Asset Impairment Charges, Tax Effect

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Business Acquisition, Cost Of Acquired Entity, Cash Paid Per Share

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- Definition

The consideration for the sale of our interest in one of our equity method investments. The buyer is to assume the cost of rehabilitation.

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Increase Decrease Earnings Per Share

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The increase or decrease in accumulated other comprehensive income.

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Increase Decrease Net Income Loss Available To Common Stockholders

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Increase Decrease Retained Earnings Accumulated Deficit

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Increase Decreases Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments

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Repayment received for expenses incurred on behalf of the client or customer and revenue from transporting freight between locations.

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For an unclassified balance sheet, amount of receivables arising from transactions with related parties.

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The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

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Percentage of voting equity interests acquired in the business combination.

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Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items, and noncontrolling interest.

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This element represents the overall income (loss) from a disposal group that is classified as a component of the entity, net of income tax, reported as a separate component of income before extraordinary items before deduction or consideration of the amount which may be allocable to noncontrolling interests, if any. Includes the following (net of tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Balance held at close of period in number of shares.

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Basis Of Presentation And Significant Accounting Policies (Narrative) (Details) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended			3 Months Ended				9 Months Ended	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2011 USD ($)	Sep. 30, 2010 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2010 USD ($)	Dec. 31, 2010 USD ($)	Sep. 30, 2011 RenewaFUEL [Member] USD ($)	Sep. 30, 2010 RenewaFUEL [Member] USD ($)	Sep. 30, 2011 RenewaFUEL [Member] USD ($)	Sep. 30, 2010 RenewaFUEL [Member] USD ($)	Sep. 30, 2011 Empire [Member] USD ($)	Jun. 30, 2011 AusQuest [Member] USD ($)	Sep. 30, 2011 WISCO [Member]	Sep. 30, 2011 Consolidated Thompson [Member]	May 12, 2011 Consolidated Thompson [Member] CAD	Sep. 30, 2011 Earnings Per Share, Basic [Member] USD ($)	Sep. 30, 2011 Immaterial Error [Member] USD ($)	Jun. 30, 2011 Immaterial Error [Member] USD ($)	Mar. 31, 2011 Immaterial Error [Member] USD ($)	Jun. 30, 2011 Immaterial Error [Member] USD ($)	Sep. 30, 2011 Immaterial Error [Member] USD ($)
Cost per share acquired														17.25
Ownership percentage in Consolidated Thompson													100.00%
Recorded impairment charges											$ 17.6
Interest Percentage												25.00%
Fair value of AusQuest closing market price					22.0						7.3
Cost of Rehabilitation, Current	20		20
Investment Owned, Balance, Shares											68.3
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	758.8	298.1	1,609.4	637.4												16.1	7.7	8.4	16.1	16.1
Earnings Per Share, Basic and Diluted																$ 0.47	$ (0.22)	$ (0.28)	$ (0.49)
Basic	$ 4.09	$ 2.20	$ 10.18	$ 4.70																$ 0.49
Diluted	$ 4.07	$ 2.18	$ 10.12	$ 4.67																$ 0.48
Net income (loss) attributable to Cliffs shareholders	589.5	297.4	1,420.6	635.4												67.9	(30.4)	(37.5)	(67.9)	67.9
Retained Earnings (Accumulated Deficit)	4,266.2		4,266.2		2,924.1											67.9				67.9
LESS: NET INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTEREST (net of tax of $0.1, $0.3, and $9.1 in 2010, 2009 and 2008)	151.8		170.1														38.1	45.9	84.0	84.0
NONCONTROLLING INTEREST	1,128.4		1,128.4		(7.2)											84.0				84.0
Reimbursement Revenue And Freight Revenue	18.4	58.8	169.4	183.1												(46.0)	(46.0)		(46.0)	(46.0)
Sales Revenue, goods, net	2,124.4	1,287.2	4,962.4	3,074.8												54.1	46.0	54.1	100.1	54.1
Related party revenue	224.9		313.6
Related party receivables	68.8		68.8
Total Related Party Revenue	837.8	379.4	1,700.0	905.4						157.1
Loss from discontinued operations, net of tax	17.5	0.7	18.7	2.0		17.5	0.7	18.7	2.0
Discontinued Operation, Tax Effect of Discontinued Operation						7.3	0.4	7.9	1.0
Impairment charge						16.7		16.7
Asset Impairment Charges, Tax Effect						7.1		7.1
Adjustment to income from continuing operations before income taxes and equity loss from ventures			22.0	12.3
Adjustment to net income attributable to shareholders			16.1	8.9
Adjustment to basic and diluted earnings per common share			$ 0.12												$ 0.07
Adjustment to retained earnings			16.1
Accumulated other comprehensive income					$ 25.3