Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash Flows From Operating Activities
Net loss	$ (532.6)	$ (1,518.7)
Loss from discontinued operations, net of income taxes	44.5	202.7
Loss from continuing operations, net of income taxes	(488.1)	(1,316.0)
Adjustments to reconcile loss from continuing operations, net of income taxes to net cash used in operating activities:
Depreciation, depletion and amortization	345.5	430.6
Noncash interest expense	30.0	22.9
Deferred income taxes	(38.9)	(53.7)
Noncash share-based compensation	8.9	20.0
Asset impairment	17.2	900.8
Net gain on disposal of assets	(17.4)	(20.2)
Loss from equity affiliates	12.6	12.3
Gain on VEBA settlement	(68.1)	0.0
Settlement of hedge positions	(25.0)	0.0
Reclassification from OCI for terminated hedge contracts	82.0	(14.9)
Noncash reorganization items, net	96.5	0.0
Changes in current assets and liabilities:
Accounts receivable	24.4	190.0
Change in receivable from accounts receivable securitization program	(168.5)	(5.0)
Inventories	47.8	55.2
Net assets from coal trading activities	7.5	(17.4)
Other current assets	(28.6)	7.6
Accounts payable and accrued expenses	5.2	(322.0)
Restricted cash	(94.8)	0.0
Asset retirement obligations	19.0	28.1
Accrued postretirement benefit costs	(0.6)	14.2
Accrued pension costs	16.4	21.1
Take-or-pay obligation settlement	(15.5)	0.0
Other, net	(25.4)	(15.6)
Net Cash (Used in) Provided by Operating Activities, Continuing Operations	(257.9)	(62.0)
Net cash used in discontinued operations	(18.9)	(28.6)
Net Cash (Used in) Provided by Operating Activities	(276.8)	(90.6)
Cash Flows From Investing Activities
Additions to property, plant, equipment and mine development	(56.6)	(76.9)
Changes in accrued expenses related to capital expenditures	(5.5)	(14.5)
Increase (Decrease) in Due from Related Parties	13.2	0.0
Federal coal lease expenditures	(249.0)	(89.8)
Proceeds from disposal of assets, net of notes receivable	134.7	39.6
Purchases of debt and equity securities	0.0	(22.6)
Proceeds from sales and maturities of debt and equity securities	0.0	33.6
Contributions to joint ventures	(241.7)	(349.8)
Distributions from joint ventures	236.7	339.8
Increase (Decrease) in Due to Related Parties	(23.3)	(3.6)
Other, net	(8.2)	(2.1)
Net cash (used in) provided by investing activities	(199.7)	(146.3)
Cash Flows From Financing Activities
Proceeds from long-term debt	1,429.8	975.7
Repayments of long-term debt	(11.2)	(666.0)
Payment of deferred financing costs	(29.8)	(28.7)
Dividends paid	0.0	(1.4)
Distributions to noncontrolling interests	(3.9)	(2.1)
Other, net	(1.9)	(4.3)
Net cash provided by financing activities	1,383.0	273.2
Net change in cash and cash equivalents	906.5	36.3
Cash and cash equivalents at beginning of period	261.3	298.0
Cash and cash equivalents at end of period	$ 1,167.8	$ 334.3