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

ASSET RETIREMENT OBLIGATIONS (Summary Of Asset Retirement Obligations) (Details)

v3.20.1

ASSET RETIREMENT OBLIGATIONS (Summary Of Asset Retirement Obligations) (Details) - USD ($)
$ in Millions

Mar. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Loss Contingencies [Line Items]

Asset Retirement Obligation

$ 181.4

^[1]

$ 165.3

^[1]

$ 172.4

Asset Retirement Obligation, Current

2.2

2.1

Asset Retirement Obligations, Noncurrent

179.2

163.2

Operating Segments [Member] | Mining and Pelletizing [Member]

Loss Contingencies [Line Items]

Asset Retirement Obligation

$ 32.5

$ 22.0

[1]	¹ Includes $32.5 million and $22.0 million related to our active operations as of March 31, 2020 and December 31, 2019, respectively.

- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

+ Details

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

- Definition

Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

+ Details

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

- Definition

Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Details

Name:	srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=clf_MiningandPelletizingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: