Segment Information (Tables)

12 Months Ended

Dec. 31, 2012

Segment Reporting [Abstract]

Operating segment results

Operating segment results for the year ended December 31, 2012 were as follows (total assets as of December 31, 2012):

	Western U.S. Mining		Midwestern U.S. Mining		Australian Mining		Trading and Brokerage		Corporate and Other			Consolidated
	(Dollars in millions)
Revenues	$	2,949.3	$	1,403.7	$	3,503.6	$	199.9	$	21.0		$	8,077.5
Adjusted EBITDA	832.8		427.0		938.9		119.7		(481.9		)	1,836.5
Total assets	3,248.6		507.7		7,990.8		544.4		3,517.5			15,809.0
Total property, plant, equipment and mine development, net	2,886.8		486.6		6,595.5		2.1		1,830.7			11,801.7
Additions to property, plant, equipment and mine development	121.4		74.7		743.4		0.1		46.4			986.0
Federal coal lease expenditures	276.5		—		—		—		—			276.5
Loss from equity affiliates	—		—		—		—		61.2			61.2

Operating segment results for the year ended December 31, 2011 were as follows (total assets as of December 31, 2011):

	Western U.S. Mining		Midwestern U.S. Mining		Australian Mining		Trading and Brokerage		Corporate and Other			Consolidated
	(Dollars in millions)
Revenues	$	2,900.4	$	1,402.6	$	3,080.7	$	475.1	$	37.1		$	7,895.9
Adjusted EBITDA	766.0		402.9		1,194.3		197.0		(437.6		)	2,122.6
Total assets	3,095.8		590.6		8,440.4		633.3		3,972.9			16,733.0
Total property, plant, equipment and mine development, net	2,785.1		502.4		6,371.3		1.7		1,591.1			11,251.6
Additions to property, plant, equipment and mine development	186.1		99.9		490.8		0.9		69.7			847.4
Federal coal lease expenditures	42.4		—		—		—		—			42.4
Loss from equity affiliates	—		—		—		—		19.2			19.2

Operating segment results for the year ended December 31, 2010 were as follows (total assets as of December 31, 2010):

	Western U.S. Mining		Midwestern U.S. Mining		Australian Mining		Trading and Brokerage		Corporate and Other			Consolidated
	(Dollars in millions)
Revenues	$	2,706.3	$	1,248.9	$	2,399.9	$	291.1	$	22.0		$	6,668.2
Adjusted EBITDA	816.7		309.9		977.4		77.2		(354.7		)	1,826.5
Total assets	3,008.4		528.5		3,556.9		398.2		3,871.1			11,363.1
Total property, plant, equipment and mine development, net	2,672.8		508.4		2,559.4		1.2		1,521.5			7,263.3
Additions to property, plant, equipment and mine development	143.3		223.0		138.7		0.9		40.1			546.0
Loss from equity affiliates	—		—		—		—		1.7			1.7

Reconciliation of Adjusted EBITDA to consolidated income from continuing operations

A reconciliation of Adjusted EBITDA to consolidated income from continuing operations, net of income taxes follows:

	Year Ended December 31,
	2012			2011			2010
	(Dollars in millions)
Total Adjusted EBITDA	$	1,836.5		$	2,122.6		$	1,826.5
Depreciation, depletion and amortization	(663.4		)	(474.3		)	(429.5		)
Asset retirement obligation expenses	(67.0		)	(52.6		)	(45.9		)
Asset impairment and mine closure costs	(929.0		)	—			—
Amortization of basis difference	(4.6		)	—			—
Interest expense	(405.6		)	(238.6		)	(222.0		)
Interest income	24.5			18.9			9.6
Income tax provision	(262.3		)	(363.2		)	(313.7		)
(Loss) income from continuing operations, net of income taxes	$	(470.9	)	$	1,012.8		$	825.0

Revenue 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,
	2012		2011		2010
U.S.	55.4	%	61.0	%	63.5	%
Japan	12.3	%	10.2	%	9.1	%
China	6.8	%	2.8	%	2.7	%
South Korea	5.8	%	5.5	%	3.7	%
India	4.1	%	5.2	%	4.9	%
Other	15.6	%	15.3	%	16.1	%
Total	100.0	%	100.0	%	100.0	%