Acquisitions And Other Investments (CLCC Purchase Price Allocation) (Details) (USD $) In Millions	Dec. 31, 2010	Mar. 31, 2010 CLCC [Member] Scenario, Previously Reported [Member]	Dec. 31, 2010 CLCC [Member] Scenario, Adjustment [Member]	Dec. 31, 2010 CLCC [Member] Scenario, Change [Member]	Dec. 31, 2010 CLCC [Member]
Cash		$ 757.0	$ 757.0		$ 757.0
Working capital adjustments		17.5	18.9	1.4	18.9
Fair value of total consideration transferred		774.5	775.9	1.4	775.9
Product inventories		20.0	20.0
Other current assets		11.8	11.8
Land and mineral rights		640.3	639.3	(1.0)
Plant and equipment		111.1	112.3	1.2
Deferred taxes		16.5	15.9	(0.6)
Intangible assets		7.5	7.5		7.5
Other non-current assets		0.8	0.8
Total identifiable assets acquired		808.0	807.6	(0.4)
Current liabilities		(22.8)	(24.1)	(1.3)
Mine closure obligations		(2.8)	(2.8)
Below- market sales contracts		(32.6)	(32.6)
Total identifiable liabilities assumed		(58.2)	(59.5)	(1.3)
Total identifiable net assets acquired		749.8	748.1	(1.7)
Preliminary goodwill		24.7	27.8	3.1
Total net assets acquired	$ (1.7)	$ 774.5	$ 775.9	$ 1.4

The amount of acquisition cost of a business combination allocated to asset retirement obligations.

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Amount of cash paid to acquire the entity.

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Fair value of noncash consideration given by the acquirer to acquire the entity. Does not include cash paid, the fair value of debt and securities issued and liabilities incurred to acquire the entity.

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The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition.

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The amount of acquisition cost of a business combination allocated to an identifiable intangible asset that will be amortized.

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The amount of acquisition cost of a business combination allocated to assets acquired.

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The total purchase price of the acquired entity. This includes cash paid to equity interest holders of the acquired entity, fair value of debt and equity securities issued to equity holders of the acquired entity, and transaction costs paid to third parties to consummate the acquisition.

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The amount of acquisition cost of a business combination allocated to prepaid expenses and other current assets. Does not include amounts allocated to cash and cash equivalents, marketable securities, receivables, inventory, and assets not to be used.

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The amount of acquisition cost of a business combination allocated to work-in-process inventory.

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The amount of acquisition cost of a business combination allocated to current liabilities of the acquired entity.

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Amount of deferred tax assets or liabilities for the differences between the values assigned and the tax bases of assets and liabilities in a business combination, net of any valuation allowance for deferred tax assets.

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Amount of goodwill arising from a business combination, which is the excess of the cost of the acquired entity over the amounts assigned to assets acquired and liabilities assumed.

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The amount of acquisition cost of a business combination allocated to liabilities assumed.

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The amount of acquisition cost of a business combination allocated to mineral rights for acquired entities in the mining industry.

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The amount of acquisition cost of a business combination allocated to noncurrent assets of the acquired entity, except for property plant and equipment, intangible assets, and goodwill.

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The amount of acquisition cost of a business combination allocated to property, plant and equipment to be used in ongoing operations.

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The amount of acquisition cost of a business combination allocated to unfavorable contracts assumed from the acquired entity.

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- Definition

This element represents the sum of the: (1) acquisition-date fair value of the total consideration transferred which consists of the sum of the acquisition-date fair values of the assets transferred by the acquirer, the liabilities incurred by the acquirer to former owners of the acquiree, and the equity interests issued by the acquirer and (2) the acquisition-date fair value of any equity interest in the acquiree held by the acquirer prior to the business combination (for example, a step acquisition).

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