    <SEC-DOCUMENT>0000764065-24-000058-index.html : 20240304
    <SEC-HEADER>0000764065-24-000058.hdr.sgml : 20240304
    <ACCEPTANCE-DATETIME>20240304172113
    ACCESSION NUMBER:		0000764065-24-000058
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		27
    CONFORMED PERIOD OF REPORT:	20240304
    ITEM INFORMATION:		Other Events
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20240304
    DATE AS OF CHANGE:		20240304

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			CLEVELAND-CLIFFS INC.
    		CENTRAL INDEX KEY:			0000764065
    		STANDARD INDUSTRIAL CLASSIFICATION:	METAL MINING [1000]
    		ORGANIZATION NAME:           	01 Energy & Transportation
    		IRS NUMBER:				341464672
    		STATE OF INCORPORATION:			OH
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-08944
    		FILM NUMBER:		24715827

    	BUSINESS ADDRESS:
    		STREET 1:		200 PUBLIC SQUARE
    		STREET 2:		STE. 3300
    		CITY:			CLEVELAND
    		STATE:			OH
    		ZIP:			44114-2315
    		BUSINESS PHONE:		216-694-5700

    	MAIL ADDRESS:
    		STREET 1:		200 PUBLIC SQUARE
    		STREET 2:		STE. 3300
    		CITY:			CLEVELAND
    		STATE:			OH
    		ZIP:			44114-2315

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	CLIFFS NATURAL RESOURCES INC.
    		DATE OF NAME CHANGE:	20081015

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	CLEVELAND CLIFFS INC
    		DATE OF NAME CHANGE:	19920703
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>clf-20240304.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: clf-20240304.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.1
    <SEQUENCE>2
    <FILENAME>a202403048-kex991.htm
    <DESCRIPTION>EX-99.1
    <TEXT>
    Document 2 - file: a202403048-kex991.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.2
    <SEQUENCE>3
    <FILENAME>a202403048-kex992.htm
    <DESCRIPTION>EX-99.2
    <TEXT>
    Document 3 - file: a202403048-kex992.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.3
    <SEQUENCE>4
    <FILENAME>a202403048-kex993.htm
    <DESCRIPTION>EX-99.3
    <TEXT>
    Document 4 - file: a202403048-kex993.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>5
    <FILENAME>clf-20240304.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 5 - file: clf-20240304.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.LAB
    <SEQUENCE>6
    <FILENAME>clf-20240304_lab.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT
    <TEXT>
    Document 6 - file: clf-20240304_lab.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.PRE
    <SEQUENCE>7
    <FILENAME>clf-20240304_pre.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT
    <TEXT>
    Document 7 - file: clf-20240304_pre.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>a202403048-kex991001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: a202403048-kex991001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>a202403048-kex991002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: a202403048-kex991002.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>a202403048-kex991003.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: a202403048-kex991003.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>a202403048-kex992001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: a202403048-kex992001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>a202403048-kex992002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: a202403048-kex992002.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>a202403048-kex992003.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: a202403048-kex992003.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>a202403048-kex993001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: a202403048-kex993001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>a202403048-kex993002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 15 - file: a202403048-kex993002.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>a202403048-kex993003.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 16 - file: a202403048-kex993003.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>a202403048-kex993004.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: a202403048-kex993004.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>18
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 18 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EXCEL
    <SEQUENCE>20
    <FILENAME>Financial_Report.xlsx
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 20 - file: Financial_Report.xlsx

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>21
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 21 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>22
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 22 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>24
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 24 - file: FilingSummary.html

    Document 24 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>26
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 26 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>27
    <FILENAME>0000764065-24-000058-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 27 - file: 0000764065-24-000058-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>28
    <FILENAME>clf-20240304_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 28 - file: clf-20240304_htm.html

    Document 28 - RAW XML: clf-20240304_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>