Asset Impairment and Mine Closure Costs (Tables)

12 Months Ended

Dec. 31, 2014

Asset Impairment and Mine Closure Costs [Abstract]

Details of Impairment of Long-Lived Assets Held and Used by Asset [Table Text Block]

The following costs are reflected in "Asset impairment and mine closure costs" in the consolidated statement of operations for the year ended December 31, 2014:

	Reportable Segment
	Australian Metallurgical Mining		Australian Thermal Mining		Powder River Basin 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

The following costs are reflected in "Asset impairment and mine closure costs" in the consolidated statement of operations for the year ended December 31, 2012:

	Reportable Segment
	Australian Metallurgical Mining		Powder River Basin Mining		Midwestern U.S. Mining		Corporate and Other		Consolidated
	(Dollars in millions)
Charges related to mine closures:
Impairment of long-lived assets	$	—	$	—	$	26.9	$	—	$	26.9
Acceleration of asset retirement obligations	—		—		7.1		—		7.1
Employee termination benefits	—		—		6.7		—		6.7
Other	—		—		4.3		—		4.3
Other asset impairment charges:
Long-lived assets	806.7		—		—		—		806.7
Marketable securities	—		—		—		35.5		35.5
Cost method investments	—		—		—		39.4		39.4
Other	—		2.4		—		—		2.4
Total	$	806.7	$	2.4	$	45.0	$	74.9	$	929.0

The following costs are reflected in "Asset impairment and mine closure costs" in the consolidated statement of operations for the year ended December 31, 2013:

	Reportable Segment
	Australian Metallurgical Mining		Corporate and Other		Consolidated
	(Dollars in millions)
Asset impairment charges:
Long-lived assets	$	390.8	$	72.8	$	463.6
Equity method investment	—		43.2		43.2
Marketable securities	—		21.5		21.5
Total	$	390.8	$	137.5	$	528.3