Goodwill and Other Intangible Assets and Liabilities (Summary of Intangible Assets and Liabilities) (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Definite lived intangible assets - Gross Carrying Amount	$ 201.3	$ 208.0
Definite lived intangible assets - Accumulated Amortization	(41.8)	(32.2)
Definite lived intangible assets - Net Carrying Amount	159.5	175.8
Below-market sales contracts - Gross Carrying Amount	(329.3)	(329.3)
Below-market sales contracts - Accumulated Amortization	131.5	107.8
Below-market sales contracts - Net Carrying Amount	(197.8)	(221.5)
Noncurrent Liabilities [Member]
Below-market sales contracts - Gross Carrying Amount	(252.3)	(252.3)
Below-market sales contracts - Accumulated Amortization	107.2	87.9
Below-market sales contracts - Net Carrying Amount	(145.1)	(164.4)
Other Current Liabilities [Member]
Below-market sales contracts - Gross Carrying Amount	(77.0)	(77.0)
Below-market sales contracts - Accumulated Amortization	24.3	19.9
Below-market sales contracts - Net Carrying Amount	(52.7)	(57.1)
Utility Contracts [Member]
Definite lived intangible assets - Gross Carrying Amount	54.7	54.7
Definite lived intangible assets - Accumulated Amortization	(15.8)	(10.2)
Definite lived intangible assets - Net Carrying Amount	38.9	44.5
Easements [Member]
Definite lived intangible assets - Gross Carrying Amount		11.7	[1]
Definite lived intangible assets - Accumulated Amortization		(0.4)	[1]
Definite lived intangible assets - Net Carrying Amount		11.3	[1]
Lease Agreements [Member]
Definite lived intangible assets - Gross Carrying Amount	5.5	5.2
Definite lived intangible assets - Accumulated Amortization	(2.9)	(2.9)
Definite lived intangible assets - Net Carrying Amount	2.6	2.3
Unpatented Technology [Member]
Definite lived intangible assets - Gross Carrying Amount	4.0	4.0
Definite lived intangible assets - Accumulated Amortization	(2.8)	(2.4)
Definite lived intangible assets - Net Carrying Amount	1.2	1.6
Permits [Member]
Definite lived intangible assets - Gross Carrying Amount	137.1	132.4
Definite lived intangible assets - Accumulated Amortization	(20.3)	(16.3)
Definite lived intangible assets - Net Carrying Amount	$ 116.8	$ 116.1

[1] Upon the acquisition of Consolidated Thompson, this intangible asset is now eliminated through intercompany eliminations. The easement agreement is between Wabush and Consolidated Thompson.