Label	Element	Value
Capital Addition Purchase Commitments [Member]
Recorded Unconditional Purchase Obligation	us-gaap_RecordedUnconditionalPurchaseObligation	$ 580,000,000
Common Stock [Member]
Common Stock, New Shares, Issued	clf_CommonStockNewSharesIssued	44,400,000
Common Stock, New Shares, Issued	clf_CommonStockNewSharesIssued	63,300,000

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25383-109308

Name:	us-gaap_RecordedUnconditionalPurchaseObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant