Cleveland-Cliffs Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

DISCONTINUED OPERATIONS DISCONTINUED OPERATIONS (Narrative) (Details)

DISCONTINUED OPERATIONS DISCONTINUED OPERATIONS (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Tax Effect of Discontinued Operation	$ 0	$ 44,300,000
Business Exit Costs	(818,700,000)	0
Cost Method Investments	0
North American Coal [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pension and Other Postretirement Defined Benefit Plans, Liabilities	330,000,000
Discontinued Operation, Tax Effect of Discontinued Operation	100,000	7,200,000
Tangible Asset Impairment Charges	(73,400,000)
Asia Pacific Iron Ore [Member] \| Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tangible Asset Impairment Charges			526,500,000
Other Current Assets [Member] \| Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loans, Associated Interest and Accounts Receivable recognized in Consolidated Financials at Fair Value	112,100,000
Other Current Liabilities [Member] \| Bloom Lake Group [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent Liabilities recognized in Consolidated Financials	166,100,000
Short-term Liabilities of Discontinued Operations [Member] \| Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities Recorded for Wholly-owned Subsidiaries of Bloom Lake Group that did not file CCAA	51,400,000
Long-term Liabilities of Discontinued Operations [Member] \| Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities Recorded for Wholly-owned Subsidiaries of Bloom Lake Group that did not file CCAA	$ 125,200,000