 million and $(0.5) million , respectively. Loss from continuing operations, net of income taxes, for the second quarter and fourth quarter of 2015 included a tax benefit related to asset impairment of $67.4 million and $7.9 million , respectively. Loss from continuing operations, net of income taxes, for the fourth quarter of 2015 included an increase in valuation allowance on certain U.S. deferred tax assets of $177.0 million . Loss from discontinued operations, net of income taxes, for the third quarter of 2015 included $155.1 million of Patriot bankruptcy related charges associated with black lung liabilities and the UMWA Combined Benefit Fund. Loss from discontinued operations, net of income taxes, for the second quarter of 2015 reflected a $34.7 million charge, net of taxes, related to adverse changes in the fair value of credit support provided to Patriot. Loss from discontinued operations for the first quarter of 2015 included a contingent loss accrual of $7.6 million associated with the QBH litigation.

Segment and Geographic Informat

Segment and Geographic Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment and Geographic Information	Segment and Geographic Information The Company reports its results of operations primarily through the following reportable segments: Powder River Basin Mining, Midwestern U.S. Mining, Western U.S. Mining, Australian Metallurgical Mining, Australian Thermal Mining, Trading and Brokerage and Corporate and Other. The principal business of the Company's mining segments in the U.S. is the mining, preparation and sale of thermal coal, sold primarily to electric utilities in the U.S. under long-term contracts, with a portion sold into the seaborne markets as market conditions warrant. The Company's Powder River Basin Mining operations consist of its mines in Wyoming. The mines in that segment are characterized by surface mining extraction processes, coal with a lower sulfur content and Btu and higher customer transportation costs (due to longer shipping distances). The Company's Midwestern U.S. Mining operations include the Company’s Illinois and Indiana mining operations, which are characterized by a mix of surface and underground mining extraction processes, coal with a higher sulfur content and Btu and lower customer transportation costs (due to shorter shipping distances). The Company's Western U.S. Mining operations reflect the aggregation of the New Mexico, Arizona and Colorado mining operations. The mines in that segment are characterized by a mix of surface and underground mining extraction processes, coal with a mid-range sulfur content and Btu. Geologically, the Company's Powder River Basin Mining operations mine sub-bituminous coal deposits, its Midwestern U.S. Mining operations mine bituminous coal deposits and its Western U.S. Mining operations mine both bituminous and sub-bituminous coal deposits. The business of the Company's Australian operating platform is primarily export focused with customers spread across several countries, while a portion of the metallurgical and thermal coal is sold within Australia. Generally, revenues from individual countries vary year by year based on electricity and steel demand, the strength of the global economy, governmental policies and several other factors, including those specific to each country. The Company’s Australian Metallurgical Mining operations consist of mines in Queensland and one in New South Wales, Australia. The mines in that segment are characterized by both surface and underground extraction processes used to mine various qualities of metallurgical coal (low-sulfur, high Btu coal). The metallurgical coal qualities include hard coking coal, semi-hard coking coal, semi-soft coking coal and low-volatile pulverized coal injection coal. The Company's Australian Thermal Mining operations consist of mines in New South Wales, Australia. The mines in that segment are characterized by both surface and underground extraction processes used to mine low-sulfur, high Btu thermal coal. The Company classifies its Australian mines within the Australian Metallurgical Mining or Australian Thermal Mining segments based on the primary customer base and coal reserve type of each mining operation. A small portion of the coal mined by the Australian Metallurgical Mining segment is of a thermal grade. Similarly, a small portion of the coal mined by the Australian Thermal Mining segment is of a metallurgical grade. Additionally, the Company may market some of its metallurgical coal products as a thermal coal product from time to time depending on market conditions. The Company's Trading and Brokerage segment engages in the direct and brokered trading of coal and freight-related contracts through its trading and business offices. Coal brokering is conducted both as principal and agent in support of various coal production-related activities that may involve coal produced from the Company's mines, coal sourcing arrangements with third-party mining companies or offtake agreements with other coal producers. The Trading and Brokerage segment also provides transportation-related services, which involves both financial derivative contracts and physical contracts. Collectively, coal and freight-related hedging activities include both economic hedging and, from time to time, cash flow hedging in support of the Company's coal trading strategy. The Company's Corporate and Other segment includes selling and administrative expenses, corporate hedging activities, mining and export/transportation joint ventures, restructuring charges and activities associated with the optimization of coal reserve and real estate holdings, minimum charges on certain transportation-related contracts, the closure of inactive mining sites and certain energy-related commercial matters. The Company’s chief operating decision maker uses Adjusted EBITDA as the primary metric to measure the segments' operating performance. Adjusted EBITDA is defined as (loss) income from continuing operations before deducting net interest expense, income taxes, asset retirement obligation expense, depreciation, depletion and amortization and reorganization items, net. Adjusted EBITDA is also adjusted for the discrete items, which are reflected in the reconciliation below, that management excluded in analyzing the segments' operating performance. Adjusted EBITDA is not intended to serve as an alternative to U.S. GAAP measures of performance and may not be comparable to similarly-titled measures presented by other companies. Segment results for the year ended December 31, 2016 were as follows: Powder River Basin Mining Midwestern U.S. Mining Western U.S. Mining Australian Metallurgical Mining Australian Thermal Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Revenues $ 1,473.3 $ 792.5 $ 526.0 $ 1,090.4 $ 824.9 $ (10.9 ) $ 19.1 $ 4,715.3 Adjusted EBITDA 379.9 217.3 101.6 (16.3 ) 217.6 (72.2 ) (335.7 ) 492.2 Additions to property, plant, equipment and mine development 33.0 18.7 20.8 29.9 22.1 — 2.1 126.6 Federal coal lease expenditures 248.4 — 0.6 — — — — 249.0 Income from equity affiliates — — — — — — (16.2 ) (16.2 ) Segment results for the year ended December 31, 2015 were as follows: Powder River Basin Mining Midwestern U.S. Mining Western U.S. Mining Australian Metallurgical Mining Australian Thermal Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Revenues $ 1,865.9 $ 981.2 $ 682.3 $ 1,181.9 $ 823.5 $ 42.8 $ 31.6 $ 5,609.2 Adjusted EBITDA 482.9 269.7 184.6 (18.2 ) 193.6 27.0 (705.0 ) 434.6 Additions to property, plant, equipment and mine development 15.0 51.3 19.3 25.5 13.6 — 2.1 126.8 Federal coal lease expenditures 276.9 — 0.3 — — — — 277.2 Loss from equity affiliates — — — — — — 15.9 15.9 Segment results for the year ended December 31, 2014 were as follows: Powder River Basin Mining Midwestern U.S. Mining Western U.S. Mining Australian Metallurgical Mining Australian Thermal Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Revenues $ 1,922.9 $ 1,198.1 $ 902.8 $ 1,613.8 $ 1,058.0 $ 58.4 $ 38.2 $ 6,792.2 Adjusted EBITDA 509.0 306.9 266.9 (151.1 ) 264.1 14.9 (396.7 ) 814.0 Additions to property, plant, equipment and mine development 19.7 57.4 18.2 53.9 30.2 — 15.0 194.4 Federal coal lease expenditures 276.5 — 0.2 — — — — 276.7 Loss from equity affiliates — — — — — — 107.6 107.6 Asset details are reflected at the division level only for the Company's mining segments and are not allocated between each individual segment as such information is not regularly reviewed by the Company's CODM. Further, some assets service more than one segment within the division and an allocation of such assets would not be meaningful or representative on a segment by segment basis. Assets as of December 31, 2016 were as follows: U.S. Mining Australian Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Total assets $ 4,255.9 $ 5,402.2 $ 128.7 $ 1,990.9 $ 11,777.7 Property, plant, equipment and mine development, net 3,970.6 3,905.8 0.2 900.1 8,776.7 Assets as of December 31, 2015 were as follows: U.S. Mining Australian Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Total assets $ 4,105.8 $ 5,319.9 $ 217.2 $ 1,304.0 $ 10,946.9 Property, plant, equipment and mine development, net 3,854.5 4,469.6 0.5 933.9 9,258.5 Assets as of December 31, 2014 were as follows: U.S. Mining Australian Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Total assets $ 4,099.1 $ 6,623.9 $ 300.7 $ 2,167.4 $ 13,191.1 Property, plant, equipment and mine development, net 3,739.9 5,503.7 1.1 1,332.6 10,577.3 A reconciliation of consolidated loss from continuing operations, net of income taxes to Adjusted EBITDA follows: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Loss from continuing operations, net of income taxes $ (674.3 ) $ (1,813.9 ) $ (749.1 ) Depreciation, depletion and amortization 465.4 572.2 655.7 Asset retirement obligation expenses 41.8 45.5 81.0 Selling and administrative expenses related to debt restructuring 21.5 — — Asset impairment 247.9 1,277.8 154.4 Change in deferred tax asset valuation allowance related to equity affiliates (7.5 ) (1.0 ) 52.3 Amortization of basis difference related to equity affiliates — 4.9 5.7 Interest expense 298.6 465.4 426.6 Loss on early debt extinguishment 29.5 67.8 1.6 Interest income (5.7 ) (7.7 ) (15.4 ) Reorganization items, net 159.0 — — Income tax (benefit) provision (84.0 ) (176.4 ) 201.2 Total Adjusted EBITDA $ 492.2 $ 434.6 $ 814.0 The following table presents revenues as a percent of total revenue from external customers by geographic region: Year Ended December 31, 2016 2015 2014 U.S. 54.7 % 57.4 % 59.5 % Japan 6.9 % 8.1 % 9.5 % China 5.4 % 7.1 % 6.1 % South Korea 1.5 % 4.1 % 5.2 % Other 31.5 % 23.3 % 19.7 % Total 100.0 % 100.0 % 100.0 % The Company attributes revenue to individual countries based on the location of the physical delivery of the coal.

Supplemental Guarantor_Non-Guar

Supplemental Guarantor/Non-Guarantor Financial Information	12 Months Ended
	Dec. 31, 2016
Supplemental Guarantor Non Guarantor Financial Information [Abstract]
Supplemental Guarantor/Non-Guarantor Financial Information	Supplemental Guarantor/Non-Guarantor Financial Information In accordance with the indentures governing the Senior Notes, certain 100% owned U.S. subsidiaries of the Company (each, a Guarantor Subsidiary) have fully and unconditionally guaranteed the Senior Notes, on a joint and several basis. The indentures governing the Senior Notes contain customary exceptions under which a guarantee of a Guarantor Subsidiary will terminate, including (a) the release or discharge of the guarantee of the Company’s 2013 Credit Facility by such Guarantor Subsidiary, except a discharge or release by or as a result of payment under such guarantee, (b) a sale or other disposition, by way of merger, consolidation or otherwise, of all of the capital stock of such Guarantor Subsidiary, and (c) the legal defeasance or discharge of the indentures. Separate financial statements and other disclosures concerning the Guarantor Subsidiaries are not presented because management believes that such information is not material to the holders of the Senior Notes. The following historical financial statement information is provided for the Guarantor/Non-Guarantor Subsidiaries. PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 2,830.0 $ 2,189.8 $ (304.5 ) $ 4,715.3 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 172.9 2,172.4 2,066.8 (304.5 ) 4,107.6 Depreciation, depletion and amortization — 217.4 248.0 — 465.4 Asset retirement obligation expenses — 15.8 26.0 — 41.8 Selling and administrative expenses 12.8 126.5 14.1 — 153.4 Restructuring charges — 11.9 3.6 — 15.5 Other operating (income) loss: Net gain on disposal of assets — (21.4 ) (1.8 ) — (23.2 ) Asset impairment — 37.5 210.4 — 247.9 Loss from equity affiliates and investment in subsidiaries 185.0 4.5 (20.7 ) (185.0 ) (16.2 ) Interest expense 288.6 19.6 24.4 (34.0 ) 298.6 Loss on early debt extinguishment 29.5 — — — 29.5 Interest income (0.2 ) (4.8 ) (34.7 ) 34.0 (5.7 ) Reorganization items, net 73.4 82.1 3.5 — 159.0 (Loss) income from continuing operations before income taxes (762.0 ) 168.5 (349.8 ) 185.0 (758.3 ) Income tax (benefit) provision (84.6 ) (11.0 ) 11.6 — (84.0 ) (Loss) income from continuing operations, net of income taxes (677.4 ) 179.5 (361.4 ) 185.0 (674.3 ) (Loss) income from discontinued operations, net of income taxes (62.4 ) (0.1 ) 4.9 — (57.6 ) Net (loss) income (739.8 ) 179.4 (356.5 ) 185.0 (731.9 ) Less: Net income attributable to noncontrolling interests — — 7.9 — 7.9 Net (loss) income attributable to common stockholders $ (739.8 ) $ 179.4 $ (364.4 ) $ 185.0 $ (739.8 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 3,535.3 $ 2,535.3 $ (461.4 ) $ 5,609.2 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 436.6 2,782.6 2,249.9 (461.4 ) 5,007.7 Depreciation, depletion and amortization — 249.7 322.5 — 572.2 Asset retirement obligation expenses — 13.2 32.3 — 45.5 Selling and administrative expenses 32.1 132.6 11.7 — 176.4 Restructuring charges (3.9 ) 11.4 16.0 — 23.5 Other operating (income) loss: Net gain on disposal of assets (2.3 ) (29.8 ) (12.9 ) — (45.0 ) Asset impairment — 308.6 969.2 — 1,277.8 Loss from equity affiliates and investment in subsidiaries 933.9 6.9 9.0 (933.9 ) 15.9 Interest expense 468.4 19.6 24.7 (47.3 ) 465.4 Loss on early debt extinguishment 67.8 — — — 67.8 Interest income (14.0 ) (2.4 ) (38.6 ) 47.3 (7.7 ) (Loss) income from continuing operations before income taxes (1,918.6 ) 42.9 (1,048.5 ) 933.9 (1,990.3 ) Income tax (benefit) provision (87.4 ) (108.2 ) 19.2 — (176.4 ) (Loss) income from continuing operations, net of income taxes (1,831.2 ) 151.1 (1,067.7 ) 933.9 (1,813.9 ) (Loss) income from discontinued operations, net of income taxes (164.8 ) 1.6 (11.8 ) — (175.0 ) Net (loss) income (1,996.0 ) 152.7 (1,079.5 ) 933.9 (1,988.9 ) Less: Net income attributable to noncontrolling interests — 0.8 6.3 — 7.1 Net (loss) income attributable to common stockholders $ (1,996.0 ) $ 151.9 $ (1,085.8 ) $ 933.9 $ (1,996.0 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 4,063.8 $ 3,311.7 $ (583.3 ) $ 6,792.2 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 49.6 3,121.9 3,128.7 (583.3 ) 5,716.9 Depreciation, depletion and amortization — 271.0 384.7 — 655.7 Asset retirement obligation expenses — 23.2 57.8 — 81.0 Selling and administrative expenses 46.8 161.1 19.2 — 227.1 Restructuring and pension settlement charges — 26.0 — — 26.0 Other operating (income) loss: Net gain on disposal of assets — (17.7 ) (23.7 ) — (41.4 ) Asset impairment 4.7 63.3 86.4 — 154.4 Loss from equity affiliates and investment in subsidiaries 128.5 7.6 100.0 (128.5 ) 107.6 Interest expense 423.1 19.5 34.3 (50.3 ) 426.6 Loss on early debt extinguishment 1.6 — — — 1.6 Interest income (15.3 ) (2.9 ) (47.5 ) 50.3 (15.4 ) (Loss) income from continuing operations before income taxes (639.0 ) 390.8 (428.2 ) 128.5 (547.9 ) Income tax provision 116.4 23.7 61.1 — 201.2 (Loss) income from continuing operations, net of income taxes (755.4 ) 367.1 (489.3 ) 128.5 (749.1 ) (Loss) income from discontinued operations, net of income taxes (31.6 ) (7.2 ) 10.6 — (28.2 ) Net (loss) income (787.0 ) 359.9 (478.7 ) 128.5 (777.3 ) Less: Net income attributable to noncontrolling interests — 5.2 4.5 — 9.7 Net (loss) income attributable to common stockholders $ (787.0 ) $ 354.7 $ (483.2 ) $ 128.5 $ (787.0 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (739.8 ) $ 179.4 $ (356.5 ) $ 185.0 $ (731.9 ) Other comprehensive income (loss), net of income taxes: Net unrealized gains on cash flow hedges (net of $85.9 tax provision) (Decrease) increase in fair value of cash flow hedges — — — — — Reclassification for realized losses included in net (loss) income 146.3 — — — 146.3 Net unrealized gains on cash flow hedges 146.3 — — — 146.3 Postretirement plans and workers' compensation obligations (net of $1.5 tax benefit) Prior service cost for the period — (4.5 ) — — (4.5 ) Net actuarial gain (loss) for the period 8.9 (22.4 ) — — (13.5 ) Amortization of actuarial (loss) gain and prior service cost included in net (loss) income (6.1 ) 21.5 — — 15.4 Postretirement plans and workers' compensation obligations 2.8 (5.4 ) — — (2.6 ) Foreign currency translation adjustment — — (1.8 ) — (1.8 ) Other comprehensive loss from investment in subsidiaries (7.2 ) — — 7.2 — Other comprehensive income (loss), net of income taxes 141.9 (5.4 ) (1.8 ) 7.2 141.9 Comprehensive (loss) income (597.9 ) 174.0 (358.3 ) 192.2 (590.0 ) Less: Comprehensive income attributable to noncontrolling interests — — 7.9 — 7.9 Comprehensive (loss) income attributable to common stockholders $ (597.9 ) $ 174.0 $ (366.2 ) $ 192.2 $ (597.9 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (1,996.0 ) $ 152.7 $ (1,079.5 ) $ 933.9 $ (1,988.9 ) Other comprehensive income (loss), net of income taxes: Net change in unrealized losses on available-for-sale securities (net of $0.1 tax benefit) Net unrealized gains (losses) on cash flow hedges (net of $72.2 tax provision) (Decrease) increase in fair value of cash flow hedges (137.1 ) — 5.8 — (131.3 ) Reclassification for realized losses (gains) included in net (loss) income 292.1 — (40.4 ) — 251.7 Net unrealized gains (losses) on cash flow hedges 155.0 — (34.6 ) — 120.4 Postretirement plans and workers' compensation obligations (net of $36.2 tax provision) Prior service credit for the period — 10.4 — — 10.4 Net actuarial gain for the period 5.5 12.6 — — 18.1 Amortization of actuarial loss (gain) and prior service cost included in net (loss) income 7.2 37.3 (12.6 ) — 31.9 Postretirement plans and workers' compensation obligations 12.7 60.3 (12.6 ) — 60.4 Foreign currency translation adjustment — — (34.9 ) — (34.9 ) Other comprehensive loss from investment in subsidiaries (21.8 ) — — 21.8 — Other comprehensive income (loss), net of income taxes 145.9 60.3 (82.1 ) 21.8 145.9 Comprehensive (loss) income (1,850.1 ) 213.0 (1,161.6 ) 955.7 (1,843.0 ) Less: Comprehensive income attributable to noncontrolling interests — 0.8 6.3 — 7.1 Comprehensive (loss) income attributable to common stockholders $ (1,850.1 ) $ 212.2 $ (1,167.9 ) $ 955.7 $ (1,850.1 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (787.0 ) $ 359.9 $ (478.7 ) $ 128.5 $ (777.3 ) Other comprehensive loss, net of income taxes: Net change in unrealized losses on available-for-sale securities (net of $0.5 tax benefit) Unrealized holding losses on available-for-sale securities (3.7 ) — — — (3.7 ) Reclassification for realized losses included in net (loss) income 2.9 — — — 2.9 Net change in unrealized losses on available-for-sale securities (0.8 ) — — — (0.8 ) Net unrealized losses on cash flow hedges (net of $54.6 tax benefit) (Decrease) increase in fair value of cash flow hedges (225.9 ) — 30.9 — (195.0 ) Reclassification for realized losses (gains) included in net (loss) income 31.3 — (41.5 ) — (10.2 ) Net unrealized losses on cash flow hedges (194.6 ) — (10.6 ) — (205.2 ) Postretirement plans and workers' compensation obligations (net of $10.3 tax benefit) Prior service credit for the period — 11.4 — — 11.4 Net actuarial (loss) gain for the period — (152.6 ) 9.9 — (142.7 ) Amortization of actuarial loss (gain) and prior service cost included in net (loss) income — 41.4 (8.7 ) — 32.7 Postretirement plans and workers' compensation obligations — (99.8 ) 1.2 — (98.6 ) Foreign currency translation adjustment — — (41.0 ) — (41.0 ) Other comprehensive income from investment in subsidiaries (150.2 ) — — 150.2 — Other comprehensive loss, net of income taxes (345.6 ) (99.8 ) (50.4 ) 150.2 (345.6 ) Comprehensive (loss) income (1,132.6 ) 260.1 (529.1 ) 278.7 (1,122.9 ) Less: Comprehensive income attributable to noncontrolling interests — 5.2 4.5 — 9.7 Comprehensive (loss) income attributable to common stockholders $ (1,132.6 ) $ 254.9 $ (533.6 ) $ 278.7 $ (1,132.6 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Reclassifications/ Eliminations Consolidated (Dollars in millions) Assets Current assets Cash and cash equivalents $ 266.6 $ 107.0 $ 498.7 $ — $ 872.3 Restricted cash 13.8 — 40.5 — 54.3 Accounts receivable, net — 5.1 467.9 — 473.0 Receivables from affiliates, net 899.9 — 783.0 (1,682.9 ) — Inventories — 76.8 126.9 — 203.7 Assets from coal trading activities, net — 0.9 — (0.2 ) 0.7 Other current assets 19.1 51.2 416.3 — 486.6 Total current assets 1,199.4 241.0 2,333.3 (1,683.1 ) 2,090.6 Property, plant, equipment and mine development, net — 4,381.6 4,395.1 — 8,776.7 Deferred income taxes — 15.8 — (15.8 ) — Investments and other assets 8,652.0 3.8 626.5 (8,371.9 ) 910.4 Notes receivable from affiliates, net — 1,036.3 — (1,036.3 ) — Total assets $ 9,851.4 $ 5,678.5 $ 7,354.9 $ (11,107.1 ) $ 11,777.7 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ — $ 19.3 $ 0.9 $ — $ 20.2 Payables to affiliates, net — 1,682.9 — (1,682.9 ) — Liabilities from coal trading activities, net — — 1.4 (0.2 ) 1.2 Accounts payable and accrued expenses 58.9 439.3 492.2 — 990.4 Total current liabilities 58.9 2,141.5 494.5 (1,683.1 ) 1,011.8 Deferred income taxes 28.0 — 5.4 (15.8 ) 17.6 Notes payable to affiliates, net 1,032.5 — 3.8 (1,036.3 ) — Other noncurrent liabilities 160.4 1,330.3 479.6 — 1,970.3 Total liabilities not subject to compromise 1,279.8 3,471.8 983.3 (2,735.2 ) 2,999.7 Liabilities subject to compromise 8,241.4 184.2 14.6 — 8,440.2 Total liabilities 9,521.2 3,656.0 997.9 (2,735.2 ) 11,439.9 Peabody Energy Corporation stockholders’ equity 330.2 2,022.5 6,349.4 (8,371.9 ) 330.2 Noncontrolling interests — — 7.6 — 7.6 Total stockholders’ equity 330.2 2,022.5 6,357.0 (8,371.9 ) 337.8 Total liabilities and stockholders’ equity $ 9,851.4 $ 5,678.5 $ 7,354.9 $ (11,107.1 ) $ 11,777.7 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Reclassifications/ Eliminations Consolidated (Dollars in millions) Assets Current assets Cash and cash equivalents $ 7.2 $ 4.7 $ 249.4 $ — $ 261.3 Accounts receivable, net — 12.1 216.7 — 228.8 Receivables from affiliates, net 582.1 — 948.1 (1,530.2 ) — Inventories — 109.4 198.4 — 307.8 Assets from coal trading activities, net — 3.2 20.3 — 23.5 Deferred income taxes — 65.3 — (11.8 ) 53.5 Other current assets 23.1 128.1 296.4 — 447.6 Total current assets 612.4 322.8 1,929.3 (1,542.0 ) 1,322.5 Property, plant, equipment and mine development, net — 4,304.8 4,953.7 — 9,258.5 Deferred income taxes — 33.1 — (30.9 ) 2.2 Investments and other assets 8,476.2 3.6 185.5 (8,301.6 ) 363.7 Notes receivable from affiliates, net — 632.7 399.9 (1,032.6 ) — Total assets $ 9,088.6 $ 5,297.0 $ 7,468.4 $ (10,907.1 ) $ 10,946.9 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ 5,844.0 $ 23.8 $ 7.1 $ — $ 5,874.9 Payables to affiliates, net — 1,530.2 — (1,530.2 ) — Deferred income taxes 11.8 — 3.8 (11.8 ) 3.8 Liabilities from coal trading activities, net — 4.8 10.8 — 15.6 Accounts payable and accrued expenses 494.8 479.8 467.9 — 1,442.5 Total current liabilities 6,350.6 2,038.6 489.6 (1,542.0 ) 7,336.8 Long-term debt, less current portion 366.3 — — — 366.3 Deferred income taxes 98.6 — 1.4 (30.9 ) 69.1 Notes payable to affiliates, net 1,032.6 — — (1,032.6 ) — Other noncurrent liabilities 323.6 1,454.9 477.7 — 2,256.2 Total liabilities 8,171.7 3,493.5 968.7 (2,605.5 ) 10,028.4 Peabody Energy Corporation stockholders’ equity 916.9 1,803.5 6,498.1 (8,301.6 ) 916.9 Noncontrolling interests — — 1.6 — 1.6 Total stockholders’ equity 916.9 1,803.5 6,499.7 (8,301.6 ) 918.5 Total liabilities and stockholders’ equity $ 9,088.6 $ 5,297.0 $ 7,468.4 $ (10,907.1 ) $ 10,946.9 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (167.3 ) $ 78.5 $ 65.9 $ (22.9 ) Net cash used in discontinued operations (16.2 ) (1.9 ) (11.8 ) (29.9 ) Net cash (used in) provided by operating activities (183.5 ) 76.6 54.1 (52.8 ) Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (55.5 ) (71.1 ) (126.6 ) Changes in accrued expenses related to capital expenditures — (0.6 ) (5.5 ) (6.1 ) Federal coal lease expenditures — (249.0 ) — (249.0 ) Proceeds from disposal of assets, net of notes receivable — 77.7 66.7 144.4 Contributions to joint ventures — — (309.5 ) (309.5 ) Distributions from joint ventures — — 312.4 312.4 Advances to related parties — — (40.4 ) (40.4 ) Repayment of loans from related parties — — 40.6 40.6 Other, net — (5.1 ) (4.8 ) (9.9 ) Net cash used in by investing activities — (232.5 ) (11.6 ) (244.1 ) Cash Flows From Financing Activities Proceeds from long-term debt 1,450.6 — 7.8 1,458.4 Repayments of long-term debt (503.0 ) (4.4 ) (6.3 ) (513.7 ) Payment of deferred financing costs (26.8 ) — (4.2 ) (31.0 ) Other, net — (5.8 ) — (5.8 ) Transactions with affiliates, net (477.9 ) 268.4 209.5 — Net cash provided by financing activities 442.9 258.2 206.8 907.9 Net change in cash and cash equivalents $ 259.4 $ 102.3 $ 249.3 $ 611.0 Cash and cash equivalents at beginning of year 7.2 4.7 249.4 261.3 Cash and cash equivalents at end of year $ 266.6 $ 107.0 $ 498.7 $ 872.3 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (692.9 ) $ 615.3 $ 96.5 $ 18.9 Net cash used in discontinued operations (27.4 ) (2.9 ) (3.0 ) (33.3 ) Net cash (used in) provided by operating activities (720.3 ) 612.4 93.5 (14.4 ) Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (70.6 ) (56.2 ) (126.8 ) Changes in accrued expenses related to capital expenditures — (2.3 ) (6.9 ) (9.2 ) Federal coal lease expenditures — (277.2 ) — (277.2 ) Proceeds from disposal of assets, net of notes receivable — 36.3 34.1 70.4 Purchases of debt and equity securities — — (28.8 ) (28.8 ) Proceeds from sales and maturities of debt and equity securities — — 90.3 90.3 Contributions to joint ventures — — (425.4 ) (425.4 ) Distributions from joint ventures — — 422.6 422.6 Advances to related parties — — (3.7 ) (3.7 ) Repayment of loan from related parties — — 0.9 0.9 Other, net — (2.7 ) (0.4 ) (3.1 ) Net cash (used in) provided by investing activities — (316.5 ) 26.5 (290.0 ) Cash Flows From Financing Activities Proceeds from long-term debt 975.7 — — 975.7 Repayments of long-term debt (662.0 ) (0.7 ) (8.6 ) (671.3 ) Payment of deferred financing costs (28.7 ) — — (28.7 ) Dividends paid (1.4 ) — — (1.4 ) Other, net 1.4 (1.8 ) (6.2 ) (6.6 ) Transactions with affiliates, net 253.8 (289.9 ) 36.1 — Net cash provided by (used in) financing activities 538.8 (292.4 ) 21.3 267.7 Net change in cash and cash equivalents $ (181.5 ) $ 3.5 $ 141.3 $ (36.7 ) Cash and cash equivalents at beginning of year 188.7 1.2 108.1 298.0 Cash and cash equivalents at end of year $ 7.2 $ 4.7 $ 249.4 $ 261.3 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (369.0 ) $ 764.7 $ 45.3 $ 441.0 Net cash used in discontinued operations (73.3 ) (4.6 ) (26.5 ) (104.4 ) Net cash (used in) provided by operating activities (442.3 ) 760.1 18.8 336.6 Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (95.8 ) (98.6 ) (194.4 ) Changes in accrued expenses related to capital expenditures — 2.2 (18.8 ) (16.6 ) Federal coal lease expenditures — (276.7 ) — (276.7 ) Proceeds from disposal of assets, net of notes receivable — 105.9 97.8 203.7 Purchases of debt and equity securities — — (15.1 ) (15.1 ) Proceeds from sales and maturities of debt and equity securities — — 13.5 13.5 Contributions to joint ventures — — (529.8 ) (529.8 ) Distributions from joint ventures — — 534.2 534.2 Advances to related parties — — (33.7 ) (33.7 ) Repayment of loans from related parties — — 5.4 5.4 Other, net — (4.2 ) (0.8 ) (5.0 ) Net cash used in investing activities — (268.6 ) (45.9 ) (314.5 ) Cash Flows From Financing Activities Proceeds from long-term debt — — 1.1 1.1 Repayments of long-term debt (12.0 ) (0.7 ) (8.3 ) (21.0 ) Payment of deferred financing costs (10.1 ) — — (10.1 ) Dividends paid (92.3 ) — — (92.3 ) Restricted cash for distributions to noncontrolling interest — — (42.5 ) (42.5 ) Other, net 3.1 (1.7 ) (4.7 ) (3.3 ) Transactions with affiliates, net 441.6 (488.2 ) 46.6 — Net cash provided by (used in) financing activities 330.3 (490.6 ) (7.8 ) (168.1 ) Net change in cash and cash equivalents $ (112.0 ) $ 0.9 $ (34.9 ) $ (146.0 ) Cash and cash equivalents at beginning of year 300.7 0.3 143.0 444.0 Cash and cash equivalents at end of year $ 188.7 $ 1.2 $ 108.1 $ 298.0

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
VALUATION AND QUALIFYING ACCOUNTS	PEABODY ENERGY CORPORATION SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS Description Balance at Charged to Deductions (1) Other Balance (Dollars in millions) Year Ended December 31, 2016 Reserves deducted from asset accounts: Advance royalty recoupment reserve $ 8.3 $ 0.5 $ (1.0 ) (2) $ — $ 7.8 Reserve for materials and supplies 4.7 4.3 (3.4 ) — 5.6 Allowance for doubtful accounts 6.6 7.9 (1.4 ) — 13.1 Tax valuation allowances 1,447.3 2,462.8 — (28.9 ) (3) 3,881.2 Year Ended December 31, 2015 Reserves deducted from asset accounts: Advance royalty recoupment reserve $ 7.6 $ — $ (0.9 ) (2) $ 1.6 (4) $ 8.3 Reserve for materials and supplies 4.6 0.4 (0.3 ) — 4.7 Allowance for doubtful accounts 5.8 8.0 (7.2 ) — 6.6 Tax valuation allowances 1,169.0 462.0 — (183.7 ) (3) 1,447.3 Year Ended December 31, 2014 Reserves deducted from asset accounts: Advance royalty recoupment reserve $ 9.7 $ (0.2 ) $ (1.9 ) (2) $ — $ 7.6 Reserve for materials and supplies 7.4 (0.1 ) (2.7 ) — 4.6 Allowance for doubtful accounts 7.4 1.5 (1.4 ) (1.7 ) (5) 5.8 Tax valuation allowances 1,634.1 569.4 — (1,034.5 ) (6) 1,169.0 (1) Reserves utilized, unless otherwise indicated. (2) Deductions to advance royalty recoupment reserve represents the termination of federal and state leases. (3) Includes the impact of the decrease in Australian dollar exchange rates. (4) Balances transferred from other accounts. (5) Represents subsequent recovery of receivable amounts previously reserved. (6) Includes the write-off of valuation allowance against deferred tax assets related to the Australian Minerals and Resource Rent Tax (MRRT) due to the repeal of that legislation in 2014, along with an increase in valuation allowance during the period reflected directly in "Accumulated other comprehensive loss" and the impact of the 2014 decrease in Australian dollar exchange rates.

Reorganization Items, Net (Note

Reorganization Items, Net (Notes)	12 Months Ended
	Dec. 31, 2016
schedule of reorganization items [Line Items]
Reorganization under Chapter 11 of US Bankruptcy Code Disclosure [Text Block]	In accordance with Accounting Standards Codification 852, "Reorganizations," the statement of operations shall portray the results of operations of the reporting entity during the pendency of the Chapter 11 Cases. Revenues, expenses (including professional fees), realized gains and losses, and provisions for losses resulting from reorganization and restructuring of the business shall be reported separately as "reorganization items". The Company's reorganization items for the year ended December 31, 2016 consisted of the following: Year Ended December 31, 2016 (Dollars in millions) Professional fees $ 88.4 Loss on termination of derivative contracts 75.2 Accounts payable settlement gains (1.8 ) Interest income (1.8 ) Other (1.0 ) Reorganization items, net $ 159.0 As a result of filing the Bankruptcy Petitions, counterparties to certain derivative contracts terminated the agreements shortly thereafter in accordance with their contractual terms and the Company adjusted the corresponding liabilities to be equivalent to the termination value and allowed claim amount of each contract. Such liabilities are considered first lien debt and are included within "Liabilities subject to compromise" in the accompanying consolidated balance sheet at December 31, 2016. Professional fees are only those that are directly related to the reorganization including, but not limited to, fees associated with advisors to the Debtors, the Creditors' Committee and certain secured and unsecured creditors. Interest income reflects interest earned due to the preservation of cash as a result of the automatic stay pursuant to Section 362 of the Bankruptcy Code. During the year ended December 31, 2016, $68.1 million of cash payments were made for "Reorganization items, net".

Liabilities Subject to Compromi

Liabilities Subject to Compromise (Notes)	12 Months Ended
	Dec. 31, 2016
Liabilities Subject to Compromise [Abstract]
liabilities subject to compromise [Text Block]	(3) Liabilities Subject to Compromise Liabilities subject to compromise include unsecured or under-secured liabilities incurred prior to the Petition Date. These liabilities represent the amounts expected to be allowed on known or potential claims to be resolved through the Chapter 11 Cases and remain subject to future adjustments based on negotiated settlements with claimants, actions of the Bankruptcy Court, rejection of executory contracts, proofs of claims or other events. Additionally, liabilities subject to compromise also include certain items that may be assumed under a plan of reorganization, and as such, may be subsequently reclassified to liabilities not subject to compromise. Generally, actions to enforce or otherwise effect payment of prepetition liabilities are subject to the automatic stay or an approved motion of the Bankruptcy Court, as discussed in Note 1. "Summary of Significant Accounting Policies". Liabilities subject to compromise consisted of the following: Previously Reported Balance Sheet Line December 31, 2016 (Dollars in millions) Debt (1) $ 8,080.3 Interest payable 172.6 Environmental liabilities 61.9 Trade payables 58.4 Postretirement benefit obligations (2) 34.6 Other accrued liabilities 32.4 Liabilities subject to compromise $ 8,440.2 (1) Includes $7,771.2 million of first lien, second lien and unsecured debt, $257.3 million of derivative contract terminations, and $51.8 million of liabilities secured by prepetition letters of credit. (2) Includes liabilities for unfunded non-qualified pension plans, all the participants of which are former employees.

Summary of Significant Accoun41

Summary of Significant Accounting Policies Discussion (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Peabody Energy Corporation and its affiliates. The Company, or Peabody, are used interchangeably to refer to Peabody Energy Corporation, to Peabody Energy Corporation and its subsidiaries, or to such subsidiaries, as appropriate to the context. Interests in subsidiaries controlled by the Company are consolidated with any outside stockholder interests reflected as noncontrolling interests, except when the Company has an undivided interest in an unincorporated joint venture. In those cases, the Company includes its proportionate share in the assets, liabilities, revenues and expenses of the jointly controlled entities within each applicable line item of the consolidated financial statements. All intercompany transactions, profits and balances have been eliminated in consolidation. As discussed below in "Newly Adopted Accounting Standards," prior year amounts of deferred financing costs have been reclassified to conform with the new standard. Pursuant to the authorization provided at a special meeting of the Company's stockholders held on September 16, 2015, the Company completed a 1-for-15 reverse stock split of the shares of the Company’s common stock on September 30, 2015 (the Reverse Stock Split). As a result of the Reverse Stock Split, every 15 shares of issued and outstanding common stock were combined into one issued and outstanding share of Common Stock, without any change in the par value per share. No fractional shares were issued as a result of the Reverse Stock Split and any fractional shares that would otherwise have resulted from the Reverse Stock Split were paid in cash. The Reverse Stock Split reduced the number of shares of common stock outstanding from approximately 278 million shares to approximately 19 million shares. The number of authorized shares of common stock was also decreased from 800 million shares to 53.3 million shares. The Company's common stock began trading on a reverse stock split-adjusted basis on October 1, 2015. All share and per share data included in this report has been retroactively restated to reflect the Reverse Stock Split. Since the par value of the common stock remained at $0.01 per share, the value for "Common stock" recorded to the Company's consolidated balance sheets has been retroactively reduced to reflect the par value of restated outstanding shares, with a corresponding increase to "Additional paid-in capital." The Company has classified items within discontinued operations in the audited consolidated financial statements for disposals (by sale or otherwise) that have occurred prior to January 1, 2015 when the operations and cash flows of a disposed component of the Company were eliminated from the ongoing operations of the Company as a result of the disposal and the Company no longer had any significant continuing involvement in the operation of that component.
Description of Business	Description of Business The Company is engaged in the mining of thermal coal for sale primarily to electric utilities and metallurgical coal for sale to industrial customers. The Company’s mining operations are located in the United States (U.S.) and Australia, including an equity-affiliate mining operation in Australia. The Company also markets and brokers coal from other coal producers, both as principal and agent, and trades coal and freight-related contracts through trading and business offices in Australia, China, Germany, the United Kingdom and the U.S. (listed alphabetically). The Company’s other energy-related commercial activities include managing its coal reserve and real estate holdings and supporting the development of clean coal technologies.
Newly Adopted Accounting Standards and Accounting Standards Not Yet Implemented	ewly Adopted Accounting Standards Going Concern. In August 2014, the Financial Accounting Standards Board (FASB) issued disclosure guidance that requires management to evaluate, at each annual and interim reporting period, whether substantial doubt exists about an entity's ability to continue as a going concern and, if applicable, to provide related disclosures. As outlined by that guidance, substantial doubt about an entity's ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that an entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued (or are available to be issued). The new guidance is effective for annual reporting periods ending after December 15, 2016 (the year ending December 31, 2016 for the Company) and interim periods thereafter, with early adoption permitted. The Company is currently operating its business as “debtors-in-possession” under the jurisdiction of the Bankruptcy Court, has incurred net losses for the years ended 2016, 2015 and 2014, and had an accumulated deficit as of December 31, 2016 and 2015. These conditions raise substantial doubt about the Company's ability to continue for one year from the date these financial statements are issued. However, the Bankruptcy Court entered an order confirming the Plan on March 17, 2017 and the Company's current projections, based on the confirmed Plan, indicate that it is probable the Company will have sufficient liquidity to meet its obligations as they become due within one year after the date of this report. The confirmed Plan provides for the elimination of the Company's existing debt outstanding at December 31, 2016, which is discussed in Note 14. "Current and Long-term Debt." The Company's projections include the debt issued and planned equity issuance as part of its restructuring which are discussed above in “Filing of Plan of Reorganization with the Bankruptcy Court." Given the Plan confirmation on March 17, 2017, management believes it is probable the Plan will become effective and consummated in early April 2017, and emergence from the Chapter 11 Cases will occur at that time. There are certain substantial conditions precedent for the confirmed Plan to become effective and legally binding. Management believes it is probable these conditions precedent to the Plan effective date will be satisfied or waived by the Company’s targeted emergence date in early April 2017. Based on the confirmation of the Plan and the Company's financial projections, management believes it is probable the conditions that raise substantial doubt about its ability to continue as a going concern have been alleviated. The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern and contemplate the realization of assets and the satisfaction of liabilities in the normal course of business, the likelihood of which has been increased by the Bankruptcy Court’s confirmation of the Company’s Plan and the Company's ability to obtain exit financing, but is contingent on the Company’s ability to successfully consummate the Plan and maintain sufficient liquidity, among other factors. As a result of the Bankruptcy Petitions, the realization of assets and the satisfaction of liabilities are subject to uncertainty. If the Plan were not to become effective and the Company continued to operate as debtors-in-possession under Chapter 11, the Company may sell or otherwise dispose of or liquidate assets or settle liabilities, subject to the approval of the Bankruptcy Court or as otherwise permitted in the ordinary course of business for amounts other than those reflected in the accompanying consolidated financial statements. Further, the Plan is expected to materially change the amounts and classifications of assets and liabilities reported in the consolidated financial statements. The accompanying consolidated financial statements do not include any adjustments related to the recoverability and classification of assets or the amounts and classification of liabilities or any other adjustments that might be necessary should the Company be unable to continue as a going concern or as a consequence of the Bankruptcy Petitions. Deferred Financing Costs. On April 7, 2015, the FASB issued accounting guidance that requires deferred financing costs to be presented as a direct reduction from the related debt liability in the financial statements rather than as a separately recognized asset. Under the new guidance, amortization of such costs will continue to be reported as interest expense. In August 2015, an update was issued that clarified that debt issuance costs associated with line-of-credit arrangements may continue to be reported as an asset. The new guidance became effective retrospectively for interim and annual periods beginning after December 15, 2015 (January 1, 2016 for the Company). There was no material impact to the Company's results of operations or cash flows in connection with the adoption of the guidance. The impact to the Company's consolidated balance sheets as of December 31, 2015 was as follows: Before Application of Accounting Guidance Adjustment After Application of Accounting Guidance (Dollars in millions) Other current assets $ 503.1 $ (55.5 ) $ 447.6 Investments and other assets 382.6 (18.9 ) 363.7 Total assets 11,021.3 (74.4 ) 10,946.9 Current portion of long-term debt 5,930.4 (55.5 ) 5,874.9 Long-term debt, less current portion 385.2 (18.9 ) 366.3 Total liabilities 10,102.8 (74.4 ) 10,028.4 Income Taxes. In November 2015, the FASB issued accounting guidance that requires entities to classify all deferred tax assets and liabilities, along with any related valuation allowance as noncurrent on the balance sheet. Under the new guidance, each jurisdiction will now only have one net noncurrent deferred tax asset or liability. The new guidance does not change the existing requirement that only permits offsetting within a jurisdiction. The new guidance will be effective prospectively or retrospectively for annual periods beginning after December 15, 2016 and interim periods therein, with early adoption permitted. The Company elected early adoption of this guidance effective December 31, 2016 on a prospective basis. There was no material impact to the Company's results of operations, financial condition, cash flows or financial statement presentation in connection with the adoption of the guidance. Compensation - Stock Compensation. In March 2016, the FASB issued accounting guidance which identifies areas for simplification involving several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, an option to recognize gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. The new guidance will be effective prospectively for annual periods beginning after December 15, 2016 and interim periods therein, with early adoption permitted. The Company elected early adoption of this guidance effective December 31, 2016. There was no material impact to the Company's results of operations, financial condition, cash flows or financial statement presentation in connection with the adoption of the guidance. Accounting Standards Not Yet Implemented Revenue Recognition. In May 2014, the FASB issued a comprehensive revenue recognition standard that will supersede nearly all existing revenue recognition guidance under U.S. GAAP. The new standard provides a single principles-based, five-step model to be applied to all contracts with customers, which steps are to (1) identify the contract(s) with the customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract and (5) recognize revenue when each performance obligation is satisfied. More specifically, revenue will be recognized when promised goods or services are transferred to the customer in an amount that reflects the consideration expected in exchange for those goods or services. The standard also requires entities to disclose sufficient qualitative and quantitative information to enable financial statement users to understand the nature, amount, timing and uncertainty of revenues and cash flows arising from contracts with customers. Under the originally issued standard, the new guidance would have been effective for interim and annual periods beginning after December 15, 2016 (January 1, 2017 for the Company). On July 9, 2015, the FASB delayed the effective date of the new revenue recognition standard by one year (January 1, 2018 for the Company) with early adoption permitted, but not before the original effective date. The standard allows for either a full retrospective adoption or a modified retrospective adoption. While the Company is in the process of evaluating the impact that the adoption of this guidance will have on its financial statement presentation, its preliminary assessment is that it will not have a material impact on its results of operations, financial condition or cash flows. Inventory. In July 2015, the FASB issued guidance which requires entities to measure most inventory “at the lower of cost and net realizable value“, thereby simplifying the current guidance under which an entity must measure inventory at the lower of cost or market (market in this context is defined as one of three different measures, one of which is net realizable value). The guidance does not apply to inventories that are measured by using either the last-in, first-out method or the retail inventory method. The new guidance will be effective prospectively for annual periods beginning after December 15, 2016 (January 1, 2017 for the Company), and interim periods therein, with early adoption permitted. While the Company is finalizing its evaluation of the impact that the adoption of this guidance will have, it does not expect a material impact to its results of operations, financial condition, cash flows and financial statement presentation. Lease Accounting. In February 2016, the FASB issued accounting guidance that will require a lessee to recognize in its balance sheet a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term for leases with lease terms of more than 12 months. Consistent with current U.S. GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. Additional qualitative disclosures along with specific quantitative disclosures will also be required. The new guidance will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 (January 1, 2019 for the Company), with early adoption permitted. Upon adoption, the Company will be required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The Company is in the process of evaluating the impact that the adoption of this guidance will have on its results of operations, financial condition, cash flows and financial statement presentation. Financial Instruments - Credit Losses. In June 2016, the FASB issued accounting guidance related to the measurement of credit losses on financial instruments. The pronouncement replaces the incurred loss methodology to record credit losses with a methodology that reflects the expected credit losses for financial assets not accounted for at fair value with gains and losses recognized through net income. This standard is effective for fiscal years beginning after December 15, 2019 (January 1, 2020 for the Company) and interim periods therein,with early adoption permitted for fiscal years, and interim periods therein, beginning after December 15, 2018. The Company is in the process of evaluating the impact that the adoption of this guidance will have on its results of operations, financial condition, cash flows and financial statement presentation. Classification of Certain Cash Receipts and Cash Payments. In August 2016, the FASB issued accounting guidance to amend the classification of certain cash receipts and cash payments in the statement of cash flows to reduce diversity in practice. The new guidance will be effective for fiscal years beginning after December 15, 2017 (January 1, 2018 for the Company) and interim periods therein, with early adoption permitted. The amendments in this update should be applied retrospectively to all periods presented, unless deemed impracticable, in which case, prospective application is permitted. The Company is currently evaluating this guidance and its impact on classification of certain cash receipts and cash payments in the Company's statements of cash flows. Restricted Cash. In November 2016, the FASB issued accounting guidance which will reduce diversity in the presentation of restricted cash and restricted cash equivalents in the statement of cash flows. The new guidance will be effective retrospectively for fiscal years beginning after December 15, 2017 (January 1, 2018 for the Company) and interim periods therein, with early adoption permitted. The Company is currently evaluating this guidance and its impact, if any, on the Company's statements of cash flows. S
Sales and Other Revenues	ales The Company’s revenue from coal sales is realized and earned when risk of loss passes to the customer. Under the typical terms of the Company’s coal supply agreements, title and risk of loss transfer to the customer at the mine or port, where coal is loaded to the transportation source(s) that serves each of the Company’s mines. The Company incurs certain “add-on” taxes and fees on coal sales. Reported coal sales include taxes and fees charged by various federal and state governmental bodies and the freight charged on destination customer contracts. Other Revenues "Other revenues" include net revenues from coal trading activities as discussed in Note 9. "Coal Trading," as well as coal sales revenues that were derived from the Company’s mining operations and sold through the Company’s coal trading business. Also included are revenues from customer contract-related payments, royalties related to coal lease agreements, sales agency commissions, farm income, property and facility rentals and generation development activities. Royalty income generally results from the lease or sublease of mineral rights to third parties, with payments based upon a percentage of the selling price or an amount per ton of coal produced. D
Discontinued Operations and Assets Held for Sale	iscontinued Operations and Assets Held for Sale The Company classifies items within discontinued operations in the consolidated financial statements when the operations and cash flows of a particular component of the Company have been (or will be) eliminated from the ongoing operations of the Company as a result of a disposal (by sale or otherwise) and represents a strategic shift that has (or will have) a major effect on the entity's operations and financial results. Refer to Note 5. "Discontinued Operations" for additional details related to discontinued operations. C
Cash and Cash Equivalents	ash and Cash Equivalents Cash and cash equivalents are stated at cost, which approximates fair value. Cash equivalents consist of highly liquid investments with original maturities of three months or less . I
Inventories	nventories Coal is reported as inventory at the point in time the coal is extracted from the mine. Raw coal represents coal stockpiles that may be sold in current condition or may be further processed prior to shipment to a customer. Saleable coal represents coal stockpiles which require no further processing prior to shipment to a customer. Coal inventory is valued at the lower of average cost or market. Coal inventory costs include labor, supplies, equipment (including depreciation thereto) and operating overhead and other related costs incurred at or on behalf of the mining location. Market represents the estimated net realizable value of the inventory, which considers the projected future sales price of the particular coal product, less applicable selling costs, and, in the case of raw coal, estimated remaining processing costs. The valuation of coal inventory is subject to several additional estimates, including those related to ground and aerial surveys used to measure quantities and processing recovery rates. Materials and supplies inventory is valued at the lower of average cost or market, less a reserve for obsolete or surplus items. This reserve incorporates several factors, such as anticipated usage, inventory turnover and inventory levels. I
Investments in Marketable Securities	nvestments in Marketable Securities The Company’s short-term investments in marketable securities, which are included in "Other current assets" in the consolidated balance sheets, are defined as those investments with original maturities upon purchase of greater than three months and up to one year. Long-term investments, which are included in "Investments and other assets" in the consolidated balance sheets, are defined as those investments with original maturities upon purchase of greater than one year. The Company classifies its investments in debt securities as either held-to-maturity or available-for-sale at the time of purchase and reevaluates such designation periodically. Such investments are classified as held-to-maturity when the Company has the intent and ability to hold the securities to maturity. Investments in debt securities not classified as held-to-maturity and investments in marketable equity securities are classified as available-for-sale. Available-for-sale securities are carried at fair value, with unrealized gains and losses, net of income taxes, generally reported in “Accumulated other comprehensive loss” in the consolidated balance sheets. Realized gains and losses, determined on a specific identification method, are included in “Interest income” in the consolidated statements of operations. At each reporting date, the Company performs separate evaluations of its marketable securities to determine if any unrealized losses present are other-than-temporary. Such evaluations involve the consideration of several factors, including, but not limited to, the length of time the market value has been less than cost, the financial condition and near-term prospects of the issuer of the securities and whether the Company has the positive intent and ability to hold the securities until recovery. No impairment losses were recorded during the years ended December 31, 2016 and 2015. Refer to Note 4. "Asset Impairment" for details regarding other-than-temporary impairment losses of $4.7 million recognized during the year ended December 31, 2014 related to the Company's marketable equity securities holdings.
Property, Plant, Equipment and Mine Development	roperty, Plant, Equipment and Mine Development Property, plant, equipment and mine development are recorded at cost. Interest costs applicable to major asset additions are capitalized during the construction period. Capitalized interest in 2016 , 2015 and 2014 was immaterial. Expenditures which extend the useful lives of existing plant and equipment assets are capitalized. Maintenance and repairs are charged to operating costs as incurred. Costs incurred to develop coal mines or to expand the capacity of operating mines are capitalized. Costs incurred to maintain current production capacity at a mine are charged to operating costs as incurred. Costs to acquire computer hardware and the development and/or purchase of software for internal use are capitalized and depreciated over the estimated useful lives. Coal reserves are recorded at cost, or at fair value in the case of nonmonetary exchanges, of reserves or business acquisitions. Depletion of coal reserves and amortization of advance royalties is computed using the units-of-production method utilizing only proven and probable reserves (as adjusted for recoverability factors) in the depletion base. Mine development costs are principally amortized over the estimated lives of the mines using the straight-line method. Depreciation of plant and equipment is computed using the straight-line method over the shorter of the asset's estimated useful life or the life of the mine. The estimated useful lives by category of assets are as follows: Years Building and improvements 3 to 34 Machinery and equipment 3 to 34 Leasehold improvements Shorter of Useful Life or Remaining Life of Lease E
Equity and Cost Method Investments	quity and Cost Method Investments The Company accounts for its investments in less than majority owned corporate joint ventures under either the equity or cost method. The Company applies the equity method to investments in joint ventures when it has the ability to exercise significant influence over the operating and financial policies of the joint venture. Investments accounted for under the equity method are initially recorded at cost and any difference between the cost of the Company’s investment and the underlying equity in the net assets of the joint venture at the investment date is amortized over the lives of the related assets that gave rise to the difference. The Company’s pro-rata share of the operating results of joint ventures and basis difference amortization is reported in the consolidated statements of operations in “(Gain) loss from equity affiliates.” Similarly, the Company's pro-rata share of the cumulative foreign currency translation adjustment of its equity method investments whose functional currency is not the U.S. dollar is reported in the consolidated balance sheet as a component of "Accumulated other comprehensive loss," with periodic changes thereto reflected in the consolidated statements of comprehensive income. The Company monitors its equity and cost method investments for indicators that a decrease in investment value has occurred that is other than temporary. Examples of such indicators include a sustained history of operating losses and adverse changes in earnings and cash flow outlook. In the absence of quoted market prices for an investment, discounted cash flow projections are used to assess fair value, the underlying assumptions to which are generally considered unobservable Level 3 inputs under the fair value hierarchy. If the fair value of an investment is determined to be below its carrying value and that loss in fair value is deemed other than temporary, an impairment loss is recognized. Refer to Note 4. "Asset Impairment" and Note 7. "Investments" for details regarding other-than-temporary impairment losses of $276.5 million recorded during the year ended December 31, 2015 related to certain of the Company's equity and cost method investments. No such impairment losses were recorded during the years ended December 31, 2016 or 2014.
Asset Retirement Obligations	sset Retirement Obligations The Company’s asset retirement obligation (ARO) liabilities primarily consist of spending estimates for surface land reclamation and support facilities at both surface and underground mines in accordance with applicable reclamation laws and regulations in the U.S. and Australia as defined by each mining permit. The Company estimates its ARO liabilities for final reclamation and mine closure based upon detailed engineering calculations of the amount and timing of the future cash spending for a third party to perform the required work. Spending estimates are escalated for inflation and then discounted at the credit-adjusted, risk-free rate. The Company records an ARO asset associated with the discounted liability for final reclamation and mine closure. The obligation and corresponding asset are recognized in the period in which the liability is incurred. The ARO asset is amortized on the units-of-production method over its expected life and the ARO liability is accreted to the projected spending date. As changes in estimates occur (such as mine plan revisions, changes in estimated costs or changes in timing of the performance of reclamation activities), the revisions to the obligation and asset are recognized at the appropriate credit-adjusted, risk-free rate. The Company also recognizes an obligation for contemporaneous reclamation liabilities incurred as a result of surface mining. Contemporaneous reclamation consists primarily of grading, topsoil replacement and re-vegetation of backfilled pit areas.
Contingent Liabilities	ontingent Liabilities From time to time, the Company is subject to legal and environmental matters related to its continuing and discontinued operations and certain historical, non-coal producing operations. In connection with such matters, the Company is required to assess the likelihood of any adverse judgments or outcomes, as well as potential ranges of probable losses. A determination of the amount of reserves required for these matters is made after considerable analysis of each individual issue. The Company accrues for legal and environmental matters within "Operating costs and expenses" when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. The Company provides disclosure surrounding loss contingencies when it believes that it is at least reasonably possible that a material loss may be incurred or an exposure to loss in excess of amounts already accrued may exist. Adjustments to contingent liabilities are made when additional information becomes available that affects the amount of estimated loss, which information may include changes in facts and circumstances, changes in interpretations of law in the relevant courts, the results of new or updated environmental remediation cost studies and the ongoing consideration of trends in environmental remediation costs. Accrued contingent liabilities exclude claims against third parties and are not discounted. The current portion of these accruals is included in “Accounts payables and accrued expenses” and the long-term portion is included in “Other noncurrent liabilities” in the consolidated balance sheets. In general, legal fees related to environmental remediation and litigation are charged to expense. The Company includes the interest component of any litigation-related penalties within "Interest expense" in the consolidated statements of operations.
Income Taxes	ncome Taxes Income taxes are accounted for using a balance sheet approach. The Company accounts for deferred income taxes by applying statutory tax rates in effect at the reporting date of the balance sheet to differences between the book and tax basis of assets and liabilities. A valuation allowance is established if it is “more likely than not” that the related tax benefits will not be realized. Significant weight is given to evidence that can be objectively verified including history of tax attribute expiration and cumulative income or loss. In determining the appropriate valuation allowance, the Company considers the projected realization of tax benefits based on expected levels of future taxable income, available tax planning strategies, reversals of existing taxable temporary differences and taxable income in carryback years. The Company recognizes the tax benefit from uncertain tax positions only if it is “more likely than not” the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. The tax benefits recognized from such a position are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement . To the extent the Company’s assessment of such tax positions changes, the change in estimate will be recorded in the period in which the determination is made. Tax-related interest and penalties are classified as a component of income tax expense. P
Postretirement Health Care and Life Insurance Benefits and Pension Plans	ostretirement Health Care and Life Insurance Benefits The Company accounts for postretirement benefits other than pensions by accruing the costs of benefits to be provided over the employees’ period of active service. These costs are determined on an actuarial basis. The Company’s consolidated balance sheets reflect the accumulated postretirement benefit obligations of its postretirement benefit plans. The Company accounts for changes in its postretirement benefit obligations as a settlement when an irrevocable action has been effected that relieves the Company of its actuarially-determined liability to individual plan participants and removes substantial risk surrounding the nature, amount and timing of the obligation’s funding and the assets used to effect the settlement. See Note 17. "Postretirement Health Care and Life Insurance Benefits" for information related to postretirement benefits. Pension Plans The Company sponsors non-contributory defined benefit pension plans accounted for by accruing the cost to provide the benefits over the employees’ period of active service. These costs are determined on an actuarial basis. The Company’s consolidated balance sheets reflect the funded status of the defined benefit pension plans. See Note 18. "Pension and Savings Plans" for information related to pension plans.
Restructuring Activities	estructuring Activities 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 market 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. Included as a component of "Restructuring and pension settlement charges" in the Company's consolidated statements of operations for the years ended December 31, 2016, 2015 and 2014 were aggregate restructuring charges of $15.5 million , $23.5 million and $26.0 million , respectively, primarily associated with voluntary and involuntary workforce reductions. The majority of the cash expenditures associated with the charges recognized in 2016 were paid in 2016.
Derivatives	erivatives The Company recognizes at fair value all contracts meeting the definition of a derivative as assets or liabilities in the consolidated balance sheets, with the exception of certain coal trading contracts for which the Company has elected to apply a normal purchases and normal sales exception. With respect to derivatives used in hedging activities, the Company assesses, both at inception and at least quarterly thereafter, whether such derivatives are highly effective at offsetting the changes in the anticipated exposure of the hedged item. The effective portion of the change in the fair value of derivatives designated as a cash flow hedge is recorded in “Accumulated other comprehensive loss” until the hedged transaction impacts reported earnings, at which time any gain or loss is reclassified to earnings. To the extent that periodic changes in the fair value of derivatives deemed highly effective exceeds such changes in the hedged item, the ineffective portion of the periodic non-cash changes are recorded in earnings in the period of the change. If the hedge ceases to qualify for hedge accounting, the Company prospectively recognizes changes in the fair value of the instrument in earnings in the period of the change. The potential for hedge ineffectiveness is present in the design of certain of the Company’s cash flow hedge relationships and is discussed in detail in Note 8. "Derivatives and Fair Value Measurements" and Note 9. "Coal Trading." Gains or losses from derivative financial instruments designated as fair value hedges are recognized immediately in earnings, along with the offsetting gain or loss related to the underlying hedged item. The Company’s asset and liability derivative positions are offset on a counterparty-by-counterparty basis if the contractual agreement provides for the net settlement of contracts with the counterparty in the event of default or termination of any one contract. Non-derivative contracts and derivative contracts for which the Company has elected to apply the normal purchases and normal sales exception are accounted for on an accrual basis. B
Business Combinations	usiness Combinations The Company accounts for business combinations using the purchase method of accounting. The purchase method requires the Company to determine the fair value of all acquired assets, including identifiable intangible assets and all assumed liabilities. The total cost of acquisitions is allocated to the underlying identifiable net assets, based on their respective estimated fair values. Determining the fair value of assets acquired and liabilities assumed requires management's judgment and the utilization of independent valuation experts, and often involves 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.
Impairment of Long-Lived Assets	mpairment of Long-Lived Assets The Company evaluates its long-lived assets held and used in operations for impairment as events and changes in circumstances indicate that the carrying amount of such assets might not be recoverable. Factors that would indicate potential impairment to be present include, but are not limited to, a sustained history of operating or cash flow losses, an unfavorable change in earnings and cash flow outlook, prolonged adverse industry or economic trends and a significant adverse change in the extent or manner in which a long-lived asset is being used or in its physical condition. The Company generally does not view short-term declines in thermal and metallurgical coal prices as a triggering event for conducting impairment tests because of historic price volatility. However, the Company generally does view a sustained trend of depressed coal pricing (for example, over periods exceeding one year) as an indicator of potential impairment. Assets are grouped at the lowest level for which there are identifiable cash flows that are largely independent of the cash flows of other groups of assets. For its active mining operations, the Company generally groups such assets at the mine level, or the mining complex level for mines that share infrastructure, with the exception of impairment evaluations triggered by mine closures. In those cases involving mine closures, the related assets are evaluated at the individual asset level for remaining economic life based on transferability to ongoing operating sites and for use in reclamation-related activities, or for expected salvage. For its development and exploration properties and portfolio of surface land and coal reserve holdings, the Company considers several factors to determine whether to evaluate those assets individually or on a grouped basis for purposes of impairment testing. Such factors include geographic proximity to one another, the expectation of shared infrastructure upon development based on future mining plans and whether it would be most advantageous to bundle such assets in the event of sale to a third party. When indicators of impairment are present, the Company evaluates its long-lived assets for recoverability by comparing the estimated undiscounted cash flows expected to be generated by those assets under various assumptions to their carrying amounts. If such undiscounted cash flows indicate that the carrying value of the asset group is not recoverable, impairment losses are measured by comparing the estimated fair value of the asset group to its carrying amount. As quoted market prices are unavailable for the Company's individual mining operations, fair value is determined through the use of an expected present value technique based on the income approach, except for non-strategic coal reserves, surface lands and undeveloped coal properties excluded from the Company's long-range mine planning. In those cases, a market approach is utilized based on the most comparable market multiples available. The estimated future cash flows and underlying assumptions used to assess recoverability and, if necessary, measure the fair value of the Company's long-lived mining assets are derived from those developed in connection with the Company's planning and budgeting process. The Company believes its assumptions to be consistent with those a market participant would use for valuation purposes. The most critical assumptions underlying the Company's projections and fair value estimates include those surrounding future tons sold, coal prices for unpriced coal, production costs (including costs for labor, commodity supplies and contractors), transportation costs, foreign currency exchange rates and a risk-adjusted, after-tax cost of capital (all of which generally constitute unobservable Level 3 inputs under the fair value hierarchy), in addition to market multiples for non-strategic coal reserves, surface lands and undeveloped coal properties excluded from the Company's long-range mine planning (which generally constitute Level 2 inputs under the fair value hierarchy). Refer to Note 4. "Asset Impairment" for details regarding impairment charges related to long-lived assets of $247.9 million , $1,001.3 million and $149.7 million recognized during the years ended December 31, 2016 , 2015 and 2014 , respectively.
Fair Value	air Value For assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements, the Company defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. F
Foreign Currency	oreign Currency Functional currency is determined by the primary economic environment in which an entity operates, which for the Company's foreign operations is generally the U.S. dollar because sales prices in international coal markets and the Company's sources of financing those operations is denominated in that currency. Accordingly, substantially all of the Company’s consolidated foreign subsidiaries utilize the U.S. dollar as their functional currency. Monetary assets and liabilities are remeasured at year-end exchange rates while non-monetary items are remeasured at historical rates. Income and expense accounts are remeasured at the average rates in effect during the year, except for those expenses related to balance sheet amounts that are remeasured at historical exchange rates. Gains and losses from foreign currency remeasurement related to tax balances are included as a component of "Income tax (benefit) provision," while all other remeasurement gains and losses are included in "Operating costs and expenses." The total impact of foreign currency remeasurement on the consolidated statements of operations was a net loss of $7.4 million , $6.4 million and $1.3 million for the years ended December 31, 2016, 2015 and 2014, respectively. The Company owns a 50% equity interest Middlemount Coal Pty Ltd. (Middlemount), which owns the Middlemount Mine in Queensland, Australia. Middlemount utilizes the Australian dollar as its functional currency. Accordingly, the assets and liabilities of that equity investee are translated to U.S. dollars at the year-end exchange rate and income and expense accounts are translated at the average rate in effect during the year. The Company's pro-rata share of the translation gains and losses of the equity investee are recorded as a component of "Accumulated other comprehensive loss." Australian dollar denominated stockholder loans to the Middlemount Mine, which are long term in nature, are considered part of the Company's net investment in that operation. Accordingly, foreign currency gains or losses on those loans are recorded as a component of foreign currency translation adjustment. The Company recorded foreign currency translation losses of $1.8 million , $34.9 million and $41.0 million for the years ended December 31, 2016, 2015 and 2014, respectively.
Share-Based Compensation	hare-Based Compensation The Company accounts for share-based compensation at the grant date fair value of awards and recognizes the related expense over the service period of the awards. See Note 20. "Share-Based Compensation" for information related to share-based compensation.
Exploration and Drilling Costs	xploration and Drilling Costs Exploration expenditures are charged to operating costs as incurred, including costs related to drilling and study costs incurred to convert or upgrade mineral resources to reserves. A
Advance Stripping Costs	dvance Stripping Costs Pre-production. At existing surface operations, additional pits may be added to increase production capacity in order to meet customer requirements. These expansions may require significant capital to purchase additional equipment, expand the workforce, build or improve existing haul roads and create the initial pre-production box cut to remove overburden (that is, advance stripping costs) for new pits at existing operations. If these pits operate in a separate and distinct area of the mine, the costs associated with initially uncovering coal (that is, advance stripping costs incurred for the initial box cuts) for production are capitalized and amortized over the life of the developed pit consistent with coal industry practices. Post-production. Advance stripping costs related to post-production are expensed as incurred. Where new pits are routinely developed as part of a contiguous mining sequence, the Company expenses such costs as incurred. The development of a contiguous pit typically reflects the planned progression of an existing pit, thus maintaining production levels from the same mining area utilizing the same employee group and equipment.
Use of Estimates in the Preparation of the Consolidated Financial Statements	se of Estimates in the Preparation of the Consolidated Financial Statements

Summary of Significant Accoun42

Summary of Significant Accounting Policies Discussion (Tables)	12 Months Ended
	Dec. 31, 2016
Estimated Useful Life of Property, Plant, Equipment and Mine Development [Line Items]
Estimated useful life of plant and equipment	he estimated useful lives by category of assets are as follows: Years Building and improvements 3 to 34 Machinery and equipment 3 to 34 Leasehold improvements Shorter of Useful Life or Remaining Life of Lease E

Asset Impairment and Mine Clo43

Asset Impairment and Mine Closure Costs (Tables)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Impaired Long-Lived Assets Held and Used [Line Items]
Details of Impairment of Long-Lived Assets Held and Used by Asset [Table Text Block]	The following costs are reflected in "Asset impairment" in the consolidated statement of operations for the year ended December 31, 2016: Reportable Segment Australian Metallurgical Mining Corporate and Other Consolidated (Dollars in millions) Asset impairment charges $ 193.2 $ 54.7 $ 247.9	The following costs are reflected in "Asset impairment" in the consolidated statement of operations for the year ended December 31, 2015: Reportable Segment Australian Metallurgical Mining Australian Thermal Mining Midwestern U.S. Mining Corporate and Other Consolidated (Dollars in millions) Asset impairment charges: Long-lived assets $ 675.2 $ 17.5 $ 40.2 $ 268.4 $ 1,001.3 Equity method investment — — — 276.5 276.5 Total $ 675.2 $ 17.5 $ 40.2 $ 544.9 $ 1,277.8	The following costs are reflected in "Asset impairment" in the consolidated statement of operations for the year ended December 31, 2014: Reportable Segment Australian Metallurgical Mining Australian Thermal Mining Western U.S. Mining Corporate and Other Consolidated (Dollars in millions) Asset impairment charges: Long-lived assets $ 66.7 $ 11.9 $ 2.7 $ 68.4 $ 149.7 Marketable securities — — — 4.7 4.7 Total $ 66.7 $ 11.9 $ 2.7 $ 73.1 $ 154.4

Discontinued Operations Tables

Discontinued Operations Tables (Tables)	12 Months Ended
	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Discontinued Operations Discontinued operations include certain former Australian Thermal Mining and Midwestern U.S. Mining segment assets that have ceased production and other previously divested legacy operations, including Patriot Coal Corporation and certain of its wholly-owned subsidiaries (Patriot). Summarized Results of Discontinued Operations Results from discontinued operations were as follows during the years ended December 31, 2016 , 2015 and 2014 : Year Ended December 31, 2016 2015 2014 (Dollars in millions) Loss from discontinued operations before income taxes $ (57.6 ) $ (182.2 ) $ (23.8 ) Income tax benefit (provision) — 7.2 (4.4 ) Loss from discontinued operations, net of income taxes $ (57.6 ) $ (175.0 ) $ (28.2 ) There were no significant revenues from discontinued operations during the years ended December 31, 2016 , 2015 and 2014. Assets and Liabilities of Discontinued Operations Assets and liabilities classified as discontinued operations included in the Company's consolidated balance sheets were as follows: December 31, 2016 2015 (Dollars in millions) Assets: Other current assets $ 0.2 $ 3.1 Investments and other assets 15.9 13.2 Total assets classified as discontinued operations $ 16.1 $ 16.3 Liabilities: Accounts payable and accrued expenses $ 55.9 $ 60.0 Other noncurrent liabilities 198.5 203.7 Liabilities subject to compromise 20.9 — Total liabilities classified as discontinued operations $ 275.3 $ 263.7 Patriot-Related Matters. Included in "Loss from discontinued operations, net of income taxes" for the year ended December 31, 2016, is a charge of $54.3 million for the UMWA 1974 Pension Plan related to the settlement of litigation. Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" for information surrounding charges recorded during the years ended December 31, 2016 and 2015 associated with the bankruptcy of Patriot. Wilkie Creek Mine. In December 2013, the Company ceased production and started reclamation of the Wilkie Creek Mine in Queensland, Australia. On June 30, 2014, Queensland Bulk Handling Pty Ltd (QBH) commenced litigation against Peabody (Wilkie Creek) Pty Limited, the indirect wholly-owned subsidiary of the Company that owns the Wilkie Creek Mine, alleging breach of a Coal Port Services Agreement (CPSA) between the parties. Included in "Loss from discontinued operations, net of income taxes" for the year ended December 31, 2015 is a $9.7 million charge related to the settlement of that litigation. In September 2016, a settlement was reached under which the Company agreed to pay $13.0 million Australian dollars ( $9.9 million USD) to QBH in a full and final settlement of all claims each party had against the other in relation to the CPSA litigation. Refer to Note 26. "Commitments and Contingencies" for additional information surrounding the QBH matter.
Results of discontinued operations [Table Text Block]	Results from discontinued operations were as follows during the years ended December 31, 2016 , 2015 and 2014 : Year Ended December 31, 2016 2015 2014 (Dollars in millions) Loss from discontinued operations before income taxes $ (57.6 ) $ (182.2 ) $ (23.8 ) Income tax benefit (provision) — 7.2 (4.4 ) Loss from discontinued operations, net of income taxes $ (57.6 ) $ (175.0 ) $ (28.2 )

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories as of December 31, 2016 and December 31, 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) Materials and supplies $ 104.5 $ 115.9 Raw coal 29.6 75.9 Saleable coal 69.6 116.0 Total $ 203.7 $ 307.8

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investments in available-for-sale securities		s
Equity Method Investments [Table Text Block]	The table below summarizes the book value of those investments, which is reported in “Investments and other assets” in the consolidated balance sheets, and the related (income) loss from equity affiliates: Book Value at December 31, (Income) Loss from Equity Affiliates for the Year Ended December 31, 2016 2015 2016 2015 2014 (Dollars in millions) Equity interest in Middlemount Coal Pty Ltd $ — $ — $ (22.6 ) $ 7.0 $ 98.5 Other equity method investments 0.5 1.5 6.4 8.9 9.1 Total equity method investments $ 0.5 $ 1.5 $ (16.2 ) $ 15.9 $ 107.6

Derivatives and Fair Value Me47

Derivatives and Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The following table summarizes the changes related to the Company’s Corporate Hedging derivative financial instruments recurring Level 3 financial liabilities: Year Ended December 31, 2016 Commodity Contracts Foreign Currency Contracts Total (Dollars in millions) Beginning of period $ 123.7 $ 200.7 $ 324.4 Total net losses realized/unrealized: Included in earnings 15.7 (48.0 ) (32.3 ) Settlements / terminations (139.4 ) (152.7 ) (292.1 ) End of period $ — $ — $ —
Non Coal Trading [Member]
Derivative [Line Items]
Classification and amounts of pre-tax gains and losses related to the Company's non-trading hedges	The tables below show the classification and amounts of pre-tax gains and losses related to the Company’s Corporate Hedging derivatives during the years ended December 31, 2016 , 2015 and 2014 : Year Ended December 31, 2016 Income Statement Classification Total realized loss recognized in income Loss (1) (Loss) gain recognized in income on derivatives Financial Instrument (Dollars in millions) Commodity swap contracts Operating costs and expenses $ (98.0 ) $ (86.1 ) $ (11.9 ) Commodity swap contracts Reorganization items, net (38.8 ) — (38.8 ) Foreign currency forward contracts Operating costs and expenses (142.9 ) (145.6 ) 2.7 Foreign currency forward contracts Reorganization items, net (36.4 ) — (36.4 ) Total $ (316.1 ) $ (231.7 ) $ (84.4 ) (1) Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $13.6 million and $9.0 million of previously unrecognized losses on foreign currency and fuel contracts, respectivley, monetized in first quarter of 2016. Year Ended December 31, 2015 Income Statement Classification Loss recognized in other comprehensive income on derivative (effective portion) Loss reclassified from other comprehensive income into income (effective portion) (1) Loss reclassified from other comprehensive income into income (ineffective portion) Financial Instrument (Dollars in millions) Commodity swap contracts Operating costs and expenses $ (77.0 ) $ (122.0 ) $ 1.6 Foreign currency forward contracts Operating costs and expenses (122.0 ) (316.4 ) — Total $ (199.0 ) $ (438.4 ) $ 1.6 (1) Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $14.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012. Year Ended December 31, 2014 Income Statement Classification Losses - Realized Loss recognized in other comprehensive income on derivative (effective portion) Loss reclassified from other comprehensive income into income (effective portion) (1) Loss reclassified from other comprehensive income into income (ineffective portion) Financial Instrument (Dollars in millions) Commodity swap contracts Operating costs and expenses $ (194.5 ) $ (20.6 ) $ (1.7 ) Foreign currency forward contracts Operating costs and expenses (100.9 ) (27.3 ) — Total $ (295.4 ) $ (47.9 ) $ (1.7 )
Classification and amount of non-coal trading derivatives, gross and net basis	Fair Value of Liabilities Presented in the Consolidated Balance Sheet as of December 31, 2015 (1) Financial Instrument (Dollars in millions) Current Liabilities: Commodity swap contracts $ 86.1 Foreign currency forward contracts 145.6 Total $ 231.7 Noncurrent Liabilities: Commodity swap contracts $ 37.6 Foreign currency forward contracts 55.1 Total $ 92.7 (1) All commodity swap contracts and foreign currency forward contracts were in a liability position as of December 31, 2015.
Fair value measured on recurring basis of net financial assets and liabilities	Financial Instruments Measured on a Recurring Basis. The following tables set forth the hierarchy of the Company’s net financial (liability) asset positions for which fair value is measured on a recurring basis: December 31, 2015 Level 1 Level 2 Level 3 Total (Dollars in millions) Investments in debt and equity securities $ — $ — $ — $ — Commodity swap contracts — — (123.7 ) (123.7 ) Foreign currency forward contracts — — (200.7 ) (200.7 ) Total net financial liabilities $ — $ — $ (324.4 ) $ (324.4 )
Carrying amounts and estimated fair values of the Company's debt	December 31, 2015 Carrying Amount Estimated Fair Value (Dollars in millions) Current and Long-term debt $ 6,241.2 $ 1,373.7

Coal Trading (Tables)

Coal Trading (Tables) - Coal Trading [Member]	12 Months Ended
	Dec. 31, 2016
Coal Trading [Line Items]
Trading revenue by type of instrument	Trading revenues recognized during the years ended December 31, 2016 , 2015 and 2014 were as follows: Year Ended December 31, Trading Revenues by Type of Instrument 2016 2015 2014 (Dollars in millions) Commodity futures, swaps and options $ (96.5 ) $ 107.3 $ 92.3 Physical commodity purchase/sale contracts 85.6 (64.5 ) (33.9 ) Total trading revenues $ (10.9 ) $ 42.8 $ 58.4
Fair value of assets and liabilities from coal trading activities and related balance sheet offsetting disclosures	The fair value of assets and liabilities from coal trading activities presented on a gross and net basis as of December 31, 2016 and 2015 is set forth below: Affected line item in the consolidated balance sheets Gross Amounts of Recognized Assets (Liabilities) Gross Amounts Offset in the Consolidated Balance Sheets Variation margin (held) posted (1) Net Amounts of Assets (Liabilities) Presented in the Consolidated Balance Sheets (Dollars in millions) Fair Value as of December 31, 2016 Assets from coal trading activities, net $ 191.2 $ (190.5 ) $ — $ 0.7 Liabilities from coal trading activities, net (249.1 ) 190.5 57.4 (1.2 ) Total, net $ (57.9 ) $ — $ 57.4 $ (0.5 ) Fair Value as of December 31, 2015 Assets from coal trading activities, net $ 128.6 $ (87.3 ) $ (17.8 ) $ 23.5 Liabilities from coal trading activities, net (110.0 ) 87.3 7.1 (15.6 ) Total, net $ 18.6 $ — $ (10.7 ) $ 7.9 (1) None of the net variation margin (held) posted at December 31, 2016 and 2015 , respectively, related to cash flow hedges.
Fair value coal trading net assets (liabilities) measured on recurring basis	The following tables set forth the hierarchy of the Company’s net financial asset (liability) coal trading positions for which fair value is measured on a recurring basis as of December 31, 2016 and 2015 : December 31, 2016 Level 1 Level 2 Level 3 Total (Dollars in millions) Commodity futures, swaps and options $ — $ (0.1 ) $ — $ (0.1 ) Physical commodity purchase/sale contracts — 0.7 (1.1 ) (0.4 ) Total net financial assets (liabilities) $ — $ 0.6 $ (1.1 ) $ (0.5 ) December 31, 2015 Level 1 Level 2 Level 3 Total (Dollars in millions) Commodity futures, swaps and options $ — $ 3.3 $ — $ 3.3 Physical commodity purchase/sale contracts — 20.2 (15.6 ) 4.6 Total net financial assets (liabilities) $ — $ 23.5 $ (15.6 ) $ 7.9
Schedule of quantitative unobservable inputs, physical commodity purchase/sale contracts	The following table summarizes the quantitative unobservable inputs utilized in the Company's internally-developed valuation models for physical purchase/sale contracts classified as Level 3 as of December 31, 2016 : Range Weighted Input Low High Average Quality adjustments 2 % 2 % 2 % Credit and non-performance risk 26 % 26 % 26 %
Change in the Company's recurring Level 3 net financial assets	The following table summarizes the changes in the Company’s recurring Level 3 net financial assets: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Beginning of period $ (15.6 ) $ 2.1 $ 2.1 Transfers into Level 3 5.3 (4.4 ) — Transfers out of Level 3 (0.4 ) — — Total gains realized/unrealized: Included in earnings (2.4 ) (10.1 ) 6.7 Purchases — (0.5 ) — Sales — (0.1 ) — Settlements 12.0 (2.6 ) (6.7 ) End of period $ (1.1 ) $ (15.6 ) $ 2.1
Changes in unrealized gains (losses) relating to Level 3 net financial assets	The following table summarizes the changes in net unrealized (losses) gains relating to Level 3 net financial assets held both as of the beginning and the end of the period: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Changes in unrealized (losses) gains (1) $ — $ (6.2 ) $ 2.1 (1) Within the consolidated statements of operations and consolidated statements of comprehensive income for the periods presented, unrealized gains and losses from Level 3 items are combined with unrealized gains and losses on positions classified in Level 1 or 2, as well as other positions that have been realized during the applicable periods.
Schedule of future realization of the Company's trading portfolio	As of December 31, 2016 , the estimated future realization of the value of the Company’s trading portfolio is expected to all be realized in 2017.

Financing Receivables Financing

Financing Receivables Financing Receivables (Tables)	12 Months Ended
	Dec. 31, 2016
Financing Receivables [Line Items]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]	The Company's total financing receivables as of December 31, 2016 and 2015 consisted of the following: December 31, Balance Sheet Classification 2016 2015 (Dollars in millions) Other current assets $ — $ 20.0 Investments and other assets 84.8 65.2 Total financing receivables $ 84.8 $ 85.2

Property, Plant, Equipment an50

Property, Plant, Equipment and Mine Development (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant, Equipment and Mine Development [Abstract]
Property, Plant and Equipment [Table Text Block]	Property, plant, equipment and mine development, net, as of December 31, 2016 and December 31, 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) Land and coal interests $ 10,330.8 $ 10,503.7 Buildings and improvements 1,507.6 1,506.0 Machinery and equipment 2,130.2 2,280.4 Less: Accumulated depreciation, depletion and amortization (5,191.9 ) (5,031.6 ) Total, net $ 8,776.7 $ 9,258.5

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Loss from continuing operations before income taxes	Loss from continuing operations before income taxes for the years ended December 31, 2016, 2015 and 2014 consisted of the following: Year Ended December 31, 2016 2015 2014 (Dollars in millions) U.S. $ (49.7 ) $ (515.9 ) $ 268.9 Non-U.S. (708.6 ) (1,474.4 ) (816.8 ) Total $ (758.3 ) $ (1,990.3 ) $ (547.9 )
Components of income tax provision (benefit)	Total income tax (benefit) provision for the years ended December 31, 2016, 2015 and 2014 consisted of the following: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Current: U.S. federal $ (12.4 ) $ (71.9 ) $ 27.1 Non-U.S. 14.4 3.7 (61.1 ) State 0.5 (0.6 ) 3.3 Total current 2.5 (68.8 ) (30.7 ) Deferred: U.S. federal (82.1 ) (117.4 ) 111.0 Non-U.S. (2.3 ) 15.7 122.3 State (2.1 ) (5.9 ) (1.4 ) Total deferred (86.5 ) (107.6 ) 231.9 Total income tax (benefit) provision $ (84.0 ) $ (176.4 ) $ 201.2
Reconciliation of the expected statutory federal income tax provision (benefit) to the Company's actual income tax provision	The following is a reconciliation of the expected statutory federal income tax benefit to the Company’s income tax (benefit) provision for the years ended December 31, 2016, 2015 and 2014: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Expected income tax benefit at U.S. federal statutory rate $ (265.4 ) $ (696.6 ) $ (191.7 ) Changes in valuation allowance, income tax 2,462.8 462.0 569.4 Worthless partnership (2,204.4 ) — — Changes in tax reserves 2.3 (21.4 ) (81.5 ) Excess depletion (37.2 ) (53.7 ) (65.3 ) Foreign earnings repatriation — — (71.4 ) Foreign earnings provision differential 27.5 146.5 28.8 General business tax credits (14.2 ) (15.7 ) (19.2 ) Minerals resource rent tax, net of federal tax — — 16.1 Remeasurement of foreign income tax accounts (0.4 ) (0.5 ) (2.7 ) State income taxes, net of federal tax benefit (90.2 ) (20.1 ) (2.3 ) Reorganization costs 29.6 — — Other, net 5.6 23.1 21.0 Total income tax (benefit) provision $ (84.0 ) $ (176.4 ) $ 201.2
Tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities	The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities as of December 31, 2016 and 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) Deferred tax assets: Tax loss carryforwards and credits $ 4,284.4 $ 1,817.4 Accrued postretirement benefit obligations 364.5 372.4 Asset retirement obligations 163.6 160.9 Financial guarantees 77.9 16.9 Employee benefits 57.0 69.6 Payable to voluntary employee beneficiary association for certain Patriot retirees (1) — 52.9 Hedge activities 21.0 26.6 Workers’ compensation obligations 7.5 13.7 Other 2.1 66.7 Total gross deferred tax assets 4,978.0 2,597.1 Deferred tax liabilities: Property, plant, equipment and mine development, principally due to differences in depreciation, depletion and asset impairments 900.4 966.6 Unamortized discount on Convertible Junior Subordinated Debentures 127.7 130.3 Investments and other assets 86.3 70.1 Total gross deferred tax liabilities 1,114.4 1,167.0 Valuation allowance, income tax (3,881.2 ) (1,447.3 ) Net deferred tax liability $ (17.6 ) $ (17.2 ) Deferred taxes are classified as follows: Current deferred income taxes $ — $ 49.7 Noncurrent deferred income taxes (17.6 ) (66.9 ) Net deferred tax liability $ (17.6 ) $ (17.2 ) (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction.
Summary of Income Tax Contingencies [Table Text Block]	Net unrecognized tax benefits (excluding interest and penalties) were recorded as follows in the consolidated balance sheets as of December 31, 2016 and 2015: December 31, 2016 2015 (Dollars in millions) Deferred income taxes $ 8.9 $ 7.9 Other noncurrent liabilities 11.2 11.7 Net unrecognized tax benefits $ 20.1 $ 19.6 Gross unrecognized tax benefits $ 20.1 $ 22.9
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for the years ended December 31, 2016, 2015 and 2014 is as follows: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Balance at beginning of period $ 22.9 $ 44.5 $ 143.9 Additions for current year tax positions 1.5 2.3 12.0 Reductions for prior year tax positions (2.8 ) (23.5 ) — Reductions for settlements with tax authorities (1.5 ) (0.4 ) (111.4 ) Balance at end of period $ 20.1 $ 22.9 $ 44.5
Summary of Companys tax (refunds) payments	The following table summarizes the Company’s income tax refunds, net for the years ended December 31, 2016, 2015 and 2014: Year Ended December 31, 2016 2015 2014 (Dollars in millions) U.S. — federal $ (56.5 ) $ (38.1 ) $ (7.7 ) U.S. — state and local 1.4 0.4 (6.8 ) Non-U.S. 15.0 11.9 (2.2 ) Total income tax refunds, net $ (40.1 ) $ (25.8 ) $ (16.7 )

Accounts Payable and Accrued 52

Accounts Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts payable and accrued expenses	Accounts payable and accrued expenses consisted of the following: December 31, 2016 2015 (Dollars in millions) Trade accounts payable $ 288.6 $ 333.3 Accrued payroll and related benefits 201.2 191.9 Other accrued expenses 190.1 225.8 Accrued taxes other than income 119.6 135.9 Accrued royalties 62.8 41.0 Asset retirement obligations 41.0 25.5 Accrued health care insurance 16.0 15.8 Workers’ compensation obligations 7.8 8.6 Income taxes payable 6.2 6.8 Accrued interest 1.2 68.8 Accrued environmental cleanup-related costs — 23.9 Other — 2.3 Payable to voluntary employee beneficiary associated for certain Patriot retirees (1) — 75.0 Commodity and foreign currency hedge contracts — 231.7 Liabilities associated with discontinued operations 55.9 60.0 Total accounts payable and accrued expenses $ 990.4 $ 1,446.3 (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Long-Term Debt	The Company’s total indebtedness as of December 31, 2016 and 2015 consisted of the following: December 31, 2016 2015 (Dollars in millions) 2013 Revolver $ 1,558.1 $ — 2013 Term Loan Facility due September 2020 1,154.5 1,156.3 6.00% Senior Notes due November 2018 1,509.9 1,508.9 6.50% Senior Notes due September 2020 645.8 645.5 6.25% Senior Notes due November 2021 1,327.7 1,327.0 10.00% Senior Secured Second Lien Notes due March 2022 962.3 960.4 7.875% Senior Notes due November 2026 245.9 245.8 Convertible Junior Subordinated Debentures due December 2066 367.1 366.3 Capital lease obligations 19.7 30.3 Other 0.4 0.7 7,791.4 6,241.2 Less: Current portion of long-term debt 20.2 5,874.9 Less: Liabilities subject to compromise 7,771.2 — Long-term debt $ — $ 366.3

Leases Leases (Tables)

Leases Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Operating Leased Assets [Line Items]
Leases And Royalty Future Minimum Payments [Table Text Block]	Future minimum lease and royalty payments as of December 31, 2016 are as follows: Capital Leases Operating Leases Coal Lease and Royalty Obligations Year Ending December 31, (Dollars in millions) 2017 $ 7.3 $ 148.7 $ 6.1 2018 8.9 100.4 5.7 2019 0.5 60.2 5.2 2020 0.5 26.4 4.9 2021 0.5 10.6 5.3 2022 and thereafter 9.6 26.6 26.6 Total minimum lease payments 27.3 $ 372.9 $ 53.8 Less interest 7.6 Present value of minimum capital lease payments $ 19.7

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2016
Asset Retirement Obligation Disclosure [Abstract]
Reconciliations of the Company's ARO liability	Reconciliations of the Company’s asset retirement obligations are as follows: December 31, 2016 2015 (Dollars in millions) Balance at beginning of year $ 712.1 $ 752.5 Liabilities incurred or acquired — 1.3 Liabilities settled or disposed (41.5 ) (53.3 ) Accretion expense 45.7 42.7 Revisions to estimates 42.5 (31.1 ) Balance at end of year $ 758.8 $ 712.1 Less: Current portion (included in "Accounts payable and accrued expenses") 41.0 25.5 Noncurrent obligation (included in "Asset retirement obligations") $ 717.8 $ 686.6 Balance at end of year — active locations $ 651.1 $ 656.8 Balance at end of year — closed or inactive locations $ 107.7 $ 55.3

Postretirement Health Care an56

Postretirement Health Care and Life Insurance Benefits (Tables) - Postretirement Health Care and Life Insurance Benefits [Member]	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Components of net periodic postretirement benefit cost	Net periodic postretirement benefit cost included the following components: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Service cost for benefits earned $ 10.4 $ 11.2 $ 12.2 Interest cost on accumulated postretirement benefit obligation 34.5 33.8 36.4 Amortization of prior service (credit) cost (9.2 ) (6.8 ) 1.3 Amortization of actuarial loss 20.4 24.9 14.5 Special termination benefits (1) — — 1.6 Net periodic postretirement benefit cost $ 56.1 $ 63.1 $ 66.0 (1) Reflected in "Restructuring and pension settlement charges" in the consolidated statement of operations for the year ended December 31, 2014.
Amounts recognized in accumulated other comprehensive loss	The following includes pre-tax amounts recorded in "Accumulated other comprehensive loss": Year Ended December 31, 2016 2015 2014 (Dollars in millions) Net actuarial loss (gain) arising during year $ 32.3 $ (35.1 ) $ 115.8 Prior service credit arising during year — — (18.0 ) Amortization: Actuarial loss (20.4 ) (24.9 ) (14.5 ) Prior service credit (cost) 9.2 6.8 (1.3 ) Settlement related to the Patriot bankruptcy: (1) Prior service cost 7.2 (16.6 ) — Total recorded in "Accumulated other comprehensive loss" $ 28.3 $ (69.8 ) $ 82.0 (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction.
Reconciled amount of plan's funded status	The following table sets forth the plans' funded status reconciled with the amounts shown in the consolidated balance sheets: December 31, 2016 2015 (Dollars in millions) Change in benefit obligation: Accumulated postretirement benefit obligation at beginning of period $ 776.1 $ 839.1 Service cost 10.4 11.2 Interest cost 34.5 33.8 Participant contributions 0.6 1.7 Plan changes (1) 7.2 (16.6 ) Benefits paid (49.0 ) (46.5 ) Actuarial loss (gain) 32.3 (35.1 ) Settlement related to the Patriot bankruptcy (1) — (15.2 ) Other — 3.7 Accumulated postretirement benefit obligation at end of period 812.1 776.1 Change in plan assets: Fair value of plan assets at beginning of period — — Employer contributions 48.4 44.8 Participant contributions 0.6 1.7 Benefits paid and administrative fees (net of Medicare Part D reimbursements) (49.0 ) (46.5 ) Fair value of plan assets at end of period — — Funded status at end of year (812.1 ) (776.1 ) Less: Current portion (included in "Accounts payable and accrued expenses") 55.8 53.2 Noncurrent obligation (included in "Accrued postretirement benefit costs") $ (756.3 ) $ (722.9 ) (1) Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to the changes in the benefit obligation.
Weighted-average assumptions used to determine the benefit obligations	The weighted-average assumptions used to determine the benefit obligations as of the end of each year were as follows: December 31, 2016 2015 Discount rate 4.15 % 4.50 % Measurement date December 31, 2016 December 31, 2015 The weighted-average assumptions used to determine net periodic benefit cost during each year were as follows: Year Ended December 31, 2016 2015 2014 Discount rate 4.50 % 4.10 % 4.90 % Measurement date December 31, 2015 December 31, 2014 December 31, 2013
Assumed health care cost trend rate	The following presents information about the assumed health care cost trend rate: Year Ended December 31, 2016 2015 Pre-Medicare: Health care cost trend rate assumed for next year 6.20 % 6.60 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 4.75 % 4.75 % Year that the rate reaches the ultimate trend rate 2021 2021 Post-Medicare: Health care cost trend rate assumed for next year 5.60 % 5.80 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 4.75 % 4.75 % Year that the rate reaches the ultimate trend rate 2021 2021
Assumed health care cost trend rates, one percentage point increase	A one-percentage-point change in the assumed health care cost trend would have the following effects: One Percentage- Point Increase One Percentage- Point Decrease (Dollars in millions) Effect on total service and interest cost components (1) $ 3.6 $ (3.2 ) Effect on total postretirement benefit obligation (1) $ 67.0 $ (61.9 ) (1) In addition to the effect on total service and interest cost components of expense, changes in trend rates would also increase or decrease the actuarial gain or loss amortization expense component. The impact on actuarial gain or loss amortization would approximate the increase or decrease in the obligation divided by 10.31 years at January 1, 2017.
Summary of estimated future benefit payments	The following benefit payments (net of retiree contributions), which reflect expected future service, as appropriate, are expected to be paid by the Company: Postretirement Benefits (Dollars in millions) 2017 $ 55.0 2018 56.2 2019 57.0 2020 57.5 2021 61.3 Years 2022-2026 290.3

Pension and Savings Plans (Tabl

Pension and Savings Plans (Tables) - Pension Plans, Defined Benefit [Member]	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic pension cost	Net periodic pension cost included the following components: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Service cost for benefits earned $ 2.5 $ 2.7 $ 2.1 Interest cost on projected benefit obligation 41.5 40.4 45.4 Expected return on plan assets (45.3 ) (48.2 ) (54.3 ) Amortization of prior service cost 0.3 1.0 1.3 Amortization of net actuarial losses 24.7 39.6 30.2 Settlement charge — — 8.7 Net periodic pension cost $ 23.7 $ 35.5 $ 33.4
Amounts recognized in accumulated other comprehensive loss	The following includes pre-tax amounts recorded in "Accumulated other comprehensive loss": Year Ended December 31, 2016 2015 2014 (Dollars in millions) Net actuarial loss arising during year $ 6.6 $ 30.6 $ 79.2 Amortization: Net actuarial loss (24.7 ) (39.6 ) (30.2 ) Prior service cost (0.3 ) (1.0 ) (1.3 ) Settlement charge — — (8.7 ) Total recorded in "Accumulated other comprehensive loss" $ (18.4 ) $ (10.0 ) $ 39.0
Summary of change in benefit obligation, change in plan assets and funded status	The following summarizes the change in benefit obligation, change in plan assets and funded status of the Pension Plans: December 31, 2016 2015 (Dollars in millions) Change in benefit obligation: Projected benefit obligation at beginning of period $ 939.3 $ 1,002.5 Service cost 2.5 2.7 Interest cost 41.5 40.4 Benefits paid (61.1 ) (62.6 ) Actuarial loss (gain) 37.1 (43.7 ) Projected benefit obligation at end of period 959.3 939.3 Change in plan assets: Fair value of plan assets at beginning of period 757.3 839.8 Actual return (loss) on plan assets 75.7 (26.1 ) Employer contributions 1.1 6.2 Benefits paid (61.1 ) (62.6 ) Fair value of plan assets at end of period 773.0 757.3 Funded status at end of year $ (186.3 ) $ (182.0 ) Amounts recognized in the consolidated balance sheets: Current obligation (included in "Accounts payable and accrued expenses") $ — $ (1.6 ) Noncurrent obligation (included in "Other noncurrent liabilities") (163.5 ) (180.4 ) Liabilities subject to compromise (22.8 ) — Net amount recognized $ (186.3 ) $ (182.0 )
Weighted-average assumptions used to determine benefit obligations	The weighted-average assumptions used to determine the benefit obligations as of the end of each year were as follows: December 31, 2016 2015 Discount rate 4.15 % 4.55 % Measurement date December 31, 2016 December 31, 2015
Weighted-average assumptions used to determine net periodic benefit cost	The weighted-average assumptions used to determine net periodic benefit cost during each year were as follows: Year Ended December 31, 2016 2015 2014 Discount rate 4.55 % 4.15 % 4.95 % Expected long-term return on plan assets 6.00 % 6.25 % 6.85 % Measurement date December 31, 2015 December 31, 2014 December 31, 2013
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy	The following tables present the fair value of assets in the Master Trust by asset category and by fair value hierarchy: December 31, 2016 Level 1 Level 2 Level 3 Total (Dollars in millions) Mutual funds $ 119.9 $ — $ — $ 119.9 Corporate bonds — 265.7 — 265.7 U.S. government securities 25.1 22.7 — 47.8 International government securities — 12.6 — 12.6 Cash funds 17.8 — — 17.8 Real estate investment trusts — — 14.1 14.1 Total assets at fair value $ 162.8 $ 301.0 $ 14.1 477.9 Assets measured at net asset value practical expedient (1) Private mutual funds 186.1 Common collective trusts 109.0 295.1 Total plan assets $ 773.0 December 31, 2015 Level 1 Level 2 Level 3 Total (Dollars in millions) Mutual funds $ 107.1 $ — $ — $ 107.1 Corporate bonds — 259.4 — 259.4 U.S. government securities 26.8 26.6 — 53.4 International government securities — 15.0 — 15.0 Cash funds 18.2 — — 18.2 Real estate investment trusts — — 23.0 23.0 Total assets at fair value $ 152.1 $ 301.0 $ 23.0 476.1 Assets measured at net asset value practical expedient (1) Private mutual funds 183.9 Common collective trusts 97.3 281.2 Total plan assets $ 757.3 (1) In accordance with Accounting Standards Update 2015-07, investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the total value of assets of the plans.
Summary of changes in the fair value of the Master Trust's Level 3 investments	The table below sets forth a summary of changes in the fair value of the Master Trust’s Level 3 investments: Year Ended December 31, 2016 2015 (Dollars in millions) Balance, beginning of year $ 23.0 $ 30.2 Realized gains 1.8 3.2 Unrealized gains relating to investments still held at the reporting date 0.2 0.2 Purchases, sales and settlements, net (10.9 ) (10.6 ) Balance, end of year $ 14.1 $ 23.0
Summary of estimated future benefit payments	The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid in connection with the Company's benefit obligation: Pension Benefits (Dollars in millions) 2017 $ 61.7 2018 62.3 2019 62.2 2020 64.0 2021 65.1 Years 2022-2026 312.4

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity (Tables) [Abstract]
Summary of common stock activity	The following table summarizes common stock activity from January 1, 2014 to December 31, 2016 : 2016 2015 2014 (In millions) Shares outstanding at the beginning of the year 18.5 18.1 18.0 Stock grants to employees — 0.2 0.1 Performance share contribution 401k — 0.2 — Shares outstanding at the end of the year 18.5 18.5 18.1

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Share-based compensation expense recorded in 'Selling and administrative expenses'	Share-based compensation expense and cash flow amounts were as follows: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Share-based compensation expense - equity classified awards $ 11.3 $ 26.2 $ 46.1 Share-based compensation expense - liability classified awards 1.5 2.0 0.7 Total share-based compensation expense 12.8 28.2 46.8 Tax benefit — — 17.3 Share-based compensation expense, net of tax benefit $ 12.8 $ 28.2 $ 29.5 Cash received upon the exercise of stock options and from employee stock purchases — 3.4 5.5 Write-off tax benefits related to share-based compensation — — (8.3 )
Summary of restricted stock award activity	A summary of restricted stock award activity is as follows: Year Ended December 31, 2016 Weighted Average Grant-Date Fair Value Nonvested at December 31, 2015 306,931 $ 184.09 Granted 7,847 7.75 Vested (76,663 ) 277.28 Forfeited (30,076 ) 167.68 Canceled (11,295 ) 82.49 Nonvested at December 31, 2016 196,744 $ 151.72
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]	A summary of restricted stock unit activity is as follows: Year Ended December 31, 2016 Weighted Average Grant-Date Fair Value Nonvested at December 31, 2015 48,780 $ 170.42 Granted 342,627 7.75 Vested (23,220 ) 149.84 Forfeited (59,629 ) 22.41 Nonvested at December 31, 2016 308,558 $ 16.98
Schedule of Share-based Compensation, Stock Options, Activity	A summary of outstanding option activity under the plans is as follows: Year Ended December 31, 2016 Weighted Average Exercise Price Weighted Average Remaining Contractual Life Aggregate Intrinsic Value (in millions) Options Outstanding at December 31, 2015 240,428 $ 388.16 6.28 $ — Forfeited (22,182 ) 419.40 Options Outstanding at December 31, 2016 218,246 $ 379.17 5.56 $ — Vested and Exercisable 162,402 $ 451.88 4.86 $ —
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The weighted-average fair values of the Company’s stock options and the assumptions used in applying the Black-Scholes option pricing model were as follows: Year Ended December 31, 2015 2014 Weighted-average fair value $ 43.66 $ 110.70 Risk-free interest rate 1.7 % 1.7 % Expected option life 5 years 5 years Expected volatility 45.2 % 48.4 % Dividend yield 2.4 % 1.7 %
Summary of performance unit activity	A summary of performance unit activity is as follows: Year Ended December 31, 2016 Weighted Average Remaining Contractual Life Nonvested at December 31, 2015 81,812 1.7 Forfeited (5,916 ) Vested (24,474 ) Nonvested at December 31, 2016 51,422 1.0
Assumptions used in the valuations for grants	The assumptions used in the valuations for grants were as follows: Year Ended December 31, 2015 2014 Risk-free interest rate 1.1 % 0.8 % Expected volatility 45.0 % 45.3 % Dividend yield 2.4 % 1.7 %

Accumulated Other Comprehensi60

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2016
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
After-tax components of comprehensive income (loss)	The following table sets forth the after-tax components of comprehensive loss: Foreign Currency Translation Adjustment Net Actuarial Loss Associated with Postretirement Plans and Workers’ Compensation Obligations Prior Service Credit (Cost) Associated with Postretirement Plans Cash Flow Hedges Available-For-Sale Securities Total Accumulated Other Comprehensive Loss (Dollars in millions) December 31, 2013 $ (70.5 ) $ (205.8 ) $ 12.0 $ (155.7 ) $ 0.8 $ (419.2 ) Net change in fair value — — — (195.0 ) (3.7 ) (198.7 ) Reclassification from other comprehensive income to earnings — 31.0 1.7 (10.2 ) 2.9 25.4 Current period change (41.0 ) (142.7 ) 11.4 — — (172.3 ) December 31, 2014 (111.5 ) (317.5 ) 25.1 (360.9 ) — (764.8 ) Net change in fair value — — — (131.3 ) — (131.3 ) Reclassification from other comprehensive income to earnings — 35.6 (3.7 ) 251.7 — 283.6 Current period change (34.9 ) 18.1 10.4 — — (6.4 ) December 31, 2015 (146.4 ) (263.8 ) 31.8 (240.5 ) — (618.9 ) Net change in fair value — — — — — — Reclassification from other comprehensive income to earnings — 21.0 (5.6 ) 146.3 — 161.7 Current period change (1.8 ) (13.5 ) (4.5 ) — — (19.8 ) December 31, 2016 $ (148.2 ) $ (256.3 ) $ 21.7 $ (94.2 ) $ — $ (477.0 )
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The following table provides additional information regarding items reclassified out of "Accumulated other comprehensive loss" into earnings during the years ended December 31, 2016 and 2015: Amount reclassified from accumulated other comprehensive loss (1) Year Ended December 31 Details about accumulated other comprehensive loss components 2016 2015 Affected line item in the consolidated statement of operations (Dollars in millions) Net actuarial loss associated with postretirement plans and workers' compensation obligations: Postretirement health care and life insurance benefits $ (20.4 ) $ (24.9 ) Operating costs and expenses Defined benefit pension plans (20.5 ) (32.9 ) Operating costs and expenses Defined benefit pension plans (4.2 ) (6.7 ) Selling and administrative expenses Workers' compensation amortization 11.7 8.0 Operating costs and expenses (33.4 ) (56.5 ) Total before income taxes 12.4 20.9 Income tax benefit $ (21.0 ) $ (35.6 ) Total after income taxes Prior service credit (cost) associated with postretirement plans: Postretirement health care and life insurance benefits $ 9.2 $ 6.8 Operating costs and expenses Defined benefit pension plans (0.3 ) (1.0 ) Operating costs and expenses 8.9 5.8 Total before income taxes (3.3 ) (2.1 ) Income tax benefit $ 5.6 $ 3.7 Total after income taxes Cash flow hedges: Foreign currency forward contracts $ (145.6 ) $ (316.4 ) Operating costs and expenses Fuel and explosives commodity swaps (86.1 ) (120.4 ) Operating costs and expenses Coal trading commodity futures, swaps and options — 51.8 Other revenues Insignificant items (0.5 ) (0.7 ) (232.2 ) (385.7 ) Total before income taxes 85.9 134.0 Income tax provision $ (146.3 ) $ (251.7 ) Total after income taxes (1) Presented as gains (losses) in the consolidated statements of operations.

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings allocation method utilized in the calculation of basic and diluted EPS	The following illustrates the earnings allocation method utilized in the calculation of basic and diluted EPS. The number of shares and per share amounts for all period presented below have been retroactively restated to reflect the Reverse Stock Split discussed in Note 1. "Summary of Significant Accounting Policies.": Year Ended December 31, 2016 2015 2014 (In millions, except per share amounts) EPS numerator: Loss from continuing operations, net of income taxes $ (674.3 ) $ (1,813.9 ) $ (749.1 ) Less: Net income attributable to noncontrolling interests 7.9 7.1 9.7 Loss from continuing operations attributable to common stockholders, before allocation of earnings to participating securities (682.2 ) (1,821.0 ) (758.8 ) Less: Earnings allocated to participating securities — — 1.0 Loss from continuing operations attributable to common stockholders, after allocation of earnings to participating securities (682.2 ) (1,821.0 ) (759.8 ) Loss from discontinued operations attributable to common stockholders, after allocation of earnings to participating securities (57.6 ) (175.0 ) (28.2 ) Net loss attributable to common stockholders, after earnings allocated to participating securities $ (739.8 ) $ (1,996.0 ) $ (788.0 ) EPS denominator: Weighted average shares outstanding — basic and diluted 18.3 18.1 17.9 Basic and diluted EPS attributable to common stockholders: Loss from continuing operations $ (37.30 ) $ (100.34 ) $ (42.52 ) Loss from discontinued operations (3.15 ) (9.64 ) (1.57 ) Net loss attributable to common stockholders $ (40.45 ) $ (109.98 ) $ (44.09 )

Management - Labor Relations Ri

Management - Labor Relations Risk Management - Labor Relations (Tables)	12 Months Ended
	Dec. 31, 2016
ScheduleofOperationsWithEmployeesRepresentedbyLaborUnions [Line Items]
Schedule of operations with employees represented by labor unions	The following table presents the Company's active mining operations as of December 31, 2016 in which the employees are represented by organized labor unions: Mine Current Agreement Expiration Date U. S. Kayenta (1) September 2019 Australia Owner-operated mines: Wambo Open-Cut December 2018 Wambo Underground (2) April 2017 North Goonyella December 2018 Metropolitan (3) December 2016 Millennium (4) October 2015 Wilpinjong (5) May 2016 Coppabella (6) December 2016 Moorvale (6) October 2019 (1) Hourly workers at the Company’s Kayenta Mine in Arizona are represented by the UMWA under the Western Surface Agreement, which is effective through September 16, 2019. This agreement covers approximately 8% of the Company’s U.S. subsidiaries’ hourly employees, who generated approximately 4% of the Company’s U.S. production during the year ended December 31, 2016 . (2) Employees of the Company's Wambo Underground Mine operate under a separate labor agreement. That agreement expired in April 2015. The parties agreed to an initial rollover for 12 months through April 2016 and agreed to a further rollover for another 12 months through April 2017. There were no wage increases for the two rollover periods and there have been no disruptions to the operation of the site as a result of the expiration of the agreement. Hourly employees of this mine comprise approximately 8% of the Company's Australian subsidiaries hourly employees, who generated approximately 10% of the Company's Australian production during the year ended December 31, 2016 . (3) Employees of the Company's Metropolitan mine operate under a separate labor agreement, which expired in September 2015. Negotiations progressed to a vote on the Company’s best offer in November 2015, which was rejected by the employees. The parties agreed to hold off on any further negotiations until the Company's emergence from the Chapter 11 Cases, expected to occur in early April 2017. There were no wage increases during this period and there have been no disruptions to the operation of the site as a result of the expiration of the agreement. There is also a Deputy labor agreement which expired in September 2015. The parties agreed to a rollover for 18 months through to December 2016. Negotiations resumed in January 2017 for a new labor agreement. There have been no disruptions to the operations of the site as a result of the expiration of the agreement. Hourly employees of this mine comprise approximately 11% of the Company's Australian subsidiaries hourly employees, who generated approximately 6% of the Company's Australian production during the year ended December 31, 2016 . (4) Employees of the Company's Millennium mine operate under a separate labor agreement. Negotiations have been ongoing for an extended period of time, where employees rejected the Company's offers in July 2016 and again in November 2016. After the second unsuccessful vote the Company informed employees it was in the process of applying for the agreement to be terminated. Employees requested the Company to vote again on the second rejected agreement with the intent to accept the offer, 70% of employees voted and accepted the offer late January 2017. The agreement was approved by the Fair Work Commission in early March 2017. Hourly employees of this mine comprise approximately 16% of the Company's Australian subsidiaries hourly employees, who generated approximately 11% of the Company's Australian production during the year ended December 31, 2016 . (5) Employees of the Company's Wilpinjong Mine operate under an enterprise agreement. Negotiations to replace the enterprise agreement that nominally expired in May 2016 commenced in April 2016. In January 2017 the workforce formally rejected Wilpinjong’s proposed replacement agreement and good faith negotiations are now continuing. Hourly employees of this mine comprise approximately 18% of the Company's Australian subsidiaries hourly employees, who generated approximately 42% of the Company's Australian production during the year ended December 31, 2016 . (6) Employees of the Company's Coppabella/Moorvale Coal Handling and Preparation Plant facility previously operated under a separate enterprise agreement. As a result of the latest negotiation process the Company was successful in its application to terminate the agreement. The negotiations resulted in the Coppabella employees requesting to be employed on individual salaried contracts (rather than a labor agreement) and the Moorvale employees accepted the Company's final offer. The Moorevale agreement expires in October 2019. Hourly employees of this mine comprise approximately 28% of the Company's Australian subsidiaries hourly employees, who generated approximately 13% of the Company's Australian production during the year ended December 31, 2016 .

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
Financial Instruments And Guarantees With Off Balance Sheet Risk Disclosure [Abstract]
Letters of credit, bank guarantees, surety bonds and corporate guarantees	As of December 31, 2016 , the Company had the following financial instruments with off-balance-sheet risk: Reclamation Bonding Requirements Coal Lease Obligations Workers’ Compensation Obligations Other (1) Total (2) Cash Collateral in Support of Financial Instruments (Dollars in millions) Self bonding $ 1,094.2 $ — $ — $ — $ 1,094.2 $ — Surety bonds (3) 319.6 94.0 19.1 15.5 448.2 64.5 Bank guarantees 54.7 — — 24.5 79.2 83.8 Other (4) 233.2 — 42.7 118.0 393.9 233.2 Total $ 1,701.7 $ 94.0 $ 61.8 $ 158.0 $ 2,015.5 $ 381.5 (1) Other includes the $37.0 million in letters of credit related to the PBGC, as described below, and an additional $121.0 million in bank guarantees, letters of credit and surety bonds related to road maintenance, performance guarantees and other operations. (2) Letters of credit held as collateral in support of surety bonds at December 31, 2016 were $48.0 million and are not reflected in the table above. (3) A total of $72.6 million of letters of credit issued as collateral to support surety bonds related to Patriot have been excluded from above as they no longer represent off-balance sheet obligations as discussed in Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation".

Summary Quarterly Financial I64

Summary Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Summary Quarterly Financial Information (Tables) [Abstract]
Summary of the unaudited quarterly results of operations	A summary of the unaudited quarterly results of operations for the years ended December 31, 2016 and 2015 is presented below. Year Ended December 31, 2016 First Quarter Second Quarter Third Quarter Fourth Quarter (In millions, except per share data) Revenues $ 1,027.2 $ 1,040.2 $ 1,207.1 $ 1,440.8 Operating loss (102.7 ) (107.7 ) (21.6 ) (44.9 ) Loss from continuing operations, net of income taxes (161.7 ) (230.8 ) (95.6 ) (186.2 ) Net loss (165.1 ) (233.8 ) (133.7 ) (199.3 ) Net loss attributable to common stockholders (165.1 ) (235.5 ) (135.5 ) (203.7 ) Basic and diluted EPS — continuing operations (1) $ (8.85 ) $ (12.71 ) $ (5.32 ) $ (10.42 ) Weighted average shares used in calculating basic and diluted EPS 18.3 18.3 18.3 18.3 (1) EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis.	Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter (In millions, except per share data) Revenues $ 1,537.9 $ 1,339.3 $ 1,418.9 $ 1,313.1 Operating profit (loss) 2.2 (975.8 ) (20.4 ) (470.8 ) Loss from continuing operations, net of income taxes (164.4 ) (1,007.2 ) (144.4 ) (497.9 ) Net loss (173.3 ) (1,043.5 ) (301.9 ) (470.2 ) Net loss attributable to common stockholders (176.6 ) (1,045.3 ) (304.7 ) (469.4 ) Basic and diluted EPS — continuing operations (1) $ (9.31 ) $ (55.59 ) $ (8.08 ) $ (27.28 ) Weighted average shares used in calculating basic and diluted EPS 18.0 18.2 18.2 18.2 (1) EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis

Segment and Geographic Inform65

Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Operating segment results	Segment results for the year ended December 31, 2016 were as follows: Powder River Basin Mining Midwestern U.S. Mining Western U.S. Mining Australian Metallurgical Mining Australian Thermal Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Revenues $ 1,473.3 $ 792.5 $ 526.0 $ 1,090.4 $ 824.9 $ (10.9 ) $ 19.1 $ 4,715.3 Adjusted EBITDA 379.9 217.3 101.6 (16.3 ) 217.6 (72.2 ) (335.7 ) 492.2 Additions to property, plant, equipment and mine development 33.0 18.7 20.8 29.9 22.1 — 2.1 126.6 Federal coal lease expenditures 248.4 — 0.6 — — — — 249.0 Income from equity affiliates — — — — — — (16.2 ) (16.2 ) Segment results for the year ended December 31, 2015 were as follows: Powder River Basin Mining Midwestern U.S. Mining Western U.S. Mining Australian Metallurgical Mining Australian Thermal Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Revenues $ 1,865.9 $ 981.2 $ 682.3 $ 1,181.9 $ 823.5 $ 42.8 $ 31.6 $ 5,609.2 Adjusted EBITDA 482.9 269.7 184.6 (18.2 ) 193.6 27.0 (705.0 ) 434.6 Additions to property, plant, equipment and mine development 15.0 51.3 19.3 25.5 13.6 — 2.1 126.8 Federal coal lease expenditures 276.9 — 0.3 — — — — 277.2 Loss from equity affiliates — — — — — — 15.9 15.9 Segment results for the year ended December 31, 2014 were as follows: Powder River Basin Mining Midwestern U.S. Mining Western U.S. Mining Australian Metallurgical Mining Australian Thermal Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Revenues $ 1,922.9 $ 1,198.1 $ 902.8 $ 1,613.8 $ 1,058.0 $ 58.4 $ 38.2 $ 6,792.2 Adjusted EBITDA 509.0 306.9 266.9 (151.1 ) 264.1 14.9 (396.7 ) 814.0 Additions to property, plant, equipment and mine development 19.7 57.4 18.2 53.9 30.2 — 15.0 194.4 Federal coal lease expenditures 276.5 — 0.2 — — — — 276.7 Loss from equity affiliates — — — — — — 107.6 107.6
Reconciliation of Assets from Segment to Consolidated [Table Text Block]	Assets as of December 31, 2016 were as follows: U.S. Mining Australian Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Total assets $ 4,255.9 $ 5,402.2 $ 128.7 $ 1,990.9 $ 11,777.7 Property, plant, equipment and mine development, net 3,970.6 3,905.8 0.2 900.1 8,776.7 Assets as of December 31, 2015 were as follows: U.S. Mining Australian Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Total assets $ 4,105.8 $ 5,319.9 $ 217.2 $ 1,304.0 $ 10,946.9 Property, plant, equipment and mine development, net 3,854.5 4,469.6 0.5 933.9 9,258.5 Assets as of December 31, 2014 were as follows: U.S. Mining Australian Mining Trading and Brokerage Corporate and Other Consolidated (Dollars in millions) Total assets $ 4,099.1 $ 6,623.9 $ 300.7 $ 2,167.4 $ 13,191.1 Property, plant, equipment and mine development, net 3,739.9 5,503.7 1.1 1,332.6 10,577.3
Reconciliation of Adjusted EBITDA to consolidated loss from continuing operations	A reconciliation of consolidated loss from continuing operations, net of income taxes to Adjusted EBITDA follows: Year Ended December 31, 2016 2015 2014 (Dollars in millions) Loss from continuing operations, net of income taxes $ (674.3 ) $ (1,813.9 ) $ (749.1 ) Depreciation, depletion and amortization 465.4 572.2 655.7 Asset retirement obligation expenses 41.8 45.5 81.0 Selling and administrative expenses related to debt restructuring 21.5 — — Asset impairment 247.9 1,277.8 154.4 Change in deferred tax asset valuation allowance related to equity affiliates (7.5 ) (1.0 ) 52.3 Amortization of basis difference related to equity affiliates — 4.9 5.7 Interest expense 298.6 465.4 426.6 Loss on early debt extinguishment 29.5 67.8 1.6 Interest income (5.7 ) (7.7 ) (15.4 ) Reorganization items, net 159.0 — — Income tax (benefit) provision (84.0 ) (176.4 ) 201.2 Total Adjusted EBITDA $ 492.2 $ 434.6 $ 814.0
Revenues as a percent of total revenue from external customers by geographic region	The following table presents revenues as a percent of total revenue from external customers by geographic region: Year Ended December 31, 2016 2015 2014 U.S. 54.7 % 57.4 % 59.5 % Japan 6.9 % 8.1 % 9.5 % China 5.4 % 7.1 % 6.1 % South Korea 1.5 % 4.1 % 5.2 % Other 31.5 % 23.3 % 19.7 % Total 100.0 % 100.0 % 100.0 %

Supplemental Guarantor_Non-Gu66

Supplemental Guarantor/Non-Guarantor Financial Information (Tables)	12 Months Ended
	Dec. 31, 2016
Supplemental Guarantor Non Guarantor Financial Information [Abstract]
Supplemental Consolidated Statement of Operations [Table Text Block]	PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 2,830.0 $ 2,189.8 $ (304.5 ) $ 4,715.3 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 172.9 2,172.4 2,066.8 (304.5 ) 4,107.6 Depreciation, depletion and amortization — 217.4 248.0 — 465.4 Asset retirement obligation expenses — 15.8 26.0 — 41.8 Selling and administrative expenses 12.8 126.5 14.1 — 153.4 Restructuring charges — 11.9 3.6 — 15.5 Other operating (income) loss: Net gain on disposal of assets — (21.4 ) (1.8 ) — (23.2 ) Asset impairment — 37.5 210.4 — 247.9 Loss from equity affiliates and investment in subsidiaries 185.0 4.5 (20.7 ) (185.0 ) (16.2 ) Interest expense 288.6 19.6 24.4 (34.0 ) 298.6 Loss on early debt extinguishment 29.5 — — — 29.5 Interest income (0.2 ) (4.8 ) (34.7 ) 34.0 (5.7 ) Reorganization items, net 73.4 82.1 3.5 — 159.0 (Loss) income from continuing operations before income taxes (762.0 ) 168.5 (349.8 ) 185.0 (758.3 ) Income tax (benefit) provision (84.6 ) (11.0 ) 11.6 — (84.0 ) (Loss) income from continuing operations, net of income taxes (677.4 ) 179.5 (361.4 ) 185.0 (674.3 ) (Loss) income from discontinued operations, net of income taxes (62.4 ) (0.1 ) 4.9 — (57.6 ) Net (loss) income (739.8 ) 179.4 (356.5 ) 185.0 (731.9 ) Less: Net income attributable to noncontrolling interests — — 7.9 — 7.9 Net (loss) income attributable to common stockholders $ (739.8 ) $ 179.4 $ (364.4 ) $ 185.0 $ (739.8 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 3,535.3 $ 2,535.3 $ (461.4 ) $ 5,609.2 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 436.6 2,782.6 2,249.9 (461.4 ) 5,007.7 Depreciation, depletion and amortization — 249.7 322.5 — 572.2 Asset retirement obligation expenses — 13.2 32.3 — 45.5 Selling and administrative expenses 32.1 132.6 11.7 — 176.4 Restructuring charges (3.9 ) 11.4 16.0 — 23.5 Other operating (income) loss: Net gain on disposal of assets (2.3 ) (29.8 ) (12.9 ) — (45.0 ) Asset impairment — 308.6 969.2 — 1,277.8 Loss from equity affiliates and investment in subsidiaries 933.9 6.9 9.0 (933.9 ) 15.9 Interest expense 468.4 19.6 24.7 (47.3 ) 465.4 Loss on early debt extinguishment 67.8 — — — 67.8 Interest income (14.0 ) (2.4 ) (38.6 ) 47.3 (7.7 ) (Loss) income from continuing operations before income taxes (1,918.6 ) 42.9 (1,048.5 ) 933.9 (1,990.3 ) Income tax (benefit) provision (87.4 ) (108.2 ) 19.2 — (176.4 ) (Loss) income from continuing operations, net of income taxes (1,831.2 ) 151.1 (1,067.7 ) 933.9 (1,813.9 ) (Loss) income from discontinued operations, net of income taxes (164.8 ) 1.6 (11.8 ) — (175.0 ) Net (loss) income (1,996.0 ) 152.7 (1,079.5 ) 933.9 (1,988.9 ) Less: Net income attributable to noncontrolling interests — 0.8 6.3 — 7.1 Net (loss) income attributable to common stockholders $ (1,996.0 ) $ 151.9 $ (1,085.8 ) $ 933.9 $ (1,996.0 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 4,063.8 $ 3,311.7 $ (583.3 ) $ 6,792.2 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 49.6 3,121.9 3,128.7 (583.3 ) 5,716.9 Depreciation, depletion and amortization — 271.0 384.7 — 655.7 Asset retirement obligation expenses — 23.2 57.8 — 81.0 Selling and administrative expenses 46.8 161.1 19.2 — 227.1 Restructuring and pension settlement charges — 26.0 — — 26.0 Other operating (income) loss: Net gain on disposal of assets — (17.7 ) (23.7 ) — (41.4 ) Asset impairment 4.7 63.3 86.4 — 154.4 Loss from equity affiliates and investment in subsidiaries 128.5 7.6 100.0 (128.5 ) 107.6 Interest expense 423.1 19.5 34.3 (50.3 ) 426.6 Loss on early debt extinguishment 1.6 — — — 1.6 Interest income (15.3 ) (2.9 ) (47.5 ) 50.3 (15.4 ) (Loss) income from continuing operations before income taxes (639.0 ) 390.8 (428.2 ) 128.5 (547.9 ) Income tax provision 116.4 23.7 61.1 — 201.2 (Loss) income from continuing operations, net of income taxes (755.4 ) 367.1 (489.3 ) 128.5 (749.1 ) (Loss) income from discontinued operations, net of income taxes (31.6 ) (7.2 ) 10.6 — (28.2 ) Net (loss) income (787.0 ) 359.9 (478.7 ) 128.5 (777.3 ) Less: Net income attributable to noncontrolling interests — 5.2 4.5 — 9.7 Net (loss) income attributable to common stockholders $ (787.0 ) $ 354.7 $ (483.2 ) $ 128.5 $ (787.0 )
SupplementalCondensedConsolidatingStatementsOfComprehensiveIncomeLoss [Table Text Block]	PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (739.8 ) $ 179.4 $ (356.5 ) $ 185.0 $ (731.9 ) Other comprehensive income (loss), net of income taxes: Net unrealized gains on cash flow hedges (net of $85.9 tax provision) (Decrease) increase in fair value of cash flow hedges — — — — — Reclassification for realized losses included in net (loss) income 146.3 — — — 146.3 Net unrealized gains on cash flow hedges 146.3 — — — 146.3 Postretirement plans and workers' compensation obligations (net of $1.5 tax benefit) Prior service cost for the period — (4.5 ) — — (4.5 ) Net actuarial gain (loss) for the period 8.9 (22.4 ) — — (13.5 ) Amortization of actuarial (loss) gain and prior service cost included in net (loss) income (6.1 ) 21.5 — — 15.4 Postretirement plans and workers' compensation obligations 2.8 (5.4 ) — — (2.6 ) Foreign currency translation adjustment — — (1.8 ) — (1.8 ) Other comprehensive loss from investment in subsidiaries (7.2 ) — — 7.2 — Other comprehensive income (loss), net of income taxes 141.9 (5.4 ) (1.8 ) 7.2 141.9 Comprehensive (loss) income (597.9 ) 174.0 (358.3 ) 192.2 (590.0 ) Less: Comprehensive income attributable to noncontrolling interests — — 7.9 — 7.9 Comprehensive (loss) income attributable to common stockholders $ (597.9 ) $ 174.0 $ (366.2 ) $ 192.2 $ (597.9 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (1,996.0 ) $ 152.7 $ (1,079.5 ) $ 933.9 $ (1,988.9 ) Other comprehensive income (loss), net of income taxes: Net change in unrealized losses on available-for-sale securities (net of $0.1 tax benefit) Net unrealized gains (losses) on cash flow hedges (net of $72.2 tax provision) (Decrease) increase in fair value of cash flow hedges (137.1 ) — 5.8 — (131.3 ) Reclassification for realized losses (gains) included in net (loss) income 292.1 — (40.4 ) — 251.7 Net unrealized gains (losses) on cash flow hedges 155.0 — (34.6 ) — 120.4 Postretirement plans and workers' compensation obligations (net of $36.2 tax provision) Prior service credit for the period — 10.4 — — 10.4 Net actuarial gain for the period 5.5 12.6 — — 18.1 Amortization of actuarial loss (gain) and prior service cost included in net (loss) income 7.2 37.3 (12.6 ) — 31.9 Postretirement plans and workers' compensation obligations 12.7 60.3 (12.6 ) — 60.4 Foreign currency translation adjustment — — (34.9 ) — (34.9 ) Other comprehensive loss from investment in subsidiaries (21.8 ) — — 21.8 — Other comprehensive income (loss), net of income taxes 145.9 60.3 (82.1 ) 21.8 145.9 Comprehensive (loss) income (1,850.1 ) 213.0 (1,161.6 ) 955.7 (1,843.0 ) Less: Comprehensive income attributable to noncontrolling interests — 0.8 6.3 — 7.1 Comprehensive (loss) income attributable to common stockholders $ (1,850.1 ) $ 212.2 $ (1,167.9 ) $ 955.7 $ (1,850.1 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (787.0 ) $ 359.9 $ (478.7 ) $ 128.5 $ (777.3 ) Other comprehensive loss, net of income taxes: Net change in unrealized losses on available-for-sale securities (net of $0.5 tax benefit) Unrealized holding losses on available-for-sale securities (3.7 ) — — — (3.7 ) Reclassification for realized losses included in net (loss) income 2.9 — — — 2.9 Net change in unrealized losses on available-for-sale securities (0.8 ) — — — (0.8 ) Net unrealized losses on cash flow hedges (net of $54.6 tax benefit) (Decrease) increase in fair value of cash flow hedges (225.9 ) — 30.9 — (195.0 ) Reclassification for realized losses (gains) included in net (loss) income 31.3 — (41.5 ) — (10.2 ) Net unrealized losses on cash flow hedges (194.6 ) — (10.6 ) — (205.2 ) Postretirement plans and workers' compensation obligations (net of $10.3 tax benefit) Prior service credit for the period — 11.4 — — 11.4 Net actuarial (loss) gain for the period — (152.6 ) 9.9 — (142.7 ) Amortization of actuarial loss (gain) and prior service cost included in net (loss) income — 41.4 (8.7 ) — 32.7 Postretirement plans and workers' compensation obligations — (99.8 ) 1.2 — (98.6 ) Foreign currency translation adjustment — — (41.0 ) — (41.0 ) Other comprehensive income from investment in subsidiaries (150.2 ) — — 150.2 — Other comprehensive loss, net of income taxes (345.6 ) (99.8 ) (50.4 ) 150.2 (345.6 ) Comprehensive (loss) income (1,132.6 ) 260.1 (529.1 ) 278.7 (1,122.9 ) Less: Comprehensive income attributable to noncontrolling interests — 5.2 4.5 — 9.7 Comprehensive (loss) income attributable to common stockholders $ (1,132.6 ) $ 254.9 $ (533.6 ) $ 278.7 $ (1,132.6 )
Supplemental Consolidated Balance Sheets [Table Text Block]	PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Reclassifications/ Eliminations Consolidated (Dollars in millions) Assets Current assets Cash and cash equivalents $ 266.6 $ 107.0 $ 498.7 $ — $ 872.3 Restricted cash 13.8 — 40.5 — 54.3 Accounts receivable, net — 5.1 467.9 — 473.0 Receivables from affiliates, net 899.9 — 783.0 (1,682.9 ) — Inventories — 76.8 126.9 — 203.7 Assets from coal trading activities, net — 0.9 — (0.2 ) 0.7 Other current assets 19.1 51.2 416.3 — 486.6 Total current assets 1,199.4 241.0 2,333.3 (1,683.1 ) 2,090.6 Property, plant, equipment and mine development, net — 4,381.6 4,395.1 — 8,776.7 Deferred income taxes — 15.8 — (15.8 ) — Investments and other assets 8,652.0 3.8 626.5 (8,371.9 ) 910.4 Notes receivable from affiliates, net — 1,036.3 — (1,036.3 ) — Total assets $ 9,851.4 $ 5,678.5 $ 7,354.9 $ (11,107.1 ) $ 11,777.7 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ — $ 19.3 $ 0.9 $ — $ 20.2 Payables to affiliates, net — 1,682.9 — (1,682.9 ) — Liabilities from coal trading activities, net — — 1.4 (0.2 ) 1.2 Accounts payable and accrued expenses 58.9 439.3 492.2 — 990.4 Total current liabilities 58.9 2,141.5 494.5 (1,683.1 ) 1,011.8 Deferred income taxes 28.0 — 5.4 (15.8 ) 17.6 Notes payable to affiliates, net 1,032.5 — 3.8 (1,036.3 ) — Other noncurrent liabilities 160.4 1,330.3 479.6 — 1,970.3 Total liabilities not subject to compromise 1,279.8 3,471.8 983.3 (2,735.2 ) 2,999.7 Liabilities subject to compromise 8,241.4 184.2 14.6 — 8,440.2 Total liabilities 9,521.2 3,656.0 997.9 (2,735.2 ) 11,439.9 Peabody Energy Corporation stockholders’ equity 330.2 2,022.5 6,349.4 (8,371.9 ) 330.2 Noncontrolling interests — — 7.6 — 7.6 Total stockholders’ equity 330.2 2,022.5 6,357.0 (8,371.9 ) 337.8 Total liabilities and stockholders’ equity $ 9,851.4 $ 5,678.5 $ 7,354.9 $ (11,107.1 ) $ 11,777.7 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Reclassifications/ Eliminations Consolidated (Dollars in millions) Assets Current assets Cash and cash equivalents $ 7.2 $ 4.7 $ 249.4 $ — $ 261.3 Accounts receivable, net — 12.1 216.7 — 228.8 Receivables from affiliates, net 582.1 — 948.1 (1,530.2 ) — Inventories — 109.4 198.4 — 307.8 Assets from coal trading activities, net — 3.2 20.3 — 23.5 Deferred income taxes — 65.3 — (11.8 ) 53.5 Other current assets 23.1 128.1 296.4 — 447.6 Total current assets 612.4 322.8 1,929.3 (1,542.0 ) 1,322.5 Property, plant, equipment and mine development, net — 4,304.8 4,953.7 — 9,258.5 Deferred income taxes — 33.1 — (30.9 ) 2.2 Investments and other assets 8,476.2 3.6 185.5 (8,301.6 ) 363.7 Notes receivable from affiliates, net — 632.7 399.9 (1,032.6 ) — Total assets $ 9,088.6 $ 5,297.0 $ 7,468.4 $ (10,907.1 ) $ 10,946.9 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ 5,844.0 $ 23.8 $ 7.1 $ — $ 5,874.9 Payables to affiliates, net — 1,530.2 — (1,530.2 ) — Deferred income taxes 11.8 — 3.8 (11.8 ) 3.8 Liabilities from coal trading activities, net — 4.8 10.8 — 15.6 Accounts payable and accrued expenses 494.8 479.8 467.9 — 1,442.5 Total current liabilities 6,350.6 2,038.6 489.6 (1,542.0 ) 7,336.8 Long-term debt, less current portion 366.3 — — — 366.3 Deferred income taxes 98.6 — 1.4 (30.9 ) 69.1 Notes payable to affiliates, net 1,032.6 — — (1,032.6 ) — Other noncurrent liabilities 323.6 1,454.9 477.7 — 2,256.2 Total liabilities 8,171.7 3,493.5 968.7 (2,605.5 ) 10,028.4 Peabody Energy Corporation stockholders’ equity 916.9 1,803.5 6,498.1 (8,301.6 ) 916.9 Noncontrolling interests — — 1.6 — 1.6 Total stockholders’ equity 916.9 1,803.5 6,499.7 (8,301.6 ) 918.5 Total liabilities and stockholders’ equity $ 9,088.6 $ 5,297.0 $ 7,468.4 $ (10,907.1 ) $ 10,946.9
Unaudited Supplemental Condensed Consolidating Statements of Cash Flows	PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (167.3 ) $ 78.5 $ 65.9 $ (22.9 ) Net cash used in discontinued operations (16.2 ) (1.9 ) (11.8 ) (29.9 ) Net cash (used in) provided by operating activities (183.5 ) 76.6 54.1 (52.8 ) Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (55.5 ) (71.1 ) (126.6 ) Changes in accrued expenses related to capital expenditures — (0.6 ) (5.5 ) (6.1 ) Federal coal lease expenditures — (249.0 ) — (249.0 ) Proceeds from disposal of assets, net of notes receivable — 77.7 66.7 144.4 Contributions to joint ventures — — (309.5 ) (309.5 ) Distributions from joint ventures — — 312.4 312.4 Advances to related parties — — (40.4 ) (40.4 ) Repayment of loans from related parties — — 40.6 40.6 Other, net — (5.1 ) (4.8 ) (9.9 ) Net cash used in by investing activities — (232.5 ) (11.6 ) (244.1 ) Cash Flows From Financing Activities Proceeds from long-term debt 1,450.6 — 7.8 1,458.4 Repayments of long-term debt (503.0 ) (4.4 ) (6.3 ) (513.7 ) Payment of deferred financing costs (26.8 ) — (4.2 ) (31.0 ) Other, net — (5.8 ) — (5.8 ) Transactions with affiliates, net (477.9 ) 268.4 209.5 — Net cash provided by financing activities 442.9 258.2 206.8 907.9 Net change in cash and cash equivalents $ 259.4 $ 102.3 $ 249.3 $ 611.0 Cash and cash equivalents at beginning of year 7.2 4.7 249.4 261.3 Cash and cash equivalents at end of year $ 266.6 $ 107.0 $ 498.7 $ 872.3 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (692.9 ) $ 615.3 $ 96.5 $ 18.9 Net cash used in discontinued operations (27.4 ) (2.9 ) (3.0 ) (33.3 ) Net cash (used in) provided by operating activities (720.3 ) 612.4 93.5 (14.4 ) Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (70.6 ) (56.2 ) (126.8 ) Changes in accrued expenses related to capital expenditures — (2.3 ) (6.9 ) (9.2 ) Federal coal lease expenditures — (277.2 ) — (277.2 ) Proceeds from disposal of assets, net of notes receivable — 36.3 34.1 70.4 Purchases of debt and equity securities — — (28.8 ) (28.8 ) Proceeds from sales and maturities of debt and equity securities — — 90.3 90.3 Contributions to joint ventures — — (425.4 ) (425.4 ) Distributions from joint ventures — — 422.6 422.6 Advances to related parties — — (3.7 ) (3.7 ) Repayment of loan from related parties — — 0.9 0.9 Other, net — (2.7 ) (0.4 ) (3.1 ) Net cash (used in) provided by investing activities — (316.5 ) 26.5 (290.0 ) Cash Flows From Financing Activities Proceeds from long-term debt 975.7 — — 975.7 Repayments of long-term debt (662.0 ) (0.7 ) (8.6 ) (671.3 ) Payment of deferred financing costs (28.7 ) — — (28.7 ) Dividends paid (1.4 ) — — (1.4 ) Other, net 1.4 (1.8 ) (6.2 ) (6.6 ) Transactions with affiliates, net 253.8 (289.9 ) 36.1 — Net cash provided by (used in) financing activities 538.8 (292.4 ) 21.3 267.7 Net change in cash and cash equivalents $ (181.5 ) $ 3.5 $ 141.3 $ (36.7 ) Cash and cash equivalents at beginning of year 188.7 1.2 108.1 298.0 Cash and cash equivalents at end of year $ 7.2 $ 4.7 $ 249.4 $ 261.3 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (369.0 ) $ 764.7 $ 45.3 $ 441.0 Net cash used in discontinued operations (73.3 ) (4.6 ) (26.5 ) (104.4 ) Net cash (used in) provided by operating activities (442.3 ) 760.1 18.8 336.6 Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (95.8 ) (98.6 ) (194.4 ) Changes in accrued expenses related to capital expenditures — 2.2 (18.8 ) (16.6 ) Federal coal lease expenditures — (276.7 ) — (276.7 ) Proceeds from disposal of assets, net of notes receivable — 105.9 97.8 203.7 Purchases of debt and equity securities — — (15.1 ) (15.1 ) Proceeds from sales and maturities of debt and equity securities — — 13.5 13.5 Contributions to joint ventures — — (529.8 ) (529.8 ) Distributions from joint ventures — — 534.2 534.2 Advances to related parties — — (33.7 ) (33.7 ) Repayment of loans from related parties — — 5.4 5.4 Other, net — (4.2 ) (0.8 ) (5.0 ) Net cash used in investing activities — (268.6 ) (45.9 ) (314.5 ) Cash Flows From Financing Activities Proceeds from long-term debt — — 1.1 1.1 Repayments of long-term debt (12.0 ) (0.7 ) (8.3 ) (21.0 ) Payment of deferred financing costs (10.1 ) — — (10.1 ) Dividends paid (92.3 ) — — (92.3 ) Restricted cash for distributions to noncontrolling interest — — (42.5 ) (42.5 ) Other, net 3.1 (1.7 ) (4.7 ) (3.3 ) Transactions with affiliates, net 441.6 (488.2 ) 46.6 — Net cash provided by (used in) financing activities 330.3 (490.6 ) (7.8 ) (168.1 ) Net change in cash and cash equivalents $ (112.0 ) $ 0.9 $ (34.9 ) $ (146.0 ) Cash and cash equivalents at beginning of year 300.7 0.3 143.0 444.0 Cash and cash equivalents at end of year $ 188.7 $ 1.2 $ 108.1 $ 298.0
Supplemental Guarantor Non Guarantor Financial Information Disclosure [Text Block]	Supplemental Guarantor/Non-Guarantor Financial Information In accordance with the indentures governing the Senior Notes, certain 100% owned U.S. subsidiaries of the Company (each, a Guarantor Subsidiary) have fully and unconditionally guaranteed the Senior Notes, on a joint and several basis. The indentures governing the Senior Notes contain customary exceptions under which a guarantee of a Guarantor Subsidiary will terminate, including (a) the release or discharge of the guarantee of the Company’s 2013 Credit Facility by such Guarantor Subsidiary, except a discharge or release by or as a result of payment under such guarantee, (b) a sale or other disposition, by way of merger, consolidation or otherwise, of all of the capital stock of such Guarantor Subsidiary, and (c) the legal defeasance or discharge of the indentures. Separate financial statements and other disclosures concerning the Guarantor Subsidiaries are not presented because management believes that such information is not material to the holders of the Senior Notes. The following historical financial statement information is provided for the Guarantor/Non-Guarantor Subsidiaries. PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 2,830.0 $ 2,189.8 $ (304.5 ) $ 4,715.3 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 172.9 2,172.4 2,066.8 (304.5 ) 4,107.6 Depreciation, depletion and amortization — 217.4 248.0 — 465.4 Asset retirement obligation expenses — 15.8 26.0 — 41.8 Selling and administrative expenses 12.8 126.5 14.1 — 153.4 Restructuring charges — 11.9 3.6 — 15.5 Other operating (income) loss: Net gain on disposal of assets — (21.4 ) (1.8 ) — (23.2 ) Asset impairment — 37.5 210.4 — 247.9 Loss from equity affiliates and investment in subsidiaries 185.0 4.5 (20.7 ) (185.0 ) (16.2 ) Interest expense 288.6 19.6 24.4 (34.0 ) 298.6 Loss on early debt extinguishment 29.5 — — — 29.5 Interest income (0.2 ) (4.8 ) (34.7 ) 34.0 (5.7 ) Reorganization items, net 73.4 82.1 3.5 — 159.0 (Loss) income from continuing operations before income taxes (762.0 ) 168.5 (349.8 ) 185.0 (758.3 ) Income tax (benefit) provision (84.6 ) (11.0 ) 11.6 — (84.0 ) (Loss) income from continuing operations, net of income taxes (677.4 ) 179.5 (361.4 ) 185.0 (674.3 ) (Loss) income from discontinued operations, net of income taxes (62.4 ) (0.1 ) 4.9 — (57.6 ) Net (loss) income (739.8 ) 179.4 (356.5 ) 185.0 (731.9 ) Less: Net income attributable to noncontrolling interests — — 7.9 — 7.9 Net (loss) income attributable to common stockholders $ (739.8 ) $ 179.4 $ (364.4 ) $ 185.0 $ (739.8 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 3,535.3 $ 2,535.3 $ (461.4 ) $ 5,609.2 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 436.6 2,782.6 2,249.9 (461.4 ) 5,007.7 Depreciation, depletion and amortization — 249.7 322.5 — 572.2 Asset retirement obligation expenses — 13.2 32.3 — 45.5 Selling and administrative expenses 32.1 132.6 11.7 — 176.4 Restructuring charges (3.9 ) 11.4 16.0 — 23.5 Other operating (income) loss: Net gain on disposal of assets (2.3 ) (29.8 ) (12.9 ) — (45.0 ) Asset impairment — 308.6 969.2 — 1,277.8 Loss from equity affiliates and investment in subsidiaries 933.9 6.9 9.0 (933.9 ) 15.9 Interest expense 468.4 19.6 24.7 (47.3 ) 465.4 Loss on early debt extinguishment 67.8 — — — 67.8 Interest income (14.0 ) (2.4 ) (38.6 ) 47.3 (7.7 ) (Loss) income from continuing operations before income taxes (1,918.6 ) 42.9 (1,048.5 ) 933.9 (1,990.3 ) Income tax (benefit) provision (87.4 ) (108.2 ) 19.2 — (176.4 ) (Loss) income from continuing operations, net of income taxes (1,831.2 ) 151.1 (1,067.7 ) 933.9 (1,813.9 ) (Loss) income from discontinued operations, net of income taxes (164.8 ) 1.6 (11.8 ) — (175.0 ) Net (loss) income (1,996.0 ) 152.7 (1,079.5 ) 933.9 (1,988.9 ) Less: Net income attributable to noncontrolling interests — 0.8 6.3 — 7.1 Net (loss) income attributable to common stockholders $ (1,996.0 ) $ 151.9 $ (1,085.8 ) $ 933.9 $ (1,996.0 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Total revenues $ — $ 4,063.8 $ 3,311.7 $ (583.3 ) $ 6,792.2 Costs and expenses Operating costs and expenses (exclusive of items shown separately below) 49.6 3,121.9 3,128.7 (583.3 ) 5,716.9 Depreciation, depletion and amortization — 271.0 384.7 — 655.7 Asset retirement obligation expenses — 23.2 57.8 — 81.0 Selling and administrative expenses 46.8 161.1 19.2 — 227.1 Restructuring and pension settlement charges — 26.0 — — 26.0 Other operating (income) loss: Net gain on disposal of assets — (17.7 ) (23.7 ) — (41.4 ) Asset impairment 4.7 63.3 86.4 — 154.4 Loss from equity affiliates and investment in subsidiaries 128.5 7.6 100.0 (128.5 ) 107.6 Interest expense 423.1 19.5 34.3 (50.3 ) 426.6 Loss on early debt extinguishment 1.6 — — — 1.6 Interest income (15.3 ) (2.9 ) (47.5 ) 50.3 (15.4 ) (Loss) income from continuing operations before income taxes (639.0 ) 390.8 (428.2 ) 128.5 (547.9 ) Income tax provision 116.4 23.7 61.1 — 201.2 (Loss) income from continuing operations, net of income taxes (755.4 ) 367.1 (489.3 ) 128.5 (749.1 ) (Loss) income from discontinued operations, net of income taxes (31.6 ) (7.2 ) 10.6 — (28.2 ) Net (loss) income (787.0 ) 359.9 (478.7 ) 128.5 (777.3 ) Less: Net income attributable to noncontrolling interests — 5.2 4.5 — 9.7 Net (loss) income attributable to common stockholders $ (787.0 ) $ 354.7 $ (483.2 ) $ 128.5 $ (787.0 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (739.8 ) $ 179.4 $ (356.5 ) $ 185.0 $ (731.9 ) Other comprehensive income (loss), net of income taxes: Net unrealized gains on cash flow hedges (net of $85.9 tax provision) (Decrease) increase in fair value of cash flow hedges — — — — — Reclassification for realized losses included in net (loss) income 146.3 — — — 146.3 Net unrealized gains on cash flow hedges 146.3 — — — 146.3 Postretirement plans and workers' compensation obligations (net of $1.5 tax benefit) Prior service cost for the period — (4.5 ) — — (4.5 ) Net actuarial gain (loss) for the period 8.9 (22.4 ) — — (13.5 ) Amortization of actuarial (loss) gain and prior service cost included in net (loss) income (6.1 ) 21.5 — — 15.4 Postretirement plans and workers' compensation obligations 2.8 (5.4 ) — — (2.6 ) Foreign currency translation adjustment — — (1.8 ) — (1.8 ) Other comprehensive loss from investment in subsidiaries (7.2 ) — — 7.2 — Other comprehensive income (loss), net of income taxes 141.9 (5.4 ) (1.8 ) 7.2 141.9 Comprehensive (loss) income (597.9 ) 174.0 (358.3 ) 192.2 (590.0 ) Less: Comprehensive income attributable to noncontrolling interests — — 7.9 — 7.9 Comprehensive (loss) income attributable to common stockholders $ (597.9 ) $ 174.0 $ (366.2 ) $ 192.2 $ (597.9 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (1,996.0 ) $ 152.7 $ (1,079.5 ) $ 933.9 $ (1,988.9 ) Other comprehensive income (loss), net of income taxes: Net change in unrealized losses on available-for-sale securities (net of $0.1 tax benefit) Net unrealized gains (losses) on cash flow hedges (net of $72.2 tax provision) (Decrease) increase in fair value of cash flow hedges (137.1 ) — 5.8 — (131.3 ) Reclassification for realized losses (gains) included in net (loss) income 292.1 — (40.4 ) — 251.7 Net unrealized gains (losses) on cash flow hedges 155.0 — (34.6 ) — 120.4 Postretirement plans and workers' compensation obligations (net of $36.2 tax provision) Prior service credit for the period — 10.4 — — 10.4 Net actuarial gain for the period 5.5 12.6 — — 18.1 Amortization of actuarial loss (gain) and prior service cost included in net (loss) income 7.2 37.3 (12.6 ) — 31.9 Postretirement plans and workers' compensation obligations 12.7 60.3 (12.6 ) — 60.4 Foreign currency translation adjustment — — (34.9 ) — (34.9 ) Other comprehensive loss from investment in subsidiaries (21.8 ) — — 21.8 — Other comprehensive income (loss), net of income taxes 145.9 60.3 (82.1 ) 21.8 145.9 Comprehensive (loss) income (1,850.1 ) 213.0 (1,161.6 ) 955.7 (1,843.0 ) Less: Comprehensive income attributable to noncontrolling interests — 0.8 6.3 — 7.1 Comprehensive (loss) income attributable to common stockholders $ (1,850.1 ) $ 212.2 $ (1,167.9 ) $ 955.7 $ (1,850.1 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated (Dollars in millions) Net (loss) income $ (787.0 ) $ 359.9 $ (478.7 ) $ 128.5 $ (777.3 ) Other comprehensive loss, net of income taxes: Net change in unrealized losses on available-for-sale securities (net of $0.5 tax benefit) Unrealized holding losses on available-for-sale securities (3.7 ) — — — (3.7 ) Reclassification for realized losses included in net (loss) income 2.9 — — — 2.9 Net change in unrealized losses on available-for-sale securities (0.8 ) — — — (0.8 ) Net unrealized losses on cash flow hedges (net of $54.6 tax benefit) (Decrease) increase in fair value of cash flow hedges (225.9 ) — 30.9 — (195.0 ) Reclassification for realized losses (gains) included in net (loss) income 31.3 — (41.5 ) — (10.2 ) Net unrealized losses on cash flow hedges (194.6 ) — (10.6 ) — (205.2 ) Postretirement plans and workers' compensation obligations (net of $10.3 tax benefit) Prior service credit for the period — 11.4 — — 11.4 Net actuarial (loss) gain for the period — (152.6 ) 9.9 — (142.7 ) Amortization of actuarial loss (gain) and prior service cost included in net (loss) income — 41.4 (8.7 ) — 32.7 Postretirement plans and workers' compensation obligations — (99.8 ) 1.2 — (98.6 ) Foreign currency translation adjustment — — (41.0 ) — (41.0 ) Other comprehensive income from investment in subsidiaries (150.2 ) — — 150.2 — Other comprehensive loss, net of income taxes (345.6 ) (99.8 ) (50.4 ) 150.2 (345.6 ) Comprehensive (loss) income (1,132.6 ) 260.1 (529.1 ) 278.7 (1,122.9 ) Less: Comprehensive income attributable to noncontrolling interests — 5.2 4.5 — 9.7 Comprehensive (loss) income attributable to common stockholders $ (1,132.6 ) $ 254.9 $ (533.6 ) $ 278.7 $ (1,132.6 ) PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Reclassifications/ Eliminations Consolidated (Dollars in millions) Assets Current assets Cash and cash equivalents $ 266.6 $ 107.0 $ 498.7 $ — $ 872.3 Restricted cash 13.8 — 40.5 — 54.3 Accounts receivable, net — 5.1 467.9 — 473.0 Receivables from affiliates, net 899.9 — 783.0 (1,682.9 ) — Inventories — 76.8 126.9 — 203.7 Assets from coal trading activities, net — 0.9 — (0.2 ) 0.7 Other current assets 19.1 51.2 416.3 — 486.6 Total current assets 1,199.4 241.0 2,333.3 (1,683.1 ) 2,090.6 Property, plant, equipment and mine development, net — 4,381.6 4,395.1 — 8,776.7 Deferred income taxes — 15.8 — (15.8 ) — Investments and other assets 8,652.0 3.8 626.5 (8,371.9 ) 910.4 Notes receivable from affiliates, net — 1,036.3 — (1,036.3 ) — Total assets $ 9,851.4 $ 5,678.5 $ 7,354.9 $ (11,107.1 ) $ 11,777.7 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ — $ 19.3 $ 0.9 $ — $ 20.2 Payables to affiliates, net — 1,682.9 — (1,682.9 ) — Liabilities from coal trading activities, net — — 1.4 (0.2 ) 1.2 Accounts payable and accrued expenses 58.9 439.3 492.2 — 990.4 Total current liabilities 58.9 2,141.5 494.5 (1,683.1 ) 1,011.8 Deferred income taxes 28.0 — 5.4 (15.8 ) 17.6 Notes payable to affiliates, net 1,032.5 — 3.8 (1,036.3 ) — Other noncurrent liabilities 160.4 1,330.3 479.6 — 1,970.3 Total liabilities not subject to compromise 1,279.8 3,471.8 983.3 (2,735.2 ) 2,999.7 Liabilities subject to compromise 8,241.4 184.2 14.6 — 8,440.2 Total liabilities 9,521.2 3,656.0 997.9 (2,735.2 ) 11,439.9 Peabody Energy Corporation stockholders’ equity 330.2 2,022.5 6,349.4 (8,371.9 ) 330.2 Noncontrolling interests — — 7.6 — 7.6 Total stockholders’ equity 330.2 2,022.5 6,357.0 (8,371.9 ) 337.8 Total liabilities and stockholders’ equity $ 9,851.4 $ 5,678.5 $ 7,354.9 $ (11,107.1 ) $ 11,777.7 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Reclassifications/ Eliminations Consolidated (Dollars in millions) Assets Current assets Cash and cash equivalents $ 7.2 $ 4.7 $ 249.4 $ — $ 261.3 Accounts receivable, net — 12.1 216.7 — 228.8 Receivables from affiliates, net 582.1 — 948.1 (1,530.2 ) — Inventories — 109.4 198.4 — 307.8 Assets from coal trading activities, net — 3.2 20.3 — 23.5 Deferred income taxes — 65.3 — (11.8 ) 53.5 Other current assets 23.1 128.1 296.4 — 447.6 Total current assets 612.4 322.8 1,929.3 (1,542.0 ) 1,322.5 Property, plant, equipment and mine development, net — 4,304.8 4,953.7 — 9,258.5 Deferred income taxes — 33.1 — (30.9 ) 2.2 Investments and other assets 8,476.2 3.6 185.5 (8,301.6 ) 363.7 Notes receivable from affiliates, net — 632.7 399.9 (1,032.6 ) — Total assets $ 9,088.6 $ 5,297.0 $ 7,468.4 $ (10,907.1 ) $ 10,946.9 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ 5,844.0 $ 23.8 $ 7.1 $ — $ 5,874.9 Payables to affiliates, net — 1,530.2 — (1,530.2 ) — Deferred income taxes 11.8 — 3.8 (11.8 ) 3.8 Liabilities from coal trading activities, net — 4.8 10.8 — 15.6 Accounts payable and accrued expenses 494.8 479.8 467.9 — 1,442.5 Total current liabilities 6,350.6 2,038.6 489.6 (1,542.0 ) 7,336.8 Long-term debt, less current portion 366.3 — — — 366.3 Deferred income taxes 98.6 — 1.4 (30.9 ) 69.1 Notes payable to affiliates, net 1,032.6 — — (1,032.6 ) — Other noncurrent liabilities 323.6 1,454.9 477.7 — 2,256.2 Total liabilities 8,171.7 3,493.5 968.7 (2,605.5 ) 10,028.4 Peabody Energy Corporation stockholders’ equity 916.9 1,803.5 6,498.1 (8,301.6 ) 916.9 Noncontrolling interests — — 1.6 — 1.6 Total stockholders’ equity 916.9 1,803.5 6,499.7 (8,301.6 ) 918.5 Total liabilities and stockholders’ equity $ 9,088.6 $ 5,297.0 $ 7,468.4 $ (10,907.1 ) $ 10,946.9 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2016 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (167.3 ) $ 78.5 $ 65.9 $ (22.9 ) Net cash used in discontinued operations (16.2 ) (1.9 ) (11.8 ) (29.9 ) Net cash (used in) provided by operating activities (183.5 ) 76.6 54.1 (52.8 ) Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (55.5 ) (71.1 ) (126.6 ) Changes in accrued expenses related to capital expenditures — (0.6 ) (5.5 ) (6.1 ) Federal coal lease expenditures — (249.0 ) — (249.0 ) Proceeds from disposal of assets, net of notes receivable — 77.7 66.7 144.4 Contributions to joint ventures — — (309.5 ) (309.5 ) Distributions from joint ventures — — 312.4 312.4 Advances to related parties — — (40.4 ) (40.4 ) Repayment of loans from related parties — — 40.6 40.6 Other, net — (5.1 ) (4.8 ) (9.9 ) Net cash used in by investing activities — (232.5 ) (11.6 ) (244.1 ) Cash Flows From Financing Activities Proceeds from long-term debt 1,450.6 — 7.8 1,458.4 Repayments of long-term debt (503.0 ) (4.4 ) (6.3 ) (513.7 ) Payment of deferred financing costs (26.8 ) — (4.2 ) (31.0 ) Other, net — (5.8 ) — (5.8 ) Transactions with affiliates, net (477.9 ) 268.4 209.5 — Net cash provided by financing activities 442.9 258.2 206.8 907.9 Net change in cash and cash equivalents $ 259.4 $ 102.3 $ 249.3 $ 611.0 Cash and cash equivalents at beginning of year 7.2 4.7 249.4 261.3 Cash and cash equivalents at end of year $ 266.6 $ 107.0 $ 498.7 $ 872.3 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2015 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (692.9 ) $ 615.3 $ 96.5 $ 18.9 Net cash used in discontinued operations (27.4 ) (2.9 ) (3.0 ) (33.3 ) Net cash (used in) provided by operating activities (720.3 ) 612.4 93.5 (14.4 ) Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (70.6 ) (56.2 ) (126.8 ) Changes in accrued expenses related to capital expenditures — (2.3 ) (6.9 ) (9.2 ) Federal coal lease expenditures — (277.2 ) — (277.2 ) Proceeds from disposal of assets, net of notes receivable — 36.3 34.1 70.4 Purchases of debt and equity securities — — (28.8 ) (28.8 ) Proceeds from sales and maturities of debt and equity securities — — 90.3 90.3 Contributions to joint ventures — — (425.4 ) (425.4 ) Distributions from joint ventures — — 422.6 422.6 Advances to related parties — — (3.7 ) (3.7 ) Repayment of loan from related parties — — 0.9 0.9 Other, net — (2.7 ) (0.4 ) (3.1 ) Net cash (used in) provided by investing activities — (316.5 ) 26.5 (290.0 ) Cash Flows From Financing Activities Proceeds from long-term debt 975.7 — — 975.7 Repayments of long-term debt (662.0 ) (0.7 ) (8.6 ) (671.3 ) Payment of deferred financing costs (28.7 ) — — (28.7 ) Dividends paid (1.4 ) — — (1.4 ) Other, net 1.4 (1.8 ) (6.2 ) (6.6 ) Transactions with affiliates, net 253.8 (289.9 ) 36.1 — Net cash provided by (used in) financing activities 538.8 (292.4 ) 21.3 267.7 Net change in cash and cash equivalents $ (181.5 ) $ 3.5 $ 141.3 $ (36.7 ) Cash and cash equivalents at beginning of year 188.7 1.2 108.1 298.0 Cash and cash equivalents at end of year $ 7.2 $ 4.7 $ 249.4 $ 261.3 PEABODY ENERGY CORPORATION (DEBTOR-IN-POSSESSION) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS Year Ended December 31, 2014 Parent Company Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidated (Dollars in millions) Cash Flows From Operating Activities Net cash (used in) provided by continuing operations $ (369.0 ) $ 764.7 $ 45.3 $ 441.0 Net cash used in discontinued operations (73.3 ) (4.6 ) (26.5 ) (104.4 ) Net cash (used in) provided by operating activities (442.3 ) 760.1 18.8 336.6 Cash Flows From Investing Activities Additions to property, plant, equipment and mine development — (95.8 ) (98.6 ) (194.4 ) Changes in accrued expenses related to capital expenditures — 2.2 (18.8 ) (16.6 ) Federal coal lease expenditures — (276.7 ) — (276.7 ) Proceeds from disposal of assets, net of notes receivable — 105.9 97.8 203.7 Purchases of debt and equity securities — — (15.1 ) (15.1 ) Proceeds from sales and maturities of debt and equity securities — — 13.5 13.5 Contributions to joint ventures — — (529.8 ) (529.8 ) Distributions from joint ventures — — 534.2 534.2 Advances to related parties — — (33.7 ) (33.7 ) Repayment of loans from related parties — — 5.4 5.4 Other, net — (4.2 ) (0.8 ) (5.0 ) Net cash used in investing activities — (268.6 ) (45.9 ) (314.5 ) Cash Flows From Financing Activities Proceeds from long-term debt — — 1.1 1.1 Repayments of long-term debt (12.0 ) (0.7 ) (8.3 ) (21.0 ) Payment of deferred financing costs (10.1 ) — — (10.1 ) Dividends paid (92.3 ) — — (92.3 ) Restricted cash for distributions to noncontrolling interest — — (42.5 ) (42.5 ) Other, net 3.1 (1.7 ) (4.7 ) (3.3 ) Transactions with affiliates, net 441.6 (488.2 ) 46.6 — Net cash provided by (used in) financing activities 330.3 (490.6 ) (7.8 ) (168.1 ) Net change in cash and cash equivalents $ (112.0 ) $ 0.9 $ (34.9 ) $ (146.0 ) Cash and cash equivalents at beginning of year 300.7 0.3 143.0 444.0 Cash and cash equivalents at end of year $ 188.7 $ 1.2 $ 108.1 $ 298.0

Valuation and Qualifying Acco67

Valuation and Qualifying Accounts Schedule II (Tables)	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Summary of Valuation Allowance [Table Text Block]	SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS Description Balance at Charged to Deductions (1) Other Balance (Dollars in millions) Year Ended December 31, 2016 Reserves deducted from asset accounts: Advance royalty recoupment reserve $ 8.3 $ 0.5 $ (1.0 ) (2) $ — $ 7.8 Reserve for materials and supplies 4.7 4.3 (3.4 ) — 5.6 Allowance for doubtful accounts 6.6 7.9 (1.4 ) — 13.1 Tax valuation allowances 1,447.3 2,462.8 — (28.9 ) (3) 3,881.2 Year Ended December 31, 2015 Reserves deducted from asset accounts: Advance royalty recoupment reserve $ 7.6 $ — $ (0.9 ) (2) $ 1.6 (4) $ 8.3 Reserve for materials and supplies 4.6 0.4 (0.3 ) — 4.7 Allowance for doubtful accounts 5.8 8.0 (7.2 ) — 6.6 Tax valuation allowances 1,169.0 462.0 — (183.7 ) (3) 1,447.3 Year Ended December 31, 2014 Reserves deducted from asset accounts: Advance royalty recoupment reserve $ 9.7 $ (0.2 ) $ (1.9 ) (2) $ — $ 7.6 Reserve for materials and supplies 7.4 (0.1 ) (2.7 ) — 4.6 Allowance for doubtful accounts 7.4 1.5 (1.4 ) (1.7 ) (5) 5.8 Tax valuation allowances 1,634.1 569.4 — (1,034.5 ) (6) 1,169.0 (1) Reserves utilized, unless otherwise indicated. (2) Deductions to advance royalty recoupment reserve represents the termination of federal and state leases. (3) Includes the impact of the decrease in Australian dollar exchange rates. (4) Balances transferred from other accounts. (5) Represents subsequent recovery of receivable amounts previously reserved. (6) Includes the write-off of valuation allowance against deferred tax assets related to the Australian Minerals and Resource Rent Tax (MRRT) due to the repeal of that legislation in 2014, along with an increase in valuation allowance during the period reflected directly in "Accumulated other comprehensive loss" and the impact of the 2014 decrease in Australian dollar exchange rates.

Reorganization Items, Net (Tabl

Reorganization Items, Net (Tables)	12 Months Ended
	Dec. 31, 2016
schedule of reorganization items [Line Items]
Reorganization under Chapter 11 of US Bankruptcy Code Disclosure [Text Block]	In accordance with Accounting Standards Codification 852, "Reorganizations," the statement of operations shall portray the results of operations of the reporting entity during the pendency of the Chapter 11 Cases. Revenues, expenses (including professional fees), realized gains and losses, and provisions for losses resulting from reorganization and restructuring of the business shall be reported separately as "reorganization items". The Company's reorganization items for the year ended December 31, 2016 consisted of the following: Year Ended December 31, 2016 (Dollars in millions) Professional fees $ 88.4 Loss on termination of derivative contracts 75.2 Accounts payable settlement gains (1.8 ) Interest income (1.8 ) Other (1.0 ) Reorganization items, net $ 159.0 As a result of filing the Bankruptcy Petitions, counterparties to certain derivative contracts terminated the agreements shortly thereafter in accordance with their contractual terms and the Company adjusted the corresponding liabilities to be equivalent to the termination value and allowed claim amount of each contract. Such liabilities are considered first lien debt and are included within "Liabilities subject to compromise" in the accompanying consolidated balance sheet at December 31, 2016. Professional fees are only those that are directly related to the reorganization including, but not limited to, fees associated with advisors to the Debtors, the Creditors' Committee and certain secured and unsecured creditors. Interest income reflects interest earned due to the preservation of cash as a result of the automatic stay pursuant to Section 362 of the Bankruptcy Code. During the year ended December 31, 2016, $68.1 million of cash payments were made for "Reorganization items, net".
schedule of reorganization items [Table Text Block]	The Company's reorganization items for the year ended December 31, 2016 consisted of the following: Year Ended December 31, 2016 (Dollars in millions) Professional fees $ 88.4 Loss on termination of derivative contracts 75.2 Accounts payable settlement gains (1.8 ) Interest income (1.8 ) Other (1.0 ) Reorganization items, net $ 159.0

Liabilities Subject to Compro69

Liabilities Subject to Compromise (Tables)	12 Months Ended
	Dec. 31, 2016
Liabilities Subject to Compromise [Abstract]
Schedule of liabilities subject to compromise [Table Text Block]	Liabilities subject to compromise consisted of the following: Previously Reported Balance Sheet Line December 31, 2016 (Dollars in millions) Debt (1) $ 8,080.3 Interest payable 172.6 Environmental liabilities 61.9 Trade payables 58.4 Postretirement benefit obligations (2) 34.6 Other accrued liabilities 32.4 Liabilities subject to compromise $ 8,440.2 (1) Includes $7,771.2 million of first lien, second lien and unsecured debt, $257.3 million of derivative contract terminations, and $51.8 million of liabilities secured by prepetition letters of credit. (2) Includes liabilities for unfunded non-qualified pension plans, all the participants of which are former employees.

Summary of Significant Accoun70

Summary of Significant Accounting Policies Discussion (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Apr. 12, 2016	Mar. 31, 2016	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Other current assets	$ 486.6	$ 486.6	$ 447.6
First Lien Exit Facility		1.95
Other Assets, Noncurrent	910.4	$ 910.4	363.7
Total assets	11,777.7	11,777.7	10,946.9	$ 13,191.1
Long-term Debt and Capital Lease Obligations, Current	20.2	20.2	5,874.9
Long-term Debt and Capital Lease Obligations	0	0	366.3
Liabilities	$ 11,439.9	$ 11,439.9	$ 10,028.4
Initial Offering Period		750
Proceeds from Issuance of Private Placement		$ 750
Equity Investment necessary to consummate Reorg Plan		1.5
Take-back Paper		1.5
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stockholders' Equity, Reverse Stock Split		Pursuant to the authorization provided at a special meeting of the Company's stockholders held on September 16, 2015, the Company completed a 1-for-15 reverse stock split of the shares of the Company’s common stock on September 30, 2015 (the Reverse Stock Split). Refer to Note 1. "Summary of Significant Accounting Policies" for additional details surrounding the Reverse Stock Split.	Pursuant to the authorization provided at a special meeting of the Company's stockholders held on September 16, 2015, the Company completed a 1-for-15 reverse stock split of the shares of the Company’s common stock on September 30, 2015 (the Reverse Stock Split). As a result of the Reverse Stock Split, every 15 shares of issued and outstanding common stock were combined into one issued and outstanding share of Common Stock, without any change in the par value per share.
Common Stock, Shares Authorized	53.3	53.3
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Cash and cash equivalents	$ 872.3	$ 872.3	$ 261.3	298		$ 652.1		$ 444
Period considered to treat short-term, highly liquid investments as cash equivalents		three months or less
Other-than-temporary impairment losses on marketable securities		$ 0	4.7	4.7
Other-than-temporary impairment losses on equity and cost method investments		$ 276.5	0
Recognition of tax benefits from uncertain tax positions		greater than fifty percent likelihood of being realized upon ultimate settlement
Restructuring charges for voluntary and involuntary workforce reductions	$ 2.8	$ 15.5	23.5	26
Asset impairment charges related to long-lived assets		247.9	1,001.3	149.7
Foreign currency remeasurement (loss) gains		7.4	(6.4)	(1.3)
Foreign currency translation adjustment		$ 1.8	$ 34.9	$ 41
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life		3 to 34
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life		3 to 34
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life		Shorter of Useful Life or Remaining Life of Lease
Interest In Middlemount Coal Pty Limited [Member]
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Ownership percentage of equity method investment	50.00%	50.00%
Minimum [Member] | Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life		1
Minimum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life		1
Maximum [Member] | Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life		37
Maximum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life		37
Common Stock [Member]
Property, Plant and Equipment [Line Items]
Stock Issued During Period, Shares, Reverse Stock Splits		278
Common Stock, Shares, issues post reverse stock split	19	19
Stock Authorized During Period, Shares, Reverse Stock Splits			800
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Common Stock, Shares Authorized	53.3	53.3	53.3
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01	$ 0.01
Debt burden reduced at exit of bankruptcy [Member]
Property, Plant and Equipment [Line Items]
Long-term Debt	$ 6,600	$ 6,600
Revolving Credit Facility [Member]
Property, Plant and Equipment [Line Items]
Long-term Debt	1,558.1	1,558.1	$ 0				$ 947
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Exit facility, maximum borrowing capacity	1,650	1,650
6.50% Senior Notes due September 2020 [Member]
Property, Plant and Equipment [Line Items]
Long-term Debt	$ 645.8	$ 645.8	645.5
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	6.50%	6.50%			6.50%
10.00% Senior Secured Second Lien Notes Due 2022 [Member]
Property, Plant and Equipment [Line Items]
Long-term Debt	$ 962.3	$ 962.3	960.4
Face amount of senior notes	$ 1,000	$ 1,000
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	10.00%	10.00%
6.00% Senior Notes due November 2018 [Member]
Property, Plant and Equipment [Line Items]
Long-term Debt	$ 1,509.9	$ 1,509.9	1,508.9
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	6.00%	6.00%
6.25% Senior Notes due November 2021 [Member]
Property, Plant and Equipment [Line Items]
Long-term Debt	$ 1,327.7	$ 1,327.7	1,327
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	6.25%	6.25%			6.25%
7.875% Senior Notes [Member]
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	7.875%	7.875%
Term Loan Facility [Member]
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	4.50%	4.50%
Exit facility, maximum borrowing capacity	$ 950	$ 950
6.000% Senior Secured Notes Due 2022 [Member]
Property, Plant and Equipment [Line Items]
Face amount of senior notes	$ 500	$ 500
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	6.00%	6.00%
6.375% Senior Secured Notes Due 2022 [Member]
Property, Plant and Equipment [Line Items]
Face amount of senior notes	$ 500	$ 500
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Stated interest rate - percentage	6.375%	6.375%
Paid to second lien noteholders in partial satisfaction of their claims [Member]
Property, Plant and Equipment [Line Items]
Cash	$ 450	$ 450
Second Lien Notes		450
First Lien Debtholders [Member]
Property, Plant and Equipment [Line Items]
First Lien Debt		450
Class 5B Claims [Member]
Property, Plant and Equipment [Line Items]
Pro Rate Share in Cash	75	$ 75
Class 5A Claims [Member]
Property, Plant and Equipment [Line Items]
Cash	5	$ 5
Eurocurrency Rate [Member] | Term Loan Facility [Member]
Property, Plant and Equipment [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum		1.00%
Non-Debtor Subsidiaries [Member]
Property, Plant and Equipment [Line Items]
Other current assets	416.2	$ 416.2
Lease Commitments		189
Other Assets, Noncurrent	596.7	$ 596.7
Total assets	6,012.9	6,012.9
Long-term Debt and Capital Lease Obligations, Current	0.9	0.9
Liabilities	2,042.7	2,042.7
Summary Of Significant Accounting Policies Discussion Textuals [Abstract]
Cash and cash equivalents	477.8	477.8				$ 543.6
Restructuring charges for voluntary and involuntary workforce reductions	0.6
Other Current Assets [Member]
Property, Plant and Equipment [Line Items]
Deferred Finance Costs, Current	(55.5)	(55.5)
Other Noncurrent Assets [Member]
Property, Plant and Equipment [Line Items]
Deferred Finance Costs, Current	(18.9)	(18.9)
Assets [Member]
Property, Plant and Equipment [Line Items]
Deferred Finance Costs, Current	(74.4)	(74.4)
Long-term Debt and Capital Lease Obligations, Current [Member]
Property, Plant and Equipment [Line Items]
Deferred Finance Costs, Current	(55.5)	(55.5)
Long-term Debt and Capital Lease Obligations [Member]
Property, Plant and Equipment [Line Items]
Deferred Finance Costs, Current	(18.9)	(18.9)
Liability [Member]
Property, Plant and Equipment [Line Items]
Deferred Finance Costs, Current	$ (74.4)	$ (74.4)
Peabody Energy [Member]
Property, Plant and Equipment [Line Items]
Other current assets			503.1
Other Assets, Noncurrent			382.6
Total assets			11,021.3
Long-term Debt and Capital Lease Obligations, Current			5,930.4
Long-term Debt and Capital Lease Obligations			385.2
Liabilities			$ 10,102.8

Asset Impairment and Mine Clo71

Asset Impairment and Mine Closure Costs (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of Long-Lived Assets to be Disposed of (after tax)	$ 193.2
Long-lived assets						$ 247.9	$ 1,001.3	$ 149.7
Marketable securities						0	4.7	4.7
Equity method investment							276.5
Asset Impairment	230.7	$ 17.2	$ 377	$ 900.8	$ 230.7	247.9	1,277.8	154.4
Asset realization risk	1,407.3				$ 1,407.3	1,407.3
Additional asset impairment charge deemed necessary for assets at risk						0
Australian Metallurgical Mining [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets							66.7
Australian Mining [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets related to mine closures						17.2
Long-lived assets	144.5			$ 230.5		193.2	675.2	66.7
Marketable securities								0
Equity method investment							0
Asset Impairment							675.2	66.7
Australian Thermal Mining [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets							17.5	11.9
Marketable securities								0
Equity method investment							0
Asset Impairment							17.5	11.9
Western U.S. Mining [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets								2.7
Marketable securities								0
Asset Impairment								2.7
Midwestern U.S. Mining [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets	9.7					37.5	40.2
Equity method investment							0
Asset Impairment							40.2
Corporate and Other [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets related to mine closures						182.2
Long-lived assets	86.2					54.7	268.4	68.4
Marketable securities								4.7
Equity method investment							276.5
Asset Impairment							544.9	$ 73.1
Remediation Property for Sale, Abandonment or Disposal [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets	$ 317.7
Midwestern Inactive Surface Mine [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets						$ 30.5
Middlemount Mine [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Equity method investment, ownership percentage	50.00%				50.00%	50.00%
Subordinated Borrowing, Name [Domain]
Impaired Long-Lived Assets Held and Used [Line Items]
Equity method investment						$ 229.9	229.9
Financing Receivable [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Investments and Other Noncurrent Assets	$ 84.8		65.2		$ 84.8	$ 84.8	65.2
Middlemount Mine [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Equity method investment, ownership percentage	50.00%				50.00%	50.00%
Middlemount Mine [Member] | Financing Receivable [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Investments and Other Noncurrent Assets	$ 84.8		$ 65.2		$ 84.8	$ 84.8	$ 65.2
Middlemount Mine [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Equity method investment						$ 46.6
Metropolitan mine [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Cash consideration for asset held for sale									$ 200

Discontinued Operations (Detail

Discontinued Operations (Details) AUD in Millions, $ in Millions	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016AUD	Sep. 30, 2016AUD
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Other Assets, Current	$ 0.2				$ 0.2	$ 0.2	$ 3.1
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax						(57.6)	(182.2)	$ (23.8)
Discontinued Operation, Tax Effect of Discontinued Operation						0	(7.2)	4.4
Loss from discontinued operations, net of income taxes	13.1	$ 38.1	$ 155.1	$ 7.6	(53.6)	(57.6)	(175)	$ (28.2)
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	15.9				15.9	15.9	13.2
Disposal Group, Including Discontinued Operation, Assets	16.1				16.1	16.1	16.3
Disposal Group, Including Discontinued Operation, Liabilities, Current	55.9				55.9	55.9	60
Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent	198.5				198.5	198.5	203.7
Liabilities Subject to Compromise	8,440.2				8,440.2	8,440.2	0
Disposal Group, Including Discontinued Operation, Liabilities	275.3				275.3	275.3	263.7
United Mine Workers of America [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations, net of income taxes	54.3
Wilkie Creek [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss Contingency, Loss in Period							9.7
Settlement charges total	9.9				9.9	9.9			AUD 13	AUD 13
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities Subject to Compromise	$ 20.9				$ 20.9	$ 20.9	$ 0

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Inventory [Line Items]
Materials and supplies	$ 104.5	$ 115.9
Raw coal	29.6	75.9
Saleable coal	69.6	116
Total	$ 203.7	$ 307.8

Inventories Details Textuals (D

Inventories Details Textuals (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reserve for materials and supplies [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Materials and supplies reserves	$ 5.6	$ 4.7	$ 4.6	$ 7.4

Investments (Details 1)

Investments (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sale of available-for-sale securities		$ 90.3	$ 13.5
Net gains on sales and maturities		0	0
Proceeds from Sale and Maturity of Marketable Securities	$ 0	90.3	13.5
Other-than-temporary impairment losses on marketable securities	$ 0	$ 4.7	4.7
Middlemount Mine [Member]
Schedule of Available-for-sale Securities [Line Items]
Valuation Allowances and Reserves, Balance			$ 52.3

Investments (Details 2)

Investments (Details 2) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Marketable securities			$ 0	$ 4.7	$ 4.7
Equity method investments	$ 0.5	$ 0.5	0.5	1.5
(Gain) loss from equity affiliates	(28.8)	26.2	(16.2)	15.9	107.6
Other-than-temporary impairment losses on equity method investments				276.5
Middlemount Mine [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Summarized Financial Information, Revenue			183	160	165
Change in deferred tax asset valuation allowance related to equity affiliates					(52.3)
Other-than-temporary impairment losses on equity method investments				46.6
Equity Method Investment, Summarized Financial Information, Current Assets	47.3	47.3	47.3	31.7
Equity Method Investment, Summarized Financial Information, Noncurrent Assets	263.4	263.4	263.4	348
Equity Method Investment, Summarized Financial Information, Current Liabilities	363.5	363.5	363.5	362.2
Equity Method Investment, Summarized Financial Information, Noncurrent Liabilities	50.3	50.3	50.3	10.5
Interest In Middlemount Coal Pty Limited [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 0	$ 0	0	0
(Gain) loss from equity affiliates			$ (22.6)	7	98.5
Equity method investment, ownership percentage	50.00%	50.00%	50.00%
Other-than-temporary impairment losses on equity method investments				276.5
Subordinated Borrowing, Name [Domain]
Schedule of Equity Method Investments [Line Items]
Other-than-temporary impairment losses on equity method investments			$ 229.9	229.9
Other Equity Method Investments [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 0.5	$ 0.5	0.5	1.5
(Gain) loss from equity affiliates			$ 6.4	8.9	9.1
Middlemount Mine [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%	50.00%
Corporate and Other [Member]
Schedule of Equity Method Investments [Line Items]
Marketable securities					4.7
(Gain) loss from equity affiliates			$ (16.2)	15.9	$ 107.6
Other-than-temporary impairment losses on equity method investments				276.5
Financing Receivable [Member]
Schedule of Equity Method Investments [Line Items]
Investments and Other Noncurrent Assets	$ 84.8	$ 84.8	$ 84.8	65.2
Middlemount Mine [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%	50.00%
Middlemount Mine [Member] | Financing Receivable [Member]
Schedule of Equity Method Investments [Line Items]
Investments and Other Noncurrent Assets	$ 84.8	$ 84.8	$ 84.8	$ 65.2

Derivatives and Fair Value Me77

Derivatives and Fair Value Measurements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016
Derivatives, Fair Value [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements		$ 257,300,000
Company's foreign currency and commodity positions by Year of Maturity and Account Classification
Fair Value Net Liability			$ 0
Timing differences between the hedge settlement and the purchase transaction		Less than a day and up to a maximum of 30 days
Scenario, Forecast [Member] | Foreign currency forward contracts [Member]
Company's foreign currency and commodity positions by Year of Maturity and Account Classification
Net loss to be reclassified from accumulated other comprehensive loss to earnings over the next 12 months	$ 93,000,000

Derivatives and Fair Value Me78

Derivatives and Fair Value Measurements (Details 1) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Monetization of foreign currency hedge positions		$ (25)	$ (14.9)		$ (136.9)
Gain (loss) recognized in other comprehensive income on derivative (effective portion)			(199)		(295.4)
Gain (loss) reclassified from other comprehensive income into income (effective portion)			(438.4)	[1]	(47.9)	[2]
Gain (loss) reclassified from other comprehensive income into income (ineffective portion)			1.6		(1.7)
Gains realized on previously monetized foreign currency cash flow hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain reclassified to earnings for previously monetized foreign currency forward contracts			14.9		136.9
Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		(316.1)
Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
loss reclassified from Accumulated OCI into income	[3]	(231.7)
loss recognized in income on derivatives		(84.4)
Commodity swap contracts [Member] | Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		(98)
Commodity swap contracts [Member] | Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified into earnings, net		(9)
loss reclassified from Accumulated OCI into income	[3]	(86.1)
loss recognized in income on derivatives		(11.9)
Commodity swap contracts [Member] | Operating costs and expenses [Member] | Cash flow hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income on derivative (effective portion)			(77)		(194.5)
Gain (loss) reclassified from other comprehensive income into income (effective portion)			(122)		(20.6)
Gain (loss) reclassified from other comprehensive income into income (ineffective portion)			1.6		(1.7)
Commodity swap contracts [Member] | Reorganization items [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		(38.8)
Commodity swap contracts [Member] | Reorganization items [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
loss reclassified from Accumulated OCI into income		0
loss recognized in income on derivatives		(38.8)
Foreign currency forward contracts [Member] | Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified into earnings, net		(13.6)
Derivative, Gain (Loss) on Derivative, Net		(142.9)
Foreign currency forward contracts [Member] | Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
loss reclassified from Accumulated OCI into income	[3]	(145.6)
loss recognized in income on derivatives		2.7
Foreign currency forward contracts [Member] | Operating costs and expenses [Member] | Cash flow hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income on derivative (effective portion)			(122)		(100.9)
Gain (loss) reclassified from other comprehensive income into income (effective portion)			(316.4)	[1]	(27.3)	[2]
Gain (loss) reclassified from other comprehensive income into income (ineffective portion)			$ 0		$ 0
Foreign currency forward contracts [Member] | Reorganization items [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		(36.4)
Foreign currency forward contracts [Member] | Reorganization items [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
loss reclassified from Accumulated OCI into income		0
loss recognized in income on derivatives		$ (36.4)
[1]	(1) Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $14.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.
[2]	Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $136.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.
[3]	Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $13.6 million and $9.0 million of previously unrecognized losses on foreign currency and fuel contracts, respectivley, monetized in first quarter of 2016.

Derivatives and Fair Value Me79

Derivatives and Fair Value Measurements (Details 2) - Net amounts presented in the consolidated balance sheet $ in Millions	Dec. 31, 2015USD ($)	[1]
Derivative [Line Items]
Derivative Liability, Current	$ 231.7
Derivative Liability, Noncurrent	92.7
Commodity swap contracts [Member]
Derivative [Line Items]
Derivative Liability, Current	86.1
Derivative Liability, Noncurrent	37.6
Foreign currency forward contracts [Member]
Derivative [Line Items]
Derivative Liability, Current	145.6
Derivative Liability, Noncurrent	$ 55.1
[1]	All commodity swap contracts and foreign currency forward contracts were in a liability position as of December 31, 2015.

Derivatives and Fair Value Me80

Derivatives and Fair Value Measurements (Details 3) - USD ($)	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$ 0		$ 324,400,000
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net		$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(32,300,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(292,100,000)
Level 1 to Level 2 transfers	0		0
Level 2 to Level 1 transfers	0		0
Foreign currency forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	0		200,700,000
Fair value of asset (liability) positions measured on a recurring basis
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(48,000,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(152,700,000)
Commodity swap contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	0		123,700,000
Fair value of asset (liability) positions measured on a recurring basis
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	15,700,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	$ (139,400,000)
Fair Value, Measurements, Recurring [Member]
Fair value of asset (liability) positions measured on a recurring basis
Investments in debt and equity securities			0
Total net financial assets (liabilities)			(324,400,000)
Fair Value, Measurements, Recurring [Member] | Foreign currency forward contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			(200,700,000)
Fair Value, Measurements, Recurring [Member] | Commodity swap contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			(123,700,000)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair value of asset (liability) positions measured on a recurring basis
Investments in debt and equity securities			0
Total net financial assets (liabilities)			0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Foreign currency forward contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Commodity swap contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value of asset (liability) positions measured on a recurring basis
Investments in debt and equity securities			0
Total net financial assets (liabilities)			0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Foreign currency forward contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Commodity swap contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair value of asset (liability) positions measured on a recurring basis
Investments in debt and equity securities			0
Total net financial assets (liabilities)			(324,400,000)
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Foreign currency forward contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			(200,700,000)
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Commodity swap contracts [Member]
Fair value of asset (liability) positions measured on a recurring basis
Derivative assets (liabilities), at fair value, net			$ (123,700,000)

Derivatives and Fair Value Me81

Derivatives and Fair Value Measurements (Details 4) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Carrying amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value		$ 7,791.4	$ 6,241.2
Estimated fair value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value			1,373.7
Net amounts presented in the consolidated balance sheet
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability, Current	[1]		231.7
Derivative Liability, Noncurrent	[1]		92.7
Net amounts presented in the consolidated balance sheet | Commodity Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability, Current	[1]		86.1
Derivative Liability, Noncurrent	[1]		37.6
Net amounts presented in the consolidated balance sheet | Foreign Exchange Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability, Current	[1]		145.6
Derivative Liability, Noncurrent	[1]		$ 55.1
[1]	All commodity swap contracts and foreign currency forward contracts were in a liability position as of December 31, 2015.

Coal Trading (Details)

Coal Trading (Details) - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016
Coal trading derivative instruments and balance sheet offsetting disclosures:
Net assets (liabilities) from coal trading activities					$ 0
Coal Trading [Member]
Trading revenue
Trading revenue		$ (10,900,000)	$ 42,800,000	$ 58,400,000
Coal trading derivative instruments and balance sheet offsetting disclosures:
Assets from coal trading activities, gross amounts of recognized assets		191,200,000	128,600,000
Liabilities from coal trading activities, gross amounts of recognized liabilities		(249,100,000)	(110,000,000)
Assets and (liabilities) from coal trading activities, net amounts recognized before the application of variation margin		(57,900,000)	18,600,000
Gross amounts of coal trading liabilities offset against associated coal trading assets		(190,500,000)	(87,300,000)
Gross amounts of coal trading assets offset against associated coal trading liabilities		190,500,000	87,300,000
Net coal trading assets (liabilities) offset against associated (liabilities) assets		0	0
Variation margin held offset against assets from coal trading activities		0	(17,800,000)
Variation margin posted offset against liabilities from coal trading activities		57,400,000	7,100,000
Net variation margin (held) posted	[1]	57,400,000	10,700,000
Assets from coal trading activities, net		700,000	23,500,000
Liabilities from coal trading activities, net		(1,200,000)	(15,600,000)
Net assets (liabilities) from coal trading activities		(500,000)	7,900,000
Commodity futures, swaps and options [Member] | Coal Trading [Member]
Trading revenue
Trading revenue		(96,500,000)	107,300,000	92,300,000
Physical commodity purchase / sale contracts [Member] | Coal Trading [Member]
Trading revenue
Trading revenue		$ 85,600,000	(64,500,000)	$ (33,900,000)
Cash Flow Hedging [Member] | Coal Trading [Member]
Coal trading derivative instruments and balance sheet offsetting disclosures:
Net variation margin (held) posted			$ 0
[1]	None of the net variation margin (held) posted at December 31, 2016 and 2015, respectively, related to cash flow hedges.

Coal Trading (Details 1)

Coal Trading (Details 1) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in the Company's recurring Level 3 net financial assets
Beginning of year		$ 281.2
Total gains (realized/unrealized):
End of year		295.1	$ 281.2
Coal Trading (Textuals) [Abstract]
Fair value hierarchy transfers from Level 1 to Level 2		0	0
Fair value hierarchy transfers from Level 2 to Level 1		0	0
Coal Trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Transfers Into Level 3		5.3	(4.4)	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(0.4)	0	0
Changes in the Company's recurring Level 3 net financial assets
Beginning of year		(15.6)	2.1	2.1
Total gains (realized/unrealized):
Included in earnings		(2.4)	(10.1)	6.7
Purchases		0	(0.5)	0
Sales		0	(0.1)	0
Settlements		12	(2.6)	(6.7)
End of year		(1.1)	(15.6)	2.1
Changes in unrealized gains (losses) relating to Level 3 net financial assets held both at the beginning and the end of the period
Changes in unrealized (losses) gains	[1]	0	(6.2)	2.1
Coal Trading (Textuals) [Abstract]
Cash flow hedge derivative instrument assets at fair value		0
Fair value hierarchy transfers from Level 1 to Level 2		0	0	0
Fair value hierarchy transfers from Level 2 to Level 1		0	0	0
Fair Value hierarchy transfers out of Level 3			0	$ 0
Fair Value, Measurements, Recurring [Member] | Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis
Commodity futures, swaps and options		(0.1)	3.3
Physical commodity purchase/sale contracts		(0.4)	4.6
Total net financial assets (liabilities)		(0.5)	7.9
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis
Commodity futures, swaps and options		0	0
Physical commodity purchase/sale contracts		0	0
Total net financial assets (liabilities)		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis
Commodity futures, swaps and options		(0.1)	3.3
Physical commodity purchase/sale contracts		0.7	20.2
Total net financial assets (liabilities)		0.6	23.5
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Coal Trading [Member]
Fair value coal trading net assets (liabilities) measured on recurring basis
Commodity futures, swaps and options		0	0
Physical commodity purchase/sale contracts		(1.1)	(15.6)
Total net financial assets (liabilities)		$ (1.1)	$ (15.6)
Minimum [Member] | Coal Trading [Member]
Coal Trading (Textuals) [Abstract]
Quality adjustment Level 3 unobservable inputs as percentage of overall valuation		2.00%
Credit and non-performance risk, level 3 unobservable input as a percentage of overall valuation		26.00%
Maximum [Member] | Coal Trading [Member]
Coal Trading (Textuals) [Abstract]
Quality adjustment Level 3 unobservable inputs as percentage of overall valuation		2.00%
Credit and non-performance risk, level 3 unobservable input as a percentage of overall valuation		26.00%
Weighted Average [Member] | Coal Trading [Member]
Coal Trading (Textuals) [Abstract]
Quality adjustment Level 3 unobservable inputs as percentage of overall valuation		2.00%
Credit and non-performance risk, level 3 unobservable input as a percentage of overall valuation		26.00%
[1]	Within the consolidated statements of operations and consolidated statements of comprehensive income for the periods presented, unrealized gains and losses from Level 3 items are combined with unrealized gains and losses on positions classified in Level 1 or 2, as well as other positions that have been realized during the applicable periods.

Coal Trading (Details 2)

Coal Trading (Details 2) $ in Millions		12 Months Ended
		Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Concentration Risk [Line Items]
Number of major credit rating agencies that adjusted corporate credit rating		3
Coal Trading [Member]
Concentration Risk [Line Items]
Potential collateralization that may be requested by counterparties related to material adverse event		$ 2	$ 21
Margin posted to counterparties related to material adverse event		1	0
Additional potential collateral requirements for a credit downgrade		0	0
Margin posted to counterparties related to credit rating		0	0
Net variation margin held	[1]	(57.4)	(10.7)
Initial margin posted		16.2	9.2
Margin in excess of the exchange-required variation and initial margin		$ 2	$ 0.7
External Credit Rating, Investment Grade [Member] | Credit Concentration Risk [Member] | Coal Trading Positions [Member] | Coal Trading [Member]
Concentration Risk [Line Items]
Credit concentration risk percentage		22.00%
External Credit Rating, Non Investment Grade [Member] | Credit Concentration Risk [Member] | Coal Trading Positions [Member] | Coal Trading [Member]
Concentration Risk [Line Items]
Credit concentration risk percentage		7.00%
Non Rated [Member] | Credit Concentration Risk [Member] | Coal Trading Positions [Member] | Coal Trading [Member]
Concentration Risk [Line Items]
Credit concentration risk percentage		71.00%
[1]	None of the net variation margin (held) posted at December 31, 2016 and 2015, respectively, related to cash flow hedges.

Financing Receivables (Details)

Financing Receivables (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2011	Dec. 31, 2012
Financing Receivables [Line Items]
Other current assets	$ 486.6		$ 447.6		$ 486.6	$ 486.6	$ 447.6
Interest income					4	5.7	7.7	$ 15.4
Asset Impairment	$ 230.7	$ 17.2	377	$ 900.8	$ 230.7	$ 247.9	1,277.8	$ 154.4
Middlemount Mine [Member]
Financing Receivables [Line Items]
Equity method investment, ownership percentage	50.00%				50.00%	50.00%
Basis spread over Australian Bank Bill Swap Reference Rate						3.50%
Debt Instrument, Interest Rate Terms						0.15
Codrilla Mine Project [Member]
Financing Receivables [Line Items]
Percentage of ownership before selldown									85.00%
Percentage of agreed sale price as final installment payment due	40.00%				40.00%	40.00%
Financing Receivable [Member]
Financing Receivables [Line Items]
Other current assets	$ 0		20		$ 0	$ 0	20
Investments and other assets	84.8		65.2		84.8	84.8	65.2
Total financing receivables	84.8		85.2		84.8	84.8	85.2
Financing Receivable [Member] | Middlemount Mine [Member]
Financing Receivables [Line Items]
Investments and other assets	84.8		65.2		84.8	84.8	65.2
Intercompany Loans	$ 60				$ 60	$ 60
Financing Receivable [Member] | Codrilla Mine Project [Member]
Financing Receivables [Line Items]
Investments and other assets			$ 20				$ 20
Middlemount Mine [Member]
Financing Receivables [Line Items]
Equity method investment, ownership percentage	50.00%				50.00%	50.00%
Coppabella, Moorvale, and Codrilla Mines [Member]
Financing Receivables [Line Items]
Percentage of undivided interests acquired										73.30%

Property, Plant, Equipment an86

Property, Plant, Equipment and Mine Development (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant, Equipment and Mine Development[Line Items]
Land and coal interests	$ 10,330.8	$ 10,503.7
Buildings and improvements	1,507.6	1,506
Machinery and equipment	2,130.2	2,280.4
Less: accumulated depreciation, depletion and amortization	(5,191.9)	(5,031.6)
Total, net	8,776.7	9,258.5	$ 10,577.3
Coal reserves	5,500	5,700
Acquired interest in mineral rights	1,200
Coal reserves not subject to depletion	1,600	1,700
Mining Properties and Mineral Rights [Member]
Property, Plant, Equipment and Mine Development[Line Items]
Mineral rights and advanced royalties	4,400	$ 4,600
Coal reserves held by fee ownership [Member]
Property, Plant, Equipment and Mine Development[Line Items]
Coal reserves	$ 1,100

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss from continuing operations before income taxes
U.S.		$ (49.7)	$ (515.9)	$ 268.9
Non-U.S.		(708.6)	(1,474.4)	(816.8)
Loss from continuing operations before income taxes	$ (446.3)	$ (758.3)	$ (1,990.3)	$ (547.9)

Income Taxes (Details 1)

Income Taxes (Details 1) - USD ($) $ in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
U.S. federal				$ (12.4)	$ (71.9)	$ 27.1
Non-U.S.				14.4	3.7	(61.1)
State				0.5	(0.6)	3.3
Total current				2.5	(68.8)	(30.7)
Deferred:
U.S. federal				(82.1)	(117.4)	111
Non-U.S.				(2.3)	15.7	122.3
State				(2.1)	(5.9)	(1.4)
Total deferred				(86.5)	(107.6)	231.9
Income tax (benefit) provision	$ 7.9	$ 67.4	$ (6.2)	$ (84)	$ (176.4)	$ 201.2

Income Taxes (Details 2)

Income Taxes (Details 2) - USD ($) $ in Millions	3 Months Ended							9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of the expected statutory federal income tax provision to the Company's actual income tax provision
Expected income tax benefit at U.S. federal statutory rate									$ (265.4)	$ (696.6)	$ (191.7)
Changes in valuation allowance, income tax									2,462.8	462	569.4
Worthless Partnership Deduction									(2,204.4)	0	0
Changes in tax reserves									2.3	(21.4)	(81.5)
Excess depletion									(37.2)	(53.7)	(65.3)
Foreign earnings repatriation									0	0	(71.4)
Foreign earnings provision differential									27.5	146.5	28.8
General business tax credits									(14.2)	(15.7)	(19.2)
Minerals resource rent tax, net of federal tax									0	0	16.1
Remeasurement of foreign income tax accounts				$ 0.5	$ (0.8)		$ (0.2)		(0.4)	(0.5)	(2.7)
State income taxes, net of federal tax benefit									(90.2)	(20.1)	(2.3)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Restructuring Charges, Percent									29.6
Reorganization Items	$ 33.9	$ 29.7	$ 95.4					$ 159	159	0	0
Other, net									5.6	23.1	21
Income tax (benefit) provision				$ 7.9		$ 67.4		$ (6.2)	$ (84)	$ (176.4)	$ 201.2

Income Taxes (Details 3)

Income Taxes (Details 3) - USD ($) $ in Millions		3 Months Ended			9 Months Ended	12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Reorganization Items		$ 33.9	$ 29.7	$ 95.4	$ 159	$ 159	$ 0	$ 0
Deferred Tax Assets, Valuation Allowance, Current		0			0	0	49.7
Deferred tax assets:
Tax credits and loss carryforwards		4,284.4			4,284.4	4,284.4	1,817.4
Accrued postretirement benefit obligations		364.5			364.5	364.5	372.4
Asset retirement obligations		163.6			163.6	163.6	160.9
Employee benefits		57			57	57	69.6
Payable to voluntary employee beneficiary association for certain Patriot retirees	[1]	0			0	0	52.9
Hedge activities		21			21	21	26.6
Financial guarantees		77.9			77.9	77.9	16.9
Workers' compensation obligations		7.5			7.5	7.5	13.7
Other		2.1			2.1	2.1	66.7
Total gross deferred tax assets		4,978			4,978	4,978	2,597.1
Deferred tax liabilities:
Property, plant, equipment and mine development, principally due to differences in depreciation, depletion and asset impairments		900.4			900.4	900.4	966.6
Unamortized discount on Convertible Junior Subordinated Debentures		127.7			127.7	127.7	130.3
Investments and other assets		86.3			86.3	86.3	70.1
Total gross deferred tax liabilities		1,114.4			1,114.4	1,114.4	1,167
Valuation allowance, income tax		(3,881.2)			(3,881.2)	(3,881.2)	(1,447.3)
Net deferred tax liability		(17.6)			(17.6)	(17.6)	(17.2)
Deferred taxes are classified as follows:
Noncurrent deferred income taxes		(17.6)			(17.6)	(17.6)	(66.9)
Net deferred tax liability		$ (17.6)			$ (17.6)	$ (17.6)	$ (17.2)
[1]	Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction.

Income Taxes (Details 4)

Income Taxes (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 267.9
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance at beginning of period	22.9	$ 44.5	$ 143.9
Additions for current year tax positions	1.5	2.3	12
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(2.8)	(23.5)	0
Reductions for settlements with tax authorities	(1.5)	(0.4)	(111.4)
Balance at end of period	$ 20.1	$ 22.9	$ 44.5

Income Taxes (Details 5)

Income Taxes (Details 5) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of Company's tax payments
Tax (refunds) payments	$ (40.1)	$ (25.8)	$ (16.7)
Domestic Tax Authority [Member]
Summary of Company's tax payments
Tax (refunds) payments	(56.5)	(38.1)	(7.7)
State and Local Jurisdiction [Member]
Summary of Company's tax payments
Tax (refunds) payments	1.4	0.4	(6.8)
Foreign Tax Authority [Member]
Summary of Company's tax payments
Tax (refunds) payments	$ 15	$ 11.9	$ (2.2)

Income Taxes (Details Textuals)

Income Taxes (Details Textuals) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation Allowance [Line Items]
Operating Income (Loss)		$ 6,300
Income Taxes (Textuals) [Abstract]
Alternative minimum tax credits		264.3
General business credits		119.4
Deferred Tax Assets, Operating Loss Carryforwards, Domestic		2,340.4
State net operating loss carryforwards		127.9
Deferred Tax Assets, Charitable Contribution Carryforwards		1.3
Foreign loss carryforwards included in Company's tax credits and loss carryforwards		1,102.2
Valuation allowance reserve for U.S. capital losses, state NOLs, foreign NOLs and certain foreign deferred tax assets	$ (1,447.3)	(3,881.2)	$ (1,447.3)
Minerals resource rent tax, net of federal tax		0	0	$ 16.1
Change in unrecognized tax benefit		2.8
Net unrecognized tax benefits	19.6	20.1	19.6
Accrued interest related to unrecognized tax benefits included in income tax provision		0.4	2.1	$ 8
Accrued interest related to uncertain tax positions	0.4	2.4	$ 0.4
Australia Deferred Tax Assets [Member]
Income Taxes (Textuals) [Abstract]
Valuation Allowance, Deferred Tax Asset, Change in Amount		91
US Deferred Tax Assets [Member]
Income Taxes (Textuals) [Abstract]
Capital loss		60.8
Valuation Allowance, Deferred Tax Asset, Change in Amount	$ (177)	$ 2,342.9

Income Taxes (Details 6)

Income Taxes (Details 6) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Deferred income taxes	$ 8.9	$ 7.9
Other noncurrent liabilities	11.2	11.7
Net unrecognized tax benefits	20.1	19.6
Gross unrecognized tax benefits	$ 20.1	$ 22.9	$ 44.5	$ 143.9

Accounts Payable and Accrued 95

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Accounts payable and accrued expenses [Line Items]
Trade accounts payable		$ 288.6	$ 333.3
Commodity and foreign currency hedge contracts		0	231.7
Other accrued expenses		190.1	225.8
Accrued payroll and related benefits		201.2	191.9
Accrued royalties		119.6	135.9
Payable to voluntary employee beneficiary association for certain Patriot retirees	[1]	0	75
Accrued royalties		62.8	41
Accrued interest		1.2	68.8
Asset Retirement Obligations		41	25.5
Accrued environmental cleanup-related costs		0	23.9
Accounts Payable, Other		0	2.3
Workers' compensation obligations		7.8	8.6
Income taxes payable		6.2	6.8
Accrued health care insurance		16	15.8
Liabilities associated with discontinued operations		55.9	60
Total accounts payable and accrued expenses		$ 990.4	$ 1,446.3
[1]	Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction.

Debt Debt Schedule (Details)

Debt Debt Schedule (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	May 18, 2016	Apr. 18, 2016	Apr. 15, 2016	Apr. 13, 2016	Mar. 31, 2016
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount (Premium), Net	$ 89				$ 89	$ 89
Loss on early debt extinguishment	(29.5)		$ 8.3	$ 59.5	(29.5)	29.5	$ 67.8	$ 1.6
Capital lease obligations	19.7				19.7	19.7	30.3
Other long-term debt	0.4				0.4	0.4	0.7
Liabilities Subject to Compromise	8,440.2				8,440.2	8,440.2	0
Long-term Debt and Capital Lease Obligations, Current	20.2				20.2	20.2	5,874.9
Long-term Debt and Capital Lease Obligations	0				0	0	366.3
Contractual interest expense						564.9
Interest Expense, Stayed Amount						266.3
DIP Facility - Bonding Accommodation Facility [Member]
Debt Instrument [Line Items]
Long-term Debt											$ 200	$ 200
DIP Credit Agreement [Member]
Debt Instrument [Line Items]
Aggregate Letters of Credit, Maximum												50
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt	1,558.1				1,558.1	1,558.1	0						$ 947
Exit facility, maximum borrowing capacity	1,650				1,650	1,650
Letters of Credit Outstanding, Amount	$ 611				$ 611	$ 611						675
Term Loan Facility [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	4.50%				4.50%	4.50%
Exit facility, maximum borrowing capacity	$ 950				$ 950	$ 950
2013 Term Loan Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Outstanding Principal	1,170				1,170	1,170
Long-term Debt	1,154.5				1,154.5	1,154.5	1,156.3
Exit facility, maximum borrowing capacity	$ 1,200				$ 1,200	$ 1,200
7.375% Senior Notes due November 2016 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	7.375%				7.375%	7.375%
Loss on early debt extinguishment						$ 67.8
Write-off of debt issuance costs						$ 1.4
6.00% Senior Notes due November 2018 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.00%				6.00%	6.00%
Debt Instrument, Outstanding Principal	$ 1,518.8				$ 1,518.8	$ 1,518.8
Long-term Debt	$ 1,509.9				$ 1,509.9	$ 1,509.9	1,508.9
6.50% Senior Notes due September 2020 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.50%	6.50%			6.50%	6.50%
Debt Instrument, Outstanding Principal	$ 650				$ 650	$ 650
Long-term Debt	$ 645.8				$ 645.8	$ 645.8	645.5
6.25% Senior Notes due November 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.25%	6.25%			6.25%	6.25%
Debt Instrument, Outstanding Principal	$ 1,339.6				$ 1,339.6	$ 1,339.6
Long-term Debt	$ 1,327.7				$ 1,327.7	$ 1,327.7	1,327
10.00% Senior Secured Second Lien Notes Due 2022 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	10.00%				10.00%	10.00%
Debt Instrument, Outstanding Principal	$ 1,000				$ 1,000	$ 1,000
Long-term Debt	962.3				962.3	962.3	960.4
Face amount of senior notes	$ 1,000				$ 1,000	$ 1,000
7.875% Senior Notes due November 2026 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	7.875%	7.875%			7.875%	7.875%
Debt Instrument, Outstanding Principal	$ 250				$ 250	$ 250
Long-term Debt	245.9				245.9	245.9	245.8
Convertible Junior Subordinated Debentures [Member]
Debt Instrument [Line Items]
Debt Instrument, Outstanding Principal	732.5				732.5	732.5
Long-term Debt	367.1				367.1	367.1	366.3
Long-term Debt [Member]
Debt Instrument [Line Items]
Liabilities Subject to Compromise	$ 7,771.2				$ 7,771.2	7,771.2	0
DIP Facility - Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt												500
DIP Facility - Initially Available [Member]
Debt Instrument [Line Items]
Long-term Debt										$ 200	200	200
DIP Facility - Remaining Availability [Member]
Debt Instrument [Line Items]
Long-term Debt									$ 300			300
DIP Term Loan Facility [Member]
Debt Instrument [Line Items]
Debt Issuance Cost		$ 26.8
Loss on early debt extinguishment						$ (29.5)
Early Repayment of DIP Financing						10
Write-off of debt issuance costs						$ 19.5
DIP Facility - Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount											$ 100	$ 100
6.000% Senior Secured Notes Due 2022 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.00%				6.00%	6.00%
Face amount of senior notes	$ 500				$ 500	$ 500
6.375% Senior Secured Notes Due 2025 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.375%				6.375%	6.375%
Face amount of senior notes	$ 500				$ 500	$ 500
Reported Value Measurement [Member]
Debt Instrument [Line Items]
Debt and capital lease obligations	$ 7,791.4				$ 7,791.4	$ 7,791.4	$ 6,241.2
Eurocurrency Rate [Member] | Term Loan Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum						1.00%

Debt Credit Agreement (Details)

Debt Credit Agreement (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Apr. 13, 2016
Line of Credit Facility [Line Items]
Interest Expense, Adequate Protection Payments				$ 121.4
Proceeds from long-term debt			$ 511.4	1,458.4	$ 975.7	$ 1.1
Payments of Debt Restructuring Costs	$ 10.3	$ 26.4
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Exit facility, maximum borrowing capacity			1,650	1,650
Long-term Debt		$ 947	1,558.1	1,558.1	0
Letters of credit outstanding			611	611				$ 675
Investments and Other Noncurrent Assets			479.3	479.3
Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Exit facility, maximum borrowing capacity			$ 950	$ 950
Stated interest rate - percentage			4.50%	4.50%
2013 Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Exit facility, maximum borrowing capacity			$ 1,200	$ 1,200
Long-term Debt			1,154.5	1,154.5	1,156.3
6.00% Senior Notes due November 2018 [Member]
Line of Credit Facility [Line Items]
Long-term Debt			$ 1,509.9	$ 1,509.9	1,508.9
Stated interest rate - percentage			6.00%	6.00%
6.25% Senior Notes due November 2021 [Member]
Line of Credit Facility [Line Items]
Long-term Debt			$ 1,327.7	$ 1,327.7	1,327
Stated interest rate - percentage			6.25%	6.25%			6.25%
6.50% Senior Notes due September 2020 [Member]
Line of Credit Facility [Line Items]
Long-term Debt			$ 645.8	$ 645.8	645.5
Stated interest rate - percentage			6.50%	6.50%			6.50%
7.875% Senior Notes due November 2026 [Member]
Line of Credit Facility [Line Items]
Long-term Debt			$ 245.9	$ 245.9	$ 245.8
Stated interest rate - percentage			7.875%	7.875%			7.875%
Eurocurrency Rate [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum				1.00%

Debt Debt Maturities (Details)

Debt Debt Maturities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Interest paid	$ 132.3	$ 414.2	$ 404.4
Debt Instrument, Unamortized Discount (Premium), Net	$ 89

Debt Senior Notes (Details)

Debt Senior Notes (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Loss on early debt extinguishment	$ 29.5		$ (8.3)	$ (59.5)	$ 29.5		$ (29.5)	$ (67.8)	$ (1.6)
30-day grace period						30-day grace period
Interest Expense		$ 126.2			$ 150.4		$ 298.6	$ 465.4	$ 426.6
Term Loan Facility [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	4.50%				4.50%		4.50%
6.00% Senior Notes due November 2018 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.00%				6.00%		6.00%
6.50% Senior Notes due September 2020 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.50%				6.50%	6.50%	6.50%
Interest Expense							$ 21.1
6.25% Senior Notes due November 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	6.25%				6.25%	6.25%	6.25%

Debt Convertible Debentures (De

Debt Convertible Debentures (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Aggregate principal amount of debentures outstanding	$ 732.5	$ 732.5
Payments of Debt Issuance Costs	$ 28.2	$ 31	$ 28.7	$ 10.1
7.875% Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	7.875%	7.875%

Debt Senior Secured Second Lien

Debt Senior Secured Second Lien Notes (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Loss on early debt extinguishment	$ 29.5		$ (8.3)	$ (59.5)	$ 29.5	$ (29.5)	$ (67.8)	$ (1.6)
Interest Expense		$ 126.2			150.4	298.6	$ 465.4	$ 426.6
10.00% Senior Secured Second Lien Notes Due 2022 [Member]
Debt Instrument [Line Items]
Face amount of senior notes	$ 1,000				$ 1,000	$ 1,000
Stated interest rate - percentage	10.00%				10.00%	10.00%
Interest Expense						$ 50
7.375% Senior Notes due November 2016 [Member]
Debt Instrument [Line Items]
Stated interest rate - percentage	7.375%				7.375%	7.375%
Debt Instrument, Repurchased Face Amount	$ 650				$ 650	$ 650
Debt Instrument, Repurchase Amount	566.9				566.9	566.9
Debt Instrument Redemption 2016 Notes	$ 83.1				$ 83.1	83.1
Loss on early debt extinguishment						(67.8)
Tender Offer Premiums Paid on 2016 Senior Notes Repurchase						66.4
Write-off of debt issuance costs						$ 1.4

Leases (Details)

Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Future minimum lease and royalty payments
Capital Leases, 2017	$ 7.3
Capital Leases, 2018	8.9
Capital Leases, 2019	0.5
Capital Leases, 2020	0.5
Capital Leases, 2021	0.5
Capital Leases, 2022 and Thereafter	9.6
Capital Leases, Total minimum lease payments	27.3
Capital Leases, Less interest	7.6
Capital Leases, Present value of minimum capital lease payments	19.7
Operating Leases, 2017	148.7
Operating Leases, 2018	100.4
Operating Leases, 2019	60.2
Operating Leases, 2020	26.4
Operating Leases, 2021	10.6
Operating Leases, 2022 and thereafter	26.6
Operating Leases, Total minimum lease payments	372.9
Coal Lease and Royalty Obligation, 2017	6.1
Coal Lease and Royalty Obligation, 2018	5.7
Coal Lease and Royalty Obligation, 2019	5.2
Coal Lease and Royalty Obligation, 2020	4.9
Coal Lease and Royalty Obligation, 2021	5.3
Coal Lease and Royalty Obligation, 2022 and Thereafter	26.6
Coal Lease and Royalty Obligation, Total minimum lease payments	53.8
Leases (Textuals)
Rental expense under operating leases	264.7	$ 290.1	$ 306
Contingent lease expense	0	0	0
Property, plant, equipment and mine development assets, gross value under capital leases	77.9	77.5
Accumulated depreciation of property, plant, equipment and mine development assets under capital leases	48.6	32.2
Total royalty expenses on coal reserve leases	$ 389.7	$ 444.5	$ 507.8
Initial lease term for federal leases	ten years
Minimum annual production on federal leases	1.00%
Monthly royalty percentage on federal leases for coal sales using surface mining methods	12.50%
Monthly royalty percentage on federal leases for coal production using underground mining methods	8.00%
Period to redetermine royalty rates on leased coal reserves in Arizona	every ten years
Company's lease obligations secured by outstanding surety bonds	$ 94

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Total asset retirement obligation		$ 758.8	$ 758.8	$ 712.1	$ 752.5
Current portion		41	41	25.5
Liabilities incurred or acquired			0	1.3
Liabilities settled or disposed			(41.5)	(53.3)
Accretion expense			45.7	42.7
Revision to estimates			42.5	(31.1)
Noncurrent obligation		717.8	717.8	686.6
Balance at end of year — active locations		651.1	651.1	656.8
Balance at end of year — closed or inactive locations		107.7	107.7	55.3
Net gain on disposal of assets	$ (13.7)	21.4	(23.2)	$ (45)	$ (41.4)
Credit adjusted, risk-free interest rates				50.83%	6.82%
Surety bonds and bank guarantees outstanding to secure reclamation obligations or activities		374.3	374.3	$ 609.4
Amount of reclamation self-bonding in certain states in which the company qualifies		1,094.2	1,094.2	1,430.8
Letters of credit in support of reclamation obligations or activities		80	80	$ 126.6		$ 15.7
Cash collateral in support of reclamation obligations or activities		$ 233.2	$ 233.2
U.S. Obligations [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Credit adjusted, risk-free interest rates		13.45%	13.45%
Australian Operations [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Credit adjusted, risk-free interest rates		4.92%	4.92%

Postretirement Health Care a104

Postretirement Health Care and Life Insurance Benefits (Details) - Postretirement Health Care and Life Insurance Benefits [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of net periodic postretirement benefit cost
Service cost for benefits earned		$ 10.4	$ 11.2	$ 12.2
Interest cost on accumulated postretirement benefit obligation		34.5	33.8	36.4
Amortization of prior service (credit) cost		(9.2)	(6.8)	1.3
Amortization of actuarial loss		20.4	24.9	14.5
Special termination benefits	[1]	0	0	1.6
Total net periodic postretirement or pension cost		$ 56.1	$ 63.1	$ 66
[1]	Reflected in "Restructuring and pension settlement charges" in the consolidated statement of operations for the year ended December 31, 2014.

Postretirement Health Care a105

Postretirement Health Care and Life Insurance Benefits (Details 1) $ in Millions		12 Months Ended
		Dec. 31, 2016USD ($)years	Dec. 31, 2015USD ($)years	Dec. 31, 2014USD ($)
Defined Benefit Plan Disclosure [Line Items]
Prior service (cost) credit for the period		$ 4.5	$ (10.4)	$ (11.4)
Postretirement Health Care and Life Insurance Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of actuarial gains and losses amortized		0.00%
Amortization period - future working lifetime of active employees | years		10.31	10.49
Estimated net actuarial loss that will be amortized from accumulated other comprehensive (income) loss		$ 22
Prior service (cost) credit for the period		9.2
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss (gain) arising during year		32.3	$ (35.1)	115.8
Prior service credit arising during year		0	0	(18)
Amortization:
Actuarial loss		(20.4)	(24.9)	(14.5)
Prior service credit (cost)		9.2	6.8	(1.3)
Settlement related to the Patriot bankruptcy
Prior service cost	[1]	7.2	(16.6)	0
Total recorded in other comprehensive (income) loss		$ 28.3	$ (69.8)	$ 82
[1]	Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to this transaction.

Postretirement Health Care a106

Postretirement Health Care and Life Insurance Benefits (Details 2) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Increase (Decrease) in Postretirement Obligations		$ 6.3	$ 18.7	$ 9.6
Reconciled amount of plans funded status
Other		0	3.7
Postretirement Health Care and Life Insurance Benefits [Member]
Reconciled amount of plans funded status
Projected benefit obligation at beginning of period		776.1	839.1
Service cost		10.4	11.2	12.2
Interest cost		34.5	33.8	36.4
Participant contributions		0.6	1.7
Plan changes	[1]	7.2	(16.6)
Benefits paid		(49)	(46.5)
Actuarial (gain) loss	[2]	32.3	(35.1)
Settlement charges related to the Patriot bankruptcy	[3]	0	(15.2)
Special termination benefits	[4]	0	0	1.6
Projected benefit obligation at end of period		812.1	776.1	839.1
Fair value of plan assets at beginning of period		0	0
Employer contributions		48.4	44.8
Participant contributions		0.6	1.7
Benefits paid and administrative fees (net of Medicare Part D reimbursements)		(49)	(46.5)
Fair value of plan assets at end of period		0	0	$ 0
Funded status at end of year		(812.1)	(776.1)
Less current portion (included in Accounts payable and accrued expenses)		55.8	53.2
Noncurrent obligation (included in Accrued postretirement benefit costs)		$ (756.3)	$ (722.9)
[1]	Refer to Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation" herein for additional details related to the changes in the benefit obligation.
[2]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmM4ZGM3OGZmYTM4MTQ2ZDJhNDIwYjkyYzM3MzZjOWRhfFRleHRTZWxlY3Rpb246RDg1NzJERjA1RThFNTE2RDhDMTNBOEY5MjY4NkZCQTgM}
[3]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmM4ZGM3OGZmYTM4MTQ2ZDJhNDIwYjkyYzM3MzZjOWRhfFRleHRTZWxlY3Rpb246MzM3QUI2RjEwNDVGNTEwNkI1MjMzREM5NzU2OTBFODQM}
[4]	Reflected in "Restructuring and pension settlement charges" in the consolidated statement of operations for the year ended December 31, 2014.

Postretirement Health Care a107

Postretirement Health Care and Life Insurance Benefits (Details 3) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Postretirement Health Care and Life Insurance Benefits [Member]
Weighted-average assumptions used to determine benefit obligations
Discount rate		4.15%	4.50%
Measurement date		Dec. 31, 2016	Dec. 31, 2015
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate		4.50%	4.10%	4.90%
Measurement date		December 31, 2015	December 31, 2014	December 31, 2013
Assumed health care cost trend rates, One percentage point increase
One Percentage-Point Increase Effect on total service and interest cost components	[1]	$ 3.6
One Percentage-Point Decrease Effect on total service and interest cost component	[1]	(3.2)
One Percentage-Point Increase Effect on total postretirement benefit obligation	[1]	67
One Percentage-Point Decrease Effect on total postretirement benefit obligation	[1]	$ (61.9)
Pre-Medicare [Member]
Assumed health care cost trend rate
Health care cost trend rate assumed for next year		6.20%	6.60%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)		4.75%	4.75%
Year that the rate reaches the ultimate trend rate		2,021	2,021
Post-Medicare [Member]
Assumed health care cost trend rate
Health care cost trend rate assumed for next year		5.60%	5.80%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)		4.75%	4.75%
Year that the rate reaches the ultimate trend rate		2,021	2,021
[1]	In addition to the effect on total service and interest cost components of expense, changes in trend rates would also increase or decrease the actuarial gain or loss amortization expense component. The impact on actuarial gain or loss amortization would approximate the increase or decrease in the obligation divided by 10.31 years at January 1, 2017.

Postretirement Health Care a108

Postretirement Health Care and Life Insurance Benefits (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Estimated Future Benefit Payments
Prior service (cost) credit for the period	$ 4.5	$ (10.4)	$ (11.4)
Postretirement Health Care and Life Insurance Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss that will be amortized from accumulated other comprehensive (income) loss	22
Estimated Future Benefit Payments
Postretirement Benefits, 2017	55
Postretirement Benefits, 2018	56.2
Postretirement Benefits, 2019	57
Postretirement Benefits, 2020	57.5
Postretirement Benefits, 2021	61.3
Postretirement Benefits, Years 2022-2025	290.3
Prior service (cost) credit for the period	$ 9.2

Pension and Savings Plans (Deta

Pension and Savings Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Liabilities Subject to Compromise		$ 8,440.2	$ 0
Components of net periodic pension costs
Settlement Charge		21.7	29.6	$ 28.3
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		$ 773	$ 757.3	$ 839.8
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	5.90%	6.00%	6.25%	6.85%
Components of net periodic pension costs
Service cost for benefits earned		$ 2.5	$ 2.7	$ 2.1
Interest cost on projected benefit obligation		41.5	40.4	45.4
Expected return on plan assets		(45.3)	(48.2)	(54.3)
Amortization of prior service cost		0.3	1	1.3
Amortization of actuarial losses		24.7	39.6	30.2
Settlement Charge		0	0	8.7
Total net periodic postretirement or pension cost		23.7	35.5	$ 33.4
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		14.1	23
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		162.8	152.1
Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		265.7	259.4
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		0	0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		0	0
International debt securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		12.6	15
International debt securities | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		0	0
International debt securities | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		$ 0	$ 0

Pension and Savings Plans (D110

Pension and Savings Plans (Details 1) - Pension Plan [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss (gain) arising during year	$ 6.6	$ 30.6	$ 79.2
Amortization:
Net actuarial loss	(24.7)	(39.6)	(30.2)
Prior service cost	(0.3)	(1)	(1.3)
Settlement Charge	0	0	8.7
Total recorded in other comprehensive (income) loss	$ (18.4)	$ (10)	$ 39

Pension and Savings Plans (D111

Pension and Savings Plans (Details 2) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amounts recognized in the consolidated balance sheets:
Liabilities Subject to Compromise		$ 8,440.2	$ 0
Pension Plan [Member]
Change in benefit obligation:
Projected benefit obligation at beginning of period		939.3	1,002.5
Service cost		2.5	2.7	$ 2.1
Interest cost		41.5	40.4	45.4
Benefits paid		(61.1)	(62.6)
Actuarial (gain) loss	[1]	37.1	(43.7)
Projected benefit obligation at end of period		959.3	939.3	1,002.5
Fair value of plan assets at beginning of period		757.3	839.8
Actual (loss) return on plan assets		75.7	(26.1)
Employer contributions		1.1	6.2
Fair value of plan assets at end of period		773	757.3	$ 839.8
Funded status at end of year		(186.3)	(182)
Amounts recognized in the consolidated balance sheets:
Current obligation (included in Accounts payable and accrued expenses)		0	(1.6)
Noncurrent obligation (included in Other noncurrent liabilities)		(163.5)	(180.4)
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Other		(22.8)
Net amount recognized		$ (186.3)	$ (182)
[1]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmM4ZGM3OGZmYTM4MTQ2ZDJhNDIwYjkyYzM3MzZjOWRhfFRleHRTZWxlY3Rpb246NjA3OEM4NzZGMUIyNTM2Njk4M0IyQ0MxRDYwOTQ3RkMM}

Pension and Savings Plans (D112

Pension and Savings Plans (Details 3) - Pension Plan [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted-average assumptions used to determine benefit obligations
Discount rate		4.15%	4.55%
Measurement date		Dec. 31, 2016	Dec. 31, 2015
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate		4.55%	4.15%	4.95%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	5.90%	6.00%	6.25%	6.85%
Measurement date		December 31, 2015	December 31, 2014	December 31, 2013

Pension and Savings Plans (D113

Pension and Savings Plans (Details 4) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 295.1	$ 281.2
Level 1 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	162.8	152.1
Level 2 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	301	301
Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	14.1	23
Equity Funds [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	119.9	107.1
Equity Funds [Member] | Level 1 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	119.9	107.1
Equity Funds [Member] | Level 2 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Equity Funds [Member] | Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
International equity securities | Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period		0
U.S. debt securities
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	47.8	53.4
U.S. debt securities | Level 1 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	25.1	26.8
U.S. debt securities | Level 2 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	22.7	26.6
U.S. debt securities | Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0
International debt securities
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	12.6	15
International debt securities | Level 1 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
International debt securities | Level 2 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	12.6	15
International debt securities | Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Banks, Trust and Insurance, Equities [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	109	97.3
Corporate Debt Securities [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	265.7	259.4
Corporate Debt Securities [Member] | Level 1 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Corporate Debt Securities [Member] | Level 2 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	265.7	259.4
Corporate Debt Securities [Member] | Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Short-term investments
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	17.8	18.2
Short-term investments | Level 1 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	17.8	18.2
Short-term investments | Level 2 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Short-term investments | Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Interests in real estate
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	14.1	23
Interests in real estate | Level 1 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Interests in real estate | Level 2 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	0	0
Interests in real estate | Level 3 [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	14.1	23	$ 30.2
Private Equity Funds [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	186.1	183.9
Fair Value Pension Plan Assets [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	477.9	476.1
Pension Plans, Defined Benefit [Member]
Fair value of assets in the Master Trust by category and by fair value valuation hierarchy
Fair value of plan assets at end of period	$ 773	$ 757.3	$ 839.8

Pension and Savings Plans (D114

Pension and Savings Plans (Details 5) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Corporate Debt Securities [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	$ 259.4
Assets Held At Reporting Date:
Fair value of plan assets at end of period	$ 265.7	$ 259.4
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for assets of Master Trust	2.00%	3.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for assets of Master Trust		31.00%
Fixed Income Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for assets of Master Trust		69.00%
Real Estate Investment [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	$ 23
Assets Held At Reporting Date:
Fair value of plan assets at end of period	14.1	$ 23
Private Equity Funds [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	183.9
Assets Held At Reporting Date:
Fair value of plan assets at end of period	186.1	183.9
Banks, Trust and Insurance, Equities [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	97.3
Assets Held At Reporting Date:
Fair value of plan assets at end of period	109	97.3
Fair Value, Inputs, Level 2 [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	301
Assets Held At Reporting Date:
Fair value of plan assets at end of period	301	301
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	259.4
Assets Held At Reporting Date:
Fair value of plan assets at end of period	265.7	259.4
Fair Value, Inputs, Level 2 [Member] | Real Estate Investment [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	0
Assets Held At Reporting Date:
Fair value of plan assets at end of period	0	0
Level 3 [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	23
Assets Held At Reporting Date:
Fair value of plan assets at end of period	14.1	23
Level 3 [Member] | Corporate Debt Securities [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	0
Assets Held At Reporting Date:
Fair value of plan assets at end of period	0	0
Level 3 [Member] | Real Estate Investment [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	23	30.2
Assets Held At Reporting Date:
Realized gains	1.8	3.2
Unrealized gains relatng to investments still held at the reporting date	0.2	0.2
Purchases, sales and settlements, net	(10.9)	(10.6)
Fair value of plan assets at end of period	14.1	23
Pension Plans, Defined Benefit [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	757.3	839.8
Assets Held At Reporting Date:
Fair value of plan assets at end of period	$ 773	$ 757.3

Pension and Savings Plans (D115

Pension and Savings Plans (Details 6) - Pension Plan [Member] $ in Millions	Dec. 31, 2016USD ($)
Estimated Future Benefit Payments
2,017	$ 61.7
2,018	62.3
2,019	62.2
2,020	64
2,021	65.1
Years 2022-2025	$ 312.4

Pension and Savings Plans (D116

Pension and Savings Plans (Details Textuals)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016USD ($)yearsplans	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Defined Benefit Plan Disclosure [Line Items]
Estimated prior service cost that will be amortized from accumulated other comprehensive loss		$ 4,500,000	$ (10,400,000)	$ (11,400,000)
Settlement Charge		$ 21,700,000	29,600,000	28,300,000
Defined Contribution Plans [Abstract]
Number of 401(k) plans | plans		2
Paid discretionary contributions to defined contribution pension plans, company match		$ 19,200,000	22,000,000	44,700,000
Additional discretionary contributions to defined contribution pension plans, performance feature			$ 19,500,000	18,300,000
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Settlements, Benefit Obligation				$ 41,700,000
Actuarial gains and losses amortization corridor, percentage		5.00%
Period of amortization (in years) | years		5
Estimated net actuarial loss that will be amortized from accumulated other comprehensive loss		$ 25,400,000
Estimated prior service cost that will be amortized from accumulated other comprehensive loss		$ 300,000
Expected rate of return on plan assets	5.90%	6.00%	6.25%	6.85%
Accumulated benefit obligation for pension plans		$ 959,300,000	$ 939,300,000
Minimum funded percentage defined by the Pension Protection Act of 2006		80.00%
Pension and Other Postretirement Benefit Contributions		$ 500,000
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year		5,900,000
Settlement Charge		0	$ 0	$ 8,700,000
Other Pension Plan, Postretirement or Supplemental Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefit Contributions		$ 600,000
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for assets of Master Trust			31.00%
Fixed Income Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for assets of Master Trust			69.00%
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for assets of Master Trust		2.00%	3.00%

Stockholders' Equity (Details)

Stockholders' Equity (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of common stock activity
Shares outstanding at the beginning of the year	18.5	18.1	18
Stock grants to employees	0	0.2	0.1
401k Performance contribution	0	0.2	0
Employee stock purchases	0.1	0.1	0.1
Shares relinquished	(0.1)	(0.1)	(0.1)
Shares outstanding at the end of the year	18.5	18.5	18.1

Stockholders' Equity (Details T

Stockholders' Equity (Details Textuals) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended					60 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2014shares	Dec. 31, 2008USD ($)	Dec. 31, 2006USD ($)	Dec. 31, 2017	Dec. 31, 2013shares
Class of Stock [Line Items]
Stockholders' Equity, Reverse Stock Split	Pursuant to the authorization provided at a special meeting of the Company's stockholders held on September 16, 2015, the Company completed a 1-for-15 reverse stock split of the shares of the Company’s common stock on September 30, 2015 (the Reverse Stock Split). Refer to Note 1. "Summary of Significant Accounting Policies" for additional details surrounding the Reverse Stock Split.	Pursuant to the authorization provided at a special meeting of the Company's stockholders held on September 16, 2015, the Company completed a 1-for-15 reverse stock split of the shares of the Company’s common stock on September 30, 2015 (the Reverse Stock Split). As a result of the Reverse Stock Split, every 15 shares of issued and outstanding common stock were combined into one issued and outstanding share of Common Stock, without any change in the par value per share.
Schedule Of Stock By Class (Textuals) [Abstract]
Common Stock, shares authorized	53.3
Preferred Stock, Par or Stated Value Per Share | $ / shares	$ 0.01
Common Stock, par or Stated Value Per Share | $ / shares	$ 0.01
Number of votes entitled for common stock holders	one vote per share
Aggregate principal amount of debentures outstanding | $	$ 732.5
Liquidation preference of perpetual preferred stock, per share | $ / shares	$ 1,000
Perpetual Preferred Stock annual cumulative dividend rate	3.0875%
DefinedIntervalInYearstoPayDividendsonPerpetualPreferredStock						five
ElectedMembersToServeOnCompanysBoardOfDirectors	two
Period for payment of dividend on perpetual preferred stock	10
NumberOfFailedAmountOfDividendsOnPreferredStock	six
Authorized amount for common stock repurchase | $	$ 1,000
Treasury Stock, shares	0.8	0.8
Cost of shares repurchased | $	$ 299.6			$ 199.8	$ 99.8
Amount available for repurchase of shares under share repurchase program | $	$ 700.4
Shares relinquished	0.1	0.1	0.1
Common Stock, shares outstanding	18.5	18.5	18.1				18
Common Stock [Member]
Schedule Of Stock By Class (Textuals) [Abstract]
Common Stock, shares authorized	53.3	53.3
Common Stock, par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Common Stock, shares outstanding	18.5	18.5
Preferred Stock [Member]
Schedule Of Stock By Class (Textuals) [Abstract]
Preferred Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Preferred Stock, shares outstanding	0	0
Preferred Stock, shares authorized	10	10
Series Common Stock [Member]
Schedule Of Stock By Class (Textuals) [Abstract]
Common Stock, shares authorized	40	40
Common Stock, par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Common Stock, shares outstanding	0	0
Perpetual Preferred Stock Member
Schedule Of Stock By Class (Textuals) [Abstract]
Preferred Stock, shares outstanding	0	0
Preferred Stock, shares authorized	0.8	0.8
Treasury Stock [Member]
Schedule Of Stock By Class (Textuals) [Abstract]
Treasury Stock, shares	0.5

Share-Based Compensation (Detai

Share-Based Compensation (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	0.1	1.2
Share-based compensation expense		$ 26.2	$ 46.1
Share-based Compensation, Total	$ 12.8	28.2	46.8
Tax benefit	0	0	17.3
Share-based compensation expense, net of tax benefit	12.8	28.2	29.5
Cash received upon the exercise of stock options and from employee stock purchases	0	3.4	5.5
Write-off tax benefits related to share-based compensation	0	0	(8.3)
Equity Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	11.3	26.2	46.1
Other Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1.5	$ 2	$ 0.7
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1

Share-Based Compensation (De120

Share-Based Compensation (Details 1) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	100,000	1,200,000
Share-based Compensation for equity-classified awards		$ 26.2	$ 46.1
Share-based Compensation, Total	$ 12.8	28.2	46.8
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	0	0	17.3
Share Based Compensation Expense Net of Tax	$ 12.8	28.2	29.5
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,000,000
Other Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation for equity-classified awards	$ 1.5	$ 2	$ 0.7
Restricted Stock Units (RSUs) [Member]
Summary of restricted stock award activity
Nonvested, Beginning of Period	48,780
Granted	342,627
Vested	(23,220)
Forfeited	(59,629)
Nonvested, End of Period	308,558	48,780
Weighted Average Grant-Date Fair Value, Beginning of Period	$ 170.42
Weighted Average Grant-Date Fair Value, Granted	7.75
Weighted Average Grant Date Fair Value, Vested	149.84
Weighted Average Grant Date Fair Value, Forfeited	22.41
Weighted Average Grant-Date Fair Value, End of Period	$ 16.98	$ 170.42
Restricted Stock [Member]
Summary of restricted stock award activity
Nonvested, Beginning of Period	306,931
Granted	7,847
Vested	(76,663)
Forfeited	(30,076)
Nonvested, End of Period	196,744	306,931
Weighted Average Grant-Date Fair Value, Beginning of Period	$ 184.09
Weighted Average Grant-Date Fair Value, Granted	7.75
Weighted Average Grant Date Fair Value, Vested	277.28
Weighted Average Grant Date Fair Value, Forfeited	167.68
Weighted Average Grant-Date Fair Value, End of Period	$ 151.72	$ 184.09
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Cancelled in Period	11,295
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Cancelled in Period, Weighted Average Grant Date Fair Value	$ 82.49
Performance unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	1 year	1 year 7 months 27 days
Summary of restricted stock award activity
Nonvested, Beginning of Period	81,812
Vested	(24,474)
Forfeited	(5,916)
Nonvested, End of Period	51,422	81,812

Share-Based Compensation (De121

Share-Based Compensation (Details 2) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Share-based Compensation, Stock Options, Activity
Granted	0	200,000	100,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	7,847
Schedule of Share-based Compensation, Stock Options, Activity
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 7.75
Stock Options [Member]
Schedule of Share-based Compensation, Stock Options, Activity
Options outstanding, Beginning Balance	240,428
Forfeited	(22,182)
Options outstanding, Ending Balance	218,246	240,428
Options Vested and Exercisable	162,402
Weighted Average Exercise Price, Beginning of Period	$ 388.16
Weighted Average Exercise Price, Forfeited	419.40
Weighted Average Exercise Price, End of Period	379.17	$ 388.16
Options Vested and Exercisable, Weighted Average Exercise Price	$ 451.88
Weighted Average Remaining Contractual Life	5 years 6 months 22 days	6 years 3 months 12 days
Options Vested and Exercisable, Weighted Average Remaining Contractual Life	4 years 10 months 9 days
Aggregate Intrinsic Value, End of Period	$ 0	$ 0
Options Vested and Exercisable, Aggregate Intrinsic Value	$ 0

Share-Based Compensation (De122

Share-Based Compensation (Details 3) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation for equity-classified awards		$ 26,200,000	$ 46,100,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 0	0	17,300,000
Weighted-average fair value		$ 43.66	$ 110.70
Expected option life		5 years	5 years
Cliff Vest [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Fair Value	$ 21,300,000	$ 35,700,000	$ 24,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Cancelled in Period, Weighted Average Grant Date Fair Value	$ 82.49
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	76,663
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 277.28
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	196,744	306,931
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 151.72	$ 184.09
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	7,847
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 7.75
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 167.68
Performance unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	24,474
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	51,422	81,812
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	1 year	1 year 7 months 27 days
Risk-free interest rate		1.10%	0.80%
Expected volatility		45.00%	45.30%
Dividend yield		2.40%	1.70%
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Fair Value	$ 3,500,000	$ 2,100,000	$ 100,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	23,220
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 149.84
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	308,558	48,780
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 16.98	$ 170.42
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	342,627
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 7.75
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 22.41
Other Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation for equity-classified awards	$ 1,500,000	$ 2,000,000	$ 700,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	4 years 10 months 9 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 6 months 22 days	6 years 3 months 12 days
Risk-free interest rate		1.70%	1.70%
Expected volatility		45.20%	48.40%
Dividend yield		2.40%	1.70%
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years

Share-Based Compensation (De123

Share-Based Compensation (Details 5) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Expense Net of Tax	$ 12.8	$ 28.2	$ 29.5
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	308,558	48,780
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	59,629
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	23,220
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 16.98	$ 170.42
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	196,744	306,931
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	30,076
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	76,663
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Cancelled in Period	11,295
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 151.72	$ 184.09
Vesting Period [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Cliff Vest [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Performance unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	51,422	81,812
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	5,916
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	24,474
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate		1.10%	0.80%
Expected volatility		45.00%	45.30%
Dividend yield		2.40%	1.70%

Share-Based Compensation (De124

Share-Based Compensation (Details Textuals)	12 Months Ended
	Dec. 31, 2016USD ($)yearsshares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)shares
Share-Based Compensation Textuals [Abstract]
Number of Shares Authorized | shares	100,000	1,200,000
Unrecognized compensation cost related to nonvested awards net of tax Total	$ 4,900,000
Unrecognized compensation cost period for recognition, years	1 year
Unrecognized compensation cost period for recognition, weighted-average, years | years	0.5
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Total intrinsic value of options exercised	$ 0	$ 0	$ 400,000
Maximum employee Contribution to employee stock purchase plans based on compensation, percentage			15.00%
Maximum employee Contribution to employee stock purchase plans based on compensation, amount			$ 25,000
Common stock discount under employee stock purchase plans			15.00%
Employee Stock Purchase Plans,Fair value estimation			estimated by adding the fair value of 0.15 of one share of stock to the fair value of 0.85 of an option on one share of stock
Stock Issued During Period, Shares, Employee Stock Purchase Plans | shares	100,000	100,000	100,000
Deferred Stock Units [Member]
Share-Based Compensation Textuals [Abstract]
Vesting period of performance units	1 year
Restricted Stock Awards [Member]
Share-Based Compensation Textuals [Abstract]
Vesting period of performance units	3 years
Restricted Stock [Member]
Share-Based Compensation Textuals [Abstract]
Total fair value of restricted stock awards granted	$ 100,000	$ 26,000,000	$ 25,500,000
Total fair value of restricted stock awards vested	$ 21,300,000	35,700,000	24,500,000
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Textuals [Abstract]
Vesting period of performance units	5 years
Total fair value of restricted stock awards granted	$ 2,700,000	5,500,000	4,200,000
Total fair value of restricted stock awards vested	$ 3,500,000	$ 2,100,000	$ 100,000
Vesting Period [Domain]
Share-Based Compensation Textuals [Abstract]
Vesting period of performance units	3 years
Cliff Vest [Domain]
Share-Based Compensation Textuals [Abstract]
Vesting period of performance units	3 years
Performance unit [Member]
Share-Based Compensation Textuals [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Description	three
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		1.10%	0.80%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate		45.00%	45.30%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate		2.40%	1.70%
Number of outstanding units vested | shares	24,474

Accumulated Other Comprehens125

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Other Comprehensive Income, Available-For-Sale Securities, Net Unamortized (Gain) Loss Arising During Period, Net of Tax	$ 0	$ 0		$ 0
After-tax components of comprehensive income (loss)
Foreign Currency Translation Adjustment, Beginning Balance	(146.4)	(111.5)		(70.5)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	0	0		0
Reclassification from other comprehensive income to earnings	0	0		0
Foreign currency translation adjustment	(1.8)	(34.9)		(41)
Foreign Currency Translation Adjustment, Ending Balance	(148.2)	(146.4)		(111.5)
Accumulated Other Comprehensive Income Loss Acturial Loss Associated With Postretirement Plans And Workers Compensation Obligation Net Of Tax						$ (256.3)	$ (263.8)	$ (317.5)	$ (205.8)
Other Comprehensive Income (Loss), Postretirement Plans and Workers' Compensation Obligations, Period Increase Decrease, Net of Tax	0	0		0
Reclassification from other comprehensive income to earnings	21	35.6		31
Current period change	(13.5)	18.1		(142.7)
Prior Service Cost Associated with Postretirement Plans, Beginning Balance	31.8	25.1		12
Other Comprehensive Income (Loss), Prior Service Cost Associated with Postretirement Plans, Period Increase Decrease, Net of Tax	0	0		0
Reclassification from other comprehensive income to earnings	(5.6)	(3.7)		1.7
Current period change	(4.5)	10.4		11.4
Prior Service Cost Associated with Postretirement Plans, Ending Balance	21.7	31.8		25.1
Cash Flow Hedges, Beginning Balance	(240.5)	(360.9)		(155.7)
Increase in fair value of cash flow hedges, net of tax	0	(131.3)		(195)
Reclassification for realized losses (gains) included in net loss	146.3	251.7		(10.2)
Current Period Change	0	0		0
Cash Flow Hedges, Ending Balance	(94.2)	(240.5)		(360.9)
Available-For-Sale Securities Adjustment, Beginning Balance	0	0		0.8
Unrealized holding losses on available-for-sale securities	0	0		(3.7)
Reclassification from other comprehensive income to earnings	0	0		(2.9)
Available-For-Sale Securities Adjustment, Ending Balance	0	0		0
Total Accumulated Other Comprehensive Income (Loss), Beginning Balance	(477)	(618.9)		(764.8)		$ (477)	$ (618.9)	$ (764.8)	$ (419.2)
Accumulated Other Comprehensive Loss Net Change in Fair Value of Cash Flow Hedges and Available for Sale Securities	0	(131.3)		(198.7)
Total Accumulated Other Comprehensive Income (Loss), Reclassification	161.7	283.6		25.4
Total Accumulated Other Comprehensive Income (Loss), Current period change net of tax	(19.8)	(6.4)		(172.3)
Total Accumulated Other Comprehensive Income (Loss), Ending Balance	(477)	(618.9)		(764.8)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Cash flow hedges		(438.4)	[1]	$ (47.9)	[2]
Definedbenefitpensionplanspriorservicecost [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	0.3	1
IncomeTaxProvisionCashFlowHedges [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Cash flow hedges	85.9	134
TotalBeforeIncomeTaxesCashFlowHedges [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Cash flow hedges	232.2	385.7
InsignificantItemsCashFlowHedges [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Cash flow hedges	0.5	0.7
CoalTradingOtherRevenues [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Cash flow hedges	0	(51.8)
CommoditySwapsOperatingCostsAndExpenses [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Cash flow hedges	86.1	120.4
ForeignCurrencyCashFlowHedgeContractsOperatingCostsAndExpenses [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Cash flow hedges	145.6	316.4
Incometaxprovisionpriorservicecost [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	(3.3)	(2.1)
PriorServiceCostAssociatedWithPostretirementPlansAndWorkersCompensationObligationsTotalBeforeIncomeTaxes [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	(8.9)	(5.8)
PostretirementHealthCareAndLifeInsuranceBenefitsOperatingCostsAndExpensesPriorServiceCost [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	(9.2)	(6.8)
IncomeTaxProvisionActuarialLoss [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	(12.4)	(20.9)
NetActuarialLossAssociatedWithPostretirementPlansAndWorkersCompensationObligationsTotalBeforeIncomeTaxes [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	33.4	56.5
InsignificantItemsActuarialLoss [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	(11.7)	(8)
DefinedBenefitPensionPlansSellingAndAdministrativeExpensesActuarialLoss [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	4.2	6.7
DefinedBenefitPensionPlansOperatingCostsAndExpensesActuarialLoss [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	20.5	32.9
PostretirementHealthCareAndLifeInsuranceBenefitsOperatingCostsAndExpensesActuarialLoss [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax [Abstract]
Net actuarial loss and prior service cost associated with postretirement plans and workers compensation obligations	$ 20.4	$ 24.9
[1]	(1) Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $14.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.
[2]	Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $136.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.

Resource Management, Acquisi126

Resource Management, Acquisitions and Other Commercial Events (Details) AUD in Millions, $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
	Jan. 31, 2014USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2016AUD
OtherCommercialEvents [Line Items]
Restructuring Charges				$ 2.8	$ 15.5	$ 23.5	$ 26
Held for sale, at carrying value			$ 125			125
Proceeds from disposal of assets, net of notes receivable				142.2	144.4	70.4	203.7
Liabilities			10,028.4	$ 11,439.9	$ 11,439.9	10,028.4
Gain (loss) on sale of nonstrategic asset		$ 6.2
Interest in unincorporated joint venture project				50.00%	50.00%
Cash Collateral | AUD								AUD 50
Priairie State Campus [Member]
OtherCommercialEvents [Line Items]
Proceeds from disposal of assets, net of notes receivable					$ 57.1
Gain (loss) on sale of nonstrategic asset					6.2
NewMexico/Coloradominingtenement [Member] [Member]
OtherCommercialEvents [Line Items]
Proceeds from disposal of assets, net of notes receivable						$ 358
Gain (Loss) on Contract Termination			$ 20
Nonstrategic Australian mining tenement [Member]
OtherCommercialEvents [Line Items]
Proceeds from disposal of assets, net of notes receivable	$ 62.6				64.1
Gain (loss) on sale of nonstrategic asset		$ 2.8			0
Olivedownssouthminingtenement [Member] [Domain]
OtherCommercialEvents [Line Items]
Gain (loss) on sale of nonstrategic asset					$ 2.8
Nonstrategic Kentucky Coal Reserves And Surface Lands [Member]
OtherCommercialEvents [Line Items]
Proceeds from disposal of assets, net of notes receivable							29.6
Gain (loss) on sale of nonstrategic asset							$ 13.6
Prarie State Energy Campus [Member]
OtherCommercialEvents [Line Items]
Undivided Interest Percent Of New Electricity Generation Project				5.06%	5.06%

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																9 Months Ended	12 Months Ended
	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings per Share (EPS) (Textuals) [Abstract]
Antidilutive shares excluded from EPS calculation																		0.4	0.6	0.2
EPS numerator:
Loss from continuing operations, net of income taxes	$ (186.2)		$ (95.6)		$ (230.8)		$ (161.7)		$ (497.9)		$ (144.4)		$ (1,007.2)		$ (164.4)		$ (440.1)	$ (674.3)	$ (1,813.9)	$ (749.1)
Less: Net income attributable to noncontrolling interests																	$ 7.9	7.9	7.1	9.7
Loss from continuing operations attributable to common stockholders, before allocation of earnings to participating securities																		(682.2)	(1,821)	(758.8)
Less: Earnings allocated to participating securities																		0	0	1
Loss from continuing operations attributable to common stockholders, after allocation of earnings to participating securities																		(682.2)	(1,821)	(759.8)
Loss from discontinued operations attributable to common stockholders, after allocation of earnings to participating securities																		(57.6)	(175)	(28.2)
Net loss attributable to common stockholders, after earnings allocated to participating securities																		$ (739.8)	$ (1,996)	$ (788)
EPS denominator:
Weighted average shares outstanding - basic	18.3		18.3		18.3		18.3		18.2		18.2		18.2		18			18.3	18.1	17.9
Weighted average shares outstanding - diluted																		18.3	18.1	17.9
Basic EPS attributable to common stockholders:
Loss from continuing operations	$ (10.42)	[1]	$ (5.32)	[1]	$ (12.71)	[1]	$ (8.85)	[1]	$ (27.28)	[2]	$ (8.08)	[2]	$ (55.59)	[2]	$ (9.31)	[2]		$ (37.30)	$ (100.34)	$ (42.52)
Loss from discontinued operations																		(3.15)	(9.64)	(1.57)
Net loss attributable to common stockholders																		(40.45)	(109.98)	(44.09)
Diluted EPS attributable to common stockholders:
Loss from continuing operations																		(37.30)	(100.34)	(42.52)
Loss from discontinued operations																		(3.15)	(9.64)	(1.57)
Net loss attributable to common stockholders																		$ (40.45)	$ (109.98)	$ (44.09)
[1]	EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis.
[2]	EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis

Management - Labor Relations La

Management - Labor Relations Labor Relations (Details)	12 Months Ended
	Dec. 31, 2016
Concentration Risk [Line Items]
Entity Number of Employees	6,700
Entity Number Of Hourly Employees	5,100
Percentage of hourly employees represented by organized labor unions	39.00%
Percentage Of Coal Production Generated By Hourly Employees Represented By Organized Labor Unions	22.00%
Number of US Mines Represented by Unions	1
United Mine Workers of America [Member]
Concentration Risk [Line Items]
Percentage of hourly employees represented by organized labor unions	8.00%
Percentage Of Coal Production Generated By Hourly Employees	4.00%
North Wambo UG Employees [Domain]
Concentration Risk [Line Items]
Percentage Of Coal Production Generated By Australian Hourly Employees Under Contract Negotiation	10.00%
North Wambo UG Employees [Member]
Concentration Risk [Line Items]
Percentage Of Australian Hourly Employees Under Contract Negotiations	8.00%
Metropolitan Employees [Member]
Concentration Risk [Line Items]
Percentage Of Australian Hourly Employees Under Contract Negotiations	11.00%
Percentage Of Coal Production Generated By Australian Hourly Employees Under Contract Negotiation	6.00%
Millenium Employees [Member]
Concentration Risk [Line Items]
Percentage Of Australian Hourly Employees Under Contract Negotiations	16.00%
Percentage Of Coal Production Generated By Australian Hourly Employees Under Contract Negotiation	11.00%
Wilpinjong Employees [Member]
Concentration Risk [Line Items]
Percentage Of Australian Hourly Employees Under Contract Negotiations	18.00%
Percentage Of Coal Production Generated By Australian Hourly Employees Under Contract Negotiation	42.00%
Coppabella/Moorvale Employees [Member]
Concentration Risk [Line Items]
Percentage Of Australian Hourly Employees Under Contract Negotiations	28.00%
Percentage Of Coal Production Generated By Australian Hourly Employees Under Contract Negotiation	13.00%

Financial Instruments (Details)

Financial Instruments (Details) $ in Millions		3 Months Ended	12 Months Ended
		Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Jul. 26, 2016USD ($)
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			$ 2,015.5
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Amount in bank guarantees, letters of credit and surety bonds related to road maintenance, performance guarantees and other operations			121
Amount in Letters of Credit Held as Collateral in Support of Surety Bonds			48
Amount in letters of credit issued as collateral to support surety bonds			72.6
Cash collateral in support of reclamation obligations or activities			233.2
Letters of credit in support of reclamation obligations or activities		$ 15.7	80	$ 126.6
Total consideration received by Company related to accounts receivable sold under securitization program			2,859.9
Cash up front from sale of receivables			1,541.7
Additional cash upon collection of underlying receivables			1,155.3
Non collected receivables			162.9
Reduction in accounts receivable as a result of securitization activity				168.5
Expense associated with securitization transactions			8.2	1.8	$ 1.5
Restricted Cash and Investments, Current			54.3	0
Maximum Capacity of Securitization Program			180	$ 275
Restricted Cash and Cash Equivalents			40.5
Restricted Cash and Investments, Noncurrent			71.4
DTA and PBGC [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Letters of credit outstanding			$ 37
Dominion Terminal Associates Partnership [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Ownership percentage of equity method investment			37.50%
DTA Lease Term			30
Pension Plans Agreement With PBG and TXU Europe [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Defined benefit pension plans requiring special contributions			2
Letter of credit maintained by the Company in favor of the PBGC			$ 37
Guarantee in place from TXU Europe Limited			110
Reclamation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			1,701.7
Coal Lease Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			94
Workers' Compensation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			61.8
Other [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk	[1]		158
Financial Standby Letter of Credit [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			381.5
Self bonding [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			1,094.2
Self bonding [Member] | Reclamation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			1,094.2
Self bonding [Member] | Coal Lease Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			0
Self bonding [Member] | Workers' Compensation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			0
Self bonding [Member] | Other [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk	[1]		0
Self bonding [Member] | Financial Standby Letter of Credit [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			0
Surety Bond [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			448.2
Surety Bond [Member] | Reclamation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			319.6
Surety Bond [Member] | Coal Lease Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			94
Surety Bond [Member] | Workers' Compensation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			19.1
Surety Bond [Member] | Other [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk	[1]		15.5
Surety Bond [Member] | Financial Standby Letter of Credit [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk	[2]		64.5
Bank Guarantees [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			79.2
Bank Guarantees [Member] | Reclamation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			54.7
Bank Guarantees [Member] | Coal Lease Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			0
Bank Guarantees [Member] | Workers' Compensation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			0
Bank Guarantees [Member] | Other [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk	[1]		24.5
Bank Guarantees [Member] | Financial Standby Letter of Credit [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			83.8
Letters of credit [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			393.9
Letters of credit [Member] | Reclamation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			233.2
Letters of credit [Member] | Coal Lease Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			0
Letters of credit [Member] | Workers' Compensation Obligations [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			42.7
Letters of credit [Member] | Other [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk	[1]		118
Letters of credit [Member] | Financial Standby Letter of Credit [Member]
Guarantee Obligations [Line Items]
Financial instruments with off balance sheet risk			233.2
Parent Company [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Restricted Cash and Investments, Current			13.8
Wyoming [Member] | Self bonding [Member] | Reclamation Obligations [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Letters of credit in support of reclamation obligations or activities						$ 0.8
Indiana [Member] | Self bonding [Member] | Reclamation Obligations [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Letters of credit in support of reclamation obligations or activities						7.5
Illinois [Member] | Self bonding [Member] | Reclamation Obligations [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Letters of credit in support of reclamation obligations or activities						$ 3.2
Scenario, Actual [Member] | Dominion Terminal Associates Partnership [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Repayments of Lines of Credit		39.9
Line of Credit Assumed		$ 42.7
U.S Mining [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Surety Bonds Outstanding For Reclamation			1,413.8
Costs Incurred, Asset Retirement Obligation Incurred			471.1
Australian Mining [Member]
Financial Instruments and Guarantees with Off-Balance-Sheet Risk (Textuals) [Abstract]
Costs Incurred, Asset Retirement Obligation Incurred			287.7
Cash collateral in support of reclamation obligations or activities			$ 233.2
[1]	Other includes the $37.0 million in letters of credit related to the PBGC, as described below, and an additional $121.0 million in bank guarantees, letters of credit and surety bonds related to road maintenance, performance guarantees and other operations.
[2]	A total of $72.6 million of letters of credit issued as collateral to support surety bonds related to Patriot have been excluded from above as they no longer represent off-balance sheet obligations as discussed in Note 27. "Matters Related to the Bankruptcy of Patriot Coal Corporation".

Commitments and Contingencies (

Commitments and Contingencies (Details 1) T in Millions, AUD in Millions

3 Months Ended

12 Months Ended

264 Months Ended

336 Months Ended

Sep. 30, 2012USD ($)

Jun. 30, 2012USD ($)T

Sep. 30, 2011USD ($)T

Dec. 31, 2016USD ($)

Dec. 31, 2016AUD

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Dec. 31, 2013USD ($)

Dec. 31, 2011USD ($)

Dec. 31, 2032yr

Dec. 31, 2042

Dec. 31, 2016AUD

Oct. 07, 2016USD ($)

Sep. 30, 2016USD ($)

Sep. 30, 2016AUD

Jul. 31, 2011USD ($)T

Long-term Purchase Commitment [Line Items]

Senior Notes

$ 287,000,000

Take-or-pay Arrangement Terms Years (Maximum)

26

Take-or-pay obligations

$ 1,596,900,000

Take-or-pay Obligations Due In One Year

209,900,000

Leased coal reserves adjacent to NARM | T

1,100

Weighted average bid price per mineable ton

1.10

Annual payments on coal reserves 2013 to 2016

247,900,000

$ 247,900,000

$ 247,900,000

Number Of Tons Of Coal In Which Company Was Named Winning Bidder Adjacent to Caballo | T

220

Bid Price Per Mineable Ton

$ 0.95

Annual Coal Reserve Payments Pursuant To Belle Ayr North Lease

42,100,000

42,100,000

$ 42,100,000

$ 42,100,000

Number Of Tons Of Coal In Which Company Was Named Winning Bidder In The Powder River Basin | T

130

Bid Price Per Mineable Ton In The Powder River Basin

1.10

Annual Coal Reserve Payments Pursuant To Caballo West Lease

28,600,000

28,600,000

28,600,000

28,600,000

Reimbursement for the difference in the federal coal lease payments made in 2011

$ 13,500,000

number of annual true up payments

5

Annual true up payments for the excess of the $1.10 bid price versus $0.95 under the transferred lease

$ 3,900,000

3,900,000

$ 3,900,000

$ 3,900,000

Federal Coal Lease Term Years | yr

20

Capital Additions [Member]

Long-term Purchase Commitment [Line Items]

Purchase commitments for capital expenditures

7,400,000

Berenergy [Member]

Long-term Purchase Commitment [Line Items]

Litigation Settlement Damages Awarded to Plaintiff

900,000

Loss Contingency Accrual

$ 13,100,000

Monto Coal Pty Limited [Member]

Long-term Purchase Commitment [Line Items]

Loss Contingency, Damages Sought, Value | AUD

AUD 15.6

Eagle Mining [Member]

Long-term Purchase Commitment [Line Items]

Loss Contingency Accrual

$ 23,400,000

Wilkie Creek [Member]

Long-term Purchase Commitment [Line Items]

Loss Contingency, Damages Sought, Value | AUD

AUD 113.1

Settlement charges total

$ 9,900,000

AUD 13

AUD 13

Commitments and Contingencie131

Commitments and Contingencies (Details 2) AUD in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2016AUD	Dec. 31, 2015USD ($)	Dec. 31, 2016AUD	Sep. 30, 2016AUD	Dec. 31, 2014USD ($)
Loss Contingency [Abstract]
Additional charge recorded as a result of the damages awarded to Eagle in arbitration			$ 15.6
Undiscounted environmental clean-up liabilities, current	$ 0		$ 0		$ 23.9
Monto Coal Pty Limited [Member]
Loss Contingency [Abstract]
Ownership Percentage In Subsidiaries	51.00%		51.00%			51.00%
Loss Contingency, Damages Sought, Value | AUD				AUD 15.6
Loss contingency damages sought value max | AUD				1,800
Eagle Mining [Member]
Loss Contingencies [Line Items]
Gain Related to Litigation Settlement					10.8
Loss Contingency [Abstract]
Loss Contingency Accrual								$ 23.4
Wilkie Creek [Member]
Loss Contingency [Abstract]
Loss Contingency, Damages Sought, Value | AUD				AUD 113.1
Loss Contingency, Loss in Period					9.7
Settlement charges total	$ 9.9		$ 9.9			AUD 13	AUD 13
Gold Fields [Member]
Loss Contingency [Abstract]
Undiscounted environmental clean-up liabilities, total	$ 62.8		$ 62.8		$ 66.9
Prarie State Energy Campus [Member]
Loss Contingency [Abstract]
Undivided Interest Percent Of New Electricity Generation Project	5.06%		5.06%			5.06%
Senior Notes [Member]
Loss Contingencies [Line Items]
Face amount of senior notes	$ 1,650		$ 1,650
Bankruptcy unliquidated, general unsecured claim [Member] | Blue Tee [Member]
Loss Contingency [Abstract]
Bankruptcy Claims, Amount of Claims Filed			65.6
Bankruptcy additional unliquidated, in an unknown amount [Member] | Blue Tee [Member]
Loss Contingency [Abstract]
Bankruptcy Claims, Amount of Claims Filed		$ 150
Bankruptcy unliquidated, secured and general unsecured [Member] | Gold Fields [Member]
Loss Contingency [Abstract]
Bankruptcy Claims, Amount of Claims Filed			2,700
Bankruptcy further contingent claims, at known and unknown sites [Member] | Blue Tee [Member]
Loss Contingency [Abstract]
Bankruptcy Claims, Amount of Claims Filed	$ 1,200		$ 500

Matters Related to the Bankr132

Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) (Details)	3 Months Ended				9 Months Ended		12 Months Ended				48 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2017USD ($)	Jan. 31, 2014USD ($)	Oct. 31, 2007USD ($)
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
CreditSupportToPatriotNetLettersOfCredit	$ 20,900,000				$ 20,900,000			$ 20,900,000
Letters of credit in support of reclamation obligations or activities	80,000,000	$ 15,700,000			80,000,000	$ 15,700,000		80,000,000	$ 126,600,000
Charge to Patriot credit support									34,700,000
Correction of error in Patriot credit support liability									16,600,000
Potential exposure from Patriot bankruptcy	$ 150,000,000				$ 150,000,000			$ 150,000,000
Liability recorded related to Patriot Bankruptcy								123.3
Portion of Patriot Liability Paid								0.7
estimated fund onbligation													$ 40,000,000
Patriot charge to loss from discontinued operations								$ (57,600,000)	(182,200,000)	$ (23,800,000)
Amount paid to the Combined Benefit Fund								2.6
Combined Benefit Fund Lower Estimate								$ 2,000,000
Combined Benefit Fund Future Estimate								$ 3,000,000
Liability related to Combined Benefit Fund								22.7
Number of VEBA payments from Patriot settlement	4				4			4
Initial Payment based on the negotiated settlement												$ 90,000,000
Payment to Patriot based on the construct of the negotiated settlement												$ 70,000,000
Payment to the VEBA based on the construct of the negotiated settlement									75,000,000	20,000,000
Gain on VEBA settlement						68,100,000		$ 68,100,000	0	0
Number of annual payments to VEBA	5				5			5
Payment to VEBA for start up and administrative costs								$ 100,000
Withdrawal liability related to pension plan		767,000,000				$ 767,000,000
Loss from discontinued operations, net of income taxes	$ 13,100,000	$ 38,100,000	$ 155,100,000	$ 7,600,000	$ (53,600,000)			(57,600,000)	(175,000,000)	$ (28,200,000)
Scenario, Forecast [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Funding of the newly established VEBA											$ 310,000,000
Payment to the VEBA based on the construct of the negotiated settlement							$ 70,000,000
Scenario, Actual [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Payment to the VEBA based on the construct of the negotiated settlement								75,000,000
Combined benefit fund [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Patriot charge to loss from discontinued operations								1,200,000	24,600,000
Retiree Health Care Obligations [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Payment to the VEBA based on the construct of the negotiated settlement								$ 16,100,000
United Mine Workers of America [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Loss from discontinued operations, net of income taxes	$ 54,300,000
Veba Payment [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Payment to the VEBA based on the construct of the negotiated settlement									7,500,000
Plan Effective Date [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Payment to the VEBA based on the construct of the negotiated settlement									5,000,000
90 Days after Plan Effective Date [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Payment to the VEBA based on the construct of the negotiated settlement									10,000,000
One year after previous payment date [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Payment to the VEBA based on the construct of the negotiated settlement									15,000,000
Remaining 3 years [Member]
Matters Related to the Bankruptcy of Patriot Coal Corporation (Patriot) [Line Items]
Payment to the VEBA based on the construct of the negotiated settlement									$ 15,000,000

Summary Quarterly Financial 133

Summary Quarterly Financial Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																			9 Months Ended	12 Months Ended
	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments of Debt Restructuring Costs					$ 10.3		$ 26.4
Summary of the unaudited quarterly results of operations
Revenues	$ 1,440.8		$ 1,207.1		1,040.2		1,027.2		$ 1,313.1					$ 1,418.9		$ 1,339.3		$ 1,537.9		$ 3,564.7	$ 4,715.3	$ 5,609.2	$ 6,792.2
Operating loss	(44.9)		(21.6)		(107.7)		(102.7)		(470.8)					(20.4)		(975.8)		2.2			(276.9)	(1,464.8)	(135.1)
Loss from continuing operations, net of income taxes	(186.2)		(95.6)		(230.8)		(161.7)		(497.9)					(144.4)		(1,007.2)		(164.4)		(440.1)	(674.3)	(1,813.9)	(749.1)
Net loss	(199.3)		(133.7)		(233.8)		(165.1)		(470.2)					(301.9)		(1,043.5)		(173.3)		(493.7)	(731.9)	(1,988.9)	(777.3)
Net loss attributable to common stockholders	$ (203.7)		$ (135.5)		$ (235.5)		$ (165.1)		$ (469.4)					$ (304.7)		$ (1,045.3)		$ (176.6)		(501.6)	$ (739.8)	$ (1,996)	$ (787)
Basic and diluted EPS — continuing operations(1)	$ (10.42)	[1]	$ (5.32)	[1]	$ (12.71)	[1]	$ (8.85)	[1]	$ (27.28)	[2]				$ (8.08)	[2]	$ (55.59)	[2]	$ (9.31)	[2]		$ (37.30)	$ (100.34)	$ (42.52)
Diluted EPS — continuing operations(1)																					$ (37.30)	$ (100.34)	$ (42.52)
Weighted average shares used in calculating basic and diluted EPS	18.3		18.3		18.3		18.3		18.2					18.2		18.2		18			18.3	18.1	17.9
Weighted average shares used in calculating diluted EPS																					18.3	18.1	17.9
Summary Quarterly Financial Information (Textuals) [Abstract]
Asset impairment	$ 230.7						$ 17.2		$ 377			$ 900.8								230.7	$ 247.9	$ 1,277.8	$ 154.4
Gain (Loss) on Disposition of Assets					$ 13.7															(21.4)	23.2	45	41.4
Gain (loss) on sale of nonstrategic asset					6.2
Income (Loss) from Equity Method Investments	28.8																			(26.2)	16.2	(15.9)	(107.6)
Interest Expense							$ 126.2													150.4	298.6	465.4	426.6
Reorganization Items	33.9		$ 29.7		95.4															159	159	0	0
Restructuring and pension settlement charges												21.2									15.5	23.5	26
Loss on early debt extinguishment	29.5											(8.3)	$ (59.5)							29.5	(29.5)	(67.8)	(1.6)
Loss from discontinued operations, net of income taxes	$ 13.1		$ 38.1								$ 155.1		7.6							(53.6)	(57.6)	(175)	(28.2)
Additional charge recorded as a result of the damages awarded to Eagle in arbitration																					(15.6)
Remeasurement of foreign taxes									(0.5)		$ 0.8		$ 0.2								0.4	0.5	2.7
Income tax benefit related to asset impairment									7.9			67.4								$ (6.2)	(84)	(176.4)	201.2
Change in fair value of credit support provided to Patriot												$ 34.7
Australia Deferred Tax Assets [Member]
Summary Quarterly Financial Information (Textuals) [Abstract]
Valuation Allowance, Deferred Tax Asset, Increase, Amount																					(91)
Australian Mining [Member]
Summary Quarterly Financial Information (Textuals) [Abstract]
Asset impairment																						675.2	66.7
US Deferred Tax Assets [Member]
Summary Quarterly Financial Information (Textuals) [Abstract]
Valuation Allowance, Deferred Tax Asset, Increase, Amount									$ 177												(2,342.9)
Interest In Middlemount Coal Pty Limited [Member]
Summary Quarterly Financial Information (Textuals) [Abstract]
Income (Loss) from Equity Method Investments																					22.6	$ (7)	$ (98.5)
Priairie State Campus [Member]
Summary Quarterly Financial Information (Textuals) [Abstract]
Gain (loss) on sale of nonstrategic asset																					6.2
Nonstrategic Australian mining tenement [Member]
Summary Quarterly Financial Information (Textuals) [Abstract]
Gain (loss) on sale of nonstrategic asset					$ 2.8																$ 0
[1]	EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis.
[2]	EPS for the quarters may not sum to the amounts for the year as each period is computed on a discrete basis

Segment and Geographic Infor134

Segment and Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended										9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating segment results
Revenues	$ 1,440.8	$ 1,207.1	$ 1,040.2	$ 1,027.2	$ 1,313.1			$ 1,418.9	$ 1,339.3	$ 1,537.9	$ 3,564.7	$ 4,715.3	$ 5,609.2	$ 6,792.2
Adjusted EBITDA												492.2	434.6	814
Additions to property, plant, equipment, and mine development											106.7	126.6	126.8	194.4
Federal coal lease expenditures												(249)	277.2	276.7
Loss from equity affiliates	(28.8)										26.2	(16.2)	15.9	107.6
Total assets	11,777.7				10,946.9						11,777.7	11,777.7	10,946.9	13,191.1
Property, plant, equipment and mine development, net	8,776.7				9,258.5						8,776.7	8,776.7	9,258.5	10,577.3
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												492.2	434.6	814
Depreciation, depletion and amortization											(336.7)	(465.4)	(572.2)	(655.7)
Asset retirement obligation expenses											(26.9)	(41.8)	(45.5)	(81)
Selling and Administrative expenses related to debt restructuring												21.5	0	0
Asset impairment	(230.7)			(17.2)	(377)	$ (900.8)					(230.7)	(247.9)	(1,277.8)	(154.4)
Amortization of basis related to equity affiliates												0	4.9	5.7
Interest expense												(298.6)	465.4	(426.6)
Loss on early debt extinguishment	(29.5)					8.3	$ 59.5				(29.5)	29.5	67.8	1.6
Interest income											4	5.7	7.7	15.4
Reorganization Items	(33.9)	(29.7)	(95.4)								(159)	(159)	0	0
Income tax benefit (provision)					(7.9)	$ (67.4)					6.2	84	176.4	(201.2)
Loss from continuing operations, net of income taxes	(186.2)	$ (95.6)	$ (230.8)	$ (161.7)	(497.9)			$ (144.4)	$ (1,007.2)	$ (164.4)	(440.1)	$ (674.3)	$ (1,813.9)	$ (749.1)
Revenue from external customers by geographic region
Revenue percentage												100.00%	100.00%	100.00%
U.S. [Member]
Revenue from external customers by geographic region
Revenue percentage												54.70%	57.40%	59.50%
Japan [Member]
Revenue from external customers by geographic region
Revenue percentage												6.90%	8.10%	9.50%
China [Member]
Revenue from external customers by geographic region
Revenue percentage												5.40%	7.10%	6.10%
South Korea [Member]
Revenue from external customers by geographic region
Revenue percentage												1.50%	4.10%	5.20%
Other [Member]
Revenue from external customers by geographic region
Revenue percentage												31.50%	23.30%	19.70%
Powder River Basin Mining [Member]
Operating segment results
Revenues												$ 1,473.3	$ 1,865.9	$ 1,922.9
Adjusted EBITDA												379.9	482.9	509
Additions to property, plant, equipment, and mine development												33	15	19.7
Federal coal lease expenditures												248.4	276.9	276.5
Loss from equity affiliates												0	0	0
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												379.9	482.9	509
Midwestern U.S. Mining [Member]
Operating segment results
Revenues												792.5	981.2	1,198.1
Adjusted EBITDA												217.3	269.7	306.9
Additions to property, plant, equipment, and mine development												18.7	51.3	57.4
Federal coal lease expenditures												0	0	0
Loss from equity affiliates												0	0	0
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												217.3	269.7	306.9
Asset impairment													(40.2)
Western U.S. Mining [Member]
Operating segment results
Revenues												526	682.3	902.8
Adjusted EBITDA												101.6	184.6	266.9
Additions to property, plant, equipment, and mine development												20.8	19.3	18.2
Federal coal lease expenditures												0.6	0.3	0.2
Loss from equity affiliates												0	0	0
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												101.6	184.6	266.9
Asset impairment														(2.7)
Australian Metallurgical Mining [Member]
Operating segment results
Revenues												1,090.4	1,181.9	1,613.8
Adjusted EBITDA												(16.3)	(18.2)	(151.1)
Additions to property, plant, equipment, and mine development												29.9	25.5	53.9
Federal coal lease expenditures												0	0	0
Loss from equity affiliates												0	0	0
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												(16.3)	(18.2)	(151.1)
Australian Thermal Mining [Member]
Operating segment results
Revenues												824.9	823.5	1,058
Adjusted EBITDA												217.6	193.6	264.1
Additions to property, plant, equipment, and mine development												22.1	13.6	30.2
Federal coal lease expenditures												0	0	0
Loss from equity affiliates												0	0	0
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												217.6	193.6	264.1
Asset impairment													(17.5)	(11.9)
Trading and Brokerage [Member]
Operating segment results
Revenues												(10.9)	42.8	58.4
Adjusted EBITDA												(72.2)	27	14.9
Additions to property, plant, equipment, and mine development												0	0	0
Federal coal lease expenditures												0	0	0
Loss from equity affiliates												0	0	0
Total assets	128.7				217.2						128.7	128.7	217.2	300.7
Property, plant, equipment and mine development, net	0.2				0.5						0.2	0.2	0.5	1.1
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												(72.2)	27	14.9
Corporate and Other [Member]
Operating segment results
Revenues												19.1	31.6	38.2
Adjusted EBITDA												(335.7)	(705)	(396.7)
Additions to property, plant, equipment, and mine development												2.1	2.1	15
Federal coal lease expenditures												0	0	0
Loss from equity affiliates												(16.2)	15.9	107.6
Total assets	1,990.9				1,304						1,990.9	1,990.9	1,304	2,167.4
Property, plant, equipment and mine development, net	900.1				933.9						900.1	900.1	933.9	1,332.6
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Adjusted EBITDA												(335.7)	(705)	(396.7)
Asset impairment													(544.9)	(73.1)
U.S Mining [Member]
Operating segment results
Total assets	4,255.9				4,105.8						4,255.9	4,255.9	4,105.8	4,099.1
Property, plant, equipment and mine development, net	3,970.6				3,854.5						3,970.6	3,970.6	3,854.5	3,739.9
Australian Mining [Member]
Operating segment results
Total assets	5,402.2				5,319.9						5,402.2	5,402.2	5,319.9	6,623.9
Property, plant, equipment and mine development, net	$ 3,905.8				$ 4,469.6						$ 3,905.8	3,905.8	4,469.6	5,503.7
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Asset impairment													(675.2)	(66.7)
Middlemount Mine [Member]
Segment Reporting Information [Line Items]
Valuation Allowances and Reserves, Balance														52.3
Reconciliation Of Adjusted EBITDA To Consolidated Loss From Continuing Operations [Abstract]
Change in deferred tax asset valuation allowance related to equity affiliates												$ (7.5)	$ (1)	$ 52.3

Supplemental Guarantor_Non-G135

Supplemental Guarantor/Non-Guarantor Financial Information (Details) - USD ($) $ in Millions	3 Months Ended											9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Audited Supplemental Condensed Consolidated Statements of Operations
Total revenues	$ 1,440.8	$ 1,207.1	$ 1,040.2	$ 1,027.2	$ 1,313.1				$ 1,418.9	$ 1,339.3	$ 1,537.9	$ 3,564.7	$ 4,715.3	$ 5,609.2	$ 6,792.2
Costs and expenses
Operating costs and expenses (exclusive of items shown separately below)												3,035.9	4,107.6	5,007.7	5,716.9
Depreciation, depletion and amortization												336.7	465.4	572.2	655.7
Asset retirement obligation expenses												26.9	41.8	45.5	81
Selling and administrative expenses												90.7	153.4	176.4	227.1
Restructuring and pension settlement charges							$ 21.2						15.5	23.5	26
Other operating (income) loss:
Net gain on disposal of assets			(13.7)									21.4	(23.2)	(45)	(41.4)
Asset impairment	230.7			17.2	377		900.8					230.7	247.9	1,277.8	154.4
Loss from equity affiliates and investment in subsidiaries	(28.8)											26.2	(16.2)	15.9	107.6
Interest expense				126.2								150.4	298.6	465.4	426.6
Loss on early debt extinguishment	(29.5)						8.3	$ 59.5				(29.5)	29.5	67.8	1.6
Interest income												(4)	(5.7)	(7.7)	(15.4)
Reorganization Items	33.9	29.7	95.4									159	159	0	0
(Loss) income from continuing operations before income taxes												(446.3)	(758.3)	(1,990.3)	(547.9)
Income tax (benefit) provision					7.9		$ 67.4					(6.2)	(84)	(176.4)	201.2
(Loss) income from continuing operations, net of income taxes	(186.2)	(95.6)	(230.8)	(161.7)	(497.9)				(144.4)	(1,007.2)	(164.4)	(440.1)	(674.3)	(1,813.9)	(749.1)
Loss from discontinued operations, net of income taxes	13.1	38.1				$ 155.1		$ 7.6				(53.6)	(57.6)	(175)	(28.2)
Net (loss) income	(199.3)	(133.7)	(233.8)	(165.1)	(470.2)				(301.9)	(1,043.5)	(173.3)	(493.7)	(731.9)	(1,988.9)	(777.3)
Less: Net income attributable to noncontrolling interests												7.9	7.9	7.1	9.7
Net (loss) income attributable to common stockholders	$ (203.7)	$ (135.5)	$ (235.5)	$ (165.1)	$ (469.4)				$ (304.7)	$ (1,045.3)	$ (176.6)	$ (501.6)	(739.8)	(1,996)	(787)
Parent Company [Member]
Audited Supplemental Condensed Consolidated Statements of Operations
Total revenues													0	0	0
Costs and expenses
Operating costs and expenses (exclusive of items shown separately below)													172.9	436.6	49.6
Depreciation, depletion and amortization													0	0	0
Asset retirement obligation expenses													0	0	0
Selling and administrative expenses													12.8	32.1	46.8
Restructuring and pension settlement charges													0	(3.9)	0
Other operating (income) loss:
Net gain on disposal of assets													0	(2.3)	0
Asset impairment													0	0	4.7
Loss from equity affiliates and investment in subsidiaries													185	933.9	128.5
Interest expense													288.6	468.4	423.1
Loss on early debt extinguishment													29.5	67.8	1.6
Interest income													(0.2)	(14)	(15.3)
Reorganization Items													73.4
(Loss) income from continuing operations before income taxes													(762)	(1,918.6)	(639)
Income tax (benefit) provision													(84.6)	(87.4)	116.4
(Loss) income from continuing operations, net of income taxes													(677.4)	(1,831.2)	(755.4)
Loss from discontinued operations, net of income taxes													(62.4)	(164.8)	(31.6)
Net (loss) income													(739.8)	(1,996)	(787)
Less: Net income attributable to noncontrolling interests													0	0	0
Net (loss) income attributable to common stockholders													(739.8)	(1,996)	(787)
Guarantor Subsidiaries [Member]
Audited Supplemental Condensed Consolidated Statements of Operations
Total revenues													2,830	3,535.3	4,063.8
Costs and expenses
Operating costs and expenses (exclusive of items shown separately below)													2,172.4	2,782.6	3,121.9
Depreciation, depletion and amortization													217.4	249.7	271
Asset retirement obligation expenses													15.8	13.2	23.2
Selling and administrative expenses													126.5	132.6	161.1
Restructuring and pension settlement charges													11.9	11.4	26
Other operating (income) loss:
Net gain on disposal of assets													(21.4)	(29.8)	(17.7)
Asset impairment													37.5	308.6	63.3
Loss from equity affiliates and investment in subsidiaries													4.5	6.9	7.6
Interest expense													19.6	19.6	19.5
Loss on early debt extinguishment													0	0	0
Interest income													(4.8)	(2.4)	(2.9)
Reorganization Items													82.1
(Loss) income from continuing operations before income taxes													168.5	42.9	390.8
Income tax (benefit) provision													(11)	(108.2)	23.7
(Loss) income from continuing operations, net of income taxes													179.5	151.1	367.1
Loss from discontinued operations, net of income taxes													(0.1)	1.6	(7.2)
Net (loss) income													179.4	152.7	359.9
Less: Net income attributable to noncontrolling interests													0	0.8	5.2
Net (loss) income attributable to common stockholders													179.4	151.9	354.7
Non-Guarantor Subsidiaries [Member]
Audited Supplemental Condensed Consolidated Statements of Operations
Total revenues													2,189.8	2,535.3	3,311.7
Costs and expenses
Operating costs and expenses (exclusive of items shown separately below)													2,066.8	2,249.9	3,128.7
Depreciation, depletion and amortization													248	322.5	384.7
Asset retirement obligation expenses													26	32.3	57.8
Selling and administrative expenses													14.1	11.7	19.2
Restructuring and pension settlement charges													3.6	16	0
Other operating (income) loss:
Net gain on disposal of assets													(1.8)	(12.9)	(23.7)
Asset impairment													210.4	969.2	86.4
Loss from equity affiliates and investment in subsidiaries													(20.7)	9	100
Interest expense													24.4	24.7	34.3
Loss on early debt extinguishment													0	0	0
Interest income													(34.7)	(38.6)	(47.5)
Reorganization Items													3.5
(Loss) income from continuing operations before income taxes													(349.8)	(1,048.5)	(428.2)
Income tax (benefit) provision													11.6	19.2	61.1
(Loss) income from continuing operations, net of income taxes													(361.4)	(1,067.7)	(489.3)
Loss from discontinued operations, net of income taxes													4.9	(11.8)	10.6
Net (loss) income													(356.5)	(1,079.5)	(478.7)
Less: Net income attributable to noncontrolling interests													7.9	6.3	4.5
Net (loss) income attributable to common stockholders													(364.4)	(1,085.8)	(483.2)
Consolidation, Eliminations [Member]
Audited Supplemental Condensed Consolidated Statements of Operations
Total revenues													(304.5)	(461.4)	(583.3)
Costs and expenses
Operating costs and expenses (exclusive of items shown separately below)													(304.5)	(461.4)	(583.3)
Depreciation, depletion and amortization													0	0	0
Asset retirement obligation expenses													0	0	0
Selling and administrative expenses													0	0	0
Restructuring and pension settlement charges													0	0	0
Other operating (income) loss:
Net gain on disposal of assets													0	0	0
Asset impairment													0	0	0
Loss from equity affiliates and investment in subsidiaries													(185)	(933.9)	(128.5)
Interest expense													(34)	(47.3)	(50.3)
Loss on early debt extinguishment													0	0	0
Interest income													34	47.3	50.3
Reorganization Items													0
(Loss) income from continuing operations before income taxes													185	933.9	128.5
Income tax (benefit) provision													0	0	0
(Loss) income from continuing operations, net of income taxes													185	933.9	128.5
Loss from discontinued operations, net of income taxes													0	0	0
Net (loss) income													185	933.9	128.5
Less: Net income attributable to noncontrolling interests													0	0	0
Net (loss) income attributable to common stockholders													$ 185	$ 933.9	$ 128.5

Supplemental Guarantor_Non-G136

Supplemental Guarantor/Non-Guarantor Financial Information (Details 1) - USD ($) $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 12, 2016	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	$ (199.3)	$ (133.7)	$ (233.8)	$ (165.1)	$ (470.2)	$ (301.9)	$ (1,043.5)	$ (173.3)	$ (493.7)	$ (731.9)	$ (1,988.9)	$ (777.3)
Current assets
Cash and cash equivalents	872.3				261.3				872.3	872.3	261.3	298	$ 652.1	$ 444
Restricted Cash and Investments, Current	54.3				0				54.3	54.3	0
Accounts receivable, net	473				228.8				473	473	228.8
Receivables from affiliates, net	0				0				0	0	0
Inventories	203.7				307.8				203.7	203.7	307.8
Assets from coal trading activities, net	0.7				23.5				0.7	0.7	23.5
Deferred income taxes	0				53.5				0	0	53.5
Other current assets	486.6				447.6				486.6	486.6	447.6
Total current assets	2,090.6				1,322.5				2,090.6	2,090.6	1,322.5
Property, plant, equipment and mine development, net	8,776.7				9,258.5				8,776.7	8,776.7	9,258.5	10,577.3
Deferred income taxes	0				2.2				0	0	2.2
Investments and other assets	910.4				363.7				910.4	910.4	363.7
Notes receivable from affiliates, net	0				0				0	0	0
Total assets	11,777.7				10,946.9				11,777.7	11,777.7	10,946.9	13,191.1
Current liabilities
Current portion of long-term debt	20.2				5,874.9				20.2	20.2	5,874.9
Payables to affiliates, net	0				0				0	0	0
Taxes Payable, Current	6.2								6.2	6.2
Deferred Tax Liabilities, Net, Current					3.8						3.8
Liabilities from coal trading activities, net	1.2				15.6				1.2	1.2	15.6
Accounts Payable and Accrued Liabilities, Current	990.4				1,446.3				990.4	990.4	1,446.3
Accounts Payable and Other Accrued Liabilities, Current	984.2				1,442.5				984.2	984.2	1,442.5
Total current liabilities	1,011.8				7,336.8				1,011.8	1,011.8	7,336.8
Long-term debt, less current portion	0				366.3				0	0	366.3
Deferred income taxes	17.6				69.1				17.6	17.6	69.1
Notes payable to affiliates, net	0				0				0	0	0
Other noncurrent liabilities	1,970.3				2,256.2				1,970.3	1,970.3	2,256.2
Total liabilities not subject to compromise	2,999.7				10,028.4				2,999.7	2,999.7	10,028.4
Total liabilities	11,439.9				10,028.4				11,439.9	11,439.9	10,028.4
Peabody Energy Corporation's stockholders' equity	330.2				916.9				330.2	330.2	916.9
Noncontrolling interests	7.6				1.6				7.6	7.6	1.6
Total stockholders' equity	337.8				918.5				337.8	337.8	918.5	2,726.5		3,947.9
Total liabilities and stockholders' equity	11,777.7				10,946.9				11,777.7	11,777.7	10,946.9
Liabilities Subject to Compromise	8,440.2				0				8,440.2	8,440.2	0
Net change in unrealized losses on available-for-sale securities										0	0	(0.8)
Decrease in fair value of cash flow hedges										0	(131.3)	(195)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax										(146.3)	(251.7)	10.2
Net unrealized gains (losses) on cash flow hedges										146.3	120.4	(205.2)
Prior service (cost) credit for the period										4.5	(10.4)	(11.4)
Net actuarial (loss) gain for the period										(13.5)	18.1	(142.7)
Amortization of actuarial loss and prior service cost included in net loss										15.4	31.9	32.7
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax										2.6	(60.4)	98.6
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax										(1.8)	(34.9)	(41)
Other comprehensive income from investment in subsidiaries										0	0	0
Other Comprehensive Income (Loss), Net of Tax										141.9	145.9	(345.6)
Comprehensive loss										(590)	(1,843)	(1,122.9)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										7.9	7.1	9.7
Comprehensive loss attributable to common stockholders										(597.9)	(1,850.1)	(1,132.6)
Debtor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									(501.6)
Current assets
Cash and cash equivalents	394.5								394.5	394.5			108.5
Restricted Cash and Investments, Current	13.8								13.8	13.8
Accounts receivable, net	5.2								5.2	5.2
Receivables from affiliates, net	226.9								226.9	226.9
Inventories	96.3								96.3	96.3
Assets from coal trading activities, net	0.9								0.9	0.9
Deferred income taxes	0								0	0
Other current assets	72								72	72
Total current assets	809.6								809.6	809.6
Property, plant, equipment and mine development, net	4,870.2								4,870.2	4,870.2
Deferred income taxes	0								0	0
Investments and other assets	4,282.2								4,282.2	4,282.2
Notes receivable from affiliates, net	1,036.3								1,036.3	1,036.3
Total assets	10,998.3								10,998.3	10,998.3
Current liabilities
Current portion of long-term debt	19.3								19.3	19.3
Payables to affiliates, net	0								0	0
Taxes Payable, Current	0								0	0
Liabilities from coal trading activities, net	0.1								0.1	0.1
Accounts Payable and Other Accrued Liabilities, Current	541.7								541.7	541.7
Total current liabilities	561.1								561.1	561.1
Deferred income taxes	12.1								12.1	12.1
Notes payable to affiliates, net	0								0	0
Other noncurrent liabilities	1,648.8								1,648.8	1,648.8
Total liabilities not subject to compromise	2,222								2,222	2,222
Total liabilities	10,662.2								10,662.2	10,662.2
Peabody Energy Corporation's stockholders' equity	336.1								336.1	336.1
Noncontrolling interests	0								0	0
Total stockholders' equity	336.1								336.1	336.1
Total liabilities and stockholders' equity	10,998.3								10,998.3	10,998.3
Liabilities Subject to Compromise	8,440.2								8,440.2	8,440.2
Non-Debtor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									(218.2)
Current assets
Cash and cash equivalents	477.8								477.8	477.8			$ 543.6
Restricted Cash and Investments, Current	40.5								40.5	40.5
Accounts receivable, net	467.8								467.8	467.8
Receivables from affiliates, net	0								0	0
Inventories	107.4								107.4	107.4
Assets from coal trading activities, net	0								0	0
Deferred income taxes	0								0	0
Other current assets	416.2								416.2	416.2
Total current assets	1,509.7								1,509.7	1,509.7
Property, plant, equipment and mine development, net	3,906.5								3,906.5	3,906.5
Deferred income taxes	0								0	0
Investments and other assets	596.7								596.7	596.7
Notes receivable from affiliates, net	0								0	0
Total assets	6,012.9								6,012.9	6,012.9
Current liabilities
Current portion of long-term debt	0.9								0.9	0.9
Payables to affiliates, net	226.9								226.9	226.9
Taxes Payable, Current	7.8								7.8	7.8
Liabilities from coal trading activities, net	1.3								1.3	1.3
Accounts Payable and Other Accrued Liabilities, Current	442.5								442.5	442.5
Total current liabilities	679.4								679.4	679.4
Deferred income taxes	5.5								5.5	5.5
Notes payable to affiliates, net	1,036.3								1,036.3	1,036.3
Other noncurrent liabilities	321.5								321.5	321.5
Total liabilities not subject to compromise	2,042.7								2,042.7	2,042.7
Total liabilities	2,042.7								2,042.7	2,042.7
Peabody Energy Corporation's stockholders' equity	3,962.6								3,962.6	3,962.6
Noncontrolling interests	7.6								7.6	7.6
Total stockholders' equity	3,970.2								3,970.2	3,970.2
Total liabilities and stockholders' equity	6,012.9								6,012.9	6,012.9
Liabilities Subject to Compromise	0								0	0
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										(739.8)	(1,996)	(787)
Current assets
Cash and cash equivalents	266.6				7.2				266.6	266.6	7.2	188.7		300.7
Restricted Cash and Investments, Current	13.8								13.8	13.8
Accounts receivable, net	0				0				0	0	0
Receivables from affiliates, net	899.9				582.1				899.9	899.9	582.1
Inventories	0				0				0	0	0
Assets from coal trading activities, net	0				0				0	0	0
Deferred income taxes					0						0
Other current assets	19.1				23.1				19.1	19.1	23.1
Total current assets	1,199.4				612.4				1,199.4	1,199.4	612.4
Property, plant, equipment and mine development, net	0				0				0	0	0
Deferred income taxes	0				0				0	0	0
Investments and other assets	8,652				8,476.2				8,652	8,652	8,476.2
Notes receivable from affiliates, net	0				0				0	0	0
Total assets	9,851.4				9,088.6				9,851.4	9,851.4	9,088.6
Current liabilities
Current portion of long-term debt	0				5,844				0	0	5,844
Payables to affiliates, net	0				0				0	0	0
Deferred Tax Liabilities, Net, Current					11.8						11.8
Liabilities from coal trading activities, net	0				0				0	0	0
Accounts Payable and Accrued Liabilities, Current					494.8						494.8
Accounts Payable and Other Accrued Liabilities, Current	58.9								58.9	58.9
Total current liabilities	58.9				6,350.6				58.9	58.9	6,350.6
Long-term debt, less current portion					366.3						366.3
Deferred income taxes	28				98.6				28	28	98.6
Notes payable to affiliates, net	1,032.5				1,032.6				1,032.5	1,032.5	1,032.6
Other noncurrent liabilities	160.4				323.6				160.4	160.4	323.6
Total liabilities not subject to compromise	1,279.8								1,279.8	1,279.8
Total liabilities	9,521.2				8,171.7				9,521.2	9,521.2	8,171.7
Peabody Energy Corporation's stockholders' equity	330.2				916.9				330.2	330.2	916.9
Noncontrolling interests	0				0				0	0	0
Total stockholders' equity	330.2				916.9				330.2	330.2	916.9
Total liabilities and stockholders' equity	9,851.4				9,088.6				9,851.4	9,851.4	9,088.6
Liabilities Subject to Compromise	8,241.4								8,241.4	8,241.4
Net change in unrealized losses on available-for-sale securities												(0.8)
Decrease in fair value of cash flow hedges										0	(137.1)	(225.9)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax										(146.3)	(292.1)	(31.3)
Net unrealized gains (losses) on cash flow hedges										146.3	155	(194.6)
Prior service (cost) credit for the period										0	0	0
Net actuarial (loss) gain for the period										8.9	5.5	0
Amortization of actuarial loss and prior service cost included in net loss										(6.1)	7.2	0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax										(2.8)	(12.7)	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax										0	0	0
Other comprehensive income from investment in subsidiaries										(7.2)	(21.8)	(150.2)
Other Comprehensive Income (Loss), Net of Tax										141.9	145.9	(345.6)
Comprehensive loss										(597.9)	(1,850.1)	(1,132.6)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										0	0	0
Comprehensive loss attributable to common stockholders										(597.9)	(1,850.1)	(1,132.6)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										179.4	152.7	359.9
Current assets
Cash and cash equivalents	107				4.7				107	107	4.7	1.2		0.3
Restricted Cash and Investments, Current	0								0	0
Accounts receivable, net	5.1				12.1				5.1	5.1	12.1
Receivables from affiliates, net	0				0				0	0	0
Inventories	76.8				109.4				76.8	76.8	109.4
Assets from coal trading activities, net	0.9				3.2				0.9	0.9	3.2
Deferred income taxes					65.3						65.3
Other current assets	51.2				128.1				51.2	51.2	128.1
Total current assets	241				322.8				241	241	322.8
Property, plant, equipment and mine development, net	4,381.6				4,304.8				4,381.6	4,381.6	4,304.8
Deferred income taxes	15.8				33.1				15.8	15.8	33.1
Investments and other assets	3.8				3.6				3.8	3.8	3.6
Notes receivable from affiliates, net	1,036.3				632.7				1,036.3	1,036.3	632.7
Total assets	5,678.5				5,297				5,678.5	5,678.5	5,297
Current liabilities
Current portion of long-term debt	19.3				23.8				19.3	19.3	23.8
Payables to affiliates, net	1,682.9				1,530.2				1,682.9	1,682.9	1,530.2
Deferred Tax Liabilities, Net, Current					0						0
Liabilities from coal trading activities, net	0				4.8				0	0	4.8
Accounts Payable and Accrued Liabilities, Current					479.8						479.8
Accounts Payable and Other Accrued Liabilities, Current	439.3								439.3	439.3
Total current liabilities	2,141.5				2,038.6				2,141.5	2,141.5	2,038.6
Long-term debt, less current portion					0						0
Deferred income taxes	0				0				0	0	0
Notes payable to affiliates, net	0				0				0	0	0
Other noncurrent liabilities	1,330.3				1,454.9				1,330.3	1,330.3	1,454.9
Total liabilities not subject to compromise	3,471.8								3,471.8	3,471.8
Total liabilities	3,656				3,493.5				3,656	3,656	3,493.5
Peabody Energy Corporation's stockholders' equity	2,022.5				1,803.5				2,022.5	2,022.5	1,803.5
Noncontrolling interests	0				0				0	0	0
Total stockholders' equity	2,022.5				1,803.5				2,022.5	2,022.5	1,803.5
Total liabilities and stockholders' equity	5,678.5				5,297				5,678.5	5,678.5	5,297
Liabilities Subject to Compromise	184.2								184.2	184.2
Net change in unrealized losses on available-for-sale securities												0
Decrease in fair value of cash flow hedges										0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax										0	0	0
Net unrealized gains (losses) on cash flow hedges										0	0	0
Prior service (cost) credit for the period										4.5	(10.4)	(11.4)
Net actuarial (loss) gain for the period										(22.4)	12.6	(152.6)
Amortization of actuarial loss and prior service cost included in net loss										21.5	37.3	41.4
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax										5.4	(60.3)	99.8
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax										0	0	0
Other comprehensive income from investment in subsidiaries										0	0	0
Other Comprehensive Income (Loss), Net of Tax										(5.4)	60.3	(99.8)
Comprehensive loss										174	213	260.1
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										0	0.8	5.2
Comprehensive loss attributable to common stockholders										174	212.2	254.9
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										(356.5)	(1,079.5)	(478.7)
Current assets
Cash and cash equivalents	498.7				249.4				498.7	498.7	249.4	108.1		143
Restricted Cash and Investments, Current	40.5								40.5	40.5
Accounts receivable, net	467.9				216.7				467.9	467.9	216.7
Receivables from affiliates, net	783				948.1				783	783	948.1
Inventories	126.9				198.4				126.9	126.9	198.4
Assets from coal trading activities, net	0				20.3				0	0	20.3
Deferred income taxes					0						0
Other current assets	416.3				296.4				416.3	416.3	296.4
Total current assets	2,333.3				1,929.3				2,333.3	2,333.3	1,929.3
Property, plant, equipment and mine development, net	4,395.1				4,953.7				4,395.1	4,395.1	4,953.7
Deferred income taxes	0				0				0	0	0
Investments and other assets	626.5				185.5				626.5	626.5	185.5
Notes receivable from affiliates, net	0				399.9				0	0	399.9
Total assets	7,354.9				7,468.4				7,354.9	7,354.9	7,468.4
Current liabilities
Current portion of long-term debt	0.9				7.1				0.9	0.9	7.1
Payables to affiliates, net	0				0				0	0	0
Deferred Tax Liabilities, Net, Current					3.8						3.8
Liabilities from coal trading activities, net	1.4				10.8				1.4	1.4	10.8
Accounts Payable and Accrued Liabilities, Current					467.9						467.9
Accounts Payable and Other Accrued Liabilities, Current	492.2								492.2	492.2
Total current liabilities	494.5				489.6				494.5	494.5	489.6
Long-term debt, less current portion					0						0
Deferred income taxes	5.4				1.4				5.4	5.4	1.4
Notes payable to affiliates, net	3.8				0				3.8	3.8	0
Other noncurrent liabilities	479.6				477.7				479.6	479.6	477.7
Total liabilities not subject to compromise	983.3								983.3	983.3
Total liabilities	997.9				968.7				997.9	997.9	968.7
Peabody Energy Corporation's stockholders' equity	6,349.4				6,498.1				6,349.4	6,349.4	6,498.1
Noncontrolling interests	7.6				1.6				7.6	7.6	1.6
Total stockholders' equity	6,357				6,499.7				6,357	6,357	6,499.7
Total liabilities and stockholders' equity	7,354.9				7,468.4				7,354.9	7,354.9	7,468.4
Liabilities Subject to Compromise	14.6								14.6	14.6
Net change in unrealized losses on available-for-sale securities												0
Decrease in fair value of cash flow hedges										0	5.8	30.9
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax										0	40.4	41.5
Net unrealized gains (losses) on cash flow hedges										0	(34.6)	(10.6)
Prior service (cost) credit for the period										0	0	0
Net actuarial (loss) gain for the period										0	0	9.9
Amortization of actuarial loss and prior service cost included in net loss										0	(12.6)	(8.7)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax										0	12.6	(1.2)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax										(1.8)	(34.9)	(41)
Other comprehensive income from investment in subsidiaries										0	0	0
Other Comprehensive Income (Loss), Net of Tax										(1.8)	(82.1)	(50.4)
Comprehensive loss										(358.3)	(1,161.6)	(529.1)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										7.9	6.3	4.5
Comprehensive loss attributable to common stockholders										(366.2)	(1,167.9)	(533.6)
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										185	933.9	128.5
Current assets
Cash and cash equivalents	0				0				0	0	0
Restricted Cash and Investments, Current	0								0	0
Accounts receivable, net	0				0				0	0	0
Receivables from affiliates, net	(1,682.9)				(1,530.2)				(1,682.9)	(1,682.9)	(1,530.2)
Inventories	0				0				0	0	0
Assets from coal trading activities, net	(0.2)				0				(0.2)	(0.2)	0
Deferred income taxes					(11.8)						(11.8)
Other current assets	0				0				0	0	0
Total current assets	(1,683.1)				(1,542)				(1,683.1)	(1,683.1)	(1,542)
Property, plant, equipment and mine development, net	0				0				0	0	0
Deferred income taxes	(15.8)				(30.9)				(15.8)	(15.8)	(30.9)
Investments and other assets	(8,371.9)				(8,301.6)				(8,371.9)	(8,371.9)	(8,301.6)
Notes receivable from affiliates, net	(1,036.3)				(1,032.6)				(1,036.3)	(1,036.3)	(1,032.6)
Total assets	(11,107.1)				(10,907.1)				(11,107.1)	(11,107.1)	(10,907.1)
Current liabilities
Current portion of long-term debt	0				0				0	0	0
Payables to affiliates, net	(1,682.9)				(1,530.2)				(1,682.9)	(1,682.9)	(1,530.2)
Deferred Tax Liabilities, Net, Current					(11.8)						(11.8)
Liabilities from coal trading activities, net	(0.2)				0				(0.2)	(0.2)	0
Accounts Payable and Accrued Liabilities, Current					0						0
Accounts Payable and Other Accrued Liabilities, Current	0								0	0
Total current liabilities	(1,683.1)				(1,542)				(1,683.1)	(1,683.1)	(1,542)
Long-term debt, less current portion					0						0
Deferred income taxes	(15.8)				(30.9)				(15.8)	(15.8)	(30.9)
Notes payable to affiliates, net	(1,036.3)				(1,032.6)				(1,036.3)	(1,036.3)	(1,032.6)
Other noncurrent liabilities	0				0				0	0	0
Total liabilities not subject to compromise	(2,735.2)								(2,735.2)	(2,735.2)
Total liabilities	(2,735.2)				(2,605.5)				(2,735.2)	(2,735.2)	(2,605.5)
Peabody Energy Corporation's stockholders' equity	(8,371.9)				(8,301.6)				(8,371.9)	(8,371.9)	(8,301.6)
Noncontrolling interests	0				0				0	0	0
Total stockholders' equity	(8,371.9)				(8,301.6)				(8,371.9)	(8,371.9)	(8,301.6)
Total liabilities and stockholders' equity	(11,107.1)				(10,907.1)				(11,107.1)	(11,107.1)	(10,907.1)
Liabilities Subject to Compromise	0								0	0
Net change in unrealized losses on available-for-sale securities												0
Decrease in fair value of cash flow hedges										0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax										0	0	0
Net unrealized gains (losses) on cash flow hedges										0	0	0
Prior service (cost) credit for the period										0	0	0
Net actuarial (loss) gain for the period										0	0	0
Amortization of actuarial loss and prior service cost included in net loss										0	0	0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax										0	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax										0	0	0
Other comprehensive income from investment in subsidiaries										7.2	21.8	150.2
Other Comprehensive Income (Loss), Net of Tax										7.2	21.8	150.2
Comprehensive loss										192.2	955.7	278.7
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest										0	0	0
Comprehensive loss attributable to common stockholders										192.2	955.7	278.7
Debtor Non-Debtor Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									226.1
Current assets
Cash and cash equivalents	0								0	0
Restricted Cash and Investments, Current	0								0	0
Accounts receivable, net	0								0	0
Receivables from affiliates, net	(226.9)								(226.9)	(226.9)
Inventories	0								0	0
Assets from coal trading activities, net	(0.2)								(0.2)	(0.2)
Deferred income taxes	0								0	0
Other current assets	(1.6)								(1.6)	(1.6)
Total current assets	(228.7)								(228.7)	(228.7)
Property, plant, equipment and mine development, net	0								0	0
Deferred income taxes	0								0	0
Investments and other assets	(3,968.5)								(3,968.5)	(3,968.5)
Notes receivable from affiliates, net	(1,036.3)								(1,036.3)	(1,036.3)
Total assets	(5,233.5)								(5,233.5)	(5,233.5)
Current liabilities
Current portion of long-term debt	0								0	0
Payables to affiliates, net	(226.9)								(226.9)	(226.9)
Taxes Payable, Current	(1.6)								(1.6)	(1.6)
Liabilities from coal trading activities, net	(0.2)								(0.2)	(0.2)
Accounts Payable and Other Accrued Liabilities, Current	0								0	0
Total current liabilities	(228.7)								(228.7)	(228.7)
Notes payable to affiliates, net	(1,036.3)								(1,036.3)	(1,036.3)
Other noncurrent liabilities	0								0	0
Total liabilities not subject to compromise	(1,265)								(1,265)	(1,265)
Total liabilities	(1,265)								(1,265)	(1,265)
Peabody Energy Corporation's stockholders' equity	(3,968.5)								(3,968.5)	(3,968.5)
Noncontrolling interests	0								0	0
Total stockholders' equity	(3,968.5)								(3,968.5)	(3,968.5)
Total liabilities and stockholders' equity	(5,233.5)								(5,233.5)	(5,233.5)
Liabilities Subject to Compromise	0								0	0
Noncontrolling Interest [Member]
Current liabilities
Total stockholders' equity	$ 7.6				$ 1.6				$ 7.6	$ 7.6	$ 1.6	$ 1.7		$ 39.2

Supplemental Guarantor_Non-G137

Supplemental Guarantor/Non-Guarantor Financial Information (Details 2) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Accounts Payable and Other Accrued Liabilities, Current	$ 984.2	$ 984.2	$ 1,442.5
Liabilities	11,439.9	11,439.9	10,028.4
Liabilities Subject to Compromise	8,440.2	8,440.2	0
Restricted Cash and Investments, Current	54.3	54.3	0
Deferred Tax Liabilities, Net, Current			3.8
Cash Flows From Operating Activities
Net cash provided by continuing operations	490	(22.9)	18.9	$ 441
Net cash used in discontinued operations	(29.2)	(29.9)	(33.3)	(104.4)
Net Cash Provided by (Used in) Operating Activities	460.8	(52.8)	(14.4)	336.6
Cash Flows From Investing Activities
Additions to property, plant, equipment and mine development	(106.7)	(126.6)	(126.8)	(194.4)
Changes in accrued expenses related to capital expenditures	(2.1)	(6.1)	(9.2)	(16.6)
Federal coal lease expenditures		(249)	277.2	276.7
Proceeds from disposal of assets, net of notes receivable	142.2	144.4	70.4	203.7
Purchases of debt and equity securities		0	(28.8)	(15.1)
Proceeds from sales and maturities of debt and equity securities		0	90.3	13.5
Contributions to joint ventures	(208.3)	(309.5)	(425.4)	(529.8)
Distributions from joint ventures	215.4	312.4	422.6	534.2
Advances to related parties	(39.3)	(40.4)	(3.7)	(33.7)
Repayment of loans from related parties	(39.8)	40.6	0.9	5.4
Other, net	(4.6)	(9.9)	(3.1)	(5)
Net cash used in continuing operations	(213.1)	(244.1)	(290)	(314.5)
Net cash used in investing activities		(244.1)	(290)	(314.5)
Cash Flows From Financing Activities
Proceeds from long-term debt	511.4	1,458.4	975.7	1.1
Repayments of long-term debt	(506.6)	(513.7)	(671.3)	(21)
Payment of deferred financing costs	(28.2)	(31)	(28.7)	(10.1)
Dividends paid		0	(1.4)	(92.3)
Restricted cash for distributions to noncontrolling interests			(2)
Restricted cash for distributions to noncontrolling interests		0	0	(42.5)
Other, net	(0.1)	(5.8)	(6.6)	(3.3)
Transactions with affiliates, net	0	0	0	0
Net cash provided by (used in) financing activities	(27.5)	907.9	267.7	(168.1)
Net change in cash and cash equivalents	220.2	611	(36.7)	(146)
Cash and cash equivalents at beginning of year	652.1	261.3	298	444
Cash and cash equivalents at end of year	872.3	872.3	261.3	298
Accounts Payable and Accrued Liabilities, Current	990.4	990.4	1,446.3
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Accounts Payable and Other Accrued Liabilities, Current	58.9	58.9
Liabilities	9,521.2	9,521.2	8,171.7
Liabilities Subject to Compromise	8,241.4	8,241.4
Restricted Cash and Investments, Current	13.8	13.8
Deferred Tax Liabilities, Net, Current			11.8
Cash Flows From Operating Activities
Net cash provided by continuing operations		(167.3)	(692.9)	(369)
Net cash used in discontinued operations		(16.2)	(27.4)	(73.3)
Net Cash Provided by (Used in) Operating Activities		(183.5)	(720.3)	(442.3)
Cash Flows From Investing Activities
Additions to property, plant, equipment and mine development		0	0	0
Changes in accrued expenses related to capital expenditures		0	0	0
Federal coal lease expenditures		0	0	0
Proceeds from disposal of assets, net of notes receivable		0	0	0
Purchases of debt and equity securities			0	0
Proceeds from sales and maturities of debt and equity securities			0	0
Contributions to joint ventures		0	0	0
Distributions from joint ventures		0	0	0
Advances to related parties		0	0	0
Repayment of loans from related parties		0	0	0
Other, net		0	0	0
Net cash used in investing activities		0	0	0
Cash Flows From Financing Activities
Proceeds from long-term debt		1,450.6	975.7	0
Repayments of long-term debt		(503)	(662)	(12)
Payment of deferred financing costs		(26.8)	(28.7)	(10.1)
Dividends paid			(1.4)	(92.3)
Restricted cash for distributions to noncontrolling interests				0
Other, net		0	1.4	3.1
Transactions with affiliates, net		(477.9)	253.8	441.6
Net cash provided by (used in) financing activities		442.9	538.8	330.3
Net change in cash and cash equivalents		259.4	(181.5)	(112)
Cash and cash equivalents at beginning of year		7.2	188.7	300.7
Cash and cash equivalents at end of year	266.6	266.6	7.2	188.7
Accounts Payable and Accrued Liabilities, Current			494.8
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Accounts Payable and Other Accrued Liabilities, Current	439.3	439.3
Liabilities	3,656	3,656	3,493.5
Liabilities Subject to Compromise	184.2	184.2
Restricted Cash and Investments, Current	0	0
Deferred Tax Liabilities, Net, Current			0
Cash Flows From Operating Activities
Net cash provided by continuing operations		78.5	615.3	764.7
Net cash used in discontinued operations		(1.9)	(2.9)	(4.6)
Net Cash Provided by (Used in) Operating Activities		76.6	612.4	760.1
Cash Flows From Investing Activities
Additions to property, plant, equipment and mine development		(55.5)	(70.6)	(95.8)
Changes in accrued expenses related to capital expenditures		(0.6)	(2.3)	2.2
Federal coal lease expenditures		(249)	(277.2)	(276.7)
Proceeds from disposal of assets, net of notes receivable		77.7	36.3	105.9
Purchases of debt and equity securities			0	0
Proceeds from sales and maturities of debt and equity securities			0	0
Contributions to joint ventures		0	0	0
Distributions from joint ventures		0	0	0
Advances to related parties		0	0	0
Repayment of loans from related parties		0	0	0
Other, net		(5.1)	(2.7)	(4.2)
Net cash used in investing activities		(232.5)	(316.5)	(268.6)
Cash Flows From Financing Activities
Proceeds from long-term debt		0	0	0
Repayments of long-term debt		(4.4)	(0.7)	(0.7)
Payment of deferred financing costs		0	0	0
Dividends paid			0	0
Restricted cash for distributions to noncontrolling interests				0
Other, net		(5.8)	(1.8)	(1.7)
Transactions with affiliates, net		268.4	(289.9)	(488.2)
Net cash provided by (used in) financing activities		258.2	(292.4)	(490.6)
Net change in cash and cash equivalents		102.3	3.5	0.9
Cash and cash equivalents at beginning of year		4.7	1.2	0.3
Cash and cash equivalents at end of year	107	107	4.7	1.2
Accounts Payable and Accrued Liabilities, Current			479.8
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Accounts Payable and Other Accrued Liabilities, Current	492.2	492.2
Liabilities	997.9	997.9	968.7
Liabilities Subject to Compromise	14.6	14.6
Restricted Cash and Investments, Current	40.5	40.5
Deferred Tax Liabilities, Net, Current			3.8
Cash Flows From Operating Activities
Net cash provided by continuing operations		65.9	96.5	45.3
Net cash used in discontinued operations		(11.8)	(3)	(26.5)
Net Cash Provided by (Used in) Operating Activities		54.1	93.5	18.8
Cash Flows From Investing Activities
Additions to property, plant, equipment and mine development		(71.1)	(56.2)	(98.6)
Changes in accrued expenses related to capital expenditures		(5.5)	(6.9)	(18.8)
Federal coal lease expenditures		0	0	0
Proceeds from disposal of assets, net of notes receivable		66.7	34.1	97.8
Purchases of debt and equity securities			(28.8)	(15.1)
Proceeds from sales and maturities of debt and equity securities			90.3	13.5
Contributions to joint ventures		(309.5)	(425.4)	(529.8)
Distributions from joint ventures		312.4	422.6	534.2
Advances to related parties		(40.4)	(3.7)	(33.7)
Repayment of loans from related parties		40.6	0.9	5.4
Other, net		(4.8)	(0.4)	(0.8)
Net cash used in investing activities		(11.6)	26.5	(45.9)
Cash Flows From Financing Activities
Proceeds from long-term debt		7.8	0	1.1
Repayments of long-term debt		(6.3)	(8.6)	(8.3)
Payment of deferred financing costs		(4.2)	0	0
Dividends paid			0	0
Restricted cash for distributions to noncontrolling interests				42.5
Other, net		0	(6.2)	(4.7)
Transactions with affiliates, net		209.5	36.1	46.6
Net cash provided by (used in) financing activities		206.8	21.3	(7.8)
Net change in cash and cash equivalents		249.3	141.3	(34.9)
Cash and cash equivalents at beginning of year		249.4	108.1	143
Cash and cash equivalents at end of year	498.7	498.7	249.4	$ 108.1
Accounts Payable and Accrued Liabilities, Current			467.9
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Accounts Payable and Other Accrued Liabilities, Current	0	0
Liabilities	(2,735.2)	(2,735.2)	(2,605.5)
Liabilities Subject to Compromise	0	0
Restricted Cash and Investments, Current	0	0
Deferred Tax Liabilities, Net, Current			(11.8)
Cash Flows From Financing Activities
Cash and cash equivalents at beginning of year		0
Cash and cash equivalents at end of year	$ 0	$ 0	0
Accounts Payable and Accrued Liabilities, Current			$ 0

Supplemental Guarantor_Non-G138

Supplemental Guarantor/Non-Guarantor Financial Information Supplemental Guarantor/Non-Guarantor Financial Information (Details 3) - USD ($) $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	$ (199.3)	$ (133.7)	$ (233.8)	$ (165.1)	$ (470.2)	$ (301.9)	$ (1,043.5)	$ (173.3)	$ (493.7)	$ (731.9)	$ (1,988.9)	$ (777.3)
Unrealized holding losses on available-for-sale securities										0	0	(3.7)
Reclassification for realized losses included in net (loss) income										0	0	2.9
Net change in unrealized losses on available-for-sale securities										0	0	(0.8)
Decrease in fair value of cash flow hedges										0	(131.3)	(195)
Reclassification for realized losses (gains) included in net loss										146.3	251.7	(10.2)
Net unrealized gains (losses) on cash flow hedges										146.3	120.4	(205.2)
Prior service (cost) credit for the period										(4.5)	10.4	11.4
Net actuarial gain (loss) for the period										(13.5)	18.1	(142.7)
Amortization of actuarial loss and prior service cost included in net (loss) income										15.4	31.9	32.7
Postretirement plans and workers' compensation obligations										(2.6)	60.4	(98.6)
Foreign currency translation adjustment										(1.8)	(34.9)	(41)
Other comprehensive income from investment in subsidiaries										0	0	0
Other comprehensive income (loss), net of income taxes										141.9	145.9	(345.6)
Comprehensive loss										(590)	(1,843)	(1,122.9)
Less: Comprehensive income attributable to noncontrolling interests										7.9	7.1	9.7
Comprehensive loss attributable to common stockholders										(597.9)	(1,850.1)	(1,132.6)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										(739.8)	(1,996)	(787)
Unrealized holding losses on available-for-sale securities												(3.7)
Reclassification for realized losses included in net (loss) income												2.9
Net change in unrealized losses on available-for-sale securities												(0.8)
Decrease in fair value of cash flow hedges										0	(137.1)	(225.9)
Reclassification for realized losses (gains) included in net loss										146.3	292.1	31.3
Net unrealized gains (losses) on cash flow hedges										146.3	155	(194.6)
Prior service (cost) credit for the period										0	0	0
Net actuarial gain (loss) for the period										8.9	5.5	0
Amortization of actuarial loss and prior service cost included in net (loss) income										(6.1)	7.2	0
Postretirement plans and workers' compensation obligations										2.8	12.7	0
Foreign currency translation adjustment										0	0	0
Other comprehensive income from investment in subsidiaries										(7.2)	(21.8)	(150.2)
Other comprehensive income (loss), net of income taxes										141.9	145.9	(345.6)
Comprehensive loss										(597.9)	(1,850.1)	(1,132.6)
Less: Comprehensive income attributable to noncontrolling interests										0	0	0
Comprehensive loss attributable to common stockholders										(597.9)	(1,850.1)	(1,132.6)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										179.4	152.7	359.9
Unrealized holding losses on available-for-sale securities												0
Reclassification for realized losses included in net (loss) income												0
Net change in unrealized losses on available-for-sale securities												0
Decrease in fair value of cash flow hedges										0	0	0
Reclassification for realized losses (gains) included in net loss										0	0	0
Net unrealized gains (losses) on cash flow hedges										0	0	0
Prior service (cost) credit for the period										(4.5)	10.4	11.4
Net actuarial gain (loss) for the period										(22.4)	12.6	(152.6)
Amortization of actuarial loss and prior service cost included in net (loss) income										21.5	37.3	41.4
Postretirement plans and workers' compensation obligations										(5.4)	60.3	(99.8)
Foreign currency translation adjustment										0	0	0
Other comprehensive income from investment in subsidiaries										0	0	0
Other comprehensive income (loss), net of income taxes										(5.4)	60.3	(99.8)
Comprehensive loss										174	213	260.1
Less: Comprehensive income attributable to noncontrolling interests										0	0.8	5.2
Comprehensive loss attributable to common stockholders										174	212.2	254.9
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										(356.5)	(1,079.5)	(478.7)
Unrealized holding losses on available-for-sale securities												0
Reclassification for realized losses included in net (loss) income												0
Net change in unrealized losses on available-for-sale securities												0
Decrease in fair value of cash flow hedges										0	5.8	30.9
Reclassification for realized losses (gains) included in net loss										0	(40.4)	(41.5)
Net unrealized gains (losses) on cash flow hedges										0	(34.6)	(10.6)
Prior service (cost) credit for the period										0	0	0
Net actuarial gain (loss) for the period										0	0	9.9
Amortization of actuarial loss and prior service cost included in net (loss) income										0	(12.6)	(8.7)
Postretirement plans and workers' compensation obligations										0	(12.6)	1.2
Foreign currency translation adjustment										(1.8)	(34.9)	(41)
Other comprehensive income from investment in subsidiaries										0	0	0
Other comprehensive income (loss), net of income taxes										(1.8)	(82.1)	(50.4)
Comprehensive loss										(358.3)	(1,161.6)	(529.1)
Less: Comprehensive income attributable to noncontrolling interests										7.9	6.3	4.5
Comprehensive loss attributable to common stockholders										(366.2)	(1,167.9)	(533.6)
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income										185	933.9	128.5
Unrealized holding losses on available-for-sale securities												0
Reclassification for realized losses included in net (loss) income												0
Net change in unrealized losses on available-for-sale securities												0
Decrease in fair value of cash flow hedges										0	0	0
Reclassification for realized losses (gains) included in net loss										0	0	0
Net unrealized gains (losses) on cash flow hedges										0	0	0
Prior service (cost) credit for the period										0	0	0
Net actuarial gain (loss) for the period										0	0	0
Amortization of actuarial loss and prior service cost included in net (loss) income										0	0	0
Postretirement plans and workers' compensation obligations										0	0	0
Foreign currency translation adjustment										0	0	0
Other comprehensive income from investment in subsidiaries										7.2	21.8	150.2
Other comprehensive income (loss), net of income taxes										7.2	21.8	150.2
Comprehensive loss										192.2	955.7	278.7
Less: Comprehensive income attributable to noncontrolling interests										0	0	0
Comprehensive loss attributable to common stockholders										$ 192.2	$ 955.7	$ 278.7

Supplemental Guarantor_Non-G139

Supplemental Guarantor/Non-Guarantor Financial Information (Details Textuals)	12 Months Ended
	Dec. 31, 2016
Supplemental Guarantor Non Guarantor Financial Information [Abstract]
Percent of ownership of certain U.S. subsidiaries that fully and unconditionally guarantee the Senior Notes	100.00%

Supplemental Guarantor_Non-G140

Supplemental Guarantor/Non-Guarantor Financial Information Supplemental DND financial information details 5 (Details) - USD ($) $ in Millions	Dec. 31, 2016	Apr. 12, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash and cash equivalents	$ 872.3	$ 652.1	$ 261.3	$ 298	$ 444
Restricted Cash and Investments, Current	54.3		0
Accounts receivable, net	473		228.8
Receivables from affiliates, net	0		0
Inventory, Net	203.7		307.8
Assets From Coal Trading Activities, Net	0.7		23.5
Deferred Tax Assets, Net of Valuation Allowance, Current	0		53.5
Other current assets	486.6		447.6
Assets, Current	2,090.6		1,322.5
Property, Plant and Equipment, Net	8,776.7		9,258.5	10,577.3
Deferred income taxes	0		2.2
Other Assets, Noncurrent	910.4		363.7
Notes Receivable, Related Parties	0		0
Total assets	11,777.7		10,946.9	13,191.1
Long-term Debt and Capital Lease Obligations, Current	20.2		5,874.9
Payables to affiliates, net	0		0
Taxes Payable, Current	6.2
Liabilities from coal trading activities, net	1.2		15.6
Accounts Payable and Other Accrued Liabilities, Current	984.2		1,442.5
Liabilities, Current	1,011.8		7,336.8
Deferred Tax Liabilities, Net, Noncurrent	17.6		69.1
Notes Payable, Related Parties, Noncurrent	0		0
Other noncurrent liabilities	1,970.3		2,256.2
Total liabilities not subject to compromise	2,999.7		10,028.4
Liabilities Subject to Compromise	8,440.2		0
Liabilities	11,439.9		10,028.4
Peabody Energy Corporation's stockholders' equity	330.2		916.9
Stockholders' Equity Attributable to Noncontrolling Interest	7.6		1.6
Total stockholders' equity	337.8		918.5	2,726.5	3,947.9
Liabilities and Equity	11,777.7		10,946.9
Noncontrolling Interest [Member]
Total stockholders' equity	7.6		$ 1.6	$ 1.7	$ 39.2
Debtor Non-Debtor Eliminations [Member]
Cash and cash equivalents	0
Restricted Cash and Investments, Current	0
Accounts receivable, net	0
Receivables from affiliates, net	(226.9)
Inventory, Net	0
Assets From Coal Trading Activities, Net	(0.2)
Deferred Tax Assets, Net of Valuation Allowance, Current	0
Other current assets	(1.6)
Assets, Current	(228.7)
Property, Plant and Equipment, Net	0
Deferred income taxes	0
Other Assets, Noncurrent	(3,968.5)
Notes Receivable, Related Parties	(1,036.3)
Total assets	(5,233.5)
Long-term Debt and Capital Lease Obligations, Current	0
Payables to affiliates, net	(226.9)
Taxes Payable, Current	(1.6)
Liabilities from coal trading activities, net	(0.2)
Accounts Payable and Other Accrued Liabilities, Current	0
Liabilities, Current	(228.7)
Notes Payable, Related Parties, Noncurrent	(1,036.3)
Other noncurrent liabilities	0
Total liabilities not subject to compromise	(1,265)
Liabilities Subject to Compromise	0
Liabilities	(1,265)
Peabody Energy Corporation's stockholders' equity	(3,968.5)
Stockholders' Equity Attributable to Noncontrolling Interest	0
Total stockholders' equity	(3,968.5)
Liabilities and Equity	$ (5,233.5)

Supplemental Guarantor_Non-G141

Supplemental Guarantor/Non-Guarantor Financial Information DND CF (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted cash for distributions to noncontrolling interests		$ 0	$ 0	$ (42.5)
Net cash provided by continuing operations	$ 490	(22.9)	18.9	441
Net cash used in discontinued operations	(29.2)	(29.9)	(33.3)	(104.4)
Net Cash Provided by (Used in) Operating Activities	460.8	(52.8)	(14.4)	336.6
Payments to Acquire Property, Plant, and Equipment	(106.7)	(126.6)	(126.8)	(194.4)
Changes in accrued expenses related to capital expenditures	(2.1)	(6.1)	(9.2)	(16.6)
Federal Coal Lease Expenditures	(248.5)
Proceeds from disposal of assets, net of notes receivable	142.2	144.4	70.4	203.7
Contributions to joint ventures	(208.3)	(309.5)	(425.4)	(529.8)
Distributions from joint ventures	215.4	312.4	422.6	534.2
Repayment of loans from related parties	(39.8)	40.6	0.9	5.4
Increase (Decrease) in Due from Related Parties	39.3	40.4	3.7	33.7
Other, net	(4.6)	(9.9)	(3.1)	(5)
Net cash used in continuing operations	(213.1)	(244.1)	(290)	(314.5)
Proceeds from long-term debt	511.4	1,458.4	975.7	1.1
Repayments of long-term debt	(506.6)	(513.7)	(671.3)	(21)
Payment of deferred financing costs	(28.2)	(31)	(28.7)	(10.1)
Minority Interest, Increase from Contributions to Noncontrolling Interest Holders	(4)
Proceeds from (Payments for) Other Financing Activities	(0.1)	(5.8)	(6.6)	(3.3)
Transactions with affiliates, net	0	0	0	0
Net cash provided by (used in) financing activities	(27.5)	907.9	267.7	(168.1)
Net change in cash and cash equivalents	220.2	611	(36.7)	(146)
Cash and cash equivalents at end of year	872.3	872.3	261.3	298
Parent Company [Member]
Restricted cash for distributions to noncontrolling interests				0
Net cash provided by continuing operations		(167.3)	(692.9)	(369)
Net cash used in discontinued operations		(16.2)	(27.4)	(73.3)
Net Cash Provided by (Used in) Operating Activities		(183.5)	(720.3)	(442.3)
Payments to Acquire Property, Plant, and Equipment		0	0	0
Changes in accrued expenses related to capital expenditures		0	0	0
Proceeds from disposal of assets, net of notes receivable		0	0	0
Contributions to joint ventures		0	0	0
Distributions from joint ventures		0	0	0
Repayment of loans from related parties		0	0	0
Increase (Decrease) in Due from Related Parties		0	0	0
Other, net		0	0	0
Proceeds from long-term debt		1,450.6	975.7	0
Repayments of long-term debt		(503)	(662)	(12)
Payment of deferred financing costs		(26.8)	(28.7)	(10.1)
Proceeds from (Payments for) Other Financing Activities		0	1.4	3.1
Transactions with affiliates, net		(477.9)	253.8	441.6
Net cash provided by (used in) financing activities		442.9	538.8	330.3
Net change in cash and cash equivalents		259.4	(181.5)	(112)
Cash and cash equivalents at end of year	266.6	266.6	7.2	188.7
Debtor Subsidiaries [Member]
Net cash provided by continuing operations	435.8
Net cash used in discontinued operations	(18.3)
Net Cash Provided by (Used in) Operating Activities	417.5
Payments to Acquire Property, Plant, and Equipment	(62.6)
Changes in accrued expenses related to capital expenditures	(0.9)
Federal Coal Lease Expenditures	(248.5)
Proceeds from disposal of assets, net of notes receivable	75.6
Contributions to joint ventures	0
Distributions from joint ventures	0
Repayment of loans from related parties	0
Increase (Decrease) in Due from Related Parties	0
Other, net	(2)
Net cash used in continuing operations	(236.6)
Proceeds from long-term debt	503.6
Repayments of long-term debt	(502.9)
Payment of deferred financing costs	(26.8)
Minority Interest, Increase from Contributions to Noncontrolling Interest Holders	0
Proceeds from (Payments for) Other Financing Activities	(0.1)
Transactions with affiliates, net	131.3
Net cash provided by (used in) financing activities	105.1
Net change in cash and cash equivalents	286
Cash and cash equivalents at end of year	394.5	394.5
Non-Debtor Subsidiaries [Member]
Net cash provided by continuing operations	54.2
Net cash used in discontinued operations	(10.9)
Net Cash Provided by (Used in) Operating Activities	43.3
Payments to Acquire Property, Plant, and Equipment	(44.1)
Changes in accrued expenses related to capital expenditures	(3)
Federal Coal Lease Expenditures	0
Proceeds from disposal of assets, net of notes receivable	66.6
Contributions to joint ventures	(208.3)
Distributions from joint ventures	215.4
Repayment of loans from related parties	(39.8)
Increase (Decrease) in Due from Related Parties	39.3
Other, net	(2.6)
Net cash used in continuing operations	23.5
Proceeds from long-term debt	7.8
Repayments of long-term debt	(3.7)
Payment of deferred financing costs	(1.4)
Minority Interest, Increase from Contributions to Noncontrolling Interest Holders	(4)
Proceeds from (Payments for) Other Financing Activities	0
Transactions with affiliates, net	(131.3)
Net cash provided by (used in) financing activities	(132.6)
Net change in cash and cash equivalents	(65.8)
Cash and cash equivalents at end of year	477.8	477.8
Guarantor Subsidiaries [Member]
Restricted cash for distributions to noncontrolling interests				0
Net cash provided by continuing operations		78.5	615.3	764.7
Net cash used in discontinued operations		(1.9)	(2.9)	(4.6)
Net Cash Provided by (Used in) Operating Activities		76.6	612.4	760.1
Payments to Acquire Property, Plant, and Equipment		(55.5)	(70.6)	(95.8)
Changes in accrued expenses related to capital expenditures		(0.6)	(2.3)	2.2
Proceeds from disposal of assets, net of notes receivable		77.7	36.3	105.9
Contributions to joint ventures		0	0	0
Distributions from joint ventures		0	0	0
Repayment of loans from related parties		0	0	0
Increase (Decrease) in Due from Related Parties		0	0	0
Other, net		(5.1)	(2.7)	(4.2)
Proceeds from long-term debt		0	0	0
Repayments of long-term debt		(4.4)	(0.7)	(0.7)
Payment of deferred financing costs		0	0	0
Proceeds from (Payments for) Other Financing Activities		(5.8)	(1.8)	(1.7)
Transactions with affiliates, net		268.4	(289.9)	(488.2)
Net cash provided by (used in) financing activities		258.2	(292.4)	(490.6)
Net change in cash and cash equivalents		102.3	3.5	0.9
Cash and cash equivalents at end of year	107	107	4.7	1.2
Non-Guarantor Subsidiaries [Member]
Restricted cash for distributions to noncontrolling interests				42.5
Net cash provided by continuing operations		65.9	96.5	45.3
Net cash used in discontinued operations		(11.8)	(3)	(26.5)
Net Cash Provided by (Used in) Operating Activities		54.1	93.5	18.8
Payments to Acquire Property, Plant, and Equipment		(71.1)	(56.2)	(98.6)
Changes in accrued expenses related to capital expenditures		(5.5)	(6.9)	(18.8)
Proceeds from disposal of assets, net of notes receivable		66.7	34.1	97.8
Contributions to joint ventures		(309.5)	(425.4)	(529.8)
Distributions from joint ventures		312.4	422.6	534.2
Repayment of loans from related parties		40.6	0.9	5.4
Increase (Decrease) in Due from Related Parties		40.4	3.7	33.7
Other, net		(4.8)	(0.4)	(0.8)
Proceeds from long-term debt		7.8	0	1.1
Repayments of long-term debt		(6.3)	(8.6)	(8.3)
Payment of deferred financing costs		(4.2)	0	0
Proceeds from (Payments for) Other Financing Activities		0	(6.2)	(4.7)
Transactions with affiliates, net		209.5	36.1	46.6
Net cash provided by (used in) financing activities		206.8	21.3	(7.8)
Net change in cash and cash equivalents		249.3	141.3	(34.9)
Cash and cash equivalents at end of year	$ 498.7	$ 498.7	$ 249.4	$ 108.1

Supplemental Guarantor_Non-G142

Supplemental Guarantor/Non-Guarantor Financial Information DND IS (Details) - USD ($) $ in Millions	3 Months Ended											9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues	$ 1,440.8	$ 1,207.1	$ 1,040.2	$ 1,027.2	$ 1,313.1				$ 1,418.9	$ 1,339.3	$ 1,537.9	$ 3,564.7	$ 4,715.3	$ 5,609.2	$ 6,792.2
Operating costs and expenses (exclusive of items shown separately below)												3,035.9	4,107.6	5,007.7	5,716.9
Depreciation, depletion and amortization												336.7	465.4	572.2	655.7
Asset Retirement Obligation, Accretion Expense												26.9	41.8	45.5	81
Selling and administrative expenses												90.7	153.4	176.4	227.1
Restructuring Charges												2.8	15.5	23.5	26
Gain (Loss) on Disposition of Assets			13.7									(21.4)	23.2	45	41.4
Asset Impairment	230.7			17.2	377		$ 900.8					230.7	247.9	1,277.8	154.4
Income (Loss) from Equity Method Investments	28.8											(26.2)	16.2	(15.9)	(107.6)
Loss on early debt extinguishment	29.5						(8.3)	$ (59.5)				29.5	(29.5)	(67.8)	(1.6)
Interest Expense				126.2								150.4	298.6	465.4	426.6
Interest income												(4)	(5.7)	(7.7)	(15.4)
Reorganization Items	33.9	29.7	95.4									159	159	0	0
(Loss) income from continuing operations before income taxes												(446.3)	(758.3)	(1,990.3)	(547.9)
Income tax benefit related to asset impairment					7.9		$ 67.4					(6.2)	(84)	(176.4)	201.2
(Loss) income from continuing operations, net of income taxes	(186.2)	(95.6)	(230.8)	(161.7)	(497.9)				(144.4)	(1,007.2)	(164.4)	(440.1)	(674.3)	(1,813.9)	(749.1)
Loss from discontinued operations, net of income taxes	13.1	38.1				$ 155.1		$ 7.6				(53.6)	(57.6)	(175)	(28.2)
Net (loss) income	(199.3)	(133.7)	(233.8)	(165.1)	(470.2)				(301.9)	(1,043.5)	(173.3)	(493.7)	(731.9)	(1,988.9)	(777.3)
Less: Net income attributable to noncontrolling interests												7.9	7.9	7.1	9.7
Net loss attributable to common stockholders	$ (203.7)	$ (135.5)	$ (235.5)	$ (165.1)	$ (469.4)				$ (304.7)	$ (1,045.3)	$ (176.6)	(501.6)	$ (739.8)	$ (1,996)	$ (787)
Debtor Subsidiaries [Member]
Revenues												2,074
Operating costs and expenses (exclusive of items shown separately below)												1,692.9
Depreciation, depletion and amortization												177.6
Asset Retirement Obligation, Accretion Expense												11.6
Selling and administrative expenses												81.4
Restructuring Charges												2.2
Gain (Loss) on Disposition of Assets												(19.7)
Asset Impairment												37.5
Income (Loss) from Equity Method Investments												229.1
Loss on early debt extinguishment												29.5
Interest Expense												143.2
Interest income												(3.7)
Reorganization Items												155.1
(Loss) income from continuing operations before income taxes												(462.7)
Income tax benefit related to asset impairment												(20.6)
(Loss) income from continuing operations, net of income taxes												(442.1)
Loss from discontinued operations, net of income taxes												(59.5)
Net (loss) income												(501.6)
Less: Net income attributable to noncontrolling interests												0
Net loss attributable to common stockholders												(501.6)
Non-Debtor Subsidiaries [Member]
Revenues												1,494.7
Operating costs and expenses (exclusive of items shown separately below)												1,347
Depreciation, depletion and amortization												159.1
Asset Retirement Obligation, Accretion Expense												15.3
Selling and administrative expenses												9.3
Restructuring Charges												0.6
Gain (Loss) on Disposition of Assets												(1.7)
Asset Impairment												193.2
Income (Loss) from Equity Method Investments												(29.2)
Loss on early debt extinguishment												0
Interest Expense												16.9
Interest income												(10)
Reorganization Items												3.9
(Loss) income from continuing operations before income taxes												(209.7)
Income tax benefit related to asset impairment												14.4
(Loss) income from continuing operations, net of income taxes												(224.1)
Loss from discontinued operations, net of income taxes												5.9
Net (loss) income												(218.2)
Less: Net income attributable to noncontrolling interests												7.9
Net loss attributable to common stockholders												(226.1)
Debtor Non-Debtor Eliminations [Member]
Revenues												(4)
Operating costs and expenses (exclusive of items shown separately below)												(4)
Depreciation, depletion and amortization												0
Asset Retirement Obligation, Accretion Expense												0
Selling and administrative expenses												0
Restructuring Charges												0
Gain (Loss) on Disposition of Assets												0
Asset Impairment												0
Income (Loss) from Equity Method Investments												(226.1)
Loss on early debt extinguishment												0
Interest Expense												(9.7)
Interest income												(9.7)
Reorganization Items												0
(Loss) income from continuing operations before income taxes												226.1
Income tax benefit related to asset impairment												0
(Loss) income from continuing operations, net of income taxes												226.1
Loss from discontinued operations, net of income taxes												0
Net (loss) income												226.1
Less: Net income attributable to noncontrolling interests												0
Net loss attributable to common stockholders												$ 226.1

Valuation and Qualifying Acc143

Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Advance royalty recoupment reserve [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 8.3		$ 7.6		$ 9.7
Charged to Costs and Expenses	0.5		0		(0.2)
Deductions	(1)	[1]	(0.9)	[2]	(1.9)	[3]
Other	0		1.6	[2]	0
Balance at End of Period	7.8		8.3		7.6
Reserve for materials and supplies [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	4.7		4.6		7.4
Charged to Costs and Expenses	4.3		0.4		(0.1)
Deductions	(3.4)		(0.3)		(2.7)
Other	0		0		0
Balance at End of Period	5.6		4.7		4.6
Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	6.6		5.8		7.4
Charged to Costs and Expenses	7.9		8		1.5
Deductions	(1.4)		(7.2)		(1.4)
Other	0		0		(1.7)	[4]
Balance at End of Period	13.1		6.6		5.8
Tax valuation allowances [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	1,447.3		1,169		1,634.1
Charged to Costs and Expenses	2,462.8		462		569.4
Deductions	0		0		0
Other	(28.9)	[3]	(183.7)	[3]	(1,034.5)	[5],[6]
Balance at End of Period	$ 3,881.2		$ 1,447.3		$ 1,169
[1]	Reserves utilized, unless otherwise indicated.
[2]	Deductions to advance royalty recoupment reserve represents the termination of federal and state leases.
[3]	Includes the write-off of valuation allowance against deferred tax assets related to the Australian Minerals and Resource Rent Tax (MRRT) due to the repeal of that legislation in 2014, along with an increase in valuation allowance during the period reflected directly in "Accumulated other comprehensive loss" and the impact of the 2014 decrease in Australian dollar exchange rates.
[4]	Includes the impact of the decrease in Australian dollar exchange rates.
[5]	Balances transferred from other accounts.
[6]	Represents subsequent recovery of receivable amounts previously reserved.

Reorganization Items, Net (Deta

Reorganization Items, Net (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
schedule of reorganization items [Line Items]
Reorganization Items	$ 33.9	$ 29.7	$ 95.4	$ 159	$ 159	$ 0	$ 0
Payments for reorganization items, net					68.1
Professional fee [Member]
schedule of reorganization items [Line Items]
Reorganization Items					88.4
Loss on termination of derivative contracts [Member]
schedule of reorganization items [Line Items]
Reorganization Items					75.2
accounts payable settlement (gains) losses [Member]
schedule of reorganization items [Line Items]
Reorganization Items					(1.8)
Interest Income [Member]
schedule of reorganization items [Line Items]
Reorganization Items					(1.8)
Other reorganization items [Member]
schedule of reorganization items [Line Items]
Reorganization Items					$ (1)

Liabilities Subject to Compr145

Liabilities Subject to Compromise (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	$ 8,440,200,000	$ 0
Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	8,080,300,000
Interest Payable [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	172,600,000
Reserve for Environmental Costs [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	61,900,000
Accounts Payable [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	58,400,000
Other Pension Plan, Postretirement or Supplemental Plans, Defined Benefit [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	34,600,000
Accrued Liabilities [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	32,400,000
Debt [Member] | Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	7,771,200,000
Hedge terminations [Member] | Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	257,300,000
Liabilities secured by prepetition letters of credit [Member] | Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities Subject to Compromise	$ 51,800,000