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

Quarterly report pursuant to Section 13 or 15(d)

Cover
- Document and Entity Information
Financial Statements
Notes to Financial Statements
Accounting Policies
- BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)
Notes Tables
Notes Details

STOCK COMPENSATION PLANS (Narrative) (Details)

v2.4.1.9

STOCK COMPENSATION PLANS (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option Indexed to Issuer's Equity, Strike Price	$ 7.70
2012 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance/vesting period	3 years
2015 to 2017 Performance Period [Member] \| 2012 Equity Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout rate, as a percentage of the original grant	0.00%
2015 to 2017 Performance Period [Member] \| 2012 Equity Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout rate, as a percentage of the original grant	200.00%
Performance Shares [Member] \| 2012 Amended Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of performance shares granted	0.9
Employee Stock Option [Member] \| 2012 Amended Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of performance shares granted	0.4
Restricted Stock Units (RSUs) [Member] \| 2012 Amended Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted shares granted	0.9

- Definition

Share Based Goods and Nonemployee Services Transaction Valuation Method, Payout Rate

+ References

No definition available.

+ Details

Name:	clf_ShareBasedGoodsAndNonemployeeServicesTransactionValuationMethodPayoutRate
Namespace Prefix:	clf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Exercise or strike price stated in the contract for options indexed to the issuer's equity shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (f)(1)

-URI http://asc.fasb.org/extlink&oid=6940734&loc=d3e22047-110879

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 40

-Section 50

-Paragraph 5

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008

+ Details

Name:	us-gaap_OptionIndexedToIssuersEquityStrikePrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

+ References

No definition available.

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsByTypeOfDeferredCompensationAxis=clf_A2015to2017PerformancePeriodMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=clf_TwoThousandTwelveEquityPlanandAmendedEquityPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: