Supplemental Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 688,544		$ 742,180	$ 2,010,011	$ 2,191,927
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	540,192		647,096	1,668,766	1,955,547
Depreciation, depletion and amortization	103,965		105,155	306,211	312,042
Amortization of acquired sales contracts, net	(1,994)		(3,013)	(7,028)	(9,948)
Change in fair value of coal derivatives and coal trading activities, net	(3,559)		(3,733)	(1,128)	(5,811)
Asset impairment and mine closure costs	2,120,292	$ 19,100	5,060	2,139,438	6,572
Losses from disposed operations resulting from Patriot Coal bankruptcy	(149,314)		0	(149,314)	0
Selling, general and administrative expenses	25,731		28,136	72,604	87,203
Other operating (income) expense, net	(8,625)		(1,221)	7,864	(9,451)
Total operating expenses	2,925,316		777,480	4,336,041	2,336,154
Income (loss) from investment in subsidiaries	0		0	0	0
Loss from operations	(2,236,772)		(35,300)	(2,326,030)	(144,227)
Interest expense, net
Interest expense	(99,759)		(98,217)	(298,585)	(292,648)
Interest and investment income	672		1,949	4,007	5,828
Interest expense, net	(99,087)		(96,268)	(294,578)	(286,820)
Nonoperating expense
Expenses related to debt restructuring	(7,482)		0	(11,498)	0
Loss before income taxes	(2,343,341)		(131,568)	(2,632,106)	(431,047)
Provision for (benefit from) income taxes	(343,865)		(34,350)	(351,332)	(112,830)
Net loss	(1,999,476)		(97,218)	(2,280,774)	(318,217)
Total comprehensive income (loss)	(2,000,570)		(99,197)	(2,278,048)	(324,403)
Parent/Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0		0	0	0
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	3,211		2,442	16,589	9,378
Depreciation, depletion and amortization	896		1,175	2,969	3,993
Amortization of acquired sales contracts, net	0		0	0	0
Change in fair value of coal derivatives and coal trading activities, net	0		0	0	0
Asset impairment and mine closure costs	21,292		0	22,517	1,512
Losses from disposed operations resulting from Patriot Coal bankruptcy	(149,314)			(149,314)
Selling, general and administrative expenses	18,059		19,542	50,664	61,216
Other operating (income) expense, net	3,503		1,562	7,065	1,272
Total operating expenses	196,275		24,721	249,118	77,371
Income (loss) from investment in subsidiaries	(2,025,900)		2,005	(2,035,313)	(30,839)
Loss from operations	(2,222,175)		(22,716)	(2,284,431)	(108,210)
Interest expense, net
Interest expense	(120,404)		(116,742)	(357,690)	(346,481)
Interest and investment income	6,710		7,872	21,457	23,598
Interest expense, net	(113,694)		(108,870)	(336,233)	(322,883)
Nonoperating expense
Expenses related to debt restructuring	(7,482)			(11,498)
Loss before income taxes	(2,343,351)		(131,586)	(2,632,162)	(431,093)
Provision for (benefit from) income taxes	(343,875)		(34,368)	(351,388)	(112,876)
Net loss	(1,999,476)		(97,218)	(2,280,774)	(318,217)
Total comprehensive income (loss)	(2,000,570)		(99,197)	(2,278,048)	(324,403)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	688,544		742,180	2,010,011	2,191,927
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	537,471		645,672	1,654,348	1,948,918
Depreciation, depletion and amortization	103,069		103,971	303,240	308,022
Amortization of acquired sales contracts, net	(1,994)		(3,013)	(7,028)	(9,948)
Change in fair value of coal derivatives and coal trading activities, net	(3,559)		(3,733)	(1,128)	(5,811)
Asset impairment and mine closure costs	2,099,000		5,060	2,116,921	5,060
Losses from disposed operations resulting from Patriot Coal bankruptcy	0			0
Selling, general and administrative expenses	6,725		7,427	19,239	22,540
Other operating (income) expense, net	(12,343)		(2,942)	417	(10,869)
Total operating expenses	2,728,369		752,442	4,086,009	2,257,912
Income (loss) from investment in subsidiaries	0		0	0	0
Loss from operations	(2,039,825)		(10,262)	(2,075,998)	(65,985)
Interest expense, net
Interest expense	(6,629)		(6,577)	(19,969)	(19,466)
Interest and investment income	20,781		18,987	60,811	54,979
Interest expense, net	14,152		12,410	40,842	35,513
Nonoperating expense
Expenses related to debt restructuring	0			0
Loss before income taxes	(2,025,673)		2,148	(2,035,156)	(30,472)
Provision for (benefit from) income taxes	0		0	0	0
Net loss	(2,025,673)		2,148	(2,035,156)	(30,472)
Total comprehensive income (loss)	(2,026,697)		1,717	(2,033,102)	(33,062)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0		0	0	0
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	0		0	0	0
Depreciation, depletion and amortization	0		9	2	27
Amortization of acquired sales contracts, net	0		0	0	0
Change in fair value of coal derivatives and coal trading activities, net	0		0	0	0
Asset impairment and mine closure costs	0		0	0	0
Losses from disposed operations resulting from Patriot Coal bankruptcy	0			0
Selling, general and administrative expenses	1,489		1,679	4,262	4,971
Other operating (income) expense, net	(817)		(1,371)	(3,350)	(4,127)
Total operating expenses	672		317	914	871
Income (loss) from investment in subsidiaries	0		0	0	0
Loss from operations	(672)		(317)	(914)	(871)
Interest expense, net
Interest expense	(1,199)		(1,116)	(3,601)	(3,258)
Interest and investment income	1,654		1,308	4,414	3,808
Interest expense, net	455		192	813	550
Nonoperating expense
Expenses related to debt restructuring	0			0
Loss before income taxes	(217)		(125)	(101)	(321)
Provision for (benefit from) income taxes	10		(21)	56	46
Net loss	(227)		(104)	(157)	(367)
Total comprehensive income (loss)	(227)		(143)	(157)	(367)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0		0	0	0
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	(490)		(1,018)	(2,171)	(2,749)
Depreciation, depletion and amortization	0		0	0	0
Amortization of acquired sales contracts, net	0		0	0	0
Change in fair value of coal derivatives and coal trading activities, net	0		0	0	0
Asset impairment and mine closure costs	0		0	0	0
Losses from disposed operations resulting from Patriot Coal bankruptcy				0
Selling, general and administrative expenses	(542)		(512)	(1,561)	(1,524)
Other operating (income) expense, net	1,032		1,530	3,732	4,273
Total operating expenses	0		0	0	0
Income (loss) from investment in subsidiaries	2,025,900		(2,005)	2,035,313	30,839
Loss from operations	2,025,900		(2,005)	2,035,313	30,839
Interest expense, net
Interest expense	28,473		26,218	82,675	76,557
Interest and investment income	(28,473)		(26,218)	(82,675)	(76,557)
Interest expense, net	0		0	0	0
Nonoperating expense
Expenses related to debt restructuring	0			0
Loss before income taxes	2,025,900		(2,005)	2,035,313	30,839
Provision for (benefit from) income taxes	0		0	0	0
Net loss	2,025,900		(2,005)	2,035,313	30,839
Total comprehensive income (loss)	$ 2,026,924		$ (1,574)	$ 2,033,259	$ 33,429