Cleveland-Cliffs (CLF) 10-K 25 Feb 25 2024 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2024	Feb. 25, 2025	Jun. 30, 2024
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-8944
Entity Registrant Name	CLEVELAND-CLIFFS INC.
Entity Incorporation, State or Country Code	OH
Entity Tax Identification Number	34-1464672
Entity Address, Address Line One	200 Public Square,
Entity Address, City or Town	Cleveland,
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44114-2315
City Area Code	216
Local Phone Number	694-5700
Title of 12(b) Security	Common Shares, par value $0.125 per share
Trading Symbol	CLF
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 7,077,318,531
Entity Common Stock, Shares Outstanding		494,481,275
Documents Incorporated by Reference [Text Block]	Portions of the registrant’s proxy statement for its 2025 annual meeting of shareholders are incorporated by reference into Part III.
Entity Central Index Key	0000764065
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	false

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2024
Audit Information [Abstract]
Auditor Location	Cleveland, Ohio
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34

Statements of Consolidated Fina

Statements of Consolidated Financial Position - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 54	$ 198
Accounts receivable, net	1,576	1,840
Inventories	5,094	4,460
Other current assets	183	138
Total current assets	6,907	6,636
Non-current assets:
Property, plant and equipment, net	9,942	8,895
Goodwill	1,768	1,005
Intangible assets	1,170	201
Pension and OPEB assets	427	329
Other non-current assets	733	471
TOTAL ASSETS	20,947	17,537
Current liabilities:
Accounts payable	2,008	2,099
Accrued employment costs	447	511
Accrued expenses	375	380
Other current liabilities	492	518
Total current liabilities	3,322	3,508
Non-current liabilities:
Long-term debt	7,065	3,137
Pension and OPEB liabilities	751	821
Deferred income taxes	858	639
Asset retirement and environmental obligations	601	557
Other non-current liabilities	1,453	753
TOTAL LIABILITIES	14,050	9,415
Commitments and contingencies (See NOTE 20)
Equity:
Common Shares - par value $0.125 per share	66	66
Capital in excess of par value of shares	4,758	4,861
Retained earnings	979	1,733
Cost of 37,102,625 common shares in treasury (2023 - 26,164,757 shares)	(676)	(430)
Accumulated other comprehensive income	1,537	1,657
Total Cliffs shareholders' equity	6,664	7,887
Noncontrolling interests	233	235
TOTAL EQUITY	6,897	8,122
TOTAL LIABILITIES AND EQUITY	$ 20,947	$ 17,537

Statements of Consolidated Fi_2

Statements of Consolidated Financial Position (Parenthetical) - $ / shares	Dec. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Common shares, par value (in dollars per share)	$ 0.125	$ 0.125
Common shares, authorized (in shares)	1,200,000,000	1,200,000,000
Common shares, issued (in shares)	531,051,530	531,051,530
Common shares, outstanding (in shares)	493,948,905	504,886,773
Common shares in treasury (in shares)	37,102,625	26,164,757

Statements Of Consolidated Oper

Statements Of Consolidated Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenues	$ 19,185	$ 21,996	$ 22,989
Operating costs:
Cost of goods sold	(19,115)	(20,605)	(20,471)
Selling, general and administrative expenses	(486)	(577)	(465)
Restructuring and other charges	(129)	0	0
Acquisition-related costs	(44)	(12)	(4)
Asset impairment	(79)	0	(29)
Goodwill impairment	0	(125)	0
Miscellaneous – net	(88)	0	(81)
Total operating costs	(19,941)	(21,319)	(21,050)
Operating income (loss)	(756)	677	1,939
Other income (expense):
Interest expense, net	(370)	(289)	(276)
Loss on extinguishment of debt	(27)	0	(75)
Net periodic benefit credits other than service cost component	247	204	212
Other non-operating income (loss)	(37)	5	(4)
Total other expense	(187)	(80)	(143)
Income (loss) from continuing operations before income taxes	(943)	597	1,796
Income tax benefit (expense)	235	(148)	(423)
Income (loss) from continuing operations	(708)	449	1,373
Income from discontinued operations, net of tax	0	1	3
Net income (loss)	(708)	450	1,376
Net income attributable to noncontrolling interests	(46)	(51)	(41)
Net income (loss) attributable to Cliffs shareholders	$ (754)	$ 399	$ 1,335
Earnings (loss) per common share attributable to Cliffs shareholders - basic
Continuing operations (in dollars per share)	$ (1.57)	$ 0.78	$ 2.57
Discontinued operations (in dollars per share)	0	0	0
Earnings (loss) per common share attributable to Cliffs common shareholders - basic (in dollars per share)	(1.57)	0.78	2.57
Earnings (loss) per common share attributable to Cliffs shareholders - diluted
Continuing operations (in dollars per share)	(1.57)	0.78	2.55
Discontinued operations (in dollars per share)	0	0	0
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted (in dollars per share)	$ (1.57)	$ 0.78	$ 2.55

Statements Of Consolidated Comp

Statements Of Consolidated Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (708)	$ 450	$ 1,376
Other comprehensive income (loss):
Changes in pension and OPEB, net of tax	(167)	(20)	1,298
Changes in derivative instruments, net of tax	117	(154)	(84)
Changes in foreign currency translation	(70)	1	(2)
Total other comprehensive income (loss)	(120)	(173)	1,212
Comprehensive income (loss)	(828)	277	2,588
Comprehensive income attributable to noncontrolling interests	(46)	(51)	(41)
Comprehensive income (loss) attributable to Cliffs shareholders	$ (874)	$ 226	$ 2,547

Statements Of Consolidated Cash

Statements Of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
OPERATING ACTIVITIES
Net income (loss)	$ (708)	$ 450	$ 1,376
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	951	973	1,034
Pension and OPEB credits	(211)	(163)	(132)
Deferred income taxes	(195)	114	90
Other	485	201	226
Changes in operating assets and liabilities, net of business combination:
Accounts receivable, net	364	120	197
Inventories	(5)	670	64
Income taxes	(17)	122	(22)
Pension and OPEB payments and contributions	(195)	(94)	(204)
Payables, accrued employment and accrued expenses	(408)	4	(70)
Other, net	44	(130)	(136)
Net cash provided by operating activities	105	2,267	2,423
INVESTING ACTIVITIES
Purchase of property, plant and equipment	(695)	(646)	(943)
Other investing activities	(5)	55	38
Net cash used by investing activities	(3,212)	(591)	(936)
FINANCING ACTIVITIES
Repurchase of common shares	(733)	(152)	(240)
Proceeds from issuance of debt	3,221	750	0
Repayments of senior notes	(845)	0	(1,358)
Borrowings (repayments) under credit facilities	1,560	(1,864)	255
Debt issuance costs	(109)	(34)	0
Other financing activities	(124)	(204)	(166)
Net cash provided (used) by financing activities	2,970	(1,504)	(1,509)
Net increase (decrease) in cash and cash equivalents	(137)	172	(22)
Cash, cash equivalents, and restricted cash at beginning of year	198	26	48
Effect of exchange rate changes on cash	(1)	0	0
Cash, cash equivalents, and restricted cash at end of year	60	198	26
Restricted cash	(6)	0	0
Cash and cash equivalents	54	198	26
Stelco Holdings Inc
INVESTING ACTIVITIES
Acquisition, net of cash acquired	(2,512)	0	0
Ferrous Processing and Trading
INVESTING ACTIVITIES
Acquisition, net of cash acquired	$ 0	$ 0	$ (31)

Statements of Consolidated Chan

Statements of Consolidated Changes in Equity - USD ($) $ in Millions	Total	Stelco Holdings Inc	Common Stock	Common Stock Stelco Holdings Inc	Capital in Excess of Par Value of Shares	Capital in Excess of Par Value of Shares Stelco Holdings Inc	Retained Earnings (Deficit)	Common Shares in Treasury	Common Shares in Treasury Stelco Holdings Inc	AOCI (Loss)	Non- controlling Interests
Balance, beginning of period (in shares) at Dec. 31, 2021			500,100,000
Balance, beginning of period at Dec. 31, 2021	$ 5,774		$ 63		$ 4,892		$ (1)	$ (82)		$ 618	$ 284
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	2,588						1,335			1,212	41
Stock and other incentive plans (in shares)			1,500,000
Stock and other incentive plans, APIC					7
Stock and other incentive plans	19							12
1.500% 2025 Convertible Senior Notes redemption (in shares)			24,200,000
Stock Issued During Period, Value, Conversion of Convertible Securities, Net of Adjustments	(25)				(28)
Stock Issued During Period, Value, Conversion of Convertible Securities			$ 3
Common stock repurchases (in shares)			(12,500,000)
Common stock repurchases, net of excise tax	(240)							(240)
Net distributions to noncontrolling interests	(74)										(74)
Balance, end of period (in shares) at Dec. 31, 2022			513,300,000
Balance, end of period at Dec. 31, 2022	8,042		$ 66		4,871		1,334	(310)		1,830	251
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	277						399			(173)	51
Stock and other incentive plans (in shares)			2,000,000
Stock and other incentive plans, APIC					(10)
Stock and other incentive plans	23							33
Common stock repurchases (in shares)			(10,400,000)
Common stock repurchases, net of excise tax	(153)							(153)
Net distributions to noncontrolling interests	$ (67)										(67)
Balance, end of period (in shares) at Dec. 31, 2023	504,886,773		504,900,000
Balance, end of period at Dec. 31, 2023	$ 8,122		$ 66		4,861		1,733	(430)		1,657	235
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(828)						(754)			(120)	46
Stock Issued During Period, Value, Acquisitions		$ 343				$ (130)			$ 473
Stock and other incentive plans (in shares)			1,000,000
Acquisition (in shares)		25.9		25,900,000
Stock and other incentive plans, APIC					27
Stock and other incentive plans	45							18
Common stock repurchases (in shares)			(37,900,000)
Common stock repurchases, net of excise tax	(737)							(737)
Net distributions to noncontrolling interests	$ (48)										(48)
Balance, end of period (in shares) at Dec. 31, 2024	493,948,905		493,900,000
Balance, end of period at Dec. 31, 2024	$ 6,897		$ 66		$ 4,758		$ 979	$ (676)		$ 1,537	$ 233

BASIS OF PRESENTATION AND SIGNI

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	NOTE 1 - BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES BUSINESS, CONSOLIDATION AND PRESENTATION NATURE OF BUSINESS We are a leading North America-based steel producer with focus on value-added sheet products, particularly for the automotive industry. We are vertically integrated from the mining of iron ore, production of pellets and direct reduced iron, and processing of ferrous scrap through primary steelmaking and downstream finishing, stamping, tooling and tubing. Headquartered in Cleveland, Ohio, we employ approximately 30,000 people across our operations in the United States and Canada. More than 90% of our approximately 23,000 hourly workforce is represented by three prominent unions - USW, UAW and IAM. Unless otherwise noted, discussion of our business and results of operations in this Annual Report on Form 10-K refers to our continuing operations. STELCO ACQUISITION On November 1, 2024, pursuant to the terms of the Arrangement Agreement announced on July 15, 2024, we completed the Stelco Acquisition. In connection with closing, Stelco shareholders received CAD $60.00 in cash and 0.454 shares of Cliffs common stock per share of Stelco common stock. Refer to NOTE 3 - ACQUISITIONS for further information. BUSINESS OPERATIONS We are organized into four operating segments based on differentiated products, Steelmaking, Tubular, Tooling and Stamping and European Operations. We primarily operate through one reportable segment – the Steelmaking segment. BASIS OF CONSOLIDATION The consolidated financial statements consolidate our accounts and the accounts of our wholly owned subsidiaries, all subsidiaries in which we have a controlling interest and VIEs for which we are the primary beneficiary. All intercompany transactions and balances are eliminated upon consolidation. INVESTMENTS IN AFFILIATES We have investments in several businesses accounted for using the equity method of accounting. These investments are included within our Steelmaking segment. We review an investment for impairment when circumstances indicate that a loss in value below its carrying amount is other than temporary. Our investment in affiliates of $131 million and $123 million as of December 31, 2024 and 2023, respectively, was classified in Other non-current assets. SIGNIFICANT ACCOUNTING POLICIES We consider the following policies to be beneficial in understanding the judgments involved in the preparation of our consolidated financial statements and the uncertainties that could impact our financial condition, results of operations and cash flows. Certain prior period amounts have been reclassified to conform with the current year presentation. USE OF ESTIMATES The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Our mineral reserves; future realizable cash flow; environmental, reclamation and closure obligations; valuation of business combinations; derivative assets/liabilities; tax assets/liabilities; post-employment, post-retirement and other employee benefit liabilities; reserves for contingencies and litigation require the use of various management estimates and assumptions. Actual results could differ from estimates. Management reviews its estimates on an ongoing basis. Changes in facts and circumstances may alter such estimates and affect the results of operations and financial position in future periods. BUSINESS COMBINATIONS Assets acquired and liabilities assumed in a business combination are recognized and measured based on their estimated fair values at the acquisition date, while the acquisition-related costs are expensed as incurred. Any excess of the purchase consideration when compared to the fair value of the net tangible and intangible assets acquired, if any, is recorded as goodwill. We engage independent valuation specialists to assist with the determination of the fair value of assets acquired, liabilities assumed and goodwill associated with an acquisition. If the initial accounting for the business combination is incomplete by the end of the reporting period in which the acquisition occurs, an estimate will be recorded. Subsequent to the acquisition date, and not later than one year from the acquisition date, we will record any material adjustments to the initial estimate based on new information obtained that existed as of the date of the acquisition. Any adjustment that arises from information obtained that did not exist as of the date of the acquisition will be recorded in the period the adjustment arises. CASH, CASH EQUIVALENTS, AND RESTRICTED CASH Cash and cash equivalents include cash on hand and on deposit as well as all short-term securities held for the primary purpose of general liquidity. We routinely monitor and evaluate counterparty credit risk related to the financial institutions in which our short-term investment securities are held. Where right of offset exists, we report cash balances net. Additionally, restricted cash represents cash not readily available for our operations and includes deposits primarily associated with certain environmental obligations. This balance is classified within Other non-current assets on the Statements of Consolidated Financial Position. TRADE ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSS Trade accounts receivable are recorded at the point control transfers and represent the amount of consideration we expect to receive in exchange for transferred goods and do not bear interest. We establish provisions for expected lifetime losses on accounts receivable at the time a receivable is recorded based on historical experience, customer credit quality and forecasted economic conditions. We regularly review our accounts receivable balances and the allowance for credit loss and establish or adjust the allowance as necessary using the specific identification method. We evaluate the aggregation and risk characteristics of receivable pools and develop loss rates that reflect historical collections, current forecasts of future economic conditions over the time horizon we are exposed to credit risk, and payment terms or conditions that may materially affect future forecasts. INVENTORIES Inventories are generally stated at the lower of cost or net realizable value using average cost, excluding depreciation and amortization. Certain iron ore inventories are stated at the lower of cost or market using the LIFO method. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES We are exposed to certain risks related to the ongoing operations of our business, including those caused by changes in commodity prices and energy rates. We have established policies and procedures, including the use of certain derivative instruments, to manage such risks. Derivative instruments are recognized as either assets or liabilities on the Statements of Consolidated Financial Position and measured at fair value. On the date a qualifying hedging instrument is executed, we designate the hedging instrument as a hedge of the variability of cash flows to be received or paid related to a forecasted transaction (cash flow hedge). We formally document all relationships between hedging instruments and hedged items, as well as our risk-management objective and strategy for undertaking various hedge transactions. This process includes linking all derivatives that are designated as cash flow hedges to specific firm commitments or forecasted transactions. We also formally assess, both at the hedge's inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows of the related hedged items. When it is determined that a derivative is not highly effective as a hedge, we discontinue hedge accounting prospectively and record all future changes in fair value in the period of the instrument's earnings or losses. For derivative instruments that have been designated as cash flow hedges, the changes in fair value are recorded in Accumulated other comprehensive income . Amounts recorded in Accumulated other comprehensive income are reclassified to earnings or losses in the period the underlying hedged transaction affects earnings or when the underlying hedged transaction is no longer reasonably possible of occurring. The cash flows resulting from these derivative instruments are classified in Other, net in operating activities on the Statements of Consolidated Cash Flows. For derivative instruments that have not been designated as cash flow hedges, changes in fair value are recorded in the period of the instrument's earnings or losses. PROPERTY, PLANT AND EQUIPMENT Our properties are stated at cost less accumulated depreciation. Depreciation of plant and equipment is computed principally by the straight-line method based on estimated useful lives. Depreciation continues to be recognized when operations are idled temporarily. Depreciation and depletion are recorded over the following estimated useful lives: Asset Class Basis Life Land, land improvements and mineral rights Land and mineral rights Units of production Life of mine Land improvements Straight line 20 to 45 years Buildings Straight line 20 to 45 years Equipment Straight line/Double declining balance 3 to 45 years Governmental grants received in connection with an underlying capital project typically have associated requirements that must be met in order to ultimately earn the grant. When we receive grant funds related to a capital project, we record the amount received as a reduction of the capital project asset on the balance sheet. Grant funds received are recorded as a cash inflow, classified in Other investing activities, separate from the cash outflow related to the capital project, which are classified in Purchase of property, plant and equipment , within investing activities on the Statements of Consolidated Cash Flows. GOODWILL Goodwill represents the excess purchase price paid over the fair value of the net assets from an acquisition. Goodwill is not amortized for financial statement purposes. Goodwill is tested on a qualitative or quantitative basis for impairment at the reporting unit level on an annual basis on October 1 and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value. We have an unconditional option to bypass the qualitative test for any reporting unit in any period and proceed directly to performing the quantitative test. Should our qualitative test indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying value, we perform a quantitative test to determine the amount of impairment, if any, to the carrying value of the reporting unit and its associated goodwill. OTHER INTANGIBLE ASSETS AND LIABILITIES Intangible assets and liabilities are subject to periodic amortization on a straight-line basis over their estimated useful lives. LEASES We determine if an arrangement contains a lease at inception. We recognize right-of-use assets and lease liabilities associated with leases based on the present value of the future minimum lease payments over the lease term at the commencement date. Lease terms reflect options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Short-term leases (leases with an initial lease term of 12 months or less) are not recognized on the Statements of Consolidated Financial Position. Operating lease expense is recognized on a straight-line basis over the lease term. ASSET IMPAIRMENT We monitor conditions that may affect the carrying value of our long-lived tangible and intangible assets when events and circumstances indicate that the carrying value of the asset groups may not be recoverable. In order to determine if assets have been impaired, assets are grouped and tested at the lowest level for which identifiable, independent cash flows are available ("asset group"). The measurement of the impairment loss to be recognized is based on the difference between the fair value and the carrying value of the asset group. Fair value can be determined using a market approach, income approach or cost approach. FAIR VALUE MEASUREMENTS ASC Topic 820, Fair Value Measurements and Disclosures , establishes a three-level valuation hierarchy for classification of fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. Inputs refer broadly to the assumptions that market participants would use in pricing an asset or liability. Inputs may be observable or unobservable. Observable inputs are inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from independent sources. Unobservable inputs are inputs that reflect our own views about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. The three-tier hierarchy of inputs is summarized below: • Level 1 — Valuation is based upon quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2 — Valuation is based upon quoted prices for similar assets and liabilities in active markets, or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 — Valuation is based upon other unobservable inputs that are significant to the fair value measurement. The classification of assets and liabilities within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement in its entirety. PENSION AND OTHER POSTRETIREMENT BENEFITS We offer defined benefit pension plans, defined contribution pension plans and OPEB plans, primarily consisting of retiree healthcare benefits as part of our total compensation and benefits programs. We recognize the funded or unfunded status of our pension and OPEB obligations on the Statements of Consolidated Financial Position based on the difference between the market value of plan assets and the actuarial present value of our retirement obligations on that date, on a plan-by-plan basis. If the plan assets exceed the pension and OPEB obligations, the amount of the surplus is recorded as an asset; if the pension and OPEB obligations exceed the plan assets, the amount of the underfunded obligations is recorded as a liability. Year-end balance sheet adjustments to pension and OPEB assets and obligations are recorded as Accumulated other comprehensive income on the Statements of Consolidated Financial Position. The actuarial estimates of the PBO (Projected benefit obligation) and APBO (Accumulated postretirement benefit obligation) incorporate various assumptions including the discount rates, the rates of increases in compensation, healthcare cost trend rates, mortality, retirement timing, employee turnover and other demographic assumptions. The discount rate is determined based on the prevailing year-end rates for high-grade corporate bonds with a duration matching the expected cash flow timing of the benefit payments from the various plans. The remaining assumptions are based on our estimates of future events by incorporating historical trends and future expectations. The amount of net periodic cost that is recorded in the Statements of Consolidated Operations consists of several components including service cost, interest cost, expected return on plan assets, and amortization of previously unrecognized amounts. Service cost represents the value of the benefits earned in the current year by the participants. Interest cost represents the cost associated with the passage of time. Certain items, such as plan amendments, gains and/or losses resulting from differences between actual and assumed results for demographic and economic factors affecting the obligations and assets of the plans, and changes in other assumptions are subject to deferred recognition for income and expense purposes. The expected return on plan assets is calculated on a plan-by-plan basis using each plan's strategic asset allocation and our expected long-term capital market return assumptions. Service costs are classified within Cost of goods sold, Selling, general and administrative expenses and Miscellaneous – net while the interest cost, expected return on assets, amortization of prior service costs/credits, net actuarial gain/loss, and other costs are classified within Net periodic benefit credits other than service cost component. Cumulative actuarial gains and losses will be amortized to expense using the corridor method, where gains and losses are recognized if they exceed 10% of the greater of the fair value of plan assets or the plans' benefit obligations. The amortization period varies by plan. ASSET RETIREMENT OBLIGATIONS An asset retirement obligation is recognized when incurred if a reasonable estimate of fair value can be made, and is initially measured at fair value. The fair value of the liability is determined as the discounted value of the expected future cash flows. The asset retirement obligation is accreted over time through periodic charges to earnings. In addition, the asset retirement cost is capitalized and amortized over the life of the related asset. Reclamation costs are adjusted periodically to reflect changes in the estimated present value resulting from the passage of time and revisions to the estimates of either the timing or amount of the reclamation costs. We review, on an annual basis, unless otherwise deemed necessary, the asset retirement obligation for each applicable operation in accordance with the provisions of ASC Topic 410, Asset Retirement and Environmental Obligations . We perform an in-depth evaluation of the liability every three years in addition to our routine annual assessments. Future reclamation costs for inactive operations are accrued based on management’s best estimate at the end of each period of the costs expected to be incurred at a site. Such cost estimates include, where applicable, ongoing maintenance and monitoring costs. Changes in estimates at inactive operations are reflected in Miscellaneous – net on the Statements of Consolidated Operations in the period an estimate is revised. ENVIRONMENTAL REMEDIATION COSTS Our operating activities are subject to various laws and regulations governing protection of the environment. We conduct our operations to protect the public health and environment and believe our operations are in compliance with applicable laws and regulations in all material respects. Our environmental liabilities, including obligations for known environmental remediation exposures, have been recognized based on the estimated cost of investigation and remediation at each site. If the cost can only be estimated as a range of possible amounts with no point in the range being more likely, the minimum of the range is accrued. Future expenditures are discounted unless the amount and timing of the cash disbursements cannot be reasonably estimated. It is possible that additional environmental obligations could be incurred, the extent of which cannot be assessed. Potential insurance recoveries have not been reflected in the determination of the liabilities. REVENUE RECOGNITION Sales are recognized when our performance obligations are satisfied. Generally, our performance obligations are satisfied, control of our products is transferred and revenue is recognized at a single point in time, according to shipping terms. Shipping and other transportation costs charged to customers are treated as fulfillment activities and are recorded in both revenue and cost of sales at the time control is transferred to the customer. REPAIRS AND MAINTENANCE Repairs, maintenance and replacement of components are expensed as incurred. The cost of major equipment overhauls is capitalized and depreciated over the estimated useful life, which is the period until the next scheduled overhauls. All other planned and unplanned repairs and maintenance costs are expensed when incurred. INCOME TAXES Income taxes are based on income for financial reporting purposes, calculated using tax rates by jurisdiction, and reflect a current tax liability or asset for the estimated taxes payable or recoverable on the current year tax return and expected annual changes in deferred taxes. Any interest or penalties on income tax are recognized as a component of Income tax benefit (expense) . We account for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized within Income tax benefit (expense) in the period that includes the enactment date. We recognize income tax effects from accumulated other comprehensive income when individual assets or liabilities are sold, terminated, or extinguished. We record net deferred tax assets to the extent we believe these assets will more likely than not be realized. In making such determination, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial results of operations. Accounting for uncertainty in income taxes recognized in the financial statements requires that a tax benefit from an uncertain tax position be recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on technical merits. FOREIGN CURRENCY Our financial statements are prepared with the U.S. dollar as the reporting currency. Our functional currency is the U.S. dollar, with the exception of our Stelco and European subsidiaries, of which the functional currencies are the Canadian dollar and Euro, respectively. To the extent that the parent, or any subsidiaries of the parent, have monetary assets and liabilities, inclusive of short-term and certain long-term intercompany loans, recorded in a currency other than the foreign subsidiaries functional currency, these amounts are remeasured each reporting period, with the resulting gain or loss being included within Miscellaneous – net in the Statements of Consolidated Operations. Subsequently, the financial statements of foreign subsidiaries with a non-U.S. dollar functional currency are translated into U.S. dollars using the exchange rate at each balance sheet date for assets and liabilities and a weighted average exchange rate for each period for revenues, expenses, gains and losses. These translation adjustments are recorded to Accumulated other comprehensive income on the Statements of Consolidated Financial Position . EARNINGS PER SHARE We present both basic and diluted earnings per share amounts for continuing operations and discontinued operations. Total basic earnings per share amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders by the weighted average number of common shares outstanding during the period presented. Total diluted earnings per share amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders by the weighted average number of common shares and common share equivalents under stock plans using the treasury-stock method. Common share equivalents are excluded from EPS computations in the periods in which they have an anti-dilutive effect. VARIABLE INTEREST ENTITIES We assess whether we have a variable interest in legal entities in which we have a financial relationship and, if so, whether or not those entities are VIEs. A VIE is an entity with insufficient equity at risk for the entity to finance its activities without additional subordinated financial support or in which equity investors lack the characteristics of a controlling financial interest. If an entity is determined to be a VIE, we evaluate whether we are the primary beneficiary. The primary beneficiary analysis is a qualitative analysis based on power and economics. We conclude that we are the primary beneficiary and consolidate the VIE if we have both (i) the power to direct the activities of the VIE that most significantly influence the VIE's economic performance and (ii) the obligation to absorb losses of, or the right to receive benefits from, the VIE that could potentially be significant to the VIE. RECENT ACCOUNTING PRONOUNCEMENTS AND LEGISLATION ACCOUNTING PRONOUNCEMENTS - ISSUED AND ADOPTED In September 2022, the FASB issued ASU No. 2022-04, Liabilities - Supplier Finance Programs (Subtopic 405-50): Disclosure of Supplier Finance Program Obligations . This guidance requires annual and interim disclosure of the key terms of outstanding supplier finance programs and a roll-forward of the related obligations. The new standard does not affect the recognition, measurement or financial statement presentation of the supplier finance program obligations. At December 31, 2023, we had adopted this standard, with the exception of the roll-forward disclosure requirement, which was adopted as of December 31, 2024. Refer to NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION for further information. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . This guidance requires additional annual and interim disclosures for reportable segments. This new standard does not affect the recognition, measurement or financial statement presentation. As of December 31, 2024, we have adopted this standard and applied the amendment retrospectively to all prior periods presented. Refer to NOTE 5 - SEGMENT REPORTING for further information. ACCOUNTING PRONOUNCEMENTS - ISSUED AND NOT EFFECTIVE In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . This guidance requires additional annual and interim disclosures for income taxes. This new standard does not affect the recognition, measurement or financial statement presentation. The amendments are effective for fiscal years beginning after December 15, 2024. In November 2024, the FASB issued ASU No. 2024-03, Income Statement—Reporting Comprehensive Income (Subtopic 220-40): Disaggregation of Income Statement Expenses. This new standard does not affect the recognition, measurement or financial statement presentation. However, this guidance does require additional annual and interim disclosures related to the disaggregation of various income statement expense captions. The amendments are effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027.

SUPPLEMENTARY FINANCIAL STATEME

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION	12 Months Ended
	Dec. 31, 2024
Disclosure Text Block [Abstract]
Supplementary Financial Statement Information	NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION INVENTORIES The following table presents the detail of our Inventories on the Statements of Consolidated Financial Position: December 31, (In millions) 2024 2023 Product inventories Finished and semi-finished goods $ 2,393 $ 2,573 Raw materials 2,208 1,476 Total product inventories 4,601 4,049 Manufacturing supplies and critical spares 493 411 Inventories $ 5,094 $ 4,460 The excess of current cost over LIFO cost of iron ore inventories was $142 million and $131 million at December 31, 2024 and 2023, respectively. As of December 31, 2024, the product inventory balance for iron ore inventories increased, resulting in a LIFO increment in 2024. The effect of the inventory build was an increase in Inventories of $64 million on the Statements of Consolidated Financial Position for the year ended December 31, 2024. As of December 31, 2023, the product inventory balance for iron ore inventories increased, resulting in a LIFO increment in 2023. The effect of the inventory build was an increase in Inventories of $21 million on the Statements of Consolidated Financial Position for the year ended December 31, 2023. SUPPLY CHAIN FINANCE PROGRAMS We negotiate payment terms directly with our suppliers for the purchase of goods and services. We currently offer voluntary supply chain finance programs that enable our suppliers to sell their Company receivables to financial intermediaries, at the sole discretion of both the suppliers and financial intermediaries. No guarantees are provided by us or our subsidiaries under the supply chain finance programs. The supply chain finance programs allow our suppliers to be paid by the financial intermediaries earlier than the due date on the applicable invoice. Supply chain finance programs that extend terms or provide us an economic benefit are classified as short-term financings. As of December 31, 2024 and 2023, we had $29 million and $21 million, respectively, deemed as short-term financings that are classified in Other current liabilities . Additionally , as of December 31, 2024 and 2023, we had $76 million and $91 million, respectively, classified as Accounts payable The following is a roll-forward of our obligations related to supply chain finance programs classified in Other current liabilities : (In millions) 2024 Supply chain finance obligations as of January 1 $ 21 Invoices confirmed during the year 230 Confirmed invoices paid during the year (222) Supply chain finance obligations as of December 31 $ 29 The following is a roll-forward of our obligations related to supply chain finance programs classified in Accounts payable : (In millions) 2024 Supply chain finance obligations as of January 1 $ 91 Invoices confirmed during the year 375 Confirmed invoices paid during the year (390) Supply chain finance obligations as of December 31 $ 76 WEIRTON INDEFINITE IDLE On February 15, 2024, we announced the indefinite idle of our tinplate production plant located in Weirton, West Virginia. As of December 31, 2024, we have incurred $210 million of charges related to the idle and estimate that we will incur nominal future charges to Restructuring and other charges . The following table represents a reconciliation of our accrued liabilities related to the Weirton indefinite idle: (In millions) Employee-Related Costs Exit Costs Asset Impairment Total Balance as of December 31, 2023 $ — $ — $ — $ — Costs incurred 1 82 49 79 210 Cash payments (26) (34) — (60) Non-cash — — (79) (79) Balance as of December 31, 2024 $ 56 $ 15 $ — $ 71 1 Of the $210 million of cost incurred, $129 million was recorded in Restructuring and other charges, $79 million was recorded in Asset impairments and $2 million was recorded in Net periodic benefit credits other than service cost component . SALE OF BUSINESS On October 6, 2023, we entered into a membership interest purchase agreement for the sale of the legal entities owning, among other things, our closed coal mines in Pennsylvania. As a result of the sale, we recorded a gain of $63 million classified in Miscellaneous – net in the Statements of Consolidated Operations and as Other in operating activities on the Statements of Consolidated Cash Flows for the year ended December 31, 2023. As part of this transaction, we received $35 million in proceeds related to the sale that is classified as Other investing activities on the Statements of Consolidated Cash Flows. CASH FLOW INFORMATION A reconciliation of capital additions to cash paid for capital expenditures is as follows: Year Ended December 31, (In millions) 2024 2023 2022 Capital additions $ 817 $ 785 $ 1,033 Less: Non-cash accruals (47) (13) 35 Equipment financed with seller 72 59 — Right-of-use assets - finance leases 97 93 55 Cash paid for capital expenditures including deposits $ 695 $ 646 $ 943 Additionally, included within Other investing activities on the Statements of Consolidated Cash Flows are grant reimbursements related to governmental funded capital projects. For the years ended December 31, 2024, 2023 and 2022, grant reimbursements were $8 million, $13 million and $27 million, respectively. Cash payments (receipts) for interest and income taxes are as follows: Year Ended December 31, (In millions) 2024 2023 2022 Income taxes paid $ 17 $ 94 $ 334 Income tax refunds (47) (205) (3) Interest paid on debt obligations net of capitalized interest 1 255 256 249 1 Capitalized interest was $15 million, $12 million and $9 million for the years ended December 31, 2024, 2023 and 2022, respectively. Other non-cash investing and financing activities are as follows: Year Ended December 31, (In millions) 2024 2023 2022 Fair value of common shares issued as part of consideration in connection with the Stelco Acquisition $ 343 $ — $ — 1.500% 2025 Convertible Senior Notes redemption — — 25

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2024
Business Combinations [Abstract]
Acquisitions	NOTE 3 - ACQUISITIONS STELCO ACQUISITION OVERVIEW On November 1, 2024, pursuant to the Arrangement Agreement, we completed the Stelco Acquisition, in which we were the acquirer. The Stelco Acquisition expands our existing presence in Canada and diversifies our customer base across service centers, construction and other industrial end markets with higher volumes of spot sales. Following the Stelco Acquisition, the operating results of Stelco are included in our consolidated financial statements. For the period subsequent to the acquisition (November 1, 2024 through December 31, 2024), Stelco generated Revenues of $329 million and a loss of $58 million included within Net income (loss) attributable to Cliffs shareholders. Additionally, we incurred acquisition related costs of $42 million for the year ended December 31, 2024, in connection with the Stelco Acquisition, which were recorded in Acquisition-related costs on the Statements of Consolidated Operations. The Stelco Acquisition was accounted for under the acquisition method of accounting for business combinations. The fair value of the total purchase consideration was determined as follows: (In millions) Total cash consideration $ 2,450 Total share exchange consideration 343 Total debt consideration 415 Total purchase consideration $ 3,208 Total consideration shares are calculated as follows: Number of outstanding Stelco shares 54,448,388 Number of outstanding share-based compensation awards 2,516,415 Total consideration shares 56,964,803 Total estimated cash consideration is calculated as follows: Number of consideration shares 56,964,803 Consideration share price per share (CAD) $ 60.00 Total cash consideration (CAD) (in millions) 3,418 Exchange rate (November 1, 2024) 0.7168 Total cash consideration (USD) $ 2,450 The fair value of share exchange consideration is as follows: Number of consideration shares 56,964,803 Fixed share exchange factor 0.454 Total Cliffs exchange shares 25,862,021 Cliffs share price at closing date (November 1, 2024) $ 13.27 Total share exchange consideration (in millions) $ 343 The fair value of debt consideration includes outstanding obligations with preexisting change-in-control provisions requiring repayment at the time of closing. The debt consideration includes amounts repaid in connection with retiring Stelco's asset-based lending facility and inventory monetization arrangement. VALUATION ASSUMPTION AND PURCHASE PRICE ALLOCATION We estimated fair values at November 1, 2024 for the preliminary allocation of consideration to the net tangible and intangible assets acquired and liabilities assumed in connection with the Stelco Acquisition. During the measurement period, we will continue to obtain information to assist in finalizing the fair value of assets acquired and liabilities assumed, which may differ materially from these preliminary estimates. If we determine any measurement period adjustments are material, we will apply those adjustments, including any related impacts to net income, in the reporting period in which the adjustments are determined. We are in the process of conducting a valuation of the assets acquired and liabilities assumed related to the Stelco Acquisition, most notably, inventories, personal and real property, leases, deferred taxes, employee benefit commitments, financing obligations, environmental obligations, asset retirement obligations and intangible assets, and the final allocation will be made when completed, including the result of any identified goodwill. Accordingly, the provisional measurements noted below are preliminary and subject to modification in the future. The preliminary purchase price allocation to assets acquired and liabilities assumed in the Stelco Acquisition was: (in Millions) Cash and cash equivalents $ 341 Accounts receivable 104 Inventories 726 Other current assets 107 Property, plant and equipment 1,286 Intangible assets 1,025 Other non-current assets 250 Accounts payable (212) Accrued employment costs (29) Accrued expenses (6) Other current liabilities (71) Pension and OPEB liability, non-current (14) Deferred income taxes (449) Asset retirement and environmental obligations (20) Other non-current liabilities (616) Net identifiable assets acquired 2,422 Goodwill 786 Total net assets acquired $ 3,208 The goodwill resulting from the Stelco Acquisition primarily represents the growth opportunities through diversification within our customer base across service centers, construction and other industrial end markets with higher volumes of spot sales, as well as any synergistic benefits to be realized from the Stelco Acquisition within our Steelmaking segment. Goodwill is not expected to be deductible for U.S. federal income tax purposes. The purchase price allocated to identifiable intangible assets acquired was: (In millions) Weighted Average Life (In years) Intangible assets: Customer relationships 953 15 Trade names and trademarks 72 15 Total identifiable intangible assets $ 1,025 15 PRO FORMA RESULTS The following table provides unaudited pro forma financial information, prepared in accordance with Topic 805, as if Stelco had been acquired as of January 1, 2023: Year Ended December 31, (In millions) 2024 2023 Revenues $ 20,874 $ 24,158 Net income (loss) attributable to Cliffs shareholders (623) 216 The unaudited pro forma financial information has been calculated after applying our accounting policies and adjusting the historical results with pro forma adjustments, net of tax, that assume the Stelco Acquisition occurred on January 1, 2023. Significant non-recurring pro forma adjustments include the following: 1. The 2024 pro forma net loss was adjusted to exclude $23 million of non-recurring inventory acquisition accounting adjustments incurred during the year ended December 31, 2024. The 2023 pro forma net income was adjusted to include $23 million of non-recurring inventory acquisition accounting adjustments for the year ended December 31, 2023. 2. The 2024 pro forma net loss was adjusted to exclude $63 million of transaction costs incurred by Cliffs and Stelco in connection with the Stelco Acquisition for the year ended December 31, 2024. The 2023 pro forma net income was adjusted to include $63 million of transaction cost adjustments for the year ended December 31, 2023. The unaudited pro forma financial information does not reflect the potential realization of synergies or cost savings, nor does it reflect other costs relating to the integration of the acquired company. This unaudited pro forma financial information should not be

REVENUES

REVENUES	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenues	NOTE 4 - REVENUES We generate our revenue through product sales, in which shipping terms indicate when we have fulfilled our performance obligations and transferred control of products to our customer. Our revenue transactions consist of a single performance obligation to transfer promised goods. Our contracts with customers define the mechanism for determining the sales price, which is generally fixed upon transfer of control, but the contracts generally do not impose a specific quantity on either party. Quantities to be delivered to the customer are determined at a point near the date of delivery through purchase orders or other written instructions we receive from the customer. Spot market sales are made through purchase orders or other written instructions. We consider our performance obligation to be complete and recognize revenue when control transfers in accordance with shipping terms. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring product. We reduce the amount of revenue recognized for estimated returns and other customer credits, such as discounts and volume rebates, based on the expected value to be realized. Payment terms are consistent with terms standard to the markets we serve. Sales taxes collected from customers are excluded from revenues. Revenue by market and product are presented net of intersegment revenues, which are entirely related to the Steelmaking segment. The following table represents our Revenues by market: Year Ended December 31, (In millions) 2024 2023 2022 Steelmaking: Automotive $ 5,571 $ 7,440 $ 6,661 Infrastructure and manufacturing 5,208 5,612 5,869 Distributors and converters 5,281 5,330 6,388 Steel producers 2,469 2,949 3,465 Total Steelmaking 18,529 21,331 22,383 Other Businesses: Automotive 540 545 478 Infrastructure and manufacturing 39 38 52 Distributors and converters 77 82 76 Total Other Businesses 656 665 606 Total revenues $ 19,185 $ 21,996 $ 22,989 The following table represents our Revenues by product line: Year Ended December 31, (In millions) 2024 2023 2022 Steelmaking: Hot-rolled steel $ 4,276 $ 4,864 $ 4,529 Cold-rolled steel 2,712 2,658 3,193 Coated steel 5,773 6,661 6,905 Stainless and electrical steel 1,807 2,281 2,284 Plate 1,119 1,444 1,651 Slab and other steel products 1,178 1,329 1,492 Other 1,664 2,094 2,329 Total Steelmaking 18,529 21,331 22,383 Other Businesses: Other 656 665 606 Total revenues $ 19,185 $ 21,996 $ 22,989

SEGMENT REPORTING

SEGMENT REPORTING	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Segment Reporting	NOTE 5 - SEGMENT REPORTING We are vertically integrated from mined raw materials and direct reduced iron and ferrous scrap to primary steelmaking and downstream finishing, stamping, tooling and tubing. We are organized into four operating segments based on our differentiated products - Steelmaking, Tubular, Tooling and Stamping, and European Operations. We have one reportable segment - Steelmaking. The operating segment results of our Tubular, Tooling and Stamping, and European Operations that do not constitute reportable segments are combined and disclosed in the Other Businesses category. Our Steelmaking segment operates as a leading North America-based steel producer with focus on value-added sheet products, primarily serving the automotive, infrastructure and manufacturing, and distributors and converters markets. Our Other Businesses primarily include the operating segments that provide customer solutions with carbon and stainless steel tubing products, advanced-engineered solutions, tool design and build, hot- and cold-stamped steel components, and complex assemblies. All intersegment transactions were eliminated in consolidation. Corporate assets and capital additions are primarily related to and support the operations of the Steelmaking segment and therefore have been incorporated within the Steelmaking segment total assets and capital additions below. We allocate Corporate Selling, general and administrative expenses to our operating segments. Our CODM, Lourenco Goncalves, Chairman, President and CEO, evaluates performance on an operating segment basis, as well as a consolidated basis, based on Adjusted EBITDA, which is a non-GAAP measure. This measure is used by our CODM, management, investors, lenders and other external users of our financial statements to assess our operating performance and to compare operating performance to other companies in the steel industry. In addition, our CODM believes Adjusted EBITDA is a useful measure to assess the earnings power of the business without the impact of capital structure and can be used to assess our ability to service debt and fund future capital expenditures in the business. The following tables provide our results by segment as well as a reconciliation from consolidated Adjusted EBITDA to our consolidated Net income (loss) : Year Ended December 31, 2024 (In millions) Steelmaking Other Businesses Eliminations Total Revenues $ 18,620 $ 656 $ (91) $ 19,185 Cost of goods sold (18,605) (606) 96 (19,115) Selling, general and administrative expenses (457) (29) — (486) Net periodic benefit credits other than service cost component 247 — — 247 Excluding depreciation, depletion and amortization 919 32 — 951 Other segment items 1 (2) — — (2) Total Adjusted EBITDA $ 722 $ 53 $ 5 $ 780 Interest expense, net $ (370) Income tax benefit 235 Depreciation, depletion and amortization (951) EBITDA from noncontrolling interests 2 76 Weirton indefinite idle (217) Arbitration decision (71) Acquisition-related costs (44) Changes in fair value of derivatives, net (41) Loss on extinguishment of debt (27) Amortization of inventory step-up (26) Loss on currency exchange (20) Loss on disposal of assets (16) Other, net (16) Net loss $ (708) Capital Additions $ 812 $ 5 $ — $ 817 Assets $ 20,327 $ 620 $ — $ 20,947 1 Other segment items primarily consists of the exclusion of EBITDA of noncontrolling interests and the Arbitration decision from Adjusted EBITDA and, to a lesser extent, the inclusion of items within Miscellaneous – net and Other non-operating income (loss). 2 EBITDA of noncontrolling interests includes net income attributable to noncontrolling interests of $46 million and the exclusion of depreciation, depletion, and amortization of $30 million. Year Ended December 31, 2023 (In millions) Steelmaking Other Businesses Eliminations Total Revenues $ 21,413 $ 665 $ (82) $ 21,996 Cost of goods sold (20,055) (627) 77 (20,605) Selling, general and administrative expenses (549) (28) — (577) Net periodic benefit credits other than service cost component 204 — — 204 Excluding depreciation, depletion and amortization 938 35 — 973 Other segment items 1 (78) (2) — (80) Total Adjusted EBITDA $ 1,873 $ 43 $ (5) $ 1,911 Interest expense, net $ (289) Income tax expense (148) Depreciation, depletion and amortization (973) EBITDA from noncontrolling interests 2 83 Acquisition-related costs (12) Loss on disposal of assets (15) Goodwill impairment (125) Other, net 18 Net income $ 450 Capital Additions $ 782 $ 3 $ — $ 785 Assets $ 16,880 $ 657 $ — $ 17,537 1 Other segment items primarily consists of the exclusion of EBITDA of noncontrolling interests from Adjusted EBITDA and, to a lesser extent, the inclusion of items within Miscellaneous – net and Other non-operating income (loss). 2 EBITDA of noncontrolling interests includes net income attributable to noncontrolling interests of $51 million and the exclusion of depreciation, depletion, and amortization of $32 million. Year Ended December 31, 2022 (In millions) Steelmaking Other Businesses Eliminations Total Revenues $ 22,462 $ 606 $ (79) $ 22,989 Cost of goods sold (20,004) (557) 90 (20,471) Selling, general and administrative expenses (439) (26) — (465) Net periodic benefit credits other than service cost component 212 — — 212 Excluding depreciation, depletion and amortization 994 40 — 1,034 Other segment items 1 (136) 6 — (130) Total Adjusted EBITDA $ 3,089 $ 69 $ 11 $ 3,169 Interest expense, net $ (276) Income tax expense (423) Depreciation, depletion and amortization (1,034) EBITDA from noncontrolling interests 2 74 Acquisition-related costs (1) Loss on extinguishment of debt (75) Loss on disposal of assets (22) Other, net (36) Net income $ 1,376 Capital Additions $ 1,003 $ 30 $ — $ 1,033 Assets $ 17,918 $ 837 $ — $ 18,755 1 Other segment items primarily consists of the exclusion of EBITDA of noncontrolling interests from Adjusted EBITDA and, to a lesser extent, the inclusion of items within Miscellaneous – net and Other non-operating income (loss). 2 EBITDA of noncontrolling interests includes net income attributable to noncontrolling interests of $41 million and the exclusion of depreciation, depletion, and amortization of $33 million. Included in the consolidated financial statements are the following amounts relating to geographic location based on product destination: Year Ended December 31, (In millions) 2024 2023 2022 Revenues: United States $ 17,340 $ 20,000 $ 20,991 Canada 1,067 1,046 963 Other countries 778 950 1,035 Total revenues $ 19,185 $ 21,996 $ 22,989 Property, plant and equipment, net: United States $ 8,622 $ 8,816 $ 8,981 Canada 1,319 78 88 Other countries 1 1 1 Total property, plant and equipment, net $ 9,942 $ 8,895 $ 9,070

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	NOTE 6 - PROPERTY, PLANT AND EQUIPMENT The following table indicates the carrying value of each of the major classes of our depreciable assets: December 31, (In millions) 2024 2023 Land, land improvements and mineral rights $ 1,451 $ 1,389 Buildings 1,104 946 Equipment 11,119 9,680 Other 349 302 Construction in progress 728 590 Total property, plant and equipment 1 14,751 12,907 Allowance for depreciation and depletion (4,809) (4,012) Property, plant and equipment, net $ 9,942 $ 8,895 1 Includes right-of-use assets related to finance leases of $505 million and $306 million as of December 31, 2024 and 2023, respectively. We recorded depreciation expense of $903 million, $932 million and $988 million for the years ended December 31, 2024, 2023 and 2022, respectively. Depreciation expense for the year ended December 31, 2022 includes $23 million of accelerated depreciation related to the decision to indefinitely idle the coke facility at Middletown Works and $68 million of accelerated depreciation related to the indefinite idle of the Indiana Harbor #4 blast furnace. The net book value of the mineral and land rights are as follows: December 31, (In millions) 2024 2023 Mineral rights: Cost $ 783 $ 783 Depletion (287) (258) Net mineral rights $ 496 $ 525 Land rights $ 467 $ 427 We recorded depletion expense of $29 million, $33 million and $38 million for the years ended December 31, 2024, 2023, and 2022, respectively.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets and Liabilities	NOTE 7 - GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES GOODWILL The following is a summary of Goodwill by segment: December 31, (In millions) 2024 2023 Steelmaking $ 1,719 $ 956 Other Businesses 49 49 Total goodwill $ 1,768 $ 1,005 The increase in the balance of Goodwill in our Steelmaking segment as of December 31, 2024, compared to December 31, 2023, is due to the preliminary purchase price allocation of goodwill in 2024, related to the Stelco Acquisition. INTANGIBLE ASSETS AND LIABILITIES The following is a summary of our intangible assets and liabilities: December 31, 2024 December 31, 2023 (In millions) Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Intangible assets 1 : Customer relationships $ 1,015 $ (34) $ 981 $ 90 $ (18) $ 72 Developed technology 60 (17) 43 60 (14) 46 Trade names and trademarks 87 (8) 79 18 (5) 13 Mining permits 72 (29) 43 72 (28) 44 Supplier relationships 29 (5) 24 29 (3) 26 Total intangible assets $ 1,263 $ (93) $ 1,170 $ 269 $ (68) $ 201 Intangible liabilities 2 : Above-market supply contracts $ (71) $ 30 $ (41) $ (71) $ 24 $ (47) 1 Amortization related to mining permits is recognized in Cost of goods sold . Amortization of all other intangible assets is recognized in Selling, general and administrative expenses . 2 Intangible liabilities are classified as Other non-current liabilities . Amortization of all intangible liabilities is recognized in Cost of goods sold . Amortization expense related to Intangible assets was $24 million and $13 million for the years ended December 31, 2024 and 2023, respectively. Estimated future amortization expense related to intangible assets is $79 million annually for the years 2025 through 2029. Income from amortization related to intangible liabilities was $5 million for both the years ended December 31, 2024 and 2023. Estimated future amortization income related to the intangible liabilities is $5 million annually for the years 2025 through 2029. The increase in the balance of Intangible assets as of December 31, 2024, compared to December 31, 2023, is due to the preliminary purchase price allocation to intangible assets in 2024, related to the Stelco Acquisition.

DEBT AND CREDIT FACILITIES

DEBT AND CREDIT FACILITIES	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Debt and Credit Facilities	NOTE 8 - DEBT AND CREDIT FACILITIES The following represents a summary of our long-term debt: (In Millions) Debt Instrument Issuer 1 Annual Effective Interest Rate December 31, 2024 December 31, 2023 Senior Secured Notes: 6.750% 2026 Senior Secured Notes Cliffs 6.990% — 829 Senior Unsecured Notes: 7.000% 2027 Senior Notes Cliffs 9.240% 73 73 7.000% 2027 AK Senior Notes AK Steel 9.240% 56 56 5.875% 2027 Senior Notes Cliffs 6.490% 556 556 4.625% 2029 Senior Notes Cliffs 4.625% 368 368 6.875% 2029 Senior Notes Cliffs 6.875% 900 — 6.750% 2030 Senior Notes Cliffs 6.750% 750 750 4.875% 2031 Senior Notes Cliffs 4.875% 325 325 7.000% 2032 Senior Notes Cliffs 7.054% 1,425 — 7.375% 2033 Senior Notes Cliffs 7.375% 900 — 6.250% 2040 Senior Notes Cliffs 6.340% 235 235 ABL Facility Cliffs 2 Variable 3 1,560 — Total debt 7,148 3,192 Unamortized discounts and issuance costs (83) (55) Total long-term debt $ 7,065 $ 3,137 1 Unless otherwise noted, references in this column and throughout this NOTE 8 - DEBT AND CREDIT FACILITIES to "Cliffs" are to Cleveland-Cliffs Inc., and references to "AK Steel" are to AK Steel Corporation (n/k/a Cleveland-Cliffs Steel Corporation). 2 Refers to Cleveland-Cliffs Inc. as borrower under our ABL Facility. 3 Our ABL Facility annual effective interest rate was 5.829% as of December 31, 2024. OUTSTANDING SENIOR UNSECURED NOTES CLEVELAND-CLIFFS INC. 7.000% 2032 SENIOR NOTES - 2024 OFFERING On March 18, 2024, we entered into an indenture among Cliffs, the guarantors party thereto and U.S. Bank Trust Company, National Association, as trustee, relating to the issuance of $825 million aggregate principal amount of our 7.000% 2032 Senior Notes, which were issued at par. The 7.000% 2032 Senior Notes were issued in a private placement transaction exempt from the registration requirements of the Securities Act. On August 16, 2024, we issued an additional $600 million aggregate principal amount of our 7.000% 2032 Senior Notes in a private placement transaction exempt from the registration requirements of the Securities Act. These additional notes were issued at a price of 99.25% of their principal amount. Furthermore, the additional notes are treated as the same class and series as the initial notes issued on March 18, 2024, other than with respect to the date of issuance and issue price. The net proceeds from the transaction were used to finance a portion of the cash consideration paid in connection with the Stelco Acquisition, which we completed on November 1, 2024. The 7.000% 2032 Senior Notes bear interest at a rate of 7.000% per annum, payable semi-annually in arrears on March 15 and September 15 of each year, commencing on September 15, 2024. The 7.000% 2032 Senior Notes mature on March 15, 2032. The 7.000% 2032 Senior Notes are unsecured senior obligations and rank equally in right of payment with all of our existing and future unsecured and unsubordinated indebtedness. The 7.000% 2032 Senior Notes are guaranteed on a senior unsecured basis by our material direct and indirect wholly owned domestic subsidiaries. The 7.000% 2032 Senior Notes are structurally subordinated to all existing and future indebtedness and other liabilities of our subsidiaries that do not guarantee the 7.000% 2032 Senior Notes. The 7.000% 2032 Senior Notes may be redeemed, in whole or in part, at any time at our option not less than 10 days nor more than 60 days after prior notice is sent to the holders of the 7.000% 2032 Senior Notes. The 7.000% 2032 Senior Notes are redeemable prior to March 15, 2027, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture. We may also redeem up to 35% of the aggregate principal amount of the 7.000% 2032 Senior Notes prior to March 15, 2027, at a redemption price equal to 107.000% of the principal amount thereof with the net cash proceeds of one or more equity offerings. The 7.000% 2032 Senior Notes are redeemable beginning on March 15, 2027, at a redemption price equal to 103.500% of the principal amount thereof, decreasing to 101.750% on March 15, 2028, and are redeemable at par beginning on March 15, 2029. In each case, we pay the applicable redemption or "make-whole" premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. In addition, if a change in control triggering event, as defined in the indenture, occurs with respect to the 7.000% 2032 Senior Notes, we will be required to offer to repurchase the notes at a purchase price equal to 101% of their principal amount, plus accrued and unpaid interest, if any, to, but not including, the date of repurchase. The terms of the 7.000% 2032 Senior Notes contain certain customary covenants; however, there are no financial covenants. CLEVELAND-CLIFFS INC. 6.875% 2029 SENIOR NOTES - 2024 OFFERING On October 22, 2024, we entered into an indenture among Cliffs, the guarantors party thereto and U.S. Bank Trust Company, National Association, as trustee, relating to the issuance of $900 million aggregate principal amount of our 6.875% 2029 Senior Notes, which were issued at par. The 6.875% 2029 Senior Notes were issued in a private placement transaction that was exempt from the registration requirements of the Securities Act. The net proceeds from the transaction were used to finance a portion of the cash consideration paid in connection with the Stelco Acquisition, which we completed on November 1, 2024. The 6.875% 2029 Senior Notes bear interest at a rate of 6.875% per annum, payable semi-annually in arrears on May 1 and November 1 of each year, commencing on May 1, 2025. The 6.875% 2029 Senior Notes mature on November 1, 2029. The 6.875% 2029 Senior Notes are unsecured senior obligations and rank equally in right of payment with all of our existing and future unsecured and unsubordinated indebtedness. The 6.875% 2029 Senior Notes are guaranteed on a senior unsecured basis by our material direct and indirect wholly owned domestic subsidiaries. The 6.875% 2029 Senior Notes are structurally subordinated to all existing and future indebtedness and other liabilities of our subsidiaries that do not guarantee the 6.875% 2029 Senior Notes. The 6.875% 2029 Senior Notes may be redeemed, in whole or in part, at any time at our option not less than 10 days nor more than 60 days after prior notice is sent to the holders of the 6.875% 2029 Senior Notes. The 6.875% 2029 Senior Notes are redeemable prior to November 1, 2026, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture. We may also redeem up to 35% of the aggregate principal amount of the 6.875% 2029 Senior Notes prior to November 1, 2026, at a redemption price equal to 106.875% of the principal amount thereof with the net cash proceeds of one or more equity offerings. The 6.875% 2029 Senior Notes are redeemable beginning on November 1, 2026, at a redemption price equal to 103.438% of the principal amount thereof, decreasing to 100% on November 1, 2028. In each case, we pay the applicable redemption or "make-whole" premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. In addition, if a change in control triggering event, as defined in the indenture, occurs with respect to the 6.875% 2029 Senior Notes, we will be required to offer to repurchase the notes at a purchase price equal to 101% of their principal amount, plus accrued and unpaid interest, if any, to, but not including, the date of repurchase. The terms of the 6.875% 2029 Senior Notes contain certain customary covenants; however, there are no financial covenants. CLEVELAND-CLIFFS INC. 7.375% 2033 SENIOR NOTES - 2024 OFFERING On October 22, 2024, we entered into an indenture among Cliffs, the guarantors party thereto and U.S. Bank Trust Company, National Association, as trustee, relating to the issuance of $900 million aggregate principal amount of our 7.375% 2033 Senior Notes, which were issued at par. The 7.375% 2033 Senior Notes were issued in a private placement transaction that was exempt from the registration requirements of the Securities Act. The net proceeds from the transaction were used to finance a portion of the cash consideration paid in connection with the Stelco Acquisition, which we completed on November 1, 2024. The 7.375% 2033 Senior Notes bear interest at a rate of 7.375% per annum, payable semi-annually in arrears on May 1 and November 1 of each year, commencing on May 1, 2025. The 7.375% 2033 Senior Notes mature on May 1, 2033. The 7.375% 2033 Senior Notes are unsecured senior obligations and rank equally in right of payment with all of our existing and future unsecured and unsubordinated indebtedness. The 7.375% 2033 Senior Notes are guaranteed on a senior unsecured basis by our material direct and indirect wholly owned domestic subsidiaries. The 7.375% 2033 Senior Notes are structurally subordinated to all existing and future indebtedness and other liabilities of our subsidiaries that do not guarantee the 7.375% 2033 Senior Notes. The 7.375% 2033 Senior Notes may be redeemed, in whole or in part, at any time at our option not less than 10 days nor more than 60 days after prior notice is sent to the holders of the 7.375% 2033 Senior Notes. The 7.375% 2029 Senior Notes are redeemable prior to May 1, 2028, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture. We may also redeem up to 35% of the aggregate principal amount of the 7.375% 2033 Senior Notes prior to May 1, 2028, at a redemption price equal to 107.375% of the principal amount thereof with the net cash proceeds of one or more equity offerings. The 7.375% 2033 Senior Notes are redeemable beginning on May 1, 2028, at a redemption price equal to 103.688% of the principal amount thereof, decreasing to 100% on November 1, 2028. In each case, we pay the applicable redemption or "make-whole" premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. In addition, if a change in control triggering event, as defined in the indenture, occurs with respect to the 7.375% 2033 Senior Notes, we will be required to offer to repurchase the notes at a purchase price equal to 101% of their principal amount, plus accrued and unpaid interest, if any, to, but not including, the date of repurchase. The terms of the 7.375% 2033 Senior Notes contain certain customary covenants; however, there are no financial covenants. CLEVELAND-CLIFFS INC. OTHER OUTSTANDING UNSECURED SENIOR NOTES The following represents a summary of our other unsecured senior notes' maturity and interest payable due dates: Debt Instrument Maturity Interest Payable 7.000% 2027 Senior Notes March 15, 2027 March 15 and September 15 5.875% 2027 Senior Notes June 1, 2027 June 1 and December 1 4.625% 2029 Senior Notes March 1, 2029 March 1 and September 1 6.750% 2030 Senior Notes April 15, 2030 April 15 and October 15 4.875% 2031 Senior Notes March 1, 2031 March 1 and September 1 6.250% 2040 Senior Notes October 1, 2040 April 1 and October 1 The senior notes are unsecured obligations and rank equally in right of payment with all our other existing and future unsecured and unsubordinated indebtedness. The 7.000% 2027 Senior Notes, 5.875% 2027 Senior Notes, 4.625% 2029 Senior Notes, 6.750% 2030 Senior Notes, and 4.875% 2031 Senior Notes are guaranteed on a senior unsecured basis by our material direct and indirect wholly owned domestic subsidiaries and, therefore, are structurally senior to any of our existing and future indebtedness that is not guaranteed by such guarantors and are structurally subordinated to all existing and future indebtedness and other liabilities of our subsidiaries that do not guarantee the notes. There are no subsidiary guarantees of the interest and principal amounts for the 6.250% 2040 Senior Notes. The 7.000% 2027 Senior Notes may be redeemed, in whole or in part, at any time at our option upon not less than 30, and not more than 60, days' prior notice sent to the holders. The 7.000% 2027 Senior Notes are currently redeemable at a price equal to 101.167% of the principal amount thereof, and are redeemable at par beginning on March 15, 2025. In each case, we pay the redemption premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 5.875% 2027 Senior Notes may be redeemed, in whole or in part, at any time at our option upon not less than 30, and not more than 60, days' prior notice sent to the holders. The 5.875% 2027 Senior Notes are currently redeemable at a price equal to 100.979% of the principal amount thereof, and are redeemable at par beginning on June 1, 2025. In each case, we pay the redemption premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 4.625% 2029 Senior Notes may be redeemed, in whole or in part, on not less than 10, nor more than 60, days’ prior notice sent to the holders of the notes. The 4.625% 2029 Senior Notes are currently redeemable at a price equal to 102.313% of the principal amount thereof, decreasing to 101.156% on March 1, 2025, and are redeemable at par beginning on March 1, 2026. In each case, we pay the redemption premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 6.750% 2030 Senior Notes may be redeemed, in whole or in part, at any time at our option not less than 10 days nor more than 60 days after prior notice is sent to the holders of the 6.750% 2030 Senior Notes. The 6.750% 2030 Senior Notes are redeemable prior to April 15, 2026, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture. We may also redeem up to 35% of the aggregate principal amount of the 6.750% 2030 Senior Notes prior to April 15, 2026 at a redemption price equal to 106.750% of the principal amount thereof with the net cash proceeds of one or more equity offerings. The 6.750% 2030 Senior Notes are redeemable beginning on April 15, 2026, at a redemption price equal to 103.375% of the principal amount thereof, decreasing to 101.688% on April 15, 2027, and are redeemable at par beginning on April 15, 2028. In each case, we pay the applicable redemption and "make-whole" premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 4.875% 2031 Senior Notes may be redeemed, in whole or in part, on not less than 10, nor more than 60, days’ prior notice sent to the holders of the notes. The 4.875% 2031 Senior Notes are redeemable prior to March 1, 2026, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture. We may also redeem up to 35% of the aggregate principal amount of the 4.875% 2031 Senior Notes prior to March 1, 2026 at a redemption price equal to 104.875% of the principal amount thereof with the net cash proceeds of one or more equity offerings. The 4.875% 2031 Senior Notes are redeemable beginning on March 1, 2026, at a redemption price equal to 102.438% of the principal amount thereof, decreasing to 101.625% on March 1, 2027, and 100.813% on March 1, 2028, and are redeemable at par beginning on March 1, 2029. In each case, we pay the redemption and "make-whole" premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 6.250% 2040 Senior Notes may be redeemed any time at our option upon not less than 30, nor more than 60, days' prior notice is sent to the holders. The 6.250% 2040 Senior Notes are redeemable at a redemption price equal to the greater of (1) 100% of the principal amount of the notes to be redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest on the notes to be redeemed, discounted to the redemption date on a semi-annual basis at the treasury rate plus 40 basis points, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. In addition, if a change of control triggering event, as defined in the applicable indenture, occurs with respect to the unsecured notes, we will be required to offer to purchase the notes of the applicable series at a purchase price equal to 101% of the principal amount, plus accrued and unpaid interest, if any, to, but not including, the date of purchase. The terms of the unsecured notes contain certain customary covenants; however, there are no financial covenants. AK STEEL CORPORATION UNSECURED SENIOR NOTES As of December 31, 2024, AK Steel had outstanding a total of $56 million aggregate principal amount of 7.000% 2027 AK Senior Notes. These senior notes are unsecured obligations and rank equally in right of payment with AK Steel's guarantees of Cliffs' unsecured and unsubordinated indebtedness. These notes contain no financial covenants. The 7.000% 2027 AK Senior Notes may be redeemed, in whole or in part, at any time at our option upon not less than 30, and not more than 60, days' prior notice sent to the holders. The 7.000% 2027 AK Senior Notes are currently redeemable at a price equal to 101.167%, and are redeemable at par beginning on March 15, 2025. In each case, we pay the redemption premiums plus accrued and unpaid interest, if any, to, but not including, the date of redemption. ABL FACILITY On July 31, 2024 and September 13, 2024, in connection with the Stelco Acquisition, we entered into the fifth and sixth amendments to our ABL Facility, respectively. The amendments, among other things, (i) amend the normal conditions for borrowing loans to allow for the Stelco Acquisition and permit additional borrowings for the purpose of financing a portion of the Stelco Acquisition purchase price, and (ii) subsequent to the Stelco Acquisition and the satisfaction of customary conditions, divide the existing $4.75 billion of aggregate lending commitments under our ABL Facility into two tranches, (x) a $4.25 billion tranche of lending commitments available to be borrowed by the Company and certain U.S. subsidiaries of the Company that are designated as borrowers from time to time in accordance with the ABL Facility and (y) a $500 million tranche of lending commitments available to be borrowed by certain Canadian subsidiaries of the Company that are designated as borrowers from time to time in accordance with the ABL Facility. The maturity date of the ABL Facility remains the earlier of June 9, 2028, or 91 days prior to the maturity of certain other material debt. The ABL Facility and certain bank products and hedge obligations are guaranteed by certain of our existing wholly owned U.S. subsidiaries and are required to be guaranteed by certain of our future U.S. subsidiaries. Amounts outstanding under the ABL Facility are secured by (i) a first-priority security interest in the accounts receivable and other rights to payment, inventory, as-extracted collateral, certain investment property, deposit accounts, securities accounts, certain general intangibles and commercial tort claims, certain mobile equipment, commodities accounts and other related assets of ours, the other borrowers and the guarantors, and proceeds and products of each of the foregoing (collectively, the “ABL Collateral”) and (ii) a second-priority security interest in substantially all of our assets and the assets of the other borrowers and the guarantors other than the ABL Collateral. The ABL Facility contains customary representations and warranties and affirmative and negative covenants including, among others, covenants regarding the maintenance of certain financial ratios if certain conditions are triggered, covenants relating to financial reporting, covenants relating to the payment of dividends on, or purchase or redemption of, our capital stock, covenants relating to the incurrence or prepayment of certain debt, covenants relating to the incurrence of liens or encumbrances, covenants relating to compliance with laws, covenants relating to transactions with affiliates, covenants relating to mergers and sales of all or substantially all of our assets and limitations on changes in the nature of our business. As of December 31, 2024 and 2023, we were in compliance with the ABL Facility liquidity requirements and, therefore, the springing financial covenant requiring a minimum fixed charge coverage ratio of 1.0 to 1.0 was not applicable. The ABL Facility provides for customary events of default, including, among other things, the event of nonpayment of principal, interest, fees or other amounts, a representation or warranty proving to have been materially incorrect when made, failure to perform or observe certain covenants within a specified period of time, a cross-default to certain material indebtedness, the bankruptcy or insolvency of the Company and certain of its subsidiaries, monetary judgment defaults of a specified amount, invalidity of any loan documentation, a change of control of the Company, and ERISA defaults resulting in liability of a specified amount. If an event of default exists (beyond any applicable grace or cure period), the administrative agent may, and at the direction of the requisite number of lenders shall, declare all amounts owing under the ABL Facility immediately due and payable, terminate such lenders’ commitments to make loans under the ABL Facility and/or exercise any and all remedies and other rights under the ABL Facility. For certain events of default related to insolvency and receivership, the commitments of the lenders will be automatically terminated and all outstanding loans and other amounts will become immediately due and payable. The following represents a summary of our borrowing capacity under the ABL Facility: December 31, (In millions) 2024 Available borrowing base on ABL Facility 1 $ 4,158 Borrowings (1,560) Letter of credit obligations 2 (62) Borrowing capacity available $ 2,536 1 As of December 31, 2024, the ABL Facility has a maximum borrowing base of $4.75 billion. The available borrowing base is determined by applying customary advance rates to eligible accounts receivable, inventory and certain mobile equipment. 2 We issued standby letters of credit with certain financial institutions in order to support business obligations, including, but not limited to, operating agreements, employee severance, environmental obligations, workers' compensation, and insurance obligations. DEBT EXTINGUISHMENTS On March 18, 2024, we used a portion of the net proceeds from the initial 7.000% 2032 Senior Notes issuance to repurchase $640 million in aggregate principal amount of our 6.750% 2026 Senior Secured Notes pursuant to a tender offer. On April 3, 2024, we redeemed the remaining $189 million in aggregate principal amount of our then-outstanding 6.750% 2026 Senior Secured Notes with the remaining portion of the net proceeds from the initial 7.000% 2032 Senior Notes issuance and available liquidity. DEBT MATURITIES The following represents a summary of our debt instrument maturities based on the principal amounts outstanding at December 31, 2024 (in millions): 2025 2026 2027 2028 2029 Thereafter Total $ — $ — $ 685 $ 1,560 $ 1,268 $ 3,635 $ 7,148

PENSIONS AND OTHER POSTRETIREME

PENSIONS AND OTHER POSTRETIREMENT BENEFITS	12 Months Ended
	Dec. 31, 2024
Postemployment Benefits [Abstract]
Pension and Other Post Retirement Benefits	NOTE 9 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS We offer benefits through defined benefit pension plans, defined contribution pension plans and OPEB plans to a significant portion of our employees and retirees. Benefits are also provided through multiemployer plans for certain union members. DEFINED BENEFIT PENSION PLANS The defined benefit pension plans are largely noncontributory and limited in participation. Most plans are closed to new participants with only the legacy iron ore hourly and salaried plans still open. The pension benefit calculations vary by plan but are generally based on employees' years of service and compensation or a fixed rate and years of service. Certain salaried plans calculate benefits using a cash balance formula, which earns interest credits and allocations based on a percent of pay. As a result of the Stelco Acquisition, we assumed the obligations under Stelco's defined benefit pension plans. These Canadian defined benefit pension plans acquired amounted to a benefit obligation, net of assets, of $14 million based on a November 1, 2024 measurement. OPEB PLANS We offer postretirement health care and life insurance benefits to retirees through various funded and unfunded plans. The vast majority of our plans are closed to new participants. In lieu of retiree medical coverage, many union-represented employees receive a 401(k) contribution per hour worked to a restricted Retiree Health Care Account. Cost sharing features between the employer and retiree vary by plan and several plans include employer caps. Retiree healthcare coverage is provided through programs administered by insurance companies whose charges are based on benefits paid. Certain labor agreements require the funding of VEBAs, which, depending on funding levels, may be used to reimburse the employer for paid benefits. OBLIGATIONS AND FUNDED STATUS The following tables and information provide additional disclosures: (In millions) Pension Benefits OPEB Change in benefit obligations: 2024 2023 2024 2023 Benefit obligations — beginning of year $ 4,571 $ 4,646 $ 1,036 $ 1,233 Service cost 28 31 8 10 Interest cost 218 235 50 64 Plan amendments — 3 7 8 Actuarial loss (gain) (165) 116 162 (158) Benefits paid (429) (436) (155) (163) Participant contributions — — 36 42 Acquired through business combinations 35 — — — Foreign currency exchange (1) — — — Effect of settlement (9) (24) — — Other — — 3 — Benefit obligations — end of year $ 4,248 $ 4,571 $ 1,147 $ 1,036 Change in plan assets: Fair value of plan assets — beginning of year $ 4,282 $ 4,338 $ 739 $ 728 Actual return on plan assets 254 375 46 67 Participant contributions — — 36 42 Employer contributions 119 29 76 65 Benefits paid (429) (436) (155) (163) Acquired through business combinations 21 — — — Foreign currency exchange (1) — — — Effect of settlement (9) (24) — — Fair value of plan assets — end of year $ 4,237 $ 4,282 $ 742 $ 739 Funded status $ (11) $ (289) $ (405) $ (297) Amounts recognized in Statements of Financial Position: Non-current assets $ 239 $ 137 $ 188 $ 192 Current liabilities 1 (7) (18) (85) (76) Non-current liabilities (243) (408) (508) (413) Total amount recognized $ (11) $ (289) $ (405) $ (297) Amounts recognized in accumulated other comprehensive loss (income): Net actuarial gain $ (400) $ (304) $ (1,720) $ (2,033) Prior service cost (credit) 89 106 (109) (131) Net amount recognized $ (311) $ (198) $ (1,829) $ (2,164) 1 Current liabilities are classified within Other current liabilities on the Statements of Consolidated Financial Position. The accumulated benefit obligation for all defined benefit pension plans was $4,236 million and $4,557 million at December 31, 2024 and 2023, respectively. COMPONENTS OF NET PERIODIC BENEFIT COST (CREDIT) Pension Benefits OPEB (In millions) 2024 2023 2022 2024 2023 2022 Service cost $ 28 $ 31 $ 45 $ 8 $ 10 $ 35 Interest cost 218 235 144 50 64 72 Expected return on plan assets (320) (315) (355) (43) (43) (37) Amortization: Net actuarial loss (gain) (1) 3 13 (154) (145) (43) Prior service costs (credits) 18 18 5 (15) (17) (3) Settlements and special termination benefits (2) (4) (8) 2 — — Net periodic benefit cost (credit) $ (59) $ (32) $ (156) $ (152) $ (131) $ 24 For 2025, we estimate net periodic benefit cost (credit) as follows: (In millions) Defined benefit pension plans $ (70) OPEB plans (124) Total $ (194) COMPONENTS OF OTHER COMPREHENSIVE LOSS (INCOME) The following includes details on the significant actuarial losses (gains) impacting the benefit obligation and other components of other comprehensive loss (income): Pension Benefits OPEB (In millions) 2024 2023 2024 2023 Discount rates $ (146) $ 124 $ (43) $ 28 Demographic updates 1 (14) (5) 26 (208) Mortality — (2) — (11) Per capita healthcare costs and healthcare trend 2 — — 179 33 Other (5) (1) — — Actuarial loss (gain) on benefit obligation (165) 116 162 (158) Actual returns on assets under (over) expected 67 (60) (3) (24) Amortization of net actuarial gain (loss) 1 (3) 154 145 Amortization of prior service credits (costs) (18) (18) 15 17 Settlements 2 4 — — Plan amendments — 3 7 8 Total recognized in other comprehensive loss (income) $ (113) $ 42 $ 335 $ (12) 1 In 2023, the OPEB plans generated an actuarial gain relating to updates for demographic experience. We had adjustments relating to retirements, participation, persistency and census data updates. 2 The loss in per capita healthcare costs in 2024 relating to our OPEB plans is primarily due to unfavorable Medicare Advantage Prescription Drug healthcare rates, which are effective January 1, 2025. Additionally, we increased our short-term Medicare Advantage Prescription Drug trend rate assumption. CONTRIBUTIONS We make both required and discretionary pension contributions. Required contributions are based on minimum funding requirements pursuant to ERISA regulations. Funded OPEB plans are not subject to minimum regulatory funding requirements, but rather amounts are contributed pursuant to bargaining agreements. Contributions toward unfunded OPEB plans are payments made directly from corporate assets and are displayed net of participant contributions and other reimbursements. Company contributions and payments we expect to make in 2025, and made in 2024 and 2023 are as follows: Pension Benefits OPEB (In millions) VEBA 1 Direct Payments Total 2023 $ 29 $ — $ 65 $ 65 2024 119 — 76 76 2025 (Expected) 69 — 74 74 1 Pursuant to the applicable bargaining agreements, benefits can be paid from certain VEBAs that are at least 70% funded (all VEBAs were over 70% funded at December 31, 2024). Certain agreements with plans holding VEBA assets have capped healthcare costs. For the Cleveland-Cliffs Steel LLC VEBA, we are required to make contributions based on earnings, and we may withdraw money from the VEBA plan to the extent funds are available for costs in excess of the cap. VEBA withdrawals are represented net of direct payments. There will be no further contributions to the Cleveland-Cliffs Steel LLC VEBA based on earnings for the remainder of the labor agreement with the USW, which expires in September 2026. ESTIMATED FUTURE BENEFIT PAYMENTS (In millions) Pension Benefits OPEB 1 2025 $ 472 $ 116 2026 440 114 2027 419 109 2028 405 105 2029 382 100 2030-2034 1,663 445 1 OPEB benefit payments are displayed net of participant contributions. ASSUMPTIONS The discount rates used to measure plan liabilities as of the December 31 measurement date are determined individually for each plan. The discount rates are determined by matching the projected cash flows used to determine the plan liabilities to a projected yield curve of high-quality corporate bonds available at the measurement date. Discount rates for expense are calculated using the granular approach for each plan. We use company-specific base mortality tables for healthy annuitants in qualified pension plans. We use tables issued by the Society of Actuaries for non-annuitants in qualified pension plans, all nonqualified pension participants and OPEB participants. For tables issued by the Society of Actuaries, we use Pri-2012 mortality tables with adjustments for blue collar, white collar or no collar depending on the plan. Mortality is projected for all plans using Scale MP-2021 with generational projection for both years. In 2024, no changes have been made to the plans' mortality tables. In 2023, we switched two OPEB plans from company-specific base mortality tables to the Pri-2012 mortality tables to align with our other OPEB plans. The following represents weighted-average assumptions used to determine benefit obligations: Pension Benefits OPEB December 31, December 31, 2024 2023 2024 2023 Discount rate 5.55 % 5.12 % 5.59 % 5.15 % Interest crediting rate 5.58 5.46 N/A N/A Compensation rate increase 3.00 3.00 3.00 3.00 The following represents weighted-average assumptions used to determine net benefit cost: Pension Benefits OPEB December 31, December 31, 2024 2023 2022 2024 2023 2022 Obligation discount rate 5.08 % 5.47 % 3.21 % 5.15 % 5.52 % 3.33 % Service cost discount rate 5.29 5.61 3.49 5.28 5.65 3.91 Interest cost discount rate 5.05 5.34 2.75 5.08 5.38 3.01 Interest crediting rate 5.46 5.46 5.39 N/A N/A N/A Expected return on plan assets 7.85 7.66 6.87 5.95 5.87 4.86 Compensation rate increase 3.00 3.00 2.74 3.00 3.00 3.00 The following represents assumed weighted-average health care cost trend rates: December 31, 2024 2023 Health care cost trend rate assumed for next year 1 11.43 % 5.49 % Ultimate health care cost trend rate 4.50 % 4.50 % Year that the ultimate rate is reached 2032 2032 1 The health care trend rate is weighted for all of our OPEB plans and factors in our Medicare Advantage Prescription Drug pricing arrangements. In 2024, we maintained our assumed health care cost trend rate for self insured plans at 6.25%, which grades down on a linear basis to 4.50% by 2032. In 2024, the health care trend rate for the Medicare Advantage Prescription Drug plans assumes a 16.25% rate, which is primarily driven by our expectation that the impacts from the Inflation Reduction Act will negatively impact Medicare Advantage Prescription Drug plan costs for the next year. We assume the healthcare trend rate for the Medicare Advantage Prescription Drug plans will realign with the self insured plans after the one time increase. PLAN ASSETS Our investment objectives with respect to our pension and OPEB assets are to maximize investment returns within reasonable and prudent levels of risk and maintain sufficient liquidity to meet benefit obligations over the life of each plan. The asset allocations are tailored to each individual plan and are determined by analyzing each plan's duration of benefit obligations, funded status and risk profile. Our investment strategy utilizes a broad mix of equity, fixed income and alternative investments to generate returns and manage risk. Equity investments are diversified across large-cap, mid-cap and small-cap companies located in the U.S. and worldwide, with a bias towards U.S. companies. Fixed income investments primarily include corporate bonds and government debt securities, which are generally customized based on a plan's obligation duration. Certain plans have strategies that invest in fixed income funds that hold hedging investment products which are designed to protect the fund's funded status. To enhance our diversification, we also invest in hedge funds, private equity, structured credit and real estate. We review investment performance, asset allocations and policy compliance on a quarterly basis. The expected return on plan assets is calculated on a plan-by-plan basis and take into account each plan's strategic asset allocation. The calculation of rates by asset class are based primarily on our future expected returns and take into consideration the duration of the cash flows, active management and fees. Assets for OPEB plans include VEBA trusts pursuant to bargaining agreements that are available to fund retired employees’ life insurance obligations and medical benefits. The following table reflects the actual asset allocations for pension and VEBA assets as of December 31, 2024 and 2023, as well as the 2025 weighted average target asset allocations: Pension Assets VEBA Assets Asset Category 2025 Actual Asset Allocation at December 31, 2025 Actual Asset Allocation at December 31, 2024 2023 2024 2023 Equity securities 34.0 % 32.7 % 32.1 % 17.2 % 17.6 % 18.4 % Fixed income 40.8 38.9 38.8 78.4 76.6 74.5 Hedge funds 9.4 9.6 9.4 1.0 1.2 1.5 Private equity 3.4 3.6 3.4 — — — Structured credit 2.5 4.0 5.1 0.3 0.5 0.9 Real estate 9.9 11.2 11.2 3.1 4.1 4.7 Total 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % FAIR VALUE MEASUREMENTS Investments classified as Level 1 primarily include equity investments and fixed income mutual funds that are based on observable quoted market prices on an active exchange. Fixed income investments classified as Level 2 include U.S. Treasury STRIPS which are priced daily through a bond pricing vendor as well as corporate bonds, mortgage-backed securities and non-U.S. bonds which have valuations based on their bid-ask spreads or quoted prices of securities with similar characteristics. Certain investments in hedge funds, private equity, structured credit and real estate are classified as Level 3 due to the absence of quoted market prices and inherent lack of liquidity. These investments are generally valued at estimated fair value based on financial inputs from our investment advisors, investment managers or third party appraisers. Certain Level 3 investments may be lagged up to three months if there are no financial inputs available. Investment commitments are made in private equity funds and capital calls are made over the life of the funds to fund the commitments. As of December 31, 2024, remaining commitments for our private equity investments total $47 million for our pension and OPEB plans. Committed amounts are funded from plan assets when capital calls are made. As a practical expedient, in accordance with ASC 820-10, certain investments that are measured at fair value using the NAV per share have not been classified in the fair value hierarchy below. NAV is based on the value of the underlying assets owned by the fund, minus its liabilities, and then divided by its number of shares outstanding. The fair value of our pension assets by asset category is as follows: (In millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Investments Measured at Net Asset Value Total Asset Category 2024 2023 2024 2023 2024 2023 2024 2023 2024 2023 Equity securities: U.S. equities $ 816 $ 809 $ — $ — $ — $ — $ — $ — $ 816 $ 809 Global equities 501 502 — — — — 69 65 570 567 Fixed income: U.S. government securities 1 32 22 577 657 — — 146 142 755 821 U.S. corporate bonds 583 587 — — — — 115 94 698 681 Non U.S. and other bonds 9 — — — — — 185 160 194 160 Hedge funds — — — — 128 118 280 285 408 403 Private equity — — — — 151 146 — — 151 146 Structured credit — — — — 171 220 — — 171 220 Real estate — — — — 242 286 232 189 474 475 Total $ 1,941 $ 1,920 $ 577 $ 657 $ 692 $ 770 $ 1,027 $ 935 $ 4,237 $ 4,282 1 Includes cash equivalents. The fair value of our VEBA assets by asset category is as follows: (In millions) Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Investments Measured at Net Asset Value Total Asset Category 2024 2023 2024 2023 2024 2023 2024 2023 2024 2023 Equity securities: U.S. equities $ 99 $ 102 $ — $ — $ — $ — $ — $ — $ 99 $ 102 Global equities 3 3 — — — — 28 30 31 33 Fixed income: U.S. government securities 1 130 119 50 27 — — 44 47 224 193 U.S. corporate bonds 216 214 74 94 — — 52 49 342 357 Non U.S. and other bonds 2 3 — — — — — — 2 3 Hedge funds — — — — 10 10 — — 10 10 Structured credit — — — — 4 7 — — 4 7 Real estate — — — — 5 10 25 24 30 34 Total $ 450 $ 441 $ 124 $ 121 $ 19 $ 27 $ 149 $ 150 $ 742 $ 739 1 Includes cash equivalents. The following represents the fair value measurements of changes in plan assets using significant unobservable inputs (Level 3): Pension Assets VEBA Assets (In millions) 2024 2023 2024 2023 Beginning balance — January 1 $ 770 $ 912 $ 27 $ 35 Actual return on plan assets: Relating to assets still held at the reporting date 18 (16) 1 2 Relating to assets sold during the period 7 10 — 1 Purchases 31 24 — — Sales (134) (160) (9) (11) Ending balance — December 31 $ 692 $ 770 $ 19 $ 27 DEFINED CONTRIBUTION PLANS Most employees are eligible to participate in various defined contribution plans. Certain of these plans have features with matching contributions or other Company contributions based on our financial results. Company contributions to these plans are expensed as incurred. Total expense from these plans was $63 million, $59 million and $52 million in 2024, 2023 and 2022, respectively. MULTlEMPLOYER PLANS We contribute to multiemployer pension plans according to collective bargaining agreements that cover certain union-represented employees. The risks of participating in these multiemployer plans are different from the risks of participating in single-employer pension plans in the following respects: • Assets contributed to a multiemployer plan by one employer may be used to provide benefits to employees of other participating employers. • If a participating employer stops contributing to a multiemployer plan, the unfunded obligations of the plan may be borne by the remaining participating employers. • If the multiemployer plan becomes significantly underfunded or is unable to pay its benefits, we may be required to contribute additional amounts in excess of the rate required by the collective bargaining agreements. • If we choose to stop participating in a multiemployer plan, we may be required to pay that plan an amount based on the underfunded status of the plan, referred to as a withdrawal liability. Information with respect to multiemployer plans in which we participate follows: Pension Fund EIN/Pension Plan Number Pension Protection Act Zone Status 1 FIP/RP Status Pending/Implemented 2 Contributions Surcharge Imposed 3 Expiration Date of Collective Bargaining Agreement 4 2024 2023 2024 2023 2022 Steelworkers Pension Trust 23-6648508/499 Green Green No $ 117 $ 119 $ 93 No 4/1/2025 to 9/1/2026 IAM National Pension Fund’s National Pension Plan 51-6031295/002 Red Red Yes 22 23 22 Yes 5/31/2025 to 5/15/2027 Other Plans 5 1 1 — Total $ 140 $ 143 $ 115 1 The most recent Pension Protection Act zone status available in 2024 and 2023 is for each plan's year-end at December 31, 2023 and 2022. The plan's actuary certifies the zone status. Generally, plans in the red zone are less than 65% funded, plans in the yellow zone are between 65% and 80% funded, and plans in the green zone are at least 80% funded. The IAM National Pension Fund's National Pension Plan voluntarily elected to place itself in the "Red Zone" in April 2019 and has implemented a rehabilitation plan to address its underfunded status. Additional contributions will be required as part of the rehabilitation plan until the plan exits the "Red Zone". 2 The "FIP/RP Status Pending/Implemented" column indicates plans for which a financial improvement plan or a rehabilitation plan is either pending or has been implemented, as defined by ERISA. 3 The surcharge represents an additional required contribution due as a result of the critical funding status of the plan. 4 We are party to six collective bargaining agreements that require contributions to the Steelworkers Pension Trust and three collective bargaining agreements that require contributions to the IAM National Pension Fund's National Pension Plan. 5 Plans that are not individually significant to our Company are presented in aggregate. We are one of the largest contributors to the Steelworkers Pension Trust. Our contributions exceeded 5% of total combined contributions in 2024 and 2023. As of January 1, 2024 (the last date for which we have information), the Steelworkers Pension Trust had a total actuarial liability of $6,562 million and assets with a market value of $6,494 million, for a funded ratio of about 99%.

STOCK COMPENSATION PLANS

STOCK COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock Compensation Plans	NOTE 10 - STOCK COMPENSATION PLANS At December 31, 2024, we had outstanding awards under two share-based compensation plans: the 2021 Equity Plan and the A&R 2015 Equity Plan. As of December 31, 2024, there were 20.9 million remaining shares available for grant under the 2021 Equity Plan. No additional grants were issued from the A&R 2015 Equity Plan after the date of approval of the 2021 Equity Plan; however, all awards previously granted under predecessor plans will continue in accordance with the terms of the outstanding awards. Upon vesting of share-based compensation awards, we issue shares from treasury shares before issuing new shares. Forfeitures are recognized when they occur. STOCK-BASED COMPENSATION EXPENSE The following table summarizes the total compensation expense recognized for stock-based compensation awards: Year Ended December 31, (In millions, except per share amounts) 2024 2023 2022 Cost of goods sold $ (11) $ (9) $ (5) Selling, general and administrative expenses (39) (32) (23) Stock based compensation expense (50) (41) (28) Income tax benefit 13 10 7 Stock based compensation expense, net of tax $ (37) $ (31) $ (21) Decrease in basic earnings per common share $ (0.08) $ (0.06) $ (0.04) Decrease in diluted earnings per common share $ (0.08) $ (0.06) $ (0.04) The total compensation cost related to outstanding awards not yet recognized is $60 million at December 31, 2024. This expense is expected to be recognized over the remaining weighted-average period of 1.7 years. PERFORMANCE SHARES The following table summarizes the performance award activity: 2024 2023 2022 (Shares in millions) Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Outstanding at beginning of year 2.5 $ 29.09 2.7 $ 18.53 2.4 $ 14.04 Granted 1.2 30.36 1.1 31.88 1.0 28.46 Distributed (0.5) 25.12 (1.8) 6.50 (1.1) 17.04 Performance adjustment (0.1) 25.12 0.7 6.43 0.5 17.84 Forfeited/canceled (0.1) 30.57 (0.2) 28.65 (0.1) 23.74 Outstanding at end of year 3.0 $ 30.33 2.5 $ 29.09 2.7 $ 18.53 The outstanding performance shares vest over a period of three years and are intended to be paid out in common shares. Performance is measured on the basis of relative TSR for the period and measured against the constituents of the S&P Metals and Mining ETF Index. The number of shares actually earned at the end of the three-year period will vary, based on performance, from 0% to 200% of the number of performance shares granted. We value our performance shares using a Monte Carlo simulation on the grant date. A correlation matrix of historical and projected stock prices was developed for both the Company and its predetermined peer group of metals and mining companies. The fair value assumes that the performance objective will be achieved. The expected term of the grant represents the time from the grant date to the end of the service period. We estimate the volatility of our common shares and that of the peer group of metals and mining companies using daily price intervals for all companies. The risk-free interest rate is the rate at the grant date on zero-coupon government bonds, with a term commensurate with the remaining performance period. RESTRICTED STOCK UNITS The following table summarizes the restricted stock units activity: 2024 2023 2022 (Shares in millions) Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Outstanding at beginning of year 2.5 $ 18.87 2.4 $ 13.66 2.1 $ 10.31 Granted 1.2 19.54 1.2 19.30 1.0 19.41 Distributed (0.6) 17.55 (0.9) 5.99 (0.6) 10.47 Forfeited/canceled — 19.62 (0.2) 19.84 (0.1) 17.82 Outstanding at end of year 3.1 $ 19.40 2.5 $ 18.87 2.4 $ 13.66 We value our restricted stock units using the closing price of our common shares on the grant date. All of the outstanding restricted stock units are subject to continued employment, are retention based, and are payable in common shares or cash in certain circumstances at a time determined by the Compensation Committee at its discretion. Most restricted stock units were granted under three-year cliff vesting terms. STOCK OPTIONS The following table summarizes the stock option activity: 2024 2023 2022 (Shares in millions) Number of Shares Weighted Average Exercise Price Number of Shares Weighted Average Exercise Price Number of Shares Weighted Average Exercise Price Outstanding at beginning of year 0.5 $ 9.59 0.6 $ 10.39 1.0 $ 12.75 Exercised (0.3) 7.79 (0.1) 10.22 (0.3) 16.55 Forfeited/canceled — 20.11 — 21.05 (0.1) 22.78 Outstanding at end of year 0.2 $ 11.77 0.5 $ 9.59 0.6 $ 10.39 Exercisable at end of year 0.2 $ 11.77 0.5 $ 9.59 0.6 $ 10.52 Stock options granted to date generally vest over a period from one The fair value of stock options is estimated on the date of grant using a Black-Scholes model using the grant date price of our common shares, the option exercise price, the option’s expected term, the volatility of our common shares, the risk-free interest rate and the dividend yield over the option’s expected term. NONEMPLOYEE DIRECTORS Our nonemployee directors are entitled to receive restricted share awards under the Directors’ Plan. For 2024, 2023 and 2022, nonemployee directors were granted a specified number of restricted shares, with a value equal to $140,000 in each year. The number of shares is based on the closing price of our common shares on the grant date. The restricted share awards issued under the Directors' Plan generally vest 12 months from the grant date. The awards are subject to any deferral election and the terms of the Directors’ Plan and an award agreement.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 11 - INCOME TAXES Income (loss) from continuing operations before income taxes includes the following components: Year Ended December 31, (In millions) 2024 2023 2022 United States $ (894) $ 600 $ 1,803 Foreign (49) (3) (7) Total $ (943) $ 597 $ 1,796 The components of the income tax expense (benefit) from continuing operations consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 Current provision: United States federal $ (38) $ 4 $ 201 United States state & local (6) 26 131 Foreign 3 4 1 (41) 34 333 Deferred provision (benefit): United States federal (152) 97 117 United States state & local (33) 7 (22) Foreign (9) 10 (5) Total income tax expense (benefit) from continuing operations $ (235) $ 148 $ 423 Reconciliation of our income tax attributable to continuing operations computed at the U.S. federal statutory rate is as follows: (In millions) 2024 2023 2022 Tax at U.S. statutory rate $ (198) 21 % $ 125 21 % $ 377 21 % Increase (decrease) due to: Percentage depletion in excess of cost depletion (20) 2 (32) (5) (49) (3) Valuation allowance — — 14 2 — — Unrecognized tax benefits 7 — 7 1 2 — State taxes, net (30) 3 28 5 71 4 Federal & state provision to return (4) — (20) (3) 27 1 Income not subject to tax (10) 1 (11) (2) (9) — Goodwill impairment — — 26 4 — — Other items, net 20 (2) 11 2 4 — Provision for income tax expense (benefit) and effective income tax rate including discrete items $ (235) 25 % $ 148 25 % $ 423 23 % The increase in income tax benefit in 2024, as compared to income tax expense in 2023, as well as the decrease in income tax expense in 2023 compared to 2022 are predominantly related to the decrease in the pre-tax book income year-over-year. The components of income taxes for other than continuing operations consisted of the following: (In millions) 2024 2023 2022 Other comprehensive income (loss): Pension and OPEB $ 55 $ 10 $ (425) Derivative instruments (37) 47 26 Total $ 18 $ 57 $ (399) Significant components of our deferred tax assets and liabilities are as follows: (In millions) 2024 2023 Deferred tax assets: Operating loss and other carryforwards $ 589 $ 390 Pension and OPEB liabilities 129 155 Environmental 69 67 Product inventories 53 92 State and local 36 9 Lease liabilities 87 79 Other liabilities 151 180 Total deferred tax assets before valuation allowance 1,114 972 Deferred tax asset valuation allowance (388) (396) Net deferred tax assets 726 576 Deferred tax liabilities: Investment in ventures (181) (192) Lease assets (88) (79) Property, plant and equipment and mineral rights (811) (837) Intangible assets (441) (27) Other assets (59) (76) Total deferred tax liabilities (1,580) (1,211) Net deferred tax liabilities $ (854) $ (635) We had gross domestic (including states) and foreign NOLs of $3,549 million and $1,507 million, respectively, at December 31, 2024. We had gross domestic (including states) and foreign NOLs of $1,704 million and $1,452 million, respectively, at December 31, 2023. The U.S. federal NOLs will begin to expire in 2034, and state NOLs begin to expire in 2025. The foreign NOLs begin to expire in 2035. For the year ended December 31, 2024, we had $92 million gross U.S. interest expense limitation carryforwards. For the year ended December 31, 2023, we had no gross interest expense limitation carryforwards. The changes in the valuation allowance are presented below: (In millions) 2024 2023 2022 Balance at beginning of year $ 396 $ 390 $ 409 Change in valuation allowance: Income tax (benefit) expense (8) 6 (19) Balance at end of year $ 388 $ 396 $ 390 At December 31, 2024 and 2023, we have a valuation allowance recorded of $349 million and $356 million, respectively, related to foreign deferred tax assets, and an additional $39 million and $40 million, respectively, against certain state NOLs, which are expected to expire before utilization. During 2023, we recorded a $14 million valuation allowance against a portion of our Canadian deferred tax assets due to losses in recent years. We intend to maintain a valuation allowance against these deferred tax assets, unless and until sufficient positive evidence exists to support the realization of such assets. Our losses in Luxembourg in recent periods represent sufficient negative evidence to require a full valuation allowance against the deferred tax assets in that jurisdiction. We intend to maintain a valuation allowance against the deferred tax assets related to these operating losses, unless and until sufficient positive evidence exists to support the realization of such assets. At December 31, 2024 and 2023, we had no cumulative undistributed earnings of foreign subsidiaries included in retained earnings. Accordingly, no provision has been made for U.S. deferred taxes related to future repatriation of earnings. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: (In millions) 2024 2023 2022 Unrecognized tax benefits balance as of January 1 $ 76 $ 58 $ 35 Increases for tax positions in current year 46 18 24 Decrease due to tax positions in prior year (1) — (1) Unrecognized tax benefits balance as of December 31 $ 121 $ 76 $ 58 At December 31, 2024 and 2023, we had unrecognized tax benefits of $121 million and $76 million, respectively. Of these amounts, $75 million and $76 million were included in Other non-current liabilities on the Statements of Consolidated Financial Position. Additionally, $46 million was included in Deferred income taxes at December 31, 2024. If the unrecognized tax benefits were recognized, the $75 million would impact the effective tax rate. Interest and penalties related to unrecognized tax benefits are $7 million for the year ended December 31, 2024. We do not expect that the amount of unrecognized benefits will change significantly within the next 12 months. Tax years 2016 and forward remain subject to examination for the U.S., and tax years 2020 and forward remain subject to examination for Canada.

LEASE OBLIGATIONS

LEASE OBLIGATIONS	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Lease Obligations	NOTE 12 - LEASE OBLIGATIONS Our operating leases consist primarily of leases for land, office space, rail cars and storage tanks. Our finance leases consist primarily of mining equipment and rail cars. When an implicit discount rate is not readily determinable under our leases, we use our incremental borrowing rate as the discount rate to determine the present value of the lease payments. Our incremental borrowing rate is the rate of interest that we would have to borrow on a collateralized basis over a similar term and amount in a similar economic environment to pay our lease obligations. We determine the incremental borrowing rates for our leases by adjusting the local risk-free interest rate with a credit risk premium corresponding to our credit rating. From time to time, we may enter into arrangements for the construction or purchase of an asset and then enter into a financing arrangement to lease the asset. We recognize leased assets and liabilities under these arrangements when we obtain control of the asset. The following table summarizes the lease amounts included in our Statements of Consolidated Financial Position as of December 31, 2024 and 2023: Year Ended December 31, (In millions) Balance Sheet Location 2024 2023 Assets: Finance Property, plant and equipment, net $ 505 $ 306 Operating Other non-current assets 351 228 Current liabilities Finance Other current liabilities $ 63 $ 49 Operating Other current liabilities 50 41 Non-current liabilities Finance Other non-current liabilities $ 319 $ 166 Operating Other non-current liabilities 275 197 Lease costs are presented below: Year Ended December 31, (In millions) 2024 2023 2022 Operating leases $ 64 $ 59 $ 64 Finance leases: Amortization of right-of-use assets 38 92 103 Interest on lease liabilities 15 11 8 Short-term leases 174 171 160 Total $ 291 $ 333 $ 335 Lease terms and discount rates are shown below: December 31, 2024 Weighted average lease term (in years): Operating leases 11 Finance leases 9 Weighted average discount rate: Operating leases 7 % Finance leases 6 % Other information related to leases was as follows: Year Ended December 31, (In millions) 2024 2023 2022 Cash paid for amounts included in measurement of lease liabilities: Operating leases within cash flows from operating activities $ 62 $ 57 $ 62 Finance leases within cash flows from operating activities 14 11 8 Finance leases within cash flows from financing activities 49 92 96 Right-of-use assets obtained in exchange for new finance lease liabilities 1 97 93 55 Right-of-use assets obtained in exchange for new operating lease liabilities 1 87 42 31 1 Right-of-use assets obtained as a result of the Stelco Acquisition are not included. The following is a summary of future minimum lease payments under noncancellable finance and operating leases as of December 31, 2024: (In millions) Finance Leases Operating Leases 2025 $ 81 $ 68 2026 71 61 2027 58 57 2028 56 47 2029 52 38 Thereafter 193 188 Total future minimum lease payments 511 459 Less: imputed interest 129 134 Total lease payments 382 325 Less: current portion of lease liabilities 63 50 Long-term lease liabilities $ 319 $ 275 The current and long-term portions of our finance and operating lease liabilities are included in Other current liabilities and Other non-current liabilities , respectively.

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS	12 Months Ended
	Dec. 31, 2024
Environmental Remediation Obligations [Abstract]
Asset Retirement Obligations	NOTE 13 - ASSET RETIREMENT AND ENVIRONMENTAL OBLIGATIONS ASSET RETIREMENT OBLIGATIONS The accrued closure obligation provides for contractual and legal obligations related to our indefinitely idled and closed operations and for the eventual closure of our active operations. The closure date for each of our active mine sites was determined based on the exhaustion date of the remaining mineral reserves, and the amortization of the related asset and accretion of the liability is recognized over the estimated mine lives. The closure date and expected timing of the capital requirements to meet our obligations for our indefinitely idled or closed mines is determined based on the unique circumstances of each property. For indefinitely idled or closed mines, the accretion of the liability is recognized over the anticipated timing of remediation. Asset retirement obligations at our steelmaking operations primarily include the closure and post-closure care for on-site landfills and other waste containment facilities. Asset retirement obligations have been recorded at present values using settlement dates based on when we expect these facilities to reach capacity and close. The following is a summary of our asset retirement obligations: December 31, (In millions) 2024 2023 Asset retirement obligations 1 $ 526 $ 459 Less: current portion 25 15 Long-term asset retirement obligations $ 501 $ 444 1 Includes $302 million and $259 million related to our active operations as of December 31, 2024 and 2023, respectively. The following is a roll-forward of our asset retirement obligation: (In millions) 2024 2023 Asset retirement obligation as of January 1 $ 459 $ 520 Increase from Stelco Acquisition 20 — Decrease from sale of business — (76) Accretion expense 22 26 Remediation payments (33) (21) Revision in estimated cash flows 58 10 Asset retirement obligation as of December 31 $ 526 $ 459 During the first quarter of 2024, we announced the indefinite idle of our Weirton tinplate production plant, resulting in an increase to our asset retirement obligations as a result of acceleration of the timing and refinement in the cost required. ENVIRONMENTAL OBLIGATIONS Our operations currently use, and have in the past used, hazardous materials and substances, and we have generated, and expect to continue to generate, solid and hazardous waste. We have been, and may in the future be, subject to claims under laws and regulations for toxic torts, natural resource damages and other damages, as well as for the investigation and clean-up of soil, surface water, sediments, groundwater, and other natural resources and reclamation of properties. If we reasonably can, we estimate potential remediation expenditures for those sites where future remediation efforts are probable based on identified conditions, regulatory requirements, or contractual obligations arising from the sale of a business or facility. For sites involving government required investigations, including pursuant to RCRA and CERCLA, we typically make an estimate of potential remediation expenditures only after the investigation is complete and when we better understand the nature and scope of the remediation. In general, the material factors in these estimates include the costs associated with investigations, delineations, risk assessments, remedial work, governmental response and oversight, site monitoring and preparation of reports to the appropriate environmental agencies. The following is a summary of our environmental obligations: December 31, (In millions) 2024 2023 Environmental obligations $ 114 $ 134 Less: current portion 14 21 Long-term environmental obligations $ 100 $ 113

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	NOTE 14 - FAIR VALUE OF FINANCIAL INSTRUMENTS The carrying values of certain financial instruments (e.g. Accounts receivable, net , Accounts payable and Other current liabilities ) approximate fair value and, therefore, have been excluded from the table below. See NOTE 15 - DERIVATIVE INSTRUMENTS AND HEDGING for information on our derivative instruments, which are accounted for at fair value on a recurring basis. The following table summarizes the carrying value and fair value of other financial instruments: December 31, 2024 December 31, 2023 (In millions) Classification Carrying Fair Value Carrying Fair Value Senior notes Level 1 $ 5,505 $ 5,496 $ 3,137 $ 3,118 ABL Facility - outstanding balance Level 2 1,560 1,560 — — Total $ 7,065 $ 7,056 $ 3,137 $ 3,118 The valuation of financial assets classified in Level 2 was determined using a market approach based upon quoted prices for similar assets in active markets or other inputs that were observable. EMPLOYEE BENEFIT COMMITMENT In connection with the Stelco Acquisition, we have acquired funding commitments to employee life and health trusts. These obligations pertain to plans previously sponsored by Stelco prior to its bankruptcy. The commitments primarily involve fixed scheduled payments that will continue until 2042, with an additional variable component tied to Stelco's standalone operating performance. The financial liability is recorded at fair value on a recurring basis using a discounted cash flow model, which incorporates observable and unobservable inputs for risk-free interest rates and future operating estimates. The liability is classified as a Level 3 within the fair value hierarchy. The current and non-current portions of the employee benefit commitment are classified within Other current liabilities and Other non-current liabilities on the Statements of Consolidated Financial Position, respectively. The following table summarizes the changes in fair value of the employee benefit commitment: (In millions) 2024 Beginning balance as of January 1 $ — Fair value of commitment assumed in connection with Stelco Acquisition (197) Total losses included in earnings (2) Payments 5 Foreign currency translation 6 Ending balance as of December 31 $ (188) MINNTAC OPTION Stelco is party to an option to purchase a 25% ownership interest in the MinnTac iron ore mine and related infrastructure located in Mt. Iron, Minnesota from U. S. Steel for $500 million. This option is exercisable by Stelco at any time until January 31, 2027. This option is recorded as a derivative instrument at fair value on a recurring basis and included within Other non-current assets on the Statements of Consolidated Financial Position. Any gain or loss recorded in relation to the fair value of this option is presented within Other non-operating income (loss). The fair value of the derivative asset is estimated using the Black-Scholes option pricing model, which incorporates observable or unobservable inputs for risk-free interest rates, foreign exchange rates, commodity prices, discount rates, corresponding market volatility levels and other market-based pricing factors. This option is classified as a Level 3 derivative asset within the fair value hierarchy. The following table summarizes the changes in fair value of the MinnTac option: (In millions) 2024 Beginning balance as of January 1 $ — Fair value of option acquired in connection with Stelco Acquisition 110 Total losses included in earnings (12) Foreign currency translation (3) Ending balance as of December 31 $ 95

DERIVATIVE INSTRUMENTS AND HEDG

DERIVATIVE INSTRUMENTS AND HEDGING	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging	NOTE 15 - DERIVATIVE INSTRUMENTS AND HEDGING We are exposed to price risk associated with fluctuations in the market prices of purchased raw materials and energy sources and the sales price of certain steel products. We may use cash-settled commodity purchase swaps to hedge the market risk associated with the purchase of certain of our raw materials and energy requirements and cash-settled sales swaps to hedge the sales price risk of certain steel products. Our hedging strategy is to reduce the effect on earnings from the price volatility of these various exposures. Our commodity purchase swaps are designated as cash flow hedges for accounting purposes, and we record the gains and losses for the derivatives in Accumulated other comprehensive income until we reclassify them into Cost of goods sold when we recognize the associated underlying operating costs. Impacts of our designated commodity purchase swaps are reflected within Other, net in the Statements of Consolidated Cash Flows. Refer to NOTE 17 - ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) for further information. Our commodity purchase swaps are classified as Level 2 as values were determined using a market approach based upon quoted prices for similar assets in active markets or other inputs that were observable. The following table presents the notional amount of our outstanding commodity purchase swaps: Notional Amount December 31, Commodity Purchase Swaps Unit of Measure Maturity Dates 2024 2023 Natural Gas MMBtu January 2025 - August 2027 143,250,000 168,590,000 Electricity Megawatt hours January 2025 - October 2027 3,224,227 3,501,898 At December 31, 2024, we estimate $68 million of net losses related to our commodity purchase swaps will reclassify from Accumulated other comprehensive income into Cost of goods sold during the next 12 months. These estimates are based on December 31, 2024 fair values, some of which will change before their actual reclassification into Cost of goods sold. The following table presents the fair value of our cash flow hedges and the classification on the Statements of Consolidated Financial Position: December 31, Balance Sheet Location (In millions) 2024 2023 Other current assets $ 5 $ — Other non-current assets 9 1 Other current liabilities (41) (105) Other non-current liabilities (6) (52) FOREIGN CURRENCY CONTRACTS On July 15, 2024, we announced that we had entered into the Arrangement Agreement with Stelco Holdings Inc. to acquire all of its common shares in a cash and stock transaction. We hedged a portion of the purchase price by entering into multiple foreign currency contracts. These hedge contracts were considered economic hedges and did not qualify for hedge accounting. During the year ended December 31, 2024, these contracts resulted in a loss of $29 million presented in Other non-operating income (loss) in the Statements of Consolidated Operations and in Other investing activities in the Statements of Consolidated Cash Flows . As of December 31, 2024, no foreign currency contracts are outstanding.

CAPITAL STOCK

CAPITAL STOCK	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Capital Stock	NOTE 16 - CAPITAL STOCK SHARE REPURCHASE PROGRAMS During the first quarter of 2024, we fully utilized the remaining portion of our prior $1 billion share repurchase program, which was approved by our Board of Directors on February 10, 2022. On April 22, 2024, our Board of Directors authorized a new program to repurchase our outstanding common shares in the open market or in privately negotiated transactions, which may include purchases pursuant to Rule 10b5-1 plans or accelerated share repurchases, up to a maximum of $1.5 billion . We are not obligated to make any repurchases, and the program may be suspended or discontinued at any time. The share repurchase program does not have a specific expiration date. For the years ended December 31, 2024 and 2023, we repurchased 37.9 million and 10.4 million common shares, respectively, at a cost of $733 million and $152 million in the aggregate, respectively. The cost of our share repurchases excludes the excise tax due under the Inflation Reduction Act. As of December 31, 2024, there was $1.4 billion remaining authorization under our active share repurchase program. PREFERRED STOCK We have 3 million shares of Serial Preferred Stock, Class A, without par value, authorized, and 4 million shares of Serial Preferred Stock, Class B, without par value, authorized; no preferred shares were issued or outstanding as of December 31, 2024. STELCO ACQUISITION As more fully described in NOTE 3 - ACQUISITIONS, we completed the Stelco Acquisition on November 1, 2024. At closing, each Stelco shareholder received CAD $60.00 in cash and 0.454 shares of Cliffs common stock per share of Stelco common stock. Additionally, Stelco equity award holders received CAD $60.00 in cash and 0.454 shares of Cliffs common stock per outstanding restricted share unit and deferred share unit. As a result of the Stelco Acquisition, we issued a total of 25.9 million Cliffs treasury shares at a fair value of $343 million.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	NOTE 17 - ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The components of Accumulated other comprehensive income within Cliffs shareholders’ equity and related tax effects allocated to each are shown below: December 31, (In millions) 2024 2023 2022 Foreign Currency Translation Beginning balance $ — $ (1) $ 1 Other comprehensive income (loss) before reclassifications (70) 1 (2) Ending balance $ (70) $ — $ (1) Derivative Instruments Beginning balance $ (170) $ (16) $ 68 Other comprehensive income (loss) before reclassifications (41) (345) 146 Income tax 10 81 (33) Other comprehensive income (loss) before reclassifications, net of tax (31) (264) 113 Losses (gains) reclassified from AOCI to net income 1 195 144 (256) Income tax expense (benefit) 2 (47) (34) 59 Net losses (gains) reclassified from AOCI to net income 148 110 (197) Ending balance $ (53) $ (170) $ (16) Pension and OPEB Beginning balance $ 1,827 $ 1,847 $ 549 Other comprehensive income (loss) before reclassifications 4 (68) 115 1,759 Income tax 17 (39) (434) Other comprehensive income (loss) before reclassifications, net of tax (51) 76 1,325 Gains reclassified from AOCI to net income 3 (154) (145) (36) Income tax expense 2 38 49 9 Net gains reclassified from AOCI to net income (116) (96) (27) Ending balance $ 1,660 $ 1,827 $ 1,847 Total AOCI Ending Balance $ 1,537 $ 1,657 $ 1,830 1 Amounts recognized in Cost of goods sold in the Statements of Consolidated Operations. 2 Amounts recognized in Income tax benefit (expense) in the Statements of Consolidated Operations. 3 Amounts recognized in Net periodic benefit credits other than service cost component in the Statements of Consolidated Operations. 4 Refer to NOTE 9 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information.

VARIABLE INTEREST ENTITIES

VARIABLE INTEREST ENTITIES	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	NOTE 18 - VARIABLE INTEREST ENTITIES SUNCOKE MIDDLETOWN We purchase all the coke and electrical power generated from SunCoke Middletown’s plant under long-term supply agreements and have committed to purchase all the expected production from the facility through 2032. We consolidate SunCoke Middletown as a VIE because we are the primary beneficiary despite having no ownership interest in SunCoke Middletown. SunCoke Middletown had income before income taxes of $52 million for each of the years ended December 31, 2024 and 2023, which was included in our consolidated Income (loss) from continuing operations before income taxes . Additionally, SunCoke Middletown had cash used for capital expenditures of $24 million for the year ended December 31, 2024, compared to $25 million for the year ended December 31, 2023, that are included in our consolidated Purchase of property, plant and equipment on the Statements of Consolidated Cash Flows. The assets of the consolidated VIE can only be used to settle the obligations of the consolidated VIE and not obligations of the Company. The creditors of SunCoke Middletown do not have recourse to the assets or general credit of the Company to satisfy liabilities of the VIE. The Statements of Consolidated Financial Position includes the following amounts for SunCoke Middletown: December 31, (In millions) 2024 2023 Inventories $ 27 $ 29 Property, plant and equipment, net 288 288 Accounts payable (19) (26) Other assets (liabilities), net (47) (39) Noncontrolling interests (249) (252)

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	NOTE 19 - EARNINGS PER SHARE The following table summarizes the computation of basic and diluted EPS: Year Ended December 31, (In millions, except per share amounts) 2024 2023 2022 Income (loss) from continuing operations $ (708) $ 449 $ 1,373 Income from continuing operations attributable to noncontrolling interest (46) (51) (41) Net income (loss) from continuing operations attributable to Cliffs shareholders (754) 398 1,332 Income from discontinued operations, net of tax — 1 3 Net income (loss) attributable to Cliffs shareholders $ (754) $ 399 $ 1,335 Weighted average number of shares: Basic 480 510 519 Convertible senior notes — — 2 Employee stock plans — 1 3 Diluted 480 511 524 Earnings (loss) per common share attributable to Cliffs common shareholders - basic: Continuing operations $ (1.57) $ 0.78 $ 2.57 Discontinued operations — — — $ (1.57) $ 0.78 $ 2.57 Earnings (loss) per common share attributable to Cliffs common shareholders - diluted: Continuing operations $ (1.57) $ 0.78 $ 2.55 Discontinued operations — — — $ (1.57) $ 0.78 $ 2.55 The following table summarizes the potentially dilutive shares that were excluded from the computation of diluted earnings per share because their effect would have been anti-dilutive: Year Ended December 31, (In millions) 2024 2023 2022 Employee stock plans 2 2 —

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 20 - COMMITMENTS AND CONTINGENCIES PURCHASE COMMITMENTS We purchase portions of the principal raw materials required for our steel manufacturing operations under annual and multi-year agreements, some of which have minimum quantity requirements. We also use large volumes of natural gas, electricity and industrial gases in our operations. We negotiate most of our purchases of chrome, industrial gases and a portion of our electricity under multi-year agreements. Our purchases of coke and iron ore are made under annual or multi-year agreements with periodic price adjustments. We typically purchase coal under annual fixed price agreements. We also purchase certain transportation services under multi-year contracts with minimum quantity requirements. Unconditional purchase obligations, including take-or-pay agreements, are as follows (in millions): 2025 2026 2027 2028 2029 Thereafter $ 3,073 $ 1,618 $ 1,439 $ 1,044 $ 913 $ 4,694 OTHER COMMERCIAL COMMITMENTS We use surety bonds and letters of credit to provide financial assurance for certain obligations and statutory requirements. As of December 31, 2024, we had $271 million of surety-backed letters of credit and surety bonds outstanding. Additionally, as of December 31, 2024, we had $62 million of outstanding letters of credit issued under our ABL Facility. CONTINGENCIES We are currently the subject of, or party to, various claims and legal proceedings incidental to our current and historical operations. These claims and legal proceedings are subject to inherent uncertainties and unfavorable rulings could occur. An unfavorable ruling could include monetary damages, additional funding requirements or an injunction. If an unfavorable ruling were to occur, there exists the possibility of a material adverse effect on our financial position and results of operations for the period in which the ruling occurs or future periods. However, based on currently available information, we do not believe that any pending claims or legal proceedings will result in a material adverse effect in relation to our consolidated financial statements. ENVIRONMENTAL CONTINGENCIES Our environmental remediation obligations for known environmental matters at active and closed operations have been recognized based on estimates of the cost of investigation and remediation at each facility. We cannot predict the ultimate costs for each site with certainty because of the evolving nature of the investigation and remediation process. Rather, to estimate the probable costs, we must make certain assumptions. The most significant of these assumptions is for the nature and scope of the work that will be necessary to investigate and remediate a particular site and the cost of that work. Other significant assumptions include the cleanup technology that will be used, whether and to what extent any other parties will participate in paying the investigation and remediation costs, reimbursement of past response costs and future oversight costs by governmental agencies, and the reaction of the governing environmental agencies to the proposed work plans. Costs for future investigation and remediation are not discounted to their present value, unless the amount and timing of the cash disbursements are readily known. To the extent that we have been able to reasonably estimate future liabilities, we do not believe that there is a reasonable possibility that we will incur a loss or losses that exceed the amounts we accrued that would, either individually or in the aggregate, have a material adverse effect on our consolidated financial condition, results of operations or cash flows. However, since we recognize amounts in the consolidated financial statements in accordance with GAAP that exclude potential losses that are not probable or that may not be currently estimable, the ultimate costs of these environmental matters may be higher than the liabilities we currently have recorded in our consolidated financial statements. Pursuant to RCRA, which governs the treatment, handling and disposal of hazardous waste, the EPA and authorized state environmental agencies may conduct inspections of RCRA-regulated facilities to identify areas where there have been releases of hazardous waste or hazardous constituents into the environment and may order the facilities to take corrective action to remediate such releases. Likewise, the EPA or the states may require closure or post-closure care of residual, industrial and hazardous waste management units. Environmental regulators have the authority to inspect all of our facilities. While we cannot predict the future actions of these regulators, it is possible that they may identify conditions in future inspections of these facilities that they believe require corrective action. Pursuant to CERCLA, the EPA and state environmental authorities have conducted site investigations at some of our facilities and other third-party facilities, portions of which previously may have been used for disposal of materials that are currently regulated. The results of certain of these investigations remain pending, and we could be directed to spend funds for remedial activities at the former disposal areas. Because of the uncertain status of these investigations, however, we cannot reasonably predict whether or when such spending might be required or its magnitude. In addition to the foregoing matters, we are or may be involved in proceedings with various regulatory authorities that may require us to pay fines, comply with more rigorous standards or other requirements or incur capital and operating expenses for environmental compliance. We believe that the ultimate disposition of any such proceedings will not have, individually or in the aggregate, a material adverse effect on our consolidated financial condition, results of operations or cash flows. TAX MATTERS The calculation of our tax liabilities involves dealing with uncertainties in the application of complex tax regulations. We recognize liabilities for anticipated tax audit issues based on our estimate of whether, and the extent to which, additional taxes will be due. If we ultimately determine that payment of these amounts is unnecessary, we reverse the liability and recognize a tax benefit during the period in which we determine that the liability is no longer necessary. We also recognize tax benefits to the extent that it is more likely than not that our positions will be sustained when challenged by the taxing authorities. To the extent we prevail in matters for which liabilities have been established, or are required to pay amounts in excess of our liabilities, our effective tax rate in a given period could be materially affected. An unfavorable tax settlement would require use of our cash and result in an increase in our effective tax rate in the year of resolution. A favorable tax settlement would be recognized as a reduction in our effective tax rate in the year of resolution. Refer to NOTE 11 - INCOME TAXES for further information. OTHER CONTINGENCIES In addition to the matters discussed above, there are various pending and potential claims against us and our subsidiaries involving antitrust, product liability, personal injury, commercial, employee benefits and other matters arising in the ordinary course of business. Because of the considerable uncertainties that exist for any claim, it is difficult to reliably or accurately estimate what the amount of a loss would be if a claimant prevails. If material assumptions or factual understandings we rely on to evaluate exposure for these contingencies prove to be inaccurate or otherwise change, we may be required to record a liability for an adverse outcome. If, however, we have reasonably evaluated potential future liabilities for all of these contingencies, including those described more specifically above, it is our opinion, unless we otherwise noted, that the ultimate liability from these contingencies, individually or in the aggregate, should not have a material adverse effect on our consolidated financial position, results of operations or cash flows.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	NOTE 21 - SUBSEQUENT EVENTS On February 6, 2025, we issued $850 million aggregate principal amount of 7.500% Senior Notes due 2031 at par in a private placement transaction exempt from the registration requirements of the Securities Act. The net proceeds will be used for general corporate purposes, including the repayment of borrowings under our ABL Facility.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (754)	$ 399	$ 1,335

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Management of cybersecurity risks is an integral part of our overall risk management framework and is essential for safeguarding our business and data. We have developed an information security program to assess, identify and manage material risks from cybersecurity threats. The program includes policies and procedures that identify how security measures and controls drawn from multiple security frameworks are developed, implemented and maintained. Our cybersecurity risk management program works to balance critical infrastructure, network, application, cloud and information security objectives with overall business objectives and risk tolerance. Specific controls that are used include endpoint threat detection and response, identity and access management, privileged access management, logging and monitoring involving the use of security information and event management, multi-factor authentication, firewalls and intrusion detection and prevention, and vulnerability and patch management. We use threat intelligence to inform our defensive measures. We use external and internal threat intelligence sources, including information from industry vendors and government agencies. Evolving threats and risks we are also monitoring and working to protect against include Artificial Intelligence, ransomware and nation-state attacks. We believe in continuous improvement as part of the effort to optimize security, and we work to foster that culture through various initiatives: • Cybersecurity Awareness Trainings: We educate employees on best practices for online safety and for identifying potential cybersecurity threats, including by maintaining quarterly training programs for our non-represented salaried workforce. • Simulated Cyberattacks: With assistance from qualified third-party experts, we periodically conduct penetration testing and tabletop exercises to test our technical controls and incident response plans. • Security Monitoring: We monitor our information technology environment with both our internal cybersecurity resources and third-party service providers. We also have processes in place to monitor the cybersecurity practices of various third-party service providers, including certain vendors that have access to our information systems or sensitive data. • Proactive Reporting and Investigation: As part of our training initiatives, we regularly educate employees on how to report any suspicious cyber activity or potential cybersecurity issues, and we investigate reported concerns. Third-party security firms are used in different capacities to provide or operate some of these programs, controls and technology systems, including cloud-based platforms and services.
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	The program includes policies and procedures that identify how security measures and controls drawn from multiple security frameworks are developed, implemented and maintained
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Our Board of Directors has overall oversight responsibility for our enterprise risk management program and delegates cybersecurity risk management oversight to the Audit Committee of the Board of Directors. The Audit Committee is responsible for ensuring that management has processes in place designed to identify and evaluate cybersecurity risks to which the Company is exposed and implement processes and programs to manage cybersecurity risks and mitigate cybersecurity incidents. Management, including the Chief Information Officer with support from our cybersecurity team, updates the Audit Committee on at least a biannual basis regarding our cybersecurity programs and material cybersecurity risks and mitigation strategies. The Audit Committee also regularly reports on discussions regarding cybersecurity risks to our full Board of Directors. Management is responsible for identifying, considering and assessing material cybersecurity risks on an ongoing basis, establishing processes to ensure that such potential cybersecurity risk exposures are monitored, putting in place appropriate mitigation measures and maintaining cybersecurity programs. Our cybersecurity programs are under the direction of our Chief Information Officer, who has three years of experience overseeing information technology and cyber functions and who receives reports from our cybersecurity team and monitors the prevention, detection, mitigation and remediation of cybersecurity incidents. Our cybersecurity team includes personnel that have obtained credentials from the International System Security Certification Consortium and the SANS Institute, such as Certified Information Systems Security Professional (CISSP) and GIAC Certified Incident Handler, as well as experienced information systems security professionals and information security managers. Additionally, our internal Information Security Committee, composed of leaders from key departments, collaborates on a cross-functional basis to identify practices that can counter threats and to monitor our cybersecurity programs and our cybersecurity incident response plans. We recognize the ever-present global risk of cyberattacks from diverse threat actors, including nation-states, cybercriminals, hacktivists, insiders and organized crime. In spite of our efforts, we (or third parties we rely on) may not be able to fully, continuously and effectively implement security controls as intended. As described above, we utilize a risk-based approach and judgment to determine the security controls to implement, but it is possible we may not implement appropriate controls if we do not recognize or we underestimate a particular risk. In addition, security controls, no matter how well designed or implemented, may only mitigate and not fully eliminate risks. Further, even events that are detected by security tools or third parties may not always be immediately understood or acted upon. While no organization is immune to attack attempts and we cannot eliminate all risks from cybersecurity threats or provide assurance that we have not experienced an undetected cybersecurity incident, in 2024 we did not identify any material cybersecurity events that have materially affected or are reasonably likely to materially affect our business strategy, results of operations or financial condition. For further information about these risks, please see Part I - Item 1A. Risk Factors - IV. Operational Risks - A disruption in or failure of our IT systems, including those related to cybersecurity, could adversely affect our business operations, reputation and financial performance and could expose us to third-party liability
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Our Board of Directors has overall oversight responsibility for our enterprise risk management program and delegates cybersecurity risk management oversight to the Audit Committee of the Board of Directors.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee is responsible for ensuring that management has processes in place designed to identify and evaluate cybersecurity risks to which the Company is exposed and implement processes and programs to manage cybersecurity risks and mitigate cybersecurity incidents.
Cybersecurity Risk Role of Management [Text Block]	Management, including the Chief Information Officer with support from our cybersecurity team, updates the Audit Committee on at least a biannual basis regarding our cybersecurity programs and material cybersecurity risks and mitigation strategies.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	The Audit Committee is responsible for ensuring that management has processes in place designed to identify and evaluate cybersecurity risks to which the Company is exposed and implement processes and programs to manage cybersecurity risks and mitigate cybersecurity incidents. Management, including the Chief Information Officer with support from our cybersecurity team, updates the Audit Committee on at least a biannual basis regarding our cybersecurity programs and material cybersecurity risks and mitigation strategies
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Our cybersecurity programs are under the direction of our Chief Information Officer, who has three years of experience overseeing information technology and cyber functions and who receives reports from our cybersecurity team and monitors the prevention, detection, mitigation and remediation of cybersecurity incidents.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	The Audit Committee also regularly reports on discussions regarding cybersecurity risks to our full Board of Directors.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

BASIS OF PRESENTATION AND SIG_2

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Consolidation	BASIS OF CONSOLIDATION The consolidated financial statements consolidate our accounts and the accounts of our wholly owned subsidiaries, all subsidiaries in which we have a controlling interest and VIEs for which we are the primary beneficiary. All intercompany transactions and balances are eliminated upon consolidation.
Investments in Affiliates	INVESTMENTS IN AFFILIATES We have investments in several businesses accounted for using the equity method of accounting. These investments are included within our Steelmaking segment. We review an investment for impairment when circumstances indicate that a loss in value below its carrying amount is other than temporary. Our investment in affiliates of $131 million and $123 million as of December 31, 2024 and 2023, respectively, was classified in Other non-current assets.
Use of Estimates	USE OF ESTIMATES The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Our mineral reserves; future realizable cash flow; environmental, reclamation and closure obligations; valuation of business combinations; derivative assets/liabilities; tax assets/liabilities; post-employment, post-retirement and other employee benefit liabilities; reserves for contingencies and litigation require the use of various management estimates and assumptions. Actual results could differ from estimates. Management reviews its estimates on an ongoing basis. Changes in facts and circumstances may alter such estimates and affect the results of operations and financial position in future periods.
Business Combinations	BUSINESS COMBINATIONS Assets acquired and liabilities assumed in a business combination are recognized and measured based on their estimated fair values at the acquisition date, while the acquisition-related costs are expensed as incurred. Any excess of the purchase consideration when compared to the fair value of the net tangible and intangible assets acquired, if any, is recorded as goodwill. We engage independent valuation specialists to assist with the determination of the fair value of assets acquired, liabilities assumed and goodwill associated with an acquisition. If the initial accounting for the business combination is incomplete by the end of the reporting period in which the acquisition occurs, an estimate will be recorded. Subsequent to the acquisition date, and not later than one year from the acquisition date, we will record any material adjustments to the initial estimate based on new information obtained that existed as of the date of the acquisition. Any adjustment that arises from information obtained that did not exist as of the date of the acquisition will be recorded in the period the adjustment arises.
Cash and Cash Equivalents	CASH, CASH EQUIVALENTS, AND RESTRICTED CASH Cash and cash equivalents include cash on hand and on deposit as well as all short-term securities held for the primary purpose of general liquidity. We routinely monitor and evaluate counterparty credit risk related to the financial institutions in which our short-term investment securities are held. Where right of offset exists, we report cash balances net. Additionally, restricted cash represents cash not readily available for our operations and includes deposits primarily associated with certain environmental obligations. This balance is classified within Other non-current assets on the Statements of Consolidated Financial Position.
Trade Accounts Receivable and Allowance for Credit Loss	TRADE ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSS Trade accounts receivable are recorded at the point control transfers and represent the amount of consideration we expect to receive in exchange for transferred goods and do not bear interest. We establish provisions for expected lifetime losses on accounts receivable at the time a receivable is recorded based on historical experience, customer credit quality and forecasted economic conditions. We regularly review our accounts receivable balances and the allowance for credit loss and establish or adjust the allowance as necessary using the specific identification method. We evaluate the aggregation and risk characteristics of receivable pools and develop loss rates that reflect historical collections, current forecasts of future economic conditions over the time horizon we are exposed to credit risk, and payment terms or conditions that may materially affect future forecasts.
Inventories	INVENTORIES Inventories are generally stated at the lower of cost or net realizable value using average cost, excluding depreciation and amortization. Certain iron ore inventories are stated at the lower of cost or market using the LIFO method.
Derivative Financial Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES We are exposed to certain risks related to the ongoing operations of our business, including those caused by changes in commodity prices and energy rates. We have established policies and procedures, including the use of certain derivative instruments, to manage such risks. Derivative instruments are recognized as either assets or liabilities on the Statements of Consolidated Financial Position and measured at fair value. On the date a qualifying hedging instrument is executed, we designate the hedging instrument as a hedge of the variability of cash flows to be received or paid related to a forecasted transaction (cash flow hedge). We formally document all relationships between hedging instruments and hedged items, as well as our risk-management objective and strategy for undertaking various hedge transactions. This process includes linking all derivatives that are designated as cash flow hedges to specific firm commitments or forecasted transactions. We also formally assess, both at the hedge's inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows of the related hedged items. When it is determined that a derivative is not highly effective as a hedge, we discontinue hedge accounting prospectively and record all future changes in fair value in the period of the instrument's earnings or losses. For derivative instruments that have been designated as cash flow hedges, the changes in fair value are recorded in Accumulated other comprehensive income . Amounts recorded in Accumulated other comprehensive income are reclassified to earnings or losses in the period the underlying hedged transaction affects earnings or when the underlying hedged transaction is no longer reasonably possible of occurring. The cash flows resulting from these derivative instruments are classified in Other, net in operating activities on the Statements of Consolidated Cash Flows. For derivative instruments that have not been designated as cash flow hedges, changes in fair value are recorded in the period of the instrument's earnings or losses.
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT Our properties are stated at cost less accumulated depreciation. Depreciation of plant and equipment is computed principally by the straight-line method based on estimated useful lives. Depreciation continues to be recognized when operations are idled temporarily. Depreciation and depletion are recorded over the following estimated useful lives: Asset Class Basis Life Land, land improvements and mineral rights Land and mineral rights Units of production Life of mine Land improvements Straight line 20 to 45 years Buildings Straight line 20 to 45 years Equipment Straight line/Double declining balance 3 to 45 years Governmental grants received in connection with an underlying capital project typically have associated requirements that must be met in order to ultimately earn the grant. When we receive grant funds related to a capital project, we record the amount received as a reduction of the capital project asset on the balance sheet. Grant funds received are recorded as a cash inflow, classified in Other investing activities, separate from the cash outflow related to the capital project, which are classified in Purchase of property, plant and equipment , within investing activities on the Statements of Consolidated Cash Flows.
Goodwill and Other Intangible Assets and Liabilities	GOODWILL Goodwill represents the excess purchase price paid over the fair value of the net assets from an acquisition. Goodwill is not amortized for financial statement purposes. Goodwill is tested on a qualitative or quantitative basis for impairment at the reporting unit level on an annual basis on October 1 and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value. We have an unconditional option to bypass the qualitative test for any reporting unit in any period and proceed directly to performing the quantitative test. Should our qualitative test indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying value, we perform a quantitative test to determine the amount of impairment, if any, to the carrying value of the reporting unit and its associated goodwill. OTHER INTANGIBLE ASSETS AND LIABILITIES
Leases	LEASES We determine if an arrangement contains a lease at inception. We recognize right-of-use assets and lease liabilities associated with leases based on the present value of the future minimum lease payments over the lease term at the commencement date. Lease terms reflect options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Short-term leases (leases with an initial lease term of 12 months or less) are not recognized on the Statements of Consolidated Financial Position. Operating lease expense is recognized on a straight-line basis over the lease term.
Asset Impairment	ASSET IMPAIRMENT We monitor conditions that may affect the carrying value of our long-lived tangible and intangible assets when events and circumstances indicate that the carrying value of the asset groups may not be recoverable. In order to determine if assets have been impaired, assets are grouped and tested at the lowest level for which identifiable, independent cash flows are available ("asset group"). The measurement of the impairment loss to be recognized is based on the difference between the fair value and the carrying value of the asset group. Fair value can be determined using a market approach, income approach or cost approach.
Fair Value Measurements	FAIR VALUE MEASUREMENTS ASC Topic 820, Fair Value Measurements and Disclosures , establishes a three-level valuation hierarchy for classification of fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. Inputs refer broadly to the assumptions that market participants would use in pricing an asset or liability. Inputs may be observable or unobservable. Observable inputs are inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from independent sources. Unobservable inputs are inputs that reflect our own views about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. The three-tier hierarchy of inputs is summarized below: • Level 1 — Valuation is based upon quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2 — Valuation is based upon quoted prices for similar assets and liabilities in active markets, or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 — Valuation is based upon other unobservable inputs that are significant to the fair value measurement. The classification of assets and liabilities within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement in its entirety.
Pension and Other Postretirement Plans	PENSION AND OTHER POSTRETIREMENT BENEFITS We offer defined benefit pension plans, defined contribution pension plans and OPEB plans, primarily consisting of retiree healthcare benefits as part of our total compensation and benefits programs. We recognize the funded or unfunded status of our pension and OPEB obligations on the Statements of Consolidated Financial Position based on the difference between the market value of plan assets and the actuarial present value of our retirement obligations on that date, on a plan-by-plan basis. If the plan assets exceed the pension and OPEB obligations, the amount of the surplus is recorded as an asset; if the pension and OPEB obligations exceed the plan assets, the amount of the underfunded obligations is recorded as a liability. Year-end balance sheet adjustments to pension and OPEB assets and obligations are recorded as Accumulated other comprehensive income on the Statements of Consolidated Financial Position. The actuarial estimates of the PBO (Projected benefit obligation) and APBO (Accumulated postretirement benefit obligation) incorporate various assumptions including the discount rates, the rates of increases in compensation, healthcare cost trend rates, mortality, retirement timing, employee turnover and other demographic assumptions. The discount rate is determined based on the prevailing year-end rates for high-grade corporate bonds with a duration matching the expected cash flow timing of the benefit payments from the various plans. The remaining assumptions are based on our estimates of future events by incorporating historical trends and future expectations. The amount of net periodic cost that is recorded in the Statements of Consolidated Operations consists of several components including service cost, interest cost, expected return on plan assets, and amortization of previously unrecognized amounts. Service cost represents the value of the benefits earned in the current year by the participants. Interest cost represents the cost associated with the passage of time. Certain items, such as plan amendments, gains and/or losses resulting from differences between actual and assumed results for demographic and economic factors affecting the obligations and assets of the plans, and changes in other assumptions are subject to deferred recognition for income and expense purposes. The expected return on plan assets is calculated on a plan-by-plan basis using each plan's strategic asset allocation and our expected long-term capital market return assumptions. Service costs are classified within Cost of goods sold, Selling, general and administrative expenses and Miscellaneous – net while the interest cost, expected return on assets, amortization of prior service costs/credits, net actuarial gain/loss, and other costs are classified within Net periodic benefit credits other than service cost component. Cumulative actuarial gains and losses will be amortized to expense using the corridor method, where gains and losses are recognized if they exceed 10% of the greater of the fair value of plan assets or the plans' benefit obligations. The amortization period varies by plan.
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS An asset retirement obligation is recognized when incurred if a reasonable estimate of fair value can be made, and is initially measured at fair value. The fair value of the liability is determined as the discounted value of the expected future cash flows. The asset retirement obligation is accreted over time through periodic charges to earnings. In addition, the asset retirement cost is capitalized and amortized over the life of the related asset. Reclamation costs are adjusted periodically to reflect changes in the estimated present value resulting from the passage of time and revisions to the estimates of either the timing or amount of the reclamation costs. We review, on an annual basis, unless otherwise deemed necessary, the asset retirement obligation for each applicable operation in accordance with the provisions of ASC Topic 410, Asset Retirement and Environmental Obligations . We perform an in-depth evaluation of the liability every three years in addition to our routine annual assessments. Future reclamation costs for inactive operations are accrued based on management’s best estimate at the end of each period of the costs expected to be incurred at a site. Such cost estimates include, where applicable, ongoing maintenance and monitoring costs. Changes in estimates at inactive operations are reflected in Miscellaneous – net on the Statements of Consolidated Operations in the period an estimate is revised.
Environmental Remediation Costs	ENVIRONMENTAL REMEDIATION COSTS Our operating activities are subject to various laws and regulations governing protection of the environment. We conduct our operations to protect the public health and environment and believe our operations are in compliance with applicable laws and regulations in all material respects. Our environmental liabilities, including obligations for known environmental remediation exposures, have been recognized based on the estimated cost of investigation and remediation at each site. If the cost can only be estimated as a range of possible amounts with no point in the range being more likely, the minimum of the range is accrued. Future expenditures are discounted unless the amount and timing of the cash disbursements cannot be reasonably estimated. It is possible that additional environmental obligations could be incurred, the extent of which cannot be assessed. Potential insurance recoveries have not been reflected in the determination of the liabilities.
Revenue Recognition	REVENUE RECOGNITION
Repairs And Maintenance	REPAIRS AND MAINTENANCE Repairs, maintenance and replacement of components are expensed as incurred. The cost of major equipment overhauls is capitalized and depreciated over the estimated useful life, which is the period until the next scheduled overhauls. All other planned and unplanned repairs and maintenance costs are expensed when incurred.
Income Taxes	INCOME TAXES Income taxes are based on income for financial reporting purposes, calculated using tax rates by jurisdiction, and reflect a current tax liability or asset for the estimated taxes payable or recoverable on the current year tax return and expected annual changes in deferred taxes. Any interest or penalties on income tax are recognized as a component of Income tax benefit (expense) . We account for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized within Income tax benefit (expense) in the period that includes the enactment date. We recognize income tax effects from accumulated other comprehensive income when individual assets or liabilities are sold, terminated, or extinguished. We record net deferred tax assets to the extent we believe these assets will more likely than not be realized. In making such determination, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial results of operations. Accounting for uncertainty in income taxes recognized in the financial statements requires that a tax benefit from an uncertain tax position be recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on technical merits.
Foreign Currency	FOREIGN CURRENCY Our financial statements are prepared with the U.S. dollar as the reporting currency. Our functional currency is the U.S. dollar, with the exception of our Stelco and European subsidiaries, of which the functional currencies are the Canadian dollar and Euro, respectively. To the extent that the parent, or any subsidiaries of the parent, have monetary assets and liabilities, inclusive of short-term and certain long-term intercompany loans, recorded in a currency other than the foreign subsidiaries functional currency, these amounts are remeasured each reporting period, with the resulting gain or loss being included within Miscellaneous – net in the Statements of Consolidated Operations. Subsequently, the financial statements of foreign subsidiaries with a non-U.S. dollar functional currency are translated into U.S. dollars using the exchange rate at each balance sheet date for assets and liabilities and a weighted average exchange rate for each period for revenues, expenses, gains and losses. These translation adjustments are recorded to Accumulated other comprehensive income on the Statements of Consolidated Financial Position .
Earnings Per Share	EARNINGS PER SHARE We present both basic and diluted earnings per share amounts for continuing operations and discontinued operations. Total basic earnings per share amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders by the weighted average number of common shares outstanding during the period presented. Total diluted earnings per share amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders by the weighted average number of common shares and common share equivalents under stock plans using the treasury-stock method. Common share equivalents are excluded from EPS computations in the periods in which they have an anti-dilutive effect.
Variable Interest Entities	VARIABLE INTEREST ENTITIES
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS AND LEGISLATION ACCOUNTING PRONOUNCEMENTS - ISSUED AND ADOPTED In September 2022, the FASB issued ASU No. 2022-04, Liabilities - Supplier Finance Programs (Subtopic 405-50): Disclosure of Supplier Finance Program Obligations . This guidance requires annual and interim disclosure of the key terms of outstanding supplier finance programs and a roll-forward of the related obligations. The new standard does not affect the recognition, measurement or financial statement presentation of the supplier finance program obligations. At December 31, 2023, we had adopted this standard, with the exception of the roll-forward disclosure requirement, which was adopted as of December 31, 2024. Refer to NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION for further information. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . This guidance requires additional annual and interim disclosures for reportable segments. This new standard does not affect the recognition, measurement or financial statement presentation. As of December 31, 2024, we have adopted this standard and applied the amendment retrospectively to all prior periods presented. Refer to NOTE 5 - SEGMENT REPORTING for further information. ACCOUNTING PRONOUNCEMENTS - ISSUED AND NOT EFFECTIVE In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . This guidance requires additional annual and interim disclosures for income taxes. This new standard does not affect the recognition, measurement or financial statement presentation. The amendments are effective for fiscal years beginning after December 15, 2024. In November 2024, the FASB issued ASU No. 2024-03, Income Statement—Reporting Comprehensive Income (Subtopic 220-40): Disaggregation of Income Statement Expenses. This new standard does not affect the recognition, measurement or financial statement presentation. However, this guidance does require additional annual and interim disclosures related to the disaggregation of various income statement expense captions. The amendments are effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027.

BASIS OF PRESENTATION AND SIG_3

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Estimated Useful Lives	Depreciation and depletion are recorded over the following estimated useful lives: Asset Class Basis Life Land, land improvements and mineral rights Land and mineral rights Units of production Life of mine Land improvements Straight line 20 to 45 years Buildings Straight line 20 to 45 years Equipment Straight line/Double declining balance 3 to 45 years The following table indicates the carrying value of each of the major classes of our depreciable assets: December 31, (In millions) 2024 2023 Land, land improvements and mineral rights $ 1,451 $ 1,389 Buildings 1,104 946 Equipment 11,119 9,680 Other 349 302 Construction in progress 728 590 Total property, plant and equipment 1 14,751 12,907 Allowance for depreciation and depletion (4,809) (4,012) Property, plant and equipment, net $ 9,942 $ 8,895 1 Includes right-of-use assets related to finance leases of $505 million and $306 million as of December 31, 2024 and 2023, respectively. The net book value of the mineral and land rights are as follows: December 31, (In millions) 2024 2023 Mineral rights: Cost $ 783 $ 783 Depletion (287) (258) Net mineral rights $ 496 $ 525 Land rights $ 467 $ 427

SUPPLEMENTARY FINANCIAL STATE_2

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2024
Disclosure Text Block [Abstract]
Schedule of Inventories	The following table presents the detail of our Inventories on the Statements of Consolidated Financial Position: December 31, (In millions) 2024 2023 Product inventories Finished and semi-finished goods $ 2,393 $ 2,573 Raw materials 2,208 1,476 Total product inventories 4,601 4,049 Manufacturing supplies and critical spares 493 411 Inventories $ 5,094 $ 4,460
Supplier Finance Program	The following is a roll-forward of our obligations related to supply chain finance programs classified in Other current liabilities : (In millions) 2024 Supply chain finance obligations as of January 1 $ 21 Invoices confirmed during the year 230 Confirmed invoices paid during the year (222) Supply chain finance obligations as of December 31 $ 29 The following is a roll-forward of our obligations related to supply chain finance programs classified in Accounts payable : (In millions) 2024 Supply chain finance obligations as of January 1 $ 91 Invoices confirmed during the year 375 Confirmed invoices paid during the year (390) Supply chain finance obligations as of December 31 $ 76
Schedule of Restructuring Reserve by Type of Cost	The following table represents a reconciliation of our accrued liabilities related to the Weirton indefinite idle: (In millions) Employee-Related Costs Exit Costs Asset Impairment Total Balance as of December 31, 2023 $ — $ — $ — $ — Costs incurred 1 82 49 79 210 Cash payments (26) (34) — (60) Non-cash — — (79) (79) Balance as of December 31, 2024 $ 56 $ 15 $ — $ 71 1 Of the $210 million of cost incurred, $129 million was recorded in Restructuring and other charges, $79 million was recorded in Asset impairments and $2 million was recorded in Net periodic benefit credits other than service cost component .
Schedule of Cash Flow, Supplemental Disclosures	A reconciliation of capital additions to cash paid for capital expenditures is as follows: Year Ended December 31, (In millions) 2024 2023 2022 Capital additions $ 817 $ 785 $ 1,033 Less: Non-cash accruals (47) (13) 35 Equipment financed with seller 72 59 — Right-of-use assets - finance leases 97 93 55 Cash paid for capital expenditures including deposits $ 695 $ 646 $ 943 Additionally, included within Other investing activities on the Statements of Consolidated Cash Flows are grant reimbursements related to governmental funded capital projects. For the years ended December 31, 2024, 2023 and 2022, grant reimbursements were $8 million, $13 million and $27 million, respectively. Cash payments (receipts) for interest and income taxes are as follows: Year Ended December 31, (In millions) 2024 2023 2022 Income taxes paid $ 17 $ 94 $ 334 Income tax refunds (47) (205) (3) Interest paid on debt obligations net of capitalized interest 1 255 256 249 1 Capitalized interest was $15 million, $12 million and $9 million for the years ended December 31, 2024, 2023 and 2022, respectively.
Schedule of Noncash or Part Noncash Acquisitions	Other non-cash investing and financing activities are as follows: Year Ended December 31, (In millions) 2024 2023 2022 Fair value of common shares issued as part of consideration in connection with the Stelco Acquisition $ 343 $ — $ — 1.500% 2025 Convertible Senior Notes redemption — — 25

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2024
Business Combinations [Abstract]
Schedule of Fair Value of Purchase Consideration	The fair value of the total purchase consideration was determined as follows: (In millions) Total cash consideration $ 2,450 Total share exchange consideration 343 Total debt consideration 415 Total purchase consideration $ 3,208 Total consideration shares are calculated as follows: Number of outstanding Stelco shares 54,448,388 Number of outstanding share-based compensation awards 2,516,415 Total consideration shares 56,964,803 Total estimated cash consideration is calculated as follows: Number of consideration shares 56,964,803 Consideration share price per share (CAD) $ 60.00 Total cash consideration (CAD) (in millions) 3,418 Exchange rate (November 1, 2024) 0.7168 Total cash consideration (USD) $ 2,450 The fair value of share exchange consideration is as follows: Number of consideration shares 56,964,803 Fixed share exchange factor 0.454 Total Cliffs exchange shares 25,862,021 Cliffs share price at closing date (November 1, 2024) $ 13.27 Total share exchange consideration (in millions) $ 343
Summary of the Purchase Price Allocation to Assets Acquired and Liabilities Assumed	(in Millions) Cash and cash equivalents $ 341 Accounts receivable 104 Inventories 726 Other current assets 107 Property, plant and equipment 1,286 Intangible assets 1,025 Other non-current assets 250 Accounts payable (212) Accrued employment costs (29) Accrued expenses (6) Other current liabilities (71) Pension and OPEB liability, non-current (14) Deferred income taxes (449) Asset retirement and environmental obligations (20) Other non-current liabilities (616) Net identifiable assets acquired 2,422 Goodwill 786 Total net assets acquired $ 3,208
Summary of Purchase Price Allocated to Identifiable Intangible Assets and Liabilities Acquired	The purchase price allocated to identifiable intangible assets acquired was: (In millions) Weighted Average Life (In years) Intangible assets: Customer relationships 953 15 Trade names and trademarks 72 15 Total identifiable intangible assets $ 1,025 15
Summary of Unaudited Pro Forma Financial Information	The following table provides unaudited pro forma financial information, prepared in accordance with Topic 805, as if Stelco had been acquired as of January 1, 2023: Year Ended December 31, (In millions) 2024 2023 Revenues $ 20,874 $ 24,158 Net income (loss) attributable to Cliffs shareholders (623) 216

REVENUES (Tables)

REVENUES (Tables)	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Summary of Revenue by market and product line	The following table represents our Revenues by market: Year Ended December 31, (In millions) 2024 2023 2022 Steelmaking: Automotive $ 5,571 $ 7,440 $ 6,661 Infrastructure and manufacturing 5,208 5,612 5,869 Distributors and converters 5,281 5,330 6,388 Steel producers 2,469 2,949 3,465 Total Steelmaking 18,529 21,331 22,383 Other Businesses: Automotive 540 545 478 Infrastructure and manufacturing 39 38 52 Distributors and converters 77 82 76 Total Other Businesses 656 665 606 Total revenues $ 19,185 $ 21,996 $ 22,989 The following table represents our Revenues by product line: Year Ended December 31, (In millions) 2024 2023 2022 Steelmaking: Hot-rolled steel $ 4,276 $ 4,864 $ 4,529 Cold-rolled steel 2,712 2,658 3,193 Coated steel 5,773 6,661 6,905 Stainless and electrical steel 1,807 2,281 2,284 Plate 1,119 1,444 1,651 Slab and other steel products 1,178 1,329 1,492 Other 1,664 2,094 2,329 Total Steelmaking 18,529 21,331 22,383 Other Businesses: Other 656 665 606 Total revenues $ 19,185 $ 21,996 $ 22,989

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Summary of Results by Segment	The following tables provide our results by segment as well as a reconciliation from consolidated Adjusted EBITDA to our consolidated Net income (loss) : Year Ended December 31, 2024 (In millions) Steelmaking Other Businesses Eliminations Total Revenues $ 18,620 $ 656 $ (91) $ 19,185 Cost of goods sold (18,605) (606) 96 (19,115) Selling, general and administrative expenses (457) (29) — (486) Net periodic benefit credits other than service cost component 247 — — 247 Excluding depreciation, depletion and amortization 919 32 — 951 Other segment items 1 (2) — — (2) Total Adjusted EBITDA $ 722 $ 53 $ 5 $ 780 Interest expense, net $ (370) Income tax benefit 235 Depreciation, depletion and amortization (951) EBITDA from noncontrolling interests 2 76 Weirton indefinite idle (217) Arbitration decision (71) Acquisition-related costs (44) Changes in fair value of derivatives, net (41) Loss on extinguishment of debt (27) Amortization of inventory step-up (26) Loss on currency exchange (20) Loss on disposal of assets (16) Other, net (16) Net loss $ (708) Capital Additions $ 812 $ 5 $ — $ 817 Assets $ 20,327 $ 620 $ — $ 20,947 1 Other segment items primarily consists of the exclusion of EBITDA of noncontrolling interests and the Arbitration decision from Adjusted EBITDA and, to a lesser extent, the inclusion of items within Miscellaneous – net and Other non-operating income (loss). 2 EBITDA of noncontrolling interests includes net income attributable to noncontrolling interests of $46 million and the exclusion of depreciation, depletion, and amortization of $30 million. Year Ended December 31, 2023 (In millions) Steelmaking Other Businesses Eliminations Total Revenues $ 21,413 $ 665 $ (82) $ 21,996 Cost of goods sold (20,055) (627) 77 (20,605) Selling, general and administrative expenses (549) (28) — (577) Net periodic benefit credits other than service cost component 204 — — 204 Excluding depreciation, depletion and amortization 938 35 — 973 Other segment items 1 (78) (2) — (80) Total Adjusted EBITDA $ 1,873 $ 43 $ (5) $ 1,911 Interest expense, net $ (289) Income tax expense (148) Depreciation, depletion and amortization (973) EBITDA from noncontrolling interests 2 83 Acquisition-related costs (12) Loss on disposal of assets (15) Goodwill impairment (125) Other, net 18 Net income $ 450 Capital Additions $ 782 $ 3 $ — $ 785 Assets $ 16,880 $ 657 $ — $ 17,537 1 Other segment items primarily consists of the exclusion of EBITDA of noncontrolling interests from Adjusted EBITDA and, to a lesser extent, the inclusion of items within Miscellaneous – net and Other non-operating income (loss). 2 EBITDA of noncontrolling interests includes net income attributable to noncontrolling interests of $51 million and the exclusion of depreciation, depletion, and amortization of $32 million. Year Ended December 31, 2022 (In millions) Steelmaking Other Businesses Eliminations Total Revenues $ 22,462 $ 606 $ (79) $ 22,989 Cost of goods sold (20,004) (557) 90 (20,471) Selling, general and administrative expenses (439) (26) — (465) Net periodic benefit credits other than service cost component 212 — — 212 Excluding depreciation, depletion and amortization 994 40 — 1,034 Other segment items 1 (136) 6 — (130) Total Adjusted EBITDA $ 3,089 $ 69 $ 11 $ 3,169 Interest expense, net $ (276) Income tax expense (423) Depreciation, depletion and amortization (1,034) EBITDA from noncontrolling interests 2 74 Acquisition-related costs (1) Loss on extinguishment of debt (75) Loss on disposal of assets (22) Other, net (36) Net income $ 1,376 Capital Additions $ 1,003 $ 30 $ — $ 1,033 Assets $ 17,918 $ 837 $ — $ 18,755 1 Other segment items primarily consists of the exclusion of EBITDA of noncontrolling interests from Adjusted EBITDA and, to a lesser extent, the inclusion of items within Miscellaneous – net and Other non-operating income (loss). 2 EBITDA of noncontrolling interests includes net income attributable to noncontrolling interests of $41 million and the exclusion of depreciation, depletion, and amortization of $33 million.
Summary of Amounts Relating to Geographic Location	Included in the consolidated financial statements are the following amounts relating to geographic location based on product destination: Year Ended December 31, (In millions) 2024 2023 2022 Revenues: United States $ 17,340 $ 20,000 $ 20,991 Canada 1,067 1,046 963 Other countries 778 950 1,035 Total revenues $ 19,185 $ 21,996 $ 22,989 Property, plant and equipment, net: United States $ 8,622 $ 8,816 $ 8,981 Canada 1,319 78 88 Other countries 1 1 1 Total property, plant and equipment, net $ 9,942 $ 8,895 $ 9,070

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Summary of Carrying Value of Each Major Class of Depreciable Assets	Depreciation and depletion are recorded over the following estimated useful lives: Asset Class Basis Life Land, land improvements and mineral rights Land and mineral rights Units of production Life of mine Land improvements Straight line 20 to 45 years Buildings Straight line 20 to 45 years Equipment Straight line/Double declining balance 3 to 45 years The following table indicates the carrying value of each of the major classes of our depreciable assets: December 31, (In millions) 2024 2023 Land, land improvements and mineral rights $ 1,451 $ 1,389 Buildings 1,104 946 Equipment 11,119 9,680 Other 349 302 Construction in progress 728 590 Total property, plant and equipment 1 14,751 12,907 Allowance for depreciation and depletion (4,809) (4,012) Property, plant and equipment, net $ 9,942 $ 8,895 1 Includes right-of-use assets related to finance leases of $505 million and $306 million as of December 31, 2024 and 2023, respectively. The net book value of the mineral and land rights are as follows: December 31, (In millions) 2024 2023 Mineral rights: Cost $ 783 $ 783 Depletion (287) (258) Net mineral rights $ 496 $ 525 Land rights $ 467 $ 427

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill by Segment	The following is a summary of Goodwill by segment: December 31, (In millions) 2024 2023 Steelmaking $ 1,719 $ 956 Other Businesses 49 49 Total goodwill $ 1,768 $ 1,005
Summary of Intangible Assets and Liabilities	The following is a summary of our intangible assets and liabilities: December 31, 2024 December 31, 2023 (In millions) Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Intangible assets 1 : Customer relationships $ 1,015 $ (34) $ 981 $ 90 $ (18) $ 72 Developed technology 60 (17) 43 60 (14) 46 Trade names and trademarks 87 (8) 79 18 (5) 13 Mining permits 72 (29) 43 72 (28) 44 Supplier relationships 29 (5) 24 29 (3) 26 Total intangible assets $ 1,263 $ (93) $ 1,170 $ 269 $ (68) $ 201 Intangible liabilities 2 : Above-market supply contracts $ (71) $ 30 $ (41) $ (71) $ 24 $ (47) 1 Amortization related to mining permits is recognized in Cost of goods sold . Amortization of all other intangible assets is recognized in Selling, general and administrative expenses . 2 Intangible liabilities are classified as Other non-current liabilities . Amortization of all intangible liabilities is recognized in Cost of goods sold .

DEBT AND CREDIT FACILITIES (Tab

DEBT AND CREDIT FACILITIES (Tables)	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	The following represents a summary of our long-term debt: (In Millions) Debt Instrument Issuer 1 Annual Effective Interest Rate December 31, 2024 December 31, 2023 Senior Secured Notes: 6.750% 2026 Senior Secured Notes Cliffs 6.990% — 829 Senior Unsecured Notes: 7.000% 2027 Senior Notes Cliffs 9.240% 73 73 7.000% 2027 AK Senior Notes AK Steel 9.240% 56 56 5.875% 2027 Senior Notes Cliffs 6.490% 556 556 4.625% 2029 Senior Notes Cliffs 4.625% 368 368 6.875% 2029 Senior Notes Cliffs 6.875% 900 — 6.750% 2030 Senior Notes Cliffs 6.750% 750 750 4.875% 2031 Senior Notes Cliffs 4.875% 325 325 7.000% 2032 Senior Notes Cliffs 7.054% 1,425 — 7.375% 2033 Senior Notes Cliffs 7.375% 900 — 6.250% 2040 Senior Notes Cliffs 6.340% 235 235 ABL Facility Cliffs 2 Variable 3 1,560 — Total debt 7,148 3,192 Unamortized discounts and issuance costs (83) (55) Total long-term debt $ 7,065 $ 3,137 1 Unless otherwise noted, references in this column and throughout this NOTE 8 - DEBT AND CREDIT FACILITIES to "Cliffs" are to Cleveland-Cliffs Inc., and references to "AK Steel" are to AK Steel Corporation (n/k/a Cleveland-Cliffs Steel Corporation). 2 Refers to Cleveland-Cliffs Inc. as borrower under our ABL Facility. 3 Our ABL Facility annual effective interest rate was 5.829% as of December 31, 2024. The following represents a summary of our other unsecured senior notes' maturity and interest payable due dates: Debt Instrument Maturity Interest Payable 7.000% 2027 Senior Notes March 15, 2027 March 15 and September 15 5.875% 2027 Senior Notes June 1, 2027 June 1 and December 1 4.625% 2029 Senior Notes March 1, 2029 March 1 and September 1 6.750% 2030 Senior Notes April 15, 2030 April 15 and October 15 4.875% 2031 Senior Notes March 1, 2031 March 1 and September 1 6.250% 2040 Senior Notes October 1, 2040 April 1 and October 1
Summary of Borrowing Capacity Under the ABL Facility	The following represents a summary of our borrowing capacity under the ABL Facility: December 31, (In millions) 2024 Available borrowing base on ABL Facility 1 $ 4,158 Borrowings (1,560) Letter of credit obligations 2 (62) Borrowing capacity available $ 2,536 1 As of December 31, 2024, the ABL Facility has a maximum borrowing base of $4.75 billion. The available borrowing base is determined by applying customary advance rates to eligible accounts receivable, inventory and certain mobile equipment. 2 We issued standby letters of credit with certain financial institutions in order to support business obligations, including, but not limited to, operating agreements, employee severance, environmental obligations, workers' compensation, and insurance obligations.
Summary of Debt Instrument Maturities	The following represents a summary of our debt instrument maturities based on the principal amounts outstanding at December 31, 2024 (in millions): 2025 2026 2027 2028 2029 Thereafter Total $ — $ — $ 685 $ 1,560 $ 1,268 $ 3,635 $ 7,148

PENSIONS AND OTHER POSTRETIRE_2

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Tables)	12 Months Ended
	Dec. 31, 2024
Postemployment Benefits [Abstract]
Schedule of Defined Benefit Plans Disclosures	The following tables and information provide additional disclosures: (In millions) Pension Benefits OPEB Change in benefit obligations: 2024 2023 2024 2023 Benefit obligations — beginning of year $ 4,571 $ 4,646 $ 1,036 $ 1,233 Service cost 28 31 8 10 Interest cost 218 235 50 64 Plan amendments — 3 7 8 Actuarial loss (gain) (165) 116 162 (158) Benefits paid (429) (436) (155) (163) Participant contributions — — 36 42 Acquired through business combinations 35 — — — Foreign currency exchange (1) — — — Effect of settlement (9) (24) — — Other — — 3 — Benefit obligations — end of year $ 4,248 $ 4,571 $ 1,147 $ 1,036 Change in plan assets: Fair value of plan assets — beginning of year $ 4,282 $ 4,338 $ 739 $ 728 Actual return on plan assets 254 375 46 67 Participant contributions — — 36 42 Employer contributions 119 29 76 65 Benefits paid (429) (436) (155) (163) Acquired through business combinations 21 — — — Foreign currency exchange (1) — — — Effect of settlement (9) (24) — — Fair value of plan assets — end of year $ 4,237 $ 4,282 $ 742 $ 739 Funded status $ (11) $ (289) $ (405) $ (297) Amounts recognized in Statements of Financial Position: Non-current assets $ 239 $ 137 $ 188 $ 192 Current liabilities 1 (7) (18) (85) (76) Non-current liabilities (243) (408) (508) (413) Total amount recognized $ (11) $ (289) $ (405) $ (297) Amounts recognized in accumulated other comprehensive loss (income): Net actuarial gain $ (400) $ (304) $ (1,720) $ (2,033) Prior service cost (credit) 89 106 (109) (131) Net amount recognized $ (311) $ (198) $ (1,829) $ (2,164) 1 Current liabilities are classified within Other current liabilities on the Statements of Consolidated Financial Position. Pension Benefits OPEB (In millions) VEBA 1 Direct Payments Total 2023 $ 29 $ — $ 65 $ 65 2024 119 — 76 76 2025 (Expected) 69 — 74 74 1 Pursuant to the applicable bargaining agreements, benefits can be paid from certain VEBAs that are at least 70% funded (all VEBAs were over 70% funded at December 31, 2024). Certain agreements with plans holding VEBA assets have capped healthcare costs. For the Cleveland-Cliffs Steel LLC VEBA, we are required to make contributions based on earnings, and we may withdraw money from the VEBA plan to the extent funds are available for costs in excess of the cap. VEBA withdrawals are represented net of direct payments. There will be no further contributions to the Cleveland-Cliffs Steel LLC VEBA based on earnings for the remainder of the labor agreement with the USW, which expires in September 2026. The following table summarizes the changes in fair value of the employee benefit commitment: (In millions) 2024 Beginning balance as of January 1 $ — Fair value of commitment assumed in connection with Stelco Acquisition (197) Total losses included in earnings (2) Payments 5 Foreign currency translation 6 Ending balance as of December 31 $ (188) The following table summarizes the changes in fair value of the MinnTac option: (In millions) 2024 Beginning balance as of January 1 $ — Fair value of option acquired in connection with Stelco Acquisition 110 Total losses included in earnings (12) Foreign currency translation (3) Ending balance as of December 31 $ 95
Components Of Net Periodic Benefit Cost	COMPONENTS OF NET PERIODIC BENEFIT COST (CREDIT) Pension Benefits OPEB (In millions) 2024 2023 2022 2024 2023 2022 Service cost $ 28 $ 31 $ 45 $ 8 $ 10 $ 35 Interest cost 218 235 144 50 64 72 Expected return on plan assets (320) (315) (355) (43) (43) (37) Amortization: Net actuarial loss (gain) (1) 3 13 (154) (145) (43) Prior service costs (credits) 18 18 5 (15) (17) (3) Settlements and special termination benefits (2) (4) (8) 2 — — Net periodic benefit cost (credit) $ (59) $ (32) $ (156) $ (152) $ (131) $ 24 For 2025, we estimate net periodic benefit cost (credit) as follows: (In millions) Defined benefit pension plans $ (70) OPEB plans (124) Total $ (194)
Components of Accumulated Other Comprehensive Income (Loss)	The following includes details on the significant actuarial losses (gains) impacting the benefit obligation and other components of other comprehensive loss (income): Pension Benefits OPEB (In millions) 2024 2023 2024 2023 Discount rates $ (146) $ 124 $ (43) $ 28 Demographic updates 1 (14) (5) 26 (208) Mortality — (2) — (11) Per capita healthcare costs and healthcare trend 2 — — 179 33 Other (5) (1) — — Actuarial loss (gain) on benefit obligation (165) 116 162 (158) Actual returns on assets under (over) expected 67 (60) (3) (24) Amortization of net actuarial gain (loss) 1 (3) 154 145 Amortization of prior service credits (costs) (18) (18) 15 17 Settlements 2 4 — — Plan amendments — 3 7 8 Total recognized in other comprehensive loss (income) $ (113) $ 42 $ 335 $ (12) 1 In 2023, the OPEB plans generated an actuarial gain relating to updates for demographic experience. We had adjustments relating to retirements, participation, persistency and census data updates. 2 The loss in per capita healthcare costs in 2024 relating to our OPEB plans is primarily due to unfavorable Medicare Advantage Prescription Drug healthcare rates, which are effective January 1, 2025. Additionally, we increased our short-term Medicare Advantage Prescription Drug trend rate assumption.
Estimated Future Benefit Payments	(In millions) Pension Benefits OPEB 1 2025 $ 472 $ 116 2026 440 114 2027 419 109 2028 405 105 2029 382 100 2030-2034 1,663 445 1 OPEB benefit payments are displayed net of participant contributions.
Defined Benefit Plan, Assumptions	The following represents weighted-average assumptions used to determine benefit obligations: Pension Benefits OPEB December 31, December 31, 2024 2023 2024 2023 Discount rate 5.55 % 5.12 % 5.59 % 5.15 % Interest crediting rate 5.58 5.46 N/A N/A Compensation rate increase 3.00 3.00 3.00 3.00 The following represents weighted-average assumptions used to determine net benefit cost: Pension Benefits OPEB December 31, December 31, 2024 2023 2022 2024 2023 2022 Obligation discount rate 5.08 % 5.47 % 3.21 % 5.15 % 5.52 % 3.33 % Service cost discount rate 5.29 5.61 3.49 5.28 5.65 3.91 Interest cost discount rate 5.05 5.34 2.75 5.08 5.38 3.01 Interest crediting rate 5.46 5.46 5.39 N/A N/A N/A Expected return on plan assets 7.85 7.66 6.87 5.95 5.87 4.86 Compensation rate increase 3.00 3.00 2.74 3.00 3.00 3.00
Assumed Health Care Cost Trend Rates	The following represents assumed weighted-average health care cost trend rates: December 31, 2024 2023 Health care cost trend rate assumed for next year 1 11.43 % 5.49 % Ultimate health care cost trend rate 4.50 % 4.50 % Year that the ultimate rate is reached 2032 2032 1 The health care trend rate is weighted for all of our OPEB plans and factors in our Medicare Advantage Prescription Drug pricing arrangements. In 2024, we maintained our assumed health care cost trend rate for self insured plans at 6.25%, which grades down on a linear basis to 4.50% by 2032. In 2024, the health care trend rate for the Medicare Advantage Prescription Drug plans assumes a 16.25% rate, which is primarily driven by our expectation that the impacts from the Inflation Reduction Act will negatively impact Medicare Advantage Prescription Drug plan costs for the next year. We assume the healthcare trend rate for the Medicare Advantage Prescription Drug plans will realign with the self insured plans after the one time increase.
Plan Assets and Asset Allocation	The following table reflects the actual asset allocations for pension and VEBA assets as of December 31, 2024 and 2023, as well as the 2025 weighted average target asset allocations: Pension Assets VEBA Assets Asset Category 2025 Actual Asset Allocation at December 31, 2025 Actual Asset Allocation at December 31, 2024 2023 2024 2023 Equity securities 34.0 % 32.7 % 32.1 % 17.2 % 17.6 % 18.4 % Fixed income 40.8 38.9 38.8 78.4 76.6 74.5 Hedge funds 9.4 9.6 9.4 1.0 1.2 1.5 Private equity 3.4 3.6 3.4 — — — Structured credit 2.5 4.0 5.1 0.3 0.5 0.9 Real estate 9.9 11.2 11.2 3.1 4.1 4.7 Total 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 %
Fair Value of Pension Assets by Asset Category	The fair value of our pension assets by asset category is as follows: (In millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Investments Measured at Net Asset Value Total Asset Category 2024 2023 2024 2023 2024 2023 2024 2023 2024 2023 Equity securities: U.S. equities $ 816 $ 809 $ — $ — $ — $ — $ — $ — $ 816 $ 809 Global equities 501 502 — — — — 69 65 570 567 Fixed income: U.S. government securities 1 32 22 577 657 — — 146 142 755 821 U.S. corporate bonds 583 587 — — — — 115 94 698 681 Non U.S. and other bonds 9 — — — — — 185 160 194 160 Hedge funds — — — — 128 118 280 285 408 403 Private equity — — — — 151 146 — — 151 146 Structured credit — — — — 171 220 — — 171 220 Real estate — — — — 242 286 232 189 474 475 Total $ 1,941 $ 1,920 $ 577 $ 657 $ 692 $ 770 $ 1,027 $ 935 $ 4,237 $ 4,282 1 Includes cash equivalents. The fair value of our VEBA assets by asset category is as follows: (In millions) Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Investments Measured at Net Asset Value Total Asset Category 2024 2023 2024 2023 2024 2023 2024 2023 2024 2023 Equity securities: U.S. equities $ 99 $ 102 $ — $ — $ — $ — $ — $ — $ 99 $ 102 Global equities 3 3 — — — — 28 30 31 33 Fixed income: U.S. government securities 1 130 119 50 27 — — 44 47 224 193 U.S. corporate bonds 216 214 74 94 — — 52 49 342 357 Non U.S. and other bonds 2 3 — — — — — — 2 3 Hedge funds — — — — 10 10 — — 10 10 Structured credit — — — — 4 7 — — 4 7 Real estate — — — — 5 10 25 24 30 34 Total $ 450 $ 441 $ 124 $ 121 $ 19 $ 27 $ 149 $ 150 $ 742 $ 739 1 Includes cash equivalents.
Effect of Fair Value Measurements Using Significant Unobservable Inputs on Changes in Plan Assets	The following represents the fair value measurements of changes in plan assets using significant unobservable inputs (Level 3): Pension Assets VEBA Assets (In millions) 2024 2023 2024 2023 Beginning balance — January 1 $ 770 $ 912 $ 27 $ 35 Actual return on plan assets: Relating to assets still held at the reporting date 18 (16) 1 2 Relating to assets sold during the period 7 10 — 1 Purchases 31 24 — — Sales (134) (160) (9) (11) Ending balance — December 31 $ 692 $ 770 $ 19 $ 27
Multiemployer Plan	Information with respect to multiemployer plans in which we participate follows: Pension Fund EIN/Pension Plan Number Pension Protection Act Zone Status 1 FIP/RP Status Pending/Implemented 2 Contributions Surcharge Imposed 3 Expiration Date of Collective Bargaining Agreement 4 2024 2023 2024 2023 2022 Steelworkers Pension Trust 23-6648508/499 Green Green No $ 117 $ 119 $ 93 No 4/1/2025 to 9/1/2026 IAM National Pension Fund’s National Pension Plan 51-6031295/002 Red Red Yes 22 23 22 Yes 5/31/2025 to 5/15/2027 Other Plans 5 1 1 — Total $ 140 $ 143 $ 115 1 The most recent Pension Protection Act zone status available in 2024 and 2023 is for each plan's year-end at December 31, 2023 and 2022. The plan's actuary certifies the zone status. Generally, plans in the red zone are less than 65% funded, plans in the yellow zone are between 65% and 80% funded, and plans in the green zone are at least 80% funded. The IAM National Pension Fund's National Pension Plan voluntarily elected to place itself in the "Red Zone" in April 2019 and has implemented a rehabilitation plan to address its underfunded status. Additional contributions will be required as part of the rehabilitation plan until the plan exits the "Red Zone". 2 The "FIP/RP Status Pending/Implemented" column indicates plans for which a financial improvement plan or a rehabilitation plan is either pending or has been implemented, as defined by ERISA. 3 The surcharge represents an additional required contribution due as a result of the critical funding status of the plan. 4 We are party to six collective bargaining agreements that require contributions to the Steelworkers Pension Trust and three collective bargaining agreements that require contributions to the IAM National Pension Fund's National Pension Plan. 5 Plans that are not individually significant to our Company are presented in aggregate.

STOCK COMPENSATION PLANS (Table

STOCK COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Total Compensation Expense Recognized for Stock-Based Compensation Awards	The following table summarizes the total compensation expense recognized for stock-based compensation awards: Year Ended December 31, (In millions, except per share amounts) 2024 2023 2022 Cost of goods sold $ (11) $ (9) $ (5) Selling, general and administrative expenses (39) (32) (23) Stock based compensation expense (50) (41) (28) Income tax benefit 13 10 7 Stock based compensation expense, net of tax $ (37) $ (31) $ (21) Decrease in basic earnings per common share $ (0.08) $ (0.06) $ (0.04) Decrease in diluted earnings per common share $ (0.08) $ (0.06) $ (0.04)
Summary of Performance Award Activity	The following table summarizes the performance award activity: 2024 2023 2022 (Shares in millions) Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Outstanding at beginning of year 2.5 $ 29.09 2.7 $ 18.53 2.4 $ 14.04 Granted 1.2 30.36 1.1 31.88 1.0 28.46 Distributed (0.5) 25.12 (1.8) 6.50 (1.1) 17.04 Performance adjustment (0.1) 25.12 0.7 6.43 0.5 17.84 Forfeited/canceled (0.1) 30.57 (0.2) 28.65 (0.1) 23.74 Outstanding at end of year 3.0 $ 30.33 2.5 $ 29.09 2.7 $ 18.53
Summary of Restricted Stock Unit Activity	The following table summarizes the restricted stock units activity: 2024 2023 2022 (Shares in millions) Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Outstanding at beginning of year 2.5 $ 18.87 2.4 $ 13.66 2.1 $ 10.31 Granted 1.2 19.54 1.2 19.30 1.0 19.41 Distributed (0.6) 17.55 (0.9) 5.99 (0.6) 10.47 Forfeited/canceled — 19.62 (0.2) 19.84 (0.1) 17.82 Outstanding at end of year 3.1 $ 19.40 2.5 $ 18.87 2.4 $ 13.66
Summary of Stock Option Activity	The following table summarizes the stock option activity: 2024 2023 2022 (Shares in millions) Number of Shares Weighted Average Exercise Price Number of Shares Weighted Average Exercise Price Number of Shares Weighted Average Exercise Price Outstanding at beginning of year 0.5 $ 9.59 0.6 $ 10.39 1.0 $ 12.75 Exercised (0.3) 7.79 (0.1) 10.22 (0.3) 16.55 Forfeited/canceled — 20.11 — 21.05 (0.1) 22.78 Outstanding at end of year 0.2 $ 11.77 0.5 $ 9.59 0.6 $ 10.39 Exercisable at end of year 0.2 $ 11.77 0.5 $ 9.59 0.6 $ 10.52

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of Income (Loss) From Continuing Operations Before Income Taxes, Domestic and Foreign	Income (loss) from continuing operations before income taxes includes the following components: Year Ended December 31, (In millions) 2024 2023 2022 United States $ (894) $ 600 $ 1,803 Foreign (49) (3) (7) Total $ (943) $ 597 $ 1,796
Components of the Income Tax Provision (Benefit) on Continuing Operations	The components of the income tax expense (benefit) from continuing operations consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 Current provision: United States federal $ (38) $ 4 $ 201 United States state & local (6) 26 131 Foreign 3 4 1 (41) 34 333 Deferred provision (benefit): United States federal (152) 97 117 United States state & local (33) 7 (22) Foreign (9) 10 (5) Total income tax expense (benefit) from continuing operations $ (235) $ 148 $ 423 The components of income taxes for other than continuing operations consisted of the following: (In millions) 2024 2023 2022 Other comprehensive income (loss): Pension and OPEB $ 55 $ 10 $ (425) Derivative instruments (37) 47 26 Total $ 18 $ 57 $ (399)
Reconciliation of Income Tax Attributable to Continuing Operations Computed at Statutory Rate	Reconciliation of our income tax attributable to continuing operations computed at the U.S. federal statutory rate is as follows: (In millions) 2024 2023 2022 Tax at U.S. statutory rate $ (198) 21 % $ 125 21 % $ 377 21 % Increase (decrease) due to: Percentage depletion in excess of cost depletion (20) 2 (32) (5) (49) (3) Valuation allowance — — 14 2 — — Unrecognized tax benefits 7 — 7 1 2 — State taxes, net (30) 3 28 5 71 4 Federal & state provision to return (4) — (20) (3) 27 1 Income not subject to tax (10) 1 (11) (2) (9) — Goodwill impairment — — 26 4 — — Other items, net 20 (2) 11 2 4 — Provision for income tax expense (benefit) and effective income tax rate including discrete items $ (235) 25 % $ 148 25 % $ 423 23 %
Significant Components of Deferred Tax Assets and Liabilities	Significant components of our deferred tax assets and liabilities are as follows: (In millions) 2024 2023 Deferred tax assets: Operating loss and other carryforwards $ 589 $ 390 Pension and OPEB liabilities 129 155 Environmental 69 67 Product inventories 53 92 State and local 36 9 Lease liabilities 87 79 Other liabilities 151 180 Total deferred tax assets before valuation allowance 1,114 972 Deferred tax asset valuation allowance (388) (396) Net deferred tax assets 726 576 Deferred tax liabilities: Investment in ventures (181) (192) Lease assets (88) (79) Property, plant and equipment and mineral rights (811) (837) Intangible assets (441) (27) Other assets (59) (76) Total deferred tax liabilities (1,580) (1,211) Net deferred tax liabilities $ (854) $ (635)
Summary of Changes in the Valuation Allowance	The changes in the valuation allowance are presented below: (In millions) 2024 2023 2022 Balance at beginning of year $ 396 $ 390 $ 409 Change in valuation allowance: Income tax (benefit) expense (8) 6 (19) Balance at end of year $ 388 $ 396 $ 390
Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: (In millions) 2024 2023 2022 Unrecognized tax benefits balance as of January 1 $ 76 $ 58 $ 35 Increases for tax positions in current year 46 18 24 Decrease due to tax positions in prior year (1) — (1) Unrecognized tax benefits balance as of December 31 $ 121 $ 76 $ 58

LEASE OBLIGATIONS (Tables)

LEASE OBLIGATIONS (Tables)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Summary of Lease Amounts Included in Statements of Consolidated Financial Position	The following table summarizes the lease amounts included in our Statements of Consolidated Financial Position as of December 31, 2024 and 2023: Year Ended December 31, (In millions) Balance Sheet Location 2024 2023 Assets: Finance Property, plant and equipment, net $ 505 $ 306 Operating Other non-current assets 351 228 Current liabilities Finance Other current liabilities $ 63 $ 49 Operating Other current liabilities 50 41 Non-current liabilities Finance Other non-current liabilities $ 319 $ 166 Operating Other non-current liabilities 275 197
Summary of Lease Costs	Lease costs are presented below: Year Ended December 31, (In millions) 2024 2023 2022 Operating leases $ 64 $ 59 $ 64 Finance leases: Amortization of right-of-use assets 38 92 103 Interest on lease liabilities 15 11 8 Short-term leases 174 171 160 Total $ 291 $ 333 $ 335 Lease terms and discount rates are shown below: December 31, 2024 Weighted average lease term (in years): Operating leases 11 Finance leases 9 Weighted average discount rate: Operating leases 7 % Finance leases 6 % Other information related to leases was as follows: Year Ended December 31, (In millions) 2024 2023 2022 Cash paid for amounts included in measurement of lease liabilities: Operating leases within cash flows from operating activities $ 62 $ 57 $ 62 Finance leases within cash flows from operating activities 14 11 8 Finance leases within cash flows from financing activities 49 92 96 Right-of-use assets obtained in exchange for new finance lease liabilities 1 97 93 55 Right-of-use assets obtained in exchange for new operating lease liabilities 1 87 42 31 1 Right-of-use assets obtained as a result of the Stelco Acquisition are not included.
Summary of Future Minimum Lease Payments under Noncancelable Finance and Operating Leases	The following is a summary of future minimum lease payments under noncancellable finance and operating leases as of December 31, 2024: (In millions) Finance Leases Operating Leases 2025 $ 81 $ 68 2026 71 61 2027 58 57 2028 56 47 2029 52 38 Thereafter 193 188 Total future minimum lease payments 511 459 Less: imputed interest 129 134 Total lease payments 382 325 Less: current portion of lease liabilities 63 50 Long-term lease liabilities $ 319 $ 275

ASSET RETIREMENT OBLIGATIONS (T

ASSET RETIREMENT OBLIGATIONS (Tables)	12 Months Ended
	Dec. 31, 2024
Environmental Remediation Obligations [Abstract]
Schedule of Asset Retirement Obligations	The following is a summary of our asset retirement obligations: December 31, (In millions) 2024 2023 Asset retirement obligations 1 $ 526 $ 459 Less: current portion 25 15 Long-term asset retirement obligations $ 501 $ 444 1 Includes $302 million and $259 million related to our active operations as of December 31, 2024 and 2023, respectively.
Roll-forward of Asset Retirement Obligation Liability	The following is a roll-forward of our asset retirement obligation: (In millions) 2024 2023 Asset retirement obligation as of January 1 $ 459 $ 520 Increase from Stelco Acquisition 20 — Decrease from sale of business — (76) Accretion expense 22 26 Remediation payments (33) (21) Revision in estimated cash flows 58 10 Asset retirement obligation as of December 31 $ 526 $ 459
Schedule of Environmental Obligations	The following is a summary of our environmental obligations: December 31, (In millions) 2024 2023 Environmental obligations $ 114 $ 134 Less: current portion 14 21 Long-term environmental obligations $ 100 $ 113

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Summary of Carrying Value and Fair Value of Other Financial Instruments	The following table summarizes the carrying value and fair value of other financial instruments: December 31, 2024 December 31, 2023 (In millions) Classification Carrying Fair Value Carrying Fair Value Senior notes Level 1 $ 5,505 $ 5,496 $ 3,137 $ 3,118 ABL Facility - outstanding balance Level 2 1,560 1,560 — — Total $ 7,065 $ 7,056 $ 3,137 $ 3,118
Schedule of Defined Benefit Plans Disclosures	The following tables and information provide additional disclosures: (In millions) Pension Benefits OPEB Change in benefit obligations: 2024 2023 2024 2023 Benefit obligations — beginning of year $ 4,571 $ 4,646 $ 1,036 $ 1,233 Service cost 28 31 8 10 Interest cost 218 235 50 64 Plan amendments — 3 7 8 Actuarial loss (gain) (165) 116 162 (158) Benefits paid (429) (436) (155) (163) Participant contributions — — 36 42 Acquired through business combinations 35 — — — Foreign currency exchange (1) — — — Effect of settlement (9) (24) — — Other — — 3 — Benefit obligations — end of year $ 4,248 $ 4,571 $ 1,147 $ 1,036 Change in plan assets: Fair value of plan assets — beginning of year $ 4,282 $ 4,338 $ 739 $ 728 Actual return on plan assets 254 375 46 67 Participant contributions — — 36 42 Employer contributions 119 29 76 65 Benefits paid (429) (436) (155) (163) Acquired through business combinations 21 — — — Foreign currency exchange (1) — — — Effect of settlement (9) (24) — — Fair value of plan assets — end of year $ 4,237 $ 4,282 $ 742 $ 739 Funded status $ (11) $ (289) $ (405) $ (297) Amounts recognized in Statements of Financial Position: Non-current assets $ 239 $ 137 $ 188 $ 192 Current liabilities 1 (7) (18) (85) (76) Non-current liabilities (243) (408) (508) (413) Total amount recognized $ (11) $ (289) $ (405) $ (297) Amounts recognized in accumulated other comprehensive loss (income): Net actuarial gain $ (400) $ (304) $ (1,720) $ (2,033) Prior service cost (credit) 89 106 (109) (131) Net amount recognized $ (311) $ (198) $ (1,829) $ (2,164) 1 Current liabilities are classified within Other current liabilities on the Statements of Consolidated Financial Position. Pension Benefits OPEB (In millions) VEBA 1 Direct Payments Total 2023 $ 29 $ — $ 65 $ 65 2024 119 — 76 76 2025 (Expected) 69 — 74 74 1 Pursuant to the applicable bargaining agreements, benefits can be paid from certain VEBAs that are at least 70% funded (all VEBAs were over 70% funded at December 31, 2024). Certain agreements with plans holding VEBA assets have capped healthcare costs. For the Cleveland-Cliffs Steel LLC VEBA, we are required to make contributions based on earnings, and we may withdraw money from the VEBA plan to the extent funds are available for costs in excess of the cap. VEBA withdrawals are represented net of direct payments. There will be no further contributions to the Cleveland-Cliffs Steel LLC VEBA based on earnings for the remainder of the labor agreement with the USW, which expires in September 2026. The following table summarizes the changes in fair value of the employee benefit commitment: (In millions) 2024 Beginning balance as of January 1 $ — Fair value of commitment assumed in connection with Stelco Acquisition (197) Total losses included in earnings (2) Payments 5 Foreign currency translation 6 Ending balance as of December 31 $ (188) The following table summarizes the changes in fair value of the MinnTac option: (In millions) 2024 Beginning balance as of January 1 $ — Fair value of option acquired in connection with Stelco Acquisition 110 Total losses included in earnings (12) Foreign currency translation (3) Ending balance as of December 31 $ 95

DERIVATIVE INSTRUMENTS AND HE_2

DERIVATIVE INSTRUMENTS AND HEDGING (Tables)	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Notional Amount of Outstanding Hedge Contracts	The following table presents the notional amount of our outstanding commodity purchase swaps: Notional Amount December 31, Commodity Purchase Swaps Unit of Measure Maturity Dates 2024 2023 Natural Gas MMBtu January 2025 - August 2027 143,250,000 168,590,000 Electricity Megawatt hours January 2025 - October 2027 3,224,227 3,501,898
Schedule Of Derivative Instruments In Statement Of Financial Position, Fair Value	The following table presents the fair value of our cash flow hedges and the classification on the Statements of Consolidated Financial Position: December 31, Balance Sheet Location (In millions) 2024 2023 Other current assets $ 5 $ — Other non-current assets 9 1 Other current liabilities (41) (105) Other non-current liabilities (6) (52)

ACCUMULATED OTHERCOMPREHENSIVE

ACCUMULATED OTHERCOMPREHENSIVE INCOME (LOSS) (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Components of Accumulated Other Comprehensive Income (Loss)	The components of Accumulated other comprehensive income within Cliffs shareholders’ equity and related tax effects allocated to each are shown below: December 31, (In millions) 2024 2023 2022 Foreign Currency Translation Beginning balance $ — $ (1) $ 1 Other comprehensive income (loss) before reclassifications (70) 1 (2) Ending balance $ (70) $ — $ (1) Derivative Instruments Beginning balance $ (170) $ (16) $ 68 Other comprehensive income (loss) before reclassifications (41) (345) 146 Income tax 10 81 (33) Other comprehensive income (loss) before reclassifications, net of tax (31) (264) 113 Losses (gains) reclassified from AOCI to net income 1 195 144 (256) Income tax expense (benefit) 2 (47) (34) 59 Net losses (gains) reclassified from AOCI to net income 148 110 (197) Ending balance $ (53) $ (170) $ (16) Pension and OPEB Beginning balance $ 1,827 $ 1,847 $ 549 Other comprehensive income (loss) before reclassifications 4 (68) 115 1,759 Income tax 17 (39) (434) Other comprehensive income (loss) before reclassifications, net of tax (51) 76 1,325 Gains reclassified from AOCI to net income 3 (154) (145) (36) Income tax expense 2 38 49 9 Net gains reclassified from AOCI to net income (116) (96) (27) Ending balance $ 1,660 $ 1,827 $ 1,847 Total AOCI Ending Balance $ 1,537 $ 1,657 $ 1,830 1 Amounts recognized in Cost of goods sold in the Statements of Consolidated Operations. 2 Amounts recognized in Income tax benefit (expense) in the Statements of Consolidated Operations. 3 Amounts recognized in Net periodic benefit credits other than service cost component in the Statements of Consolidated Operations. 4 Refer to NOTE 9 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information.

VARIABLE INTEREST ENTITIES (Tab

VARIABLE INTEREST ENTITIES (Tables)	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Variable Interest Entities	The Statements of Consolidated Financial Position includes the following amounts for SunCoke Middletown: December 31, (In millions) 2024 2023 Inventories $ 27 $ 29 Property, plant and equipment, net 288 288 Accounts payable (19) (26) Other assets (liabilities), net (47) (39) Noncontrolling interests (249) (252)

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share Computation	The following table summarizes the computation of basic and diluted EPS: Year Ended December 31, (In millions, except per share amounts) 2024 2023 2022 Income (loss) from continuing operations $ (708) $ 449 $ 1,373 Income from continuing operations attributable to noncontrolling interest (46) (51) (41) Net income (loss) from continuing operations attributable to Cliffs shareholders (754) 398 1,332 Income from discontinued operations, net of tax — 1 3 Net income (loss) attributable to Cliffs shareholders $ (754) $ 399 $ 1,335 Weighted average number of shares: Basic 480 510 519 Convertible senior notes — — 2 Employee stock plans — 1 3 Diluted 480 511 524 Earnings (loss) per common share attributable to Cliffs common shareholders - basic: Continuing operations $ (1.57) $ 0.78 $ 2.57 Discontinued operations — — — $ (1.57) $ 0.78 $ 2.57 Earnings (loss) per common share attributable to Cliffs common shareholders - diluted: Continuing operations $ (1.57) $ 0.78 $ 2.55 Discontinued operations — — — $ (1.57) $ 0.78 $ 2.55
Schedule of Potentially Dilutive Shares Excluded from the Computation of Diluted Earnings Per Share	The following table summarizes the potentially dilutive shares that were excluded from the computation of diluted earnings per share because their effect would have been anti-dilutive: Year Ended December 31, (In millions) 2024 2023 2022 Employee stock plans 2 2 —

COMMITMENT AND CONTINGENCIES (T

COMMITMENT AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Unrecorded Unconditional Purchase Obligations Disclosure	Unconditional purchase obligations, including take-or-pay agreements, are as follows (in millions): 2025 2026 2027 2028 2029 Thereafter $ 3,073 $ 1,618 $ 1,439 $ 1,044 $ 913 $ 4,694
Schedule of Environmental Obligations	The following is a summary of our environmental obligations: December 31, (In millions) 2024 2023 Environmental obligations $ 114 $ 134 Less: current portion 14 21 Long-term environmental obligations $ 100 $ 113

BASIS OF PRESENTATION AND SIG_4

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Nov. 01, 2024 $ / shares shares	Dec. 31, 2024 USD ($) employee segment	Nov. 01, 2024 $ / shares	Dec. 31, 2023 USD ($)
Basis of Presentation and Significant Accounting Policies [Line Items]
Number of employees | employee		30,000
Number of operating segments		4
Number of reportable segments		1
Stelco Holdings Inc
Basis of Presentation and Significant Accounting Policies [Line Items]
Share price (in dollars per share) | (per share)	$ 60		$ 13.27
Common stock per share | shares	25,862,021
Business Acquisition, Shares Exchange Ratio	0.454
Stelco Holdings Inc | Stelco Holdings Inc
Basis of Presentation and Significant Accounting Policies [Line Items]
Share price (in dollars per share) | $ / shares	$ 60
Other non-current assets
Basis of Presentation and Significant Accounting Policies [Line Items]
Investment in affiliates | $		$ 131		$ 123

BASIS OF PRESENTATION AND SIG_5

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Depreciation Methods and Useful Lives (Details)	Dec. 31, 2024
Land improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life	20 years
Land improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life	45 years
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Useful life	20 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Useful life	45 years
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	45 years

SUPPLEMENTART FINANCIAL STATEME

SUPPLEMENTART FINANCIAL STATEMENT INFORMATION - Supply Finance Program (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Other current liabilities
Supplier Finance Program, Obligation [Roll Forward]
Supplier Finance Program, Obligation, Addition	$ 230
Supplier Finance Program, Obligation, Settlement	(222)
Accounts Payable
Supplier Finance Program, Obligation [Roll Forward]
Supplier Finance Program, Obligation, Addition	375
Supplier Finance Program, Obligation, Settlement	(390)
Accounts Payable
Supplier Finance Program, Obligation [Roll Forward]
Supplier Finance Program, Obligation, Beginning Balance	91
Supplier Finance Program, Obligation, Ending Balance	$ 76
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]	Accounts payable	Accounts payable
Other current liabilities
Supplier Finance Program, Obligation [Roll Forward]
Supplier Finance Program, Obligation, Beginning Balance	$ 21
Supplier Finance Program, Obligation, Ending Balance	$ 29
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities

SUPPLEMENTARY FINANCIAL STATE_3

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Inventory (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Disclosure Text Block [Abstract]
Finished and semi-finished goods	$ 2,393	$ 2,573
Raw materials	2,208	1,476
Total product inventories	4,601	4,049
Manufacturing supplies and critical spares	493	411
Inventories	5,094	4,460
Excess of current cost over LIFO cost of iron ore inventories	142	131
Effect of inventory build	$ 64	$ 21

SUPPLEMENTARY FINANCIAL STATE_4

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Noncash or Part Noncash Acquisitions [Line Items]
Proceeds related to sale of business	$ 35
Capital additions	817	$ 785	$ 1,033
Non-cash accruals	(47)	(13)	35
Equipment financed with seller	72	59	0
Right-of-use assets - finance leases	97	93	55
Cash paid for capital expenditures including deposits	695	646	943
Proceeds from government grant reimbursements	8	13	27
Income taxes paid	17	94	334
Income tax refunds	(47)	(205)	(3)
Interest paid on debt obligations net of capitalized interest	255	256	249
Interest capitalized	15	$ 12	$ 9
Other current liabilities
Noncash or Part Noncash Acquisitions [Line Items]
Supplier Finance Program, Obligation, Addition	230
Supplier Finance Program, Obligation, Settlement	(222)
Accounts Payable
Noncash or Part Noncash Acquisitions [Line Items]
Supplier Finance Program, Obligation, Addition	375
Supplier Finance Program, Obligation, Settlement	(390)
Other Operating Income (Expense)
Noncash or Part Noncash Acquisitions [Line Items]
Gain on sale of business	$ 63

SUPPLEMENTARY FINANCIAL STATE_5

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Non-cash Investing and Financing Activities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Noncash or Part Noncash Acquisitions [Line Items]
1.500% 2025 Convertible Senior Notes redemption	$ 0	$ 0	$ 25
Stelco Holdings Inc
Noncash or Part Noncash Acquisitions [Line Items]
Other Significant Noncash Transaction, Value of Consideration Given, Common Shares	$ (343)

SUPPLEMENTARY FINANCIAL STATE_6

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Restructuring (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve		$ 71	$ 0
Restructuring, Settlement and Impairment Provisions		210
Payments for Restructuring		60
Restructuring Reserve, Settled without Cash		79
Restructuring Charges		129	0	$ 0
Restructuring Costs and Asset Impairment Charges		210
Restructuring and Related Cost, Expected Cost Remaining		0
OPEB
Restructuring Cost and Reserve [Line Items]
Defined Benefit Plan, Other Cost (Credit)		2
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve		56	0
Restructuring, Settlement and Impairment Provisions		82
Payments for Restructuring		26
Restructuring Reserve, Settled without Cash		0
Other Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve		15	0
Restructuring, Settlement and Impairment Provisions		49
Payments for Restructuring		34
Asset Impairments
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve		0	$ 0
Restructuring, Settlement and Impairment Provisions	$ 79	79
Payments for Restructuring		0
Restructuring Reserve, Settled without Cash		$ 79

ACQUISITIONS - Consideration (D

ACQUISITIONS - Consideration (Details) $ / shares in Units, $ / shares in Units, $ in Millions, $ in Millions	Nov. 01, 2024 USD ($)	Nov. 01, 2024 CAD ($) $ / shares	Nov. 18, 2021 USD ($)	Dec. 31, 2024 shares	Nov. 01, 2024 USD ($) $ / shares shares	Dec. 31, 2023 shares	Dec. 31, 2022 shares	Dec. 31, 2021 shares
Business Acquisition [Line Items]
Common shares, outstanding (in shares)				493,948,905		504,886,773
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				200,000		500,000	600,000	1,000,000
Stelco Holdings Inc
Business Acquisition [Line Items]
Total cash consideration	$ 2,450	$ 3,418
Total share exchange consideration	343	343
Total debt consideration | $					$ 415
Total purchase consideration | $			$ 3,208
Common shares, outstanding (in shares)					54,448,388
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number					2,516,415
Total consideration shares					56,964,803
Foreign Currency Exchange Rate, Translation					0.7168
Share price (in dollars per share) | (per share)		$ 60			$ 13.27
Business Acquisition, Shares Exchange Ratio	0.454	0.454

ACQUISITIONS - Preliminary Purc

ACQUISITIONS - Preliminary Purchase Price Allocation (Details) - USD ($) $ in Millions	Dec. 31, 2024	Nov. 01, 2024	Dec. 31, 2023
Business Acquisition [Line Items]
Goodwill	$ 1,768		$ 1,005
Stelco Holdings Inc
Business Acquisition [Line Items]
Cash and cash equivalents		$ 341
Accounts receivable		104
Inventories		726
Other current assets		107
Property, plant and equipment		1,286
Intangible assets		1,025
Other non-current assets		250
Accounts payable		(212)
Accrued employment costs		(29)
Accrued expenses		6
Other current liabilities		(71)
Pension and OPEB liability, non-current		14
Deferred income taxes		449
Asset retirement and environmental obligations		20
Other non-current liabilities		(616)
Net identifiable assets acquired		2,422
Goodwill		786
Total net assets acquired		$ 3,208

ACQUISITIONS - Intangible Asset

ACQUISITIONS - Intangible Assets and Liabilities (Details) - Stelco Holdings Inc $ in Millions	Nov. 01, 2024 USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 1,025
Weighted average life, finite-lived intangible assets	15 years
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 953
Weighted average life, finite-lived intangible assets	15 years
Trade names and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 72
Weighted average life, finite-lived intangible assets	15 years

ACQUISITIONS - Pro Forma (Detai

ACQUISITIONS - Pro Forma (Details) - Stelco Holdings Inc - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues	$ 20,874	$ 24,158
Business Acquisition, Pro Forma Net Income (Loss)	$ (623)	$ 216

ACQUISITIONS - Stelco Acquisiti

ACQUISITIONS - Stelco Acquisition (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Acquisition related costs	$ 42
Revenues	19,185	$ 21,996	$ 22,989
Net loss attributable to acquisition	(754)	399	$ 1,335
Stelco Holdings Inc
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	(623)	216
Revenues	329
Net loss attributable to acquisition	58
Stelco Holdings Inc | Fair Value Adjustment to Inventory
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	23	23
Stelco Holdings Inc | Acquisition-related Costs
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	$ 63	$ 63

REVENUES - By Market and Produc

REVENUES - By Market and Product Line (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 19,185	$ 21,996	$ 22,989
Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	18,620	21,413	22,462
Steelmaking | Third Party
Disaggregation of Revenue [Line Items]
Revenues	18,529	21,331	22,383
Steelmaking | Hot-rolled steel
Disaggregation of Revenue [Line Items]
Revenues	4,276	4,864	4,529
Steelmaking | Cold-rolled steel
Disaggregation of Revenue [Line Items]
Revenues	2,712	2,658	3,193
Steelmaking | Coated steel
Disaggregation of Revenue [Line Items]
Revenues	5,773	6,661	6,905
Steelmaking | Stainless and electrical steel
Disaggregation of Revenue [Line Items]
Revenues	1,807	2,281	2,284
Steelmaking | Plate
Disaggregation of Revenue [Line Items]
Revenues	1,119	1,444	1,651
Steelmaking | Slab and other steel products
Disaggregation of Revenue [Line Items]
Revenues	1,178	1,329	1,492
Steelmaking | Other
Disaggregation of Revenue [Line Items]
Revenues	1,664	2,094	2,329
Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	656	665	606
Other Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues	656	665	606
Automotive | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	5,571	7,440	6,661
Automotive | Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	540	545	478
Infrastructure and manufacturing | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	5,208	5,612	5,869
Infrastructure and manufacturing | Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	39	38	52
Distributors and converters | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	5,281	5,330	6,388
Distributors and converters | Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	77	82	76
Steel producers | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	$ 2,469	$ 2,949	$ 3,465

SEGMENT REPORTING - Schedule Of

SEGMENT REPORTING - Schedule Of Segment Reporting Information, By Segment (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment	4
Number of reportable segments | segment	1
Revenues	$ 19,185	$ 21,996	$ 22,989
Income from continuing operations attributable to noncontrolling interest	46	51	41
Net periodic benefit credits other than service cost component	247	204	212
Adjusted EBITDA	780	1,911	3,169
Net income (loss)	(708)	450	1,376
Segment Reporting, Other Segment Item, Amount	(2)	(80)	(130)
Adjusted EBITDA Calculation
Segment Reporting Information [Line Items]
Income from continuing operations attributable to noncontrolling interest			41
Steelmaking
Segment Reporting Information [Line Items]
Revenues	18,620	21,413	22,462
Net periodic benefit credits other than service cost component	247	204	212
Adjusted EBITDA	722	1,873	3,089
Segment Reporting, Other Segment Item, Amount	(2)	(78)	(136)
Other Businesses
Segment Reporting Information [Line Items]
Revenues	656	665	606
Net periodic benefit credits other than service cost component	0	0	0
Adjusted EBITDA	53	43	69
Segment Reporting, Other Segment Item, Amount	0	(2)	6
Eliminations
Segment Reporting Information [Line Items]
Revenues	(91)	(82)	(79)
Net periodic benefit credits other than service cost component	0	0	0
Adjusted EBITDA	5	(5)	11
Segment Reporting, Other Segment Item, Amount	$ 0	$ 0	$ 0

SEGMENT REPORTING - Reconciliat

SEGMENT REPORTING - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 19,185	$ 21,996	$ 22,989
Cost of goods sold	19,115	20,605	20,471
Selling, general and administrative expenses	486	577	465
Net periodic benefit credits other than service cost component	(247)	(204)	(212)
Segment Reporting, Other Segment Item, Amount	(2)	(80)	(130)
Adjusted EBITDA	780	1,911	3,169
Interest expense, net	(370)	(289)	(276)
Income tax benefit (expense)	235	(148)	(423)
Depreciation, depletion and amortization	(951)	(973)	(1,034)
Restructuring Costs and Asset Impairment Charges	210
Loss on extinguishment of debt	(27)	0	(75)
Capital additions	817	785	1,033
Net income (loss)	(708)	450	1,376
Income from continuing operations attributable to noncontrolling interest	46	51	41
Steelmaking
Segment Reporting Information [Line Items]
Revenues	18,620	21,413	22,462
Cost of goods sold	18,605	20,055	20,004
Selling, general and administrative expenses	457	549	439
Net periodic benefit credits other than service cost component	(247)	(204)	(212)
Segment Reporting, Other Segment Item, Amount	(2)	(78)	(136)
Adjusted EBITDA	722	1,873	3,089
Depreciation, depletion and amortization	(919)	(938)	(994)
Capital additions	812	782	1,003
Other Businesses
Segment Reporting Information [Line Items]
Revenues	656	665	606
Cost of goods sold	606	627	557
Selling, general and administrative expenses	29	28	26
Net periodic benefit credits other than service cost component	0	0	0
Segment Reporting, Other Segment Item, Amount	0	(2)	6
Adjusted EBITDA	53	43	69
Depreciation, depletion and amortization	(32)	(35)	(40)
Capital additions	5	3	30
Eliminations
Segment Reporting Information [Line Items]
Revenues	(91)	(82)	(79)
Cost of goods sold	(96)	(77)	(90)
Selling, general and administrative expenses	0	0	0
Net periodic benefit credits other than service cost component	0	0	0
Segment Reporting, Other Segment Item, Amount	0	0	0
Adjusted EBITDA	5	(5)	11
Depreciation, depletion and amortization	0	0	0
Capital additions	0	0	0
EBITDA Calculation
Segment Reporting Information [Line Items]
Interest expense, net	(370)	(289)	(276)
Income tax benefit (expense)	235	(148)	(423)
Depreciation, depletion and amortization	(951)	(973)	(1,034)
EBITDA of noncontrolling interests	76	83	74
Restructuring Costs and Asset Impairment Charges	(217)
Acquisition-related costs	(44)	(12)	(1)
Unrealized Gain (Loss) on Derivatives and Commodity Contracts	(41)
Amortization Of Inventory Step-Up	(26)
Expenses and Losses, Reporting Currency Denominated, Value	(20)
Gain (Loss) on Disposition of Other Assets	(16)	(15)	(22)
Other, net	(16)	18	(36)
Net income (loss)		450
Income from continuing operations attributable to noncontrolling interest	46	51
Depreciation, Depletion And Amortization Attributable To Noncontrolling Interests	30	$ 32
Adjusted EBITDA Calculation
Segment Reporting Information [Line Items]
Litigation Settlement, Amount Awarded to Other Party	(71)
Loss on extinguishment of debt	$ (27)		(75)
Income from continuing operations attributable to noncontrolling interest			41
Depreciation, Depletion And Amortization Attributable To Noncontrolling Interests			$ 33

SEGMENT REPORTING - Depreciatio

SEGMENT REPORTING - Depreciation, Depletion and Amortization and Capital Additions By Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	$ (951)	$ (973)	$ (1,034)
Capital additions	817	785	1,033
Steelmaking
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	(919)	(938)	(994)
Capital additions	812	782	1,003
Other Businesses
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	(32)	(35)	(40)
Capital additions	5	3	30
Eliminations
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	0	0	0
Capital additions	$ 0	$ 0	$ 0

SEGMENT REPORTING - Summary of

SEGMENT REPORTING - Summary of Assets by Segment (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Assets	$ 20,947	$ 17,537	$ 18,755
Steelmaking
Segment Reporting Information [Line Items]
Assets	20,327	16,880	17,918
Other Businesses
Segment Reporting Information [Line Items]
Assets	620	657	837
Eliminations
Segment Reporting Information [Line Items]
Assets	$ 0	$ 0	$ 0

SEGMENTS REPORTING - Revenues a

SEGMENTS REPORTING - Revenues and Property, Plant and Equipment, Net by Geographical Location (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 19,185	$ 21,996	$ 22,989
Property, plant and equipment, net	9,942	8,895	9,070
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	17,340	20,000	20,991
Property, plant and equipment, net	8,622	8,816	8,981
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	1,067	1,046	963
Property, plant and equipment, net	1,319	78	88
Other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	778	950	1,035
Property, plant and equipment, net	$ 1	$ 1	$ 1

PROPERTY, PLANT AND EQUIPMENT -

PROPERTY, PLANT AND EQUIPMENT - Value Of Each Of The Major Classes Of Consolidated Depreciable Assets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 14,751	$ 12,907
Allowance for depreciation and depletion	(4,809)	(4,012)
Property, plant and equipment, net	9,942	8,895	$ 9,070
Right-of-use assets related to finance leases	$ 505	$ 306
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net	Property, plant and equipment, net
Land, land improvements and mineral rights
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,451	$ 1,389
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,104	946
Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,119	9,680
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	349	302
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 728	$ 590

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation	$ 903	$ 932	$ 988
Depletion	29	33	38
Property, plant and equipment, net	9,942	8,895	$ 9,070
Right-of-use assets related to finance leases	505	306
Operating lease, right-of-use asset	351	228
Finance	63	49
Operating	50	41
Finance	319	166
Operating	$ 275	197
Middletown
Property, Plant and Equipment [Line Items]
Accelerated depreciation		23
Indiana Harbor
Property, Plant and Equipment [Line Items]
Accelerated depreciation		$ 68

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT - Book Value of Land and Mineral Rights Disclosure (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Mineral rights:
Cost	$ 783	$ 783
Depletion	(287)	(258)
Net mineral rights	496	525
Land rights	$ 467	$ 427

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES - Goodwill (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Goodwill [Line Items]
Goodwill	$ 1,768	$ 1,005
Steelmaking
Goodwill [Line Items]
Goodwill	1,719	956
Other Businesses
Goodwill [Line Items]
Goodwill	$ 49	$ 49

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES - Intangibles (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 1,263	$ 269
Finite-Lived Intangible Assets, Accumulated Amortization	(93)	(68)
Finite-Lived Intangible Assets, Net	1,170	201
Finite-Lived Intangible Liability, Gross	(71)	(71)
Finite-Lived Intangible Liability, Accumulated Amortization	30	24
Finite-Lived Intangible Liability, Net	(41)	(47)
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	1,015	90
Finite-Lived Intangible Assets, Accumulated Amortization	(34)	(18)
Finite-Lived Intangible Assets, Net	981	72
Developed technology
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	60	60
Finite-Lived Intangible Assets, Accumulated Amortization	(17)	(14)
Finite-Lived Intangible Assets, Net	43	46
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	87	18
Finite-Lived Intangible Assets, Accumulated Amortization	(8)	(5)
Finite-Lived Intangible Assets, Net	79	13
Mining permits
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	72	72
Finite-Lived Intangible Assets, Accumulated Amortization	(29)	(28)
Finite-Lived Intangible Assets, Net	43	44
Supplier Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	29	29
Finite-Lived Intangible Assets, Accumulated Amortization	(5)	(3)
Finite-Lived Intangible Assets, Net	$ 24	$ 26

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 24	$ 13
Expected asset amortization, year one	79
Expected asset amortization, year two	79
Expected asset amortization, year three	79
Expected asset amortization, year four	79
Expected asset amortization, year five	79
Amortization of intangible liability	(5)	$ (5)
Expected liability amortization, year one	(5)
Expected liability amortization, year two	(5)
Expected liability amortization, year three	(5)
Expected liability amortization, year four	(5)
Expected liability amortization, year five	$ (5)

DEBT AND CREDIT FACILITIES - Sc

DEBT AND CREDIT FACILITIES - Schedule Of Long-Term Debt (Details) - USD ($) $ in Millions				12 Months Ended
	Aug. 16, 2024	Apr. 03, 2024	Mar. 18, 2024	Dec. 31, 2024	Oct. 22, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total debt				$ 7,148		$ 3,192
Unamortized discounts and issuance costs				(83)		(55)
Total long-term debt				$ 7,065		3,137
6.750% 2026 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				6.75%
Annual Effective Interest Rate				6.99%
Total debt				$ 0		829
Extinguishment of Debt, Amount		$ 189	$ 640
7.000% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				7%
Annual Effective Interest Rate				9.24%
Total debt				$ 73		73
7.000% 2027 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage				101.167%
7.000% 2027 AK Senior Notes | AK Steel
Debt Instrument [Line Items]
Stated interest rate				7%
Annual Effective Interest Rate				9.24%
Total debt				$ 56		56
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				5.875%
Annual Effective Interest Rate				6.49%
Total debt				$ 556		556
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage				100.979%
4.625% 2029 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				4.625%
Annual Effective Interest Rate				4.625%
Total debt				$ 368		368
6.750% 2030 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				6.75%
Annual Effective Interest Rate				6.75%
Total debt				$ 750		750
6.750% 2030 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage				100%
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				4.875%
Annual Effective Interest Rate				4.875%
Total debt				$ 325		325
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				6.25%
Annual Effective Interest Rate				6.34%
Total debt				$ 235		$ 235
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage				100%
ABL Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding				$ 1,560
ABL Facility | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Annual Effective Interest Rate						5.829%
Credit facility, amount outstanding				$ 1,560		$ 0
6.875% 2029 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Annual Effective Interest Rate					6.875%
Total debt					$ 900	0
6.875% 2029 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage				100%
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				7%
Annual Effective Interest Rate				7.054%
Total debt	$ 600		$ 825	$ 1,425		0
DebtInstrumentIssuePriceAsAPercentageOfFaceAmount	99.25%
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage				100%
7.375% 2033 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Annual Effective Interest Rate					7.375%
Total debt					$ 900	$ 0
7.375% 2033 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage				100%

DEBT AND CREDIT FACILITIES - De

DEBT AND CREDIT FACILITIES - Debt Issuances and Terms (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) Days day	Oct. 22, 2024 USD ($)	Aug. 16, 2024 USD ($)	Mar. 18, 2024 USD ($)	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Total debt	$ 7,148				$ 3,192
6.750% 2026 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	6.75%
Total debt	$ 0				829
6.750% 2030 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	6.75%
Total debt	$ 750				750
6.750% 2030 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage	100%
6.750% 2030 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	103.375%
6.750% 2030 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One, Upon Equity Issuance
Debt Instrument [Line Items]
Redemption price, percentage	106.75%
Restricted Amount (percent of original aggregate principal)	35%
6.750% 2030 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price, percentage	101.688%
7.000% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	7%
Total debt	$ 73				73
7.000% 2027 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage	101.167%
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	5.875%
Total debt	$ 556				556
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage	100.979%
4.625% 2029 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	4.625%
Total debt	$ 368				368
4.625% 2029 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	102.313%
4.625% 2029 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price, percentage	101.156%
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	4.875%
Total debt	$ 325				325
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	102.438%
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One, Upon Equity Issuance
Debt Instrument [Line Items]
Redemption price, percentage	104.875%
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price, percentage	101.625%
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Four
Debt Instrument [Line Items]
Redemption price, percentage	100.813%
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	6.25%
Total debt	$ 235				235
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc. | Minimum
Debt Instrument [Line Items]
Redemption notice period | day	30
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc. | Maximum
Debt Instrument [Line Items]
Redemption notice period | day	60
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage	100%
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	0.40%
Unsecured Debt | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs	101%
7.000% 2027 AK Senior Notes | AK Steel
Debt Instrument [Line Items]
Stated interest rate	7%
Total debt	$ 56				56
7.000% 2027 AK Senior Notes | AK Steel | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	101.167%
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	7%
Repurchase price if triggering event occurs	101%
Total debt	$ 1,425		$ 600	$ 825	0
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc. | Minimum
Debt Instrument [Line Items]
Redemption notice period | Days	10
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage	100%
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	103.50%
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One, Upon Equity Issuance
Debt Instrument [Line Items]
Redemption price, percentage	107%
Restricted Amount (percent of original aggregate principal)	35%
7.000% 2032 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price, percentage	101.75%
6.875% 2029 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs	10,100%
Total debt		$ 900			0
6.875% 2029 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage	100%
6.875% 2029 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	103.438%
6.875% 2029 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One, Upon Equity Issuance
Debt Instrument [Line Items]
Redemption price, percentage	106.875%
Restricted Amount (percent of original aggregate principal)	35%
7.375% 2033 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs	10,100%
Total debt		$ 900			$ 0
7.375% 2033 Senior Notes | Cleveland-Cliffs Inc. | Minimum
Debt Instrument [Line Items]
Redemption notice period | Days	10
7.375% 2033 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage	100%
7.375% 2033 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage	103.688%
7.375% 2033 Senior Notes | Cleveland-Cliffs Inc. | Debt Instrument, Redemption, Period One, Upon Equity Issuance
Debt Instrument [Line Items]
Redemption price, percentage	107.375%
Restricted Amount (percent of original aggregate principal)	35%

DEBT AND CREDIT FACILITIES - AB

DEBT AND CREDIT FACILITIES - ABL Facility (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)	Sep. 13, 2024 USD ($)
ABL Facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	$ 4,750
Available borrowing base on ABL Facility	4,158
Borrowings and Letter of credit obligations	(1,560)
Borrowing capacity available	$ 2,536
ABL Facility | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 4,750
Minimum fixed charge coverage ratio	1
Line of Credit Facility, Maximum Borrowing Capacity, Tranche A		4,250
Line of Credit Facility, Maximum Borrowing Capacity, Tranche B		$ 500
Letter of Credit
Line of Credit Facility [Line Items]
Borrowings and Letter of credit obligations	$ (62)

DEBT AND CREDIT FACILITIES - _2

DEBT AND CREDIT FACILITIES - Schedule of Debt Instrument Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Disclosure [Abstract]
2025	$ 0
2026	0
2027	685
2028	1,560
2029	1,268
Thereafter	3,635
Long-term Debt	$ 7,148	$ 3,192

PENSION AND OTHER POSTRETIREMEN

PENSION AND OTHER POSTRETIREMENT BENEFITS - Obligations and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Amounts recognized in Statements of Financial Position:
Pension and OPEB assets	$ 427	$ 329
Non-current liabilities	(751)	(821)
Amounts recognized in accumulated other comprehensive loss (income):
Accumulated benefit obligation	4,236	4,557
Pension Benefits
Change in benefit obligations:
Benefit obligations — beginning of year	4,571	4,646
Service cost	28	31	$ 45
Interest cost	218	235	144
Plan amendments	0	3
Actuarial loss (gain)	(165)	116
Benefits paid	(429)	(436)
Participant contributions	0	0
Acquired through business combinations	35	0
Foreign currency exchange	(1)	0
Effect of settlement	(9)	(24)
Other	0	0
Benefit obligations — end of year	4,248	4,571	4,646
Change in plan assets:
Fair value of plan assets — beginning of year	4,282	4,338
Actual return on plan assets	254	375
Participant contributions	0	0
Employer contributions	119	29
Benefits paid	(429)	(436)
Acquired through business combinations	21	0
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	(1)	0
Effect of settlement	(9)	(24)
Fair value of plan assets — end of year	4,237	4,282	4,338
Funded status	(11)	(289)
Amounts recognized in Statements of Financial Position:
Pension and OPEB assets	239	137
Current liabilities	(7)	(18)
Non-current liabilities	(243)	(408)
Total amount recognized	(11)	(289)
Amounts recognized in accumulated other comprehensive loss (income):
Net actuarial gain	(400)	(304)
Prior service cost (credit)	89	106
Net amount recognized	(311)	(198)
Pension Benefits | Stelco Holdings Inc
Change in benefit obligations:
Benefit obligations — end of year	14
OPEB
Change in benefit obligations:
Benefit obligations — beginning of year	1,036	1,233
Service cost	8	10	35
Interest cost	50	64	72
Plan amendments	7	8
Actuarial loss (gain)	162	(158)
Benefits paid	(155)	(163)
Participant contributions	36	42
Acquired through business combinations	0	0
Foreign currency exchange	0	0
Effect of settlement	0	0
Other	3	0
Benefit obligations — end of year	1,147	1,036	1,233
Change in plan assets:
Fair value of plan assets — beginning of year	739	728
Actual return on plan assets	46	67
Participant contributions	36	42
Employer contributions	76	65
Benefits paid	(155)	(163)
Acquired through business combinations	0	0
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	0	0
Effect of settlement	0	0
Fair value of plan assets — end of year	742	739	$ 728
Funded status	(405)	(297)
Amounts recognized in Statements of Financial Position:
Pension and OPEB assets	188	192
Current liabilities	(85)	(76)
Non-current liabilities	(508)	(413)
Total amount recognized	(405)	(297)
Amounts recognized in accumulated other comprehensive loss (income):
Net actuarial gain	(1,720)	(2,033)
Prior service cost (credit)	(109)	(131)
Net amount recognized	$ (1,829)	$ (2,164)

PENSIONS AND OTHER POSTRETIRE_3

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Components Of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Amortization:
Net periodic benefit cost (credit)	$ (247)	$ (204)	$ (212)
Defined Benefit Plan, Expected Amounts [Abstract]
Estimated net periodic benefit cost	(194)
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	28	31	45
Interest cost	218	235	144
Expected return on plan assets	(320)	(315)	(355)
Amortization:
Net actuarial loss (gain)	(1)	3	13
Prior service costs (credits)	18	18	5
Settlements and special termination benefits	(2)	(4)	(8)
Net periodic benefit cost (credit)	(59)	(32)	(156)
Defined Benefit Plan, Expected Amounts [Abstract]
Estimated net periodic benefit cost	(70)
OPEB
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	8	10	35
Interest cost	50	64	72
Expected return on plan assets	(43)	(43)	(37)
Amortization:
Net actuarial loss (gain)	(154)	(145)	(43)
Prior service costs (credits)	(15)	(17)	(3)
Settlements and special termination benefits	2	0	0
Net periodic benefit cost (credit)	(152)	$ (131)	$ 24
Defined Benefit Plan, Expected Amounts [Abstract]
Estimated net periodic benefit cost	$ (124)

PENSION AND POST RETIREMENT BEN

PENSION AND POST RETIREMENT BENEFITS - Components of Accumulated Other Comprehensive Loss (Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	$ (113)	$ 42
Actual returns on assets under (over) expected	67	(60)
Amortization of net actuarial gain (loss)	1	(3)
Amortization of prior service credits (costs)	(18)	(18)
Settlements	2	4
Plan amendments	0	3
OPEB
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	335	(12)
Actual returns on assets under (over) expected	(3)	(24)
Amortization of net actuarial gain (loss)	154	145
Amortization of prior service credits (costs)	15	17
Settlements	0	0
Plan amendments	7	8
Discount rates | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(146)	124
Discount rates | OPEB
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(43)	28
Demographic updates | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(14)	(5)
Demographic updates | OPEB
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	26	(208)
Mortality | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	0	(2)
Mortality | OPEB
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	0	(11)
Per capita healthcare costs | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	0	0
Per capita healthcare costs | OPEB
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	179	33
Other | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(5)	(1)
Other | OPEB
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	0	0
Actuarial loss (gain) on benefit obligation | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(165)	116
Actuarial loss (gain) on benefit obligation | OPEB
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	$ 162	$ (158)

PENSIONS AND OTHER POSTRETIRE_4

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Contributions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	$ 119	$ 29
Pension benefits, employer contributions and payments	119
Expected employer contributions, next fiscal year	69
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	76	65
Employer contributions	76	65
Expected employer contributions, next fiscal year	74
OPEB | VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	0	0
Expected employer contributions, next fiscal year	0
OPEB | Direct Payments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	76	$ 65
Expected employer contributions, next fiscal year	$ 74

PENSION AND OTHER POSTRETIREM_2

PENSION AND OTHER POSTRETIREMENT BENEFITS - Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2024 USD ($)
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025	$ 472
2026	440
2027	419
2028	405
2029	382
2030-2034	1,663
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025	116
2026	114
2027	109
2028	105
2029	100
2030-2034	$ 445

PENSIONS AND OTHER POSTRETIRE_5

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Weighted-Average Assumptions Used to Determine Benefit Obligations (Details)	Dec. 31, 2024	Dec. 31, 2023
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	5.55%	5.12%
Interest crediting rate	5.58%	5.46%
Rate of compensation increase	3%	3%
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	5.59%	5.15%
Rate of compensation increase	3%	3%

PENSIONS AND OTHER POSTRETIRE_6

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Weighted-Average Assumptions Used to Determine Net Benefit Cost (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Obligation discount rate	5.08%	5.47%	3.21%
Service cost discount rate	5.29%	5.61%	3.49%
Interest cost discount rate	5.05%	5.34%	2.75%
Interest crediting rate	5.46%	5.46%	5.39%
Expected return on plan assets	7.85%	7.66%	6.87%
Compensation rate increase	3%	3%	2.74%
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Obligation discount rate	5.15%	5.52%	3.33%
Service cost discount rate	5.28%	5.65%	3.91%
Interest cost discount rate	5.08%	5.38%	3.01%
Expected return on plan assets	5.95%	5.87%	4.86%
Compensation rate increase	3%	3%	3%

PENSIONS AND OTHER POSTRETIRE_7

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Assumed Health Care Cost Trend Rates (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Postemployment Benefits [Abstract]
Health care cost trend rate assumed for next year	11.43%	5.49%
Ultimate health care cost trend rate	4.50%	4.50%
Year that the ultimate rate is reached	2032	2032

PENSIONS AND OTHER POSTRETIRE_8

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Narrative (Details) $ in Millions	Dec. 31, 2024 USD ($)
Private equity | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Reserve for investment commitments	$ 47

PENSIONS AND OTHER POSTRETIRE_9

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Target Allocation and Actual Asset Allocations for Pension and VEBA Plan Assets (Details)	Dec. 31, 2024	Dec. 31, 2023
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	100%
Percentage of Plan Assets	100%	100%
Pension Benefits | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	34%
Percentage of Plan Assets	32.70%	32.10%
Pension Benefits | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	40.80%
Percentage of Plan Assets	38.90%	38.80%
Pension Benefits | Hedge funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	9.40%
Percentage of Plan Assets	9.60%	9.40%
Pension Benefits | Private equity
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	3.40%
Percentage of Plan Assets	3.60%	3.40%
Pension Benefits | Structured credit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	2.50%
Percentage of Plan Assets	4%	5.10%
Pension Benefits | Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	9.90%
Percentage of Plan Assets	11.20%	11.20%
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	100%
Percentage of Plan Assets	100%	100%
OPEB | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	17.20%
Percentage of Plan Assets	17.60%	18.40%
OPEB | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	78.40%
Percentage of Plan Assets	76.60%	74.50%
OPEB | Hedge funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	1%
Percentage of Plan Assets	1.20%	1.50%
OPEB | Private equity
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	0%
Percentage of Plan Assets	0%	0%
OPEB | Structured credit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	0.30%
Percentage of Plan Assets	0.50%	0.90%
OPEB | Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2025 Target Allocation	3.10%
Percentage of Plan Assets	4.10%	4.70%

PENSIONS AND OTHER POSTRETIR_10

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	$ 4,237	$ 4,282	$ 4,338
OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	742	739	728
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	1,941	1,920
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	450	441
Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	577	657
Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	124	121
Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	692	770	$ 912
Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	19	27
Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	1,027	935
Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	149	150
U.S. equities | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	816	809
U.S. equities | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	99	102
U.S. equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	816	809
U.S. equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	99	102
U.S. equities | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. equities | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. equities | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. equities | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. equities | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. equities | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Global equities | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	570	567
Global equities | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	31	33
Global equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	501	502
Global equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	3	3
Global equities | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Global equities | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Global equities | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Global equities | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Global equities | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	69	65
Global equities | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	28	30
U.S. government securities | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	755	821
U.S. government securities | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	224	193
U.S. government securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	32	22
U.S. government securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	130	119
U.S. government securities | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	577	657
U.S. government securities | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	50	27
U.S. government securities | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. government securities | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. government securities | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	146	142
U.S. government securities | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	44	47
U.S. corporate bonds | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	698	681
U.S. corporate bonds | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	342	357
U.S. corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	583	587
U.S. corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	216	214
U.S. corporate bonds | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. corporate bonds | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	74	94
U.S. corporate bonds | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. corporate bonds | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. corporate bonds | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	115	94
U.S. corporate bonds | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	52	49
Non U.S. and other bonds | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	194	160
Non U.S. and other bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	9	0
Non U.S. and other bonds | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Non U.S. and other bonds | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Non U.S. and other bonds | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	185	160
Hedge funds | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	408	403
Hedge funds | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	10	10
Hedge funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Hedge funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Hedge funds | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Hedge funds | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Hedge funds | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	128	118
Hedge funds | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	10	10
Hedge funds | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	280	285
Hedge funds | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Private equity | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	151	146
Private equity | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Private equity | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Private equity | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	151	146
Private equity | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Structured credit | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	171	220
Structured credit | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	4	7
Structured credit | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Structured credit | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Structured credit | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Structured credit | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Structured credit | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	171	220
Structured credit | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	4	7
Structured credit | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Structured credit | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Debt Security, Corporate, Non-US | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	2	3
Debt Security, Corporate, Non-US | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	2	3
Debt Security, Corporate, Non-US | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Debt Security, Corporate, Non-US | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Debt Security, Corporate, Non-US | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Real estate | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	474	475
Real estate | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	30	34
Real estate | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Real estate | Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Real estate | Significant  Other Observable Inputs (Level 2) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Real estate | Significant  Other Observable Inputs (Level 2) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Real estate | Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	242	286
Real estate | Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	5	10
Real estate | Investments Measured at Net Asset Value | Pension Benefits
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	232	189
Real estate | Investments Measured at Net Asset Value | OPEB
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	$ 25	$ 24

PENSIONS AND POSTRETIREMENT BEN

PENSIONS AND POSTRETIREMENT BENEFITS - Fair Value Measurements Using Significant Unobservable Inputs (Level 3) on Changes in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	$ 4,282	$ 4,338
Actual return on plan assets:
Fair value of plan assets — end of year	4,237	4,282
Pension Benefits | Private equity
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	146
Actual return on plan assets:
Fair value of plan assets — end of year	151	146
OPEB
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	739	728
Actual return on plan assets:
Fair value of plan assets — end of year	742	739
Significant Unobservable Inputs (Level 3) | Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	770	912
Actual return on plan assets:
Relating to assets still held at the reporting date	18	(16)
Relating to assets sold during the period	7	10
Purchases	31	24
Sales	(134)	(160)
Fair value of plan assets — end of year	692	770
Significant Unobservable Inputs (Level 3) | Pension Benefits | Private equity
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	146
Actual return on plan assets:
Fair value of plan assets — end of year	151	146
Significant Unobservable Inputs (Level 3) | OPEB
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	27
Actual return on plan assets:
Fair value of plan assets — end of year	19	27
Significant Unobservable Inputs (Level 3) | OPEB | VEBA Assets
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	27	35
Actual return on plan assets:
Relating to assets still held at the reporting date	1	2
Relating to assets sold during the period	0	1
Purchases	0	0
Sales	(9)	(11)
Fair value of plan assets — end of year	$ 19	$ 27

PENSIONS AND OTHER POSTRETIR_11

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Defined Contribution Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Postemployment Benefits [Abstract]
Defined contribution pension plans	$ 63	$ 59	$ 52

PENSIONS AND OTHER POSTRETIR_12

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Multiemployer Plan (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Multiemployer Plan [Line Items]
Contributions	$ 140	$ 143	$ 115
Steelworkers Pension Trust
Multiemployer Plan [Line Items]
Pension Plan EIN	236648508
Pension Plan Number	499
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending/Implemented	No
Contributions	$ 117	$ 119	93
Surcharge Imposed	No
Total actuarial liability		6,562
Market value of assets		$ 6,494
Funded ratio		0.99
IAM National Pension Fund's National Pension Plan
Multiemployer Plan [Line Items]
Pension Plan EIN	516031295
Pension Plan Number	002
Pension Protection Act Zone Status	Red	Red
FIP/RP Status Pending/Implemented	Implemented
Contributions	$ 22	$ 23	22
Surcharge Imposed	Yes
Other Plans
Multiemployer Plan [Line Items]
Contributions	$ 1	$ 1	$ 0

STOCK COMPENSATION PLANS - Narr

STOCK COMPENSATION PLANS - Narrative (Details) shares in Millions	Dec. 31, 2024 shares
2021 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	20.9

STOCK COMPENSATION PLANS - Stoc

STOCK COMPENSATION PLANS - Stock-Based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs and Expenses	$ (50)	$ (41)	$ (28)
Income tax benefit	13	10	7
Stock based compensation expense, net of tax	$ (37)	$ (31)	$ (21)
Decrease in basic earnings per common share (in dollars per share)	$ (1.57)	$ 0.78	$ 2.57
Decrease in diluted earnings per common share (in dollars per share)	$ (1.57)	0.78	2.55
Compensation cost related to outstanding awards not yet recognized	$ 60
Expected period of recognition for outstanding awards not yet recognized	1 year 8 months 12 days
Share-based Payment Arrangement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Decrease in basic earnings per common share (in dollars per share)	$ (0.08)	(0.06)	(0.04)
Decrease in diluted earnings per common share (in dollars per share)	$ (0.08)	$ (0.06)	$ (0.04)
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs and Expenses	$ (11)	$ (9)	$ (5)
Selling, general and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs and Expenses	$ (39)	$ (32)	$ (23)

STOCK COMPENSATION PLANS - Perf

STOCK COMPENSATION PLANS - Performance Shares (Details) - Performance Shares - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)	2.5	2.7	2.4
Outstanding at beginning of year, weighted average grant date fair value (in dollars per share)	$ 29.09	$ 18.53	$ 14.04
Granted (in shares)	1.2	1.1	1
Granted, weighted average grant date fair value (in dollars per share)	$ 30.36	$ 31.88	$ 28.46
Distributed (in shares)	(0.5)	(1.8)	(1.1)
Distributed, weighted average grant date fair value (in dollars per share)	$ 25.12	$ 6.50	$ 17.04
Performance adjustment (in shares)	(0.1)	0.7	0.5
Performance adjustment, weighted average grant date fair value (in dollars per share)	$ 25.12	$ 6.43	$ 17.84
Forfeited/canceled (in shares)	(0.1)	(0.2)	(0.1)
Forfeited/canceled, weighted average grant date fair value (in dollars per share)	$ 30.57	$ 28.65	$ 23.74
Outstanding at end of year (in shares)	3	2.5	2.7
Outstanding at end of year, weighted average grant date fair value (in dollars per share)	$ 30.33	$ 29.09	$ 18.53
Performance/vesting period	3 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Percent of shares actually earned based on performance	0%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Percent of shares actually earned based on performance	200%

STOCK COMPENSATION PLANS - Rest

STOCK COMPENSATION PLANS - Restricted Stock (Details) - Restricted Stock Units (RSUs) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)	2.5	2.4	2.1
Outstanding at beginning of year, weighted average grant date fair value (in dollars per share)	$ 18.87	$ 13.66	$ 10.31
Granted (in shares)	1.2	1.2	1
Granted, weighted average grant date fair value (in dollars per share)	$ 19.54	$ 19.30	$ 19.41
Distributed (in shares)	(0.6)	(0.9)	(0.6)
Distributed, weighted average grant date fair value (in dollars per share)	$ 17.55	$ 5.99	$ 10.47
Forfeited/canceled (in shares)	0	(0.2)	(0.1)
Forfeited/canceled, weighted average grant date fair value (in dollars per share)	$ 19.62	$ 19.84	$ 17.82
Outstanding at end of year (in shares)	3.1	2.5	2.4
Outstanding at end of year, weighted average grant date fair value (in dollars per share)	$ 19.40	$ 18.87	$ 13.66
Performance/vesting period	3 years

STOCK COMPENSATION PLANS - St_2

STOCK COMPENSATION PLANS - Stock Options (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)	0.5	0.6	1
Outstanding at beginning of year, weighted average exercise price (in dollars per share)	$ 9.59	$ 10.39	$ 12.75
Exercised (in shares)	(0.3)	(0.1)	(0.3)
Exercised, weighted average exercise price (in dollars per share)	$ 7.79	$ 10.22	$ 16.55
Forfeited/canceled (in shares)	0	0	(0.1)
Forfeitured/canceled, weighted average exercise price (in dollars per share)	$ 20.11	$ 21.05	$ 22.78
Outstanding at end of year (in shares)	0.2	0.5	0.6
Outstanding at end of year, weighted average exercise price (in dollars per share)	$ 11.77	$ 9.59	$ 10.39
Exercisable (in shares)	0.2	0.5	0.6
Exercisable, weighted average exercise price (in dollars per share)	$ 11.77	$ 9.59	$ 10.52
Intrinsic value of options exercised	$ 4	$ 1
Weighted-average remaining contractual life of options outstanding	3 years
Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Performance/vesting period	1 year
Expiration period	10 years
Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Performance/vesting period	3 years

STOCK COMPENSATION PLANS - None

STOCK COMPENSATION PLANS - Nonemployee Directors (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost related to outstanding awards not yet recognized	$ 60,000,000
Share-based Payment Arrangement, Nonemployee | Director | Directors Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost related to outstanding awards not yet recognized		$ 140,000

INCOME TAXES - Schedule of Inco

INCOME TAXES - Schedule of Income Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
United States	$ (894)	$ 600	$ 1,803
Foreign	(49)	(3)	(7)
Income (loss) from continuing operations before income taxes	$ (943)	$ 597	$ 1,796

INCOME TAXES - Schedule of Comp

INCOME TAXES - Schedule of Components of Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)	$ (38)	$ 4	$ 201
Current State and Local Tax Expense (Benefit)	(6)	26	131
Current Foreign Tax Expense (Benefit)	3	4	1
Current Income Tax Expense (Benefit)	(41)	34	333
Deferred Federal Income Tax Expense (Benefit)	(152)	97	117
Deferred State and Local Income Tax Expense (Benefit)	(33)	7	(22)
Deferred Foreign Income Tax Expense (Benefit)	(9)	10	(5)
Income Tax Expense (Benefit)	$ (235)	$ 148	$ 423

INCOME TAXES - Schedule of Effe

INCOME TAXES - Schedule of Effective Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax at U.S. statutory rate	$ (198)	$ 125	$ 377
Percentage depletion in excess of cost depletion	(20)	(32)	(49)
Valuation allowance	0	14	0
Unrecognized tax benefits	7	7	2
State taxes, net	(30)	28	71
Federal & state provision to return	(4)	(20)	27
Income not subject to tax	(10)	(11)	(9)
Goodwill impairment	0	26	0
Other items, net	20	11	4
Income Tax Expense (Benefit)	$ (235)	$ 148	$ 423
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax at U.S. statutory rate, percent	21%	21%	21%
Percentage depletion in excess of depletion, percent	2%	(5.00%)	(3.00%)
Valuation Allowance, percent	0%	2%	0%
Unrecognized Tax Benefits, Percent	0%	1%	0%
State taxes, net, percent	3%	5%	4%
Federal & state provision to return, percent	0%	(3.00%)	1%
Income not subject to tax, Percent	1%	(2.00%)	0%
Goodwill impairment, percent	0%	4%	0%
Other items, net, percent	(2.00%)	2%	0%
Provision for income tax expense (benefit) and effective income tax rate including discrete items (percent)	25%	25%	23%

INCOME TAXES - Components of In

INCOME TAXES - Components of Income Taxes for Other than Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Other comprehensive income (loss), Pension and OPEB	$ 55	$ 10	$ (425)
Other comprehensive income (loss), Derivative financial instruments	(37)	47	26
Other comprehensive income (loss), Total	$ 18	$ 57	$ (399)

INCOME TAXES - Schedule of Defe

INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Operating loss and other carryforwards	$ 589	$ 390
Pension and OPEB liabilities	129	155
Environmental	69	67
Product inventories	53	92
State and local	36	9
Lease liabilities	87	79
Other liabilities	151	180
Total deferred tax assets before valuation allowance	1,114	972
Deferred tax asset valuation allowance	(388)	(396)	$ (390)	$ (409)
Net deferred tax assets	726	576
Deferred tax liabilities:
Investment in ventures	(181)	(192)
Lease assets	(88)	(79)
Property, plant and equipment and mineral rights	(811)	(837)
Intangible assets	(441)	(27)
Other assets	(59)	(76)
Total deferred tax liabilities	(1,580)	(1,211)
Net deferred tax liabilities	$ (854)	$ (635)

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Valuation Allowance [Line Items]
Domestic operating loss carryforward	$ 3,549,000,000	$ 1,704,000,000
Foreign operating loss carryforward	1,507,000,000	1,452,000,000
Interest expense limitation carryforward	92,000,000
Deferred tax asset valuation allowance	388,000,000	396,000,000	$ 390,000,000	$ 409,000,000
Undistributed earnings of foreign subsidiaries	0	0
Valuation allowance	0	14,000,000	$ 0
Foreign Tax Jurisdiction
Valuation Allowance [Line Items]
Deferred tax asset valuation allowance	349,000,000	356,000,000
Valuation allowance		14,000,000
State and Local Jurisdiction
Valuation Allowance [Line Items]
Deferred tax asset valuation allowance	$ 39,000,000	$ 40,000,000

INCOME TAXES Income Taxes - Sch

INCOME TAXES Income Taxes - Schedule of Valuation Allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Valuation Allowance [Line Items]
Balance at beginning of year	$ 396	$ 390	$ 409
Balance at end of year	388	396	390
Included in income tax expense (benefit)
Valuation Allowance [Line Items]
Change in valuation allowance	$ (8)	$ 6	$ (19)

INCOME TAXES - Schedule of Unre

INCOME TAXES - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Unrecognized Tax Benefits [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance	$ 76	$ 58	$ 35
Increases for tax positions in current year	46	18	24
Decrease due to tax positions in prior year	(1)	0	(1)
Unrecognized Tax Benefits, Ending Balance	121	76	$ 58
Interest and penalties related to unrecognized tax benefits	7
Other non-current liabilities
Unrecognized Tax Benefits [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance	76
Unrecognized Tax Benefits, Ending Balance	121	$ 76
Other Liabilities
Unrecognized Tax Benefits [Roll Forward]
Unrecognized tax benefits that would impact effective tax rate	$ 75

LEASE OBLIGATIONS - Lease Amoun

LEASE OBLIGATIONS - Lease Amounts Included in Statements of Consolidated Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Right-of-use assets related to finance leases	$ 505	$ 306
Operating lease, right-of-use asset	351	228
Current liabilities
Finance	63	49
Operating	50	41
Non-current liabilities
Finance	319	166
Operating	$ 275	$ 197
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net	Property, plant and equipment, net
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other non-current assets	Other non-current assets
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities	Other non-current liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities	Other non-current liabilities

LEASE OBLIGATIONS - Lease Costs

LEASE OBLIGATIONS - Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating leases	$ 64	$ 59	$ 64
Finance leases, Amortization of lease cost	38	92	103
Finance leases, Interest on lease liabilities	15	11	8
Short-term leases	174	171	160
Total	$ 291	$ 333	$ 335

LEASE OBLIGATIONS - Other Infor

LEASE OBLIGATIONS - Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	11 years
Finance Lease, Weighted Average Remaining Lease Term	9 years
Operating Lease, Weighted Average Discount Rate, Percent	7%
Finance Lease, Weighted Average Discount Rate, Percent	6%
Operating leases within cash flows from operating activities	$ 62	$ 57	$ 62
Finance leases within cash flows from operating activities	14	11	8
Finance leases within cash flows from financing activities	49	92	96
Right-of-use assets obtained in exchange for new finance lease liabilities	97	93	55
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 87	$ 42	$ 31

LEASE OBLIGATIONS - Future Mini

LEASE OBLIGATIONS - Future Minimum Lease Payments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Finance Lease, Liability, Payments, Due in Next Rolling Twelve Months	$ 81
Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months	68
Finance Lease, Liability, Payments, Due in Rolling Year Two	71
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Two	61
Finance Lease, Liability, Payments, Due in Rolling Year Three	58
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Three	57
Finance Lease, Liability, Payments, Due in Rolling Year Four	56
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Four	47
Finance Lease, Liability, Payments, Due in Rolling Year Five	52
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Five	38
Finance Lease, Liability, Payments, Due in Rolling after Year Five	193
Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five	188
Finance Lease, Liability, Payment, Due	511
Lessee, Operating Lease, Liability, to be Paid	459
Finance Lease, Liability, Undiscounted Excess Amount	129
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	134
Finance Lease, Liability	382
Operating Lease, Liability	325
Finance	63	$ 49
Finance	319	166
Operating	50	41
Operating	$ 275	$ 197
Finance Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities	Other non-current liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities	Other non-current liabilities

ASSET RETIREMENT OBLIGATIONS -

ASSET RETIREMENT OBLIGATIONS - Summary Of Asset Retirement Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Environmental Remediation Obligations [Abstract]
Asset Retirement Obligation	$ 526	$ 459	$ 520
Less: current portion	25	15
Long-term asset retirement obligations	501	444
Total Segment Assets
Environmental Exit Cost [Line Items]
Asset retirement obligations related to active operations	$ 302	$ 259

ASSET RETIREMENT OBLIGATIONS _2

ASSET RETIREMENT OBLIGATIONS - Asset Retirement Obligation Roll-forward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Asset Retirement Obligation [Roll Forward]
Asset Retirement Obligation at Beginning of Year	$ 459	$ 520
Increase from Stelco Acquisition	20	0
Decrease from sale of business	0	(76)
Accretion expense	22	26
Remediation payments	(33)	(21)
Revision in estimated cash flows	58	10
Asset Retirement Obligation at End of Year	$ 526	$ 459

ASSET RETIREMENT OBLIGATIONS _3

ASSET RETIREMENT OBLIGATIONS - Summary of Environmental Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Environmental Remediation Obligations [Abstract]
Accrual for Environmental Loss Contingencies, Total	$ 114	$ 134
Accrued Environmental Loss Contingencies, Current	14	21
Accrued Environmental Loss Contingencies, Noncurrent	$ 100	$ 113
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Environmental Loss Contingency, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other non-current liabilities	Other non-current liabilities

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Carrying Value And Fair Value Of Financial Instruments Disclosure (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	$ 7,065	$ 3,137
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	7,056	3,118
Senior notes | Carrying Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	5,505	3,137
Senior notes | Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	5,496	3,118
Line of Credit | Carrying Value | Significant  Other Observable Inputs (Level 2) | ABL Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	1,560	0
Line of Credit | Fair Value | Significant  Other Observable Inputs (Level 2) | ABL Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	$ 1,560	$ 0

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS - Changes in Fair Value of Employee Benefit Commitment (Details) - Commitments $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance as of January 1	$ 0
Fair value of commitment assumed in connection with Stelco Acquisition	(197)
Total losses included in earnings	(2)
Payments	5
Foreign currency translation	6
Ending balance as of December 31	$ (188)

FAIR VALUE OF FINANCIAL INSTR_5

FAIR VALUE OF FINANCIAL INSTRUMENTS - Additional Information (Details) $ in Millions	Dec. 31, 2024 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Option to acquire, amount of ownership interest	25%
Commodity Option
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Option to acquire, consideration amount	$ 500

FAIR VALUE OF FINANCIAL INSTR_6

FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Derivative Asset (Details) - Commodity Option $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance as of January 1	$ 0
Fair value of option acquired in connection with Stelco Acquisition	110
Total losses included in earnings	(12)
Foreign currency translation	(3)
Ending balance as of December 31	$ 95

DERIVATIVE INSTRUMENTS AND HE_3

DERIVATIVE INSTRUMENTS AND HEDGING - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) MMBtu MWh	Dec. 31, 2023 MMBtu MWh
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Expected reclassification of net losses related to hedge contracts	$ 68
Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss on derivative	$ (29)
Commodity Contract | Natural Gas
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount | MMBtu	143,250,000	168,590,000
Commodity Contract | Electricity
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount | MWh	3,224,227	3,501,898

DERIVATIVE INSTRUMENTS AND HE_4

DERIVATIVE INSTRUMENTS AND HEDGING - Balance Sheet Location (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Other current assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	$ 5	$ 0
Other non-current assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	9	1
Other current liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative liabilities	(41)	(105)
Other non-current liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative liabilities	$ (6)	$ (52)

CAPITAL STOCK - Narrative (Deta

CAPITAL STOCK - Narrative (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Nov. 01, 2024 $ / shares shares	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Nov. 01, 2024 $ / shares	Apr. 22, 2024 USD ($)	Feb. 10, 2022 USD ($)
Class of Stock [Line Items]
Authorized amount of stock repurchase | $						$ 1,500	$ 1,000
Repurchase of common shares | $		$ 733	$ 152	$ 240
Remaining authorized purchase amount | $		$ 1,400
Common Stock
Class of Stock [Line Items]
Common stock repurchases (in shares)		37,900,000	10,400,000	12,500,000
Common Shares in Treasury
Class of Stock [Line Items]
Repurchase of common shares | $		$ 733	$ 152
Stelco Holdings Inc
Class of Stock [Line Items]
Share price (in dollars per share) | (per share)	$ 60				$ 13.27
Common stock per share	25,862,021
Acquisition (in shares)		25.9
Stock Issued During Period, Value, Acquisitions | $		$ 343
Business Acquisition, Shares Exchange Ratio	0.454
Stelco Holdings Inc | Common Stock
Class of Stock [Line Items]
Acquisition (in shares)		25,900,000
Stelco Holdings Inc | Common Shares in Treasury
Class of Stock [Line Items]
Stock Issued During Period, Value, Acquisitions | $		$ 473
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (in shares)		4,000,000
Preferred stock issued (in shares)		0
Preferred stock outstanding (in shares)		0
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (in shares)		3,000,000
Preferred stock issued (in shares)		0
Preferred stock outstanding (in shares)		0

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in AOCI (loss) related to shareholders' equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 1,657	$ 1,830
Ending balance	1,537	1,657	$ 1,830
Foreign Currency Translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	0	(1)	1
Other comprehensive income (loss) before reclassifications, net of tax	(70)	1	(2)
Ending balance	(70)	0	(1)
Derivative Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(170)	(16)	68
Other comprehensive income (loss) before reclassifications	(41)	(345)	146
Income tax	10	81	(33)
Other comprehensive income (loss) before reclassifications, net of tax	(31)	(264)	113
Losses (gains) reclassified from AOCI to net income	195	144	(256)
Income tax expense (benefit)	(47)	(34)	59
Net losses (gains) reclassified from AOCI to net income	148	110	(197)
Ending balance	(53)	(170)	(16)
Pension and OPEB
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	1,827	1,847	549
Other comprehensive income (loss) before reclassifications	(68)	115	1,759
Income tax	17	(39)	(434)
Other comprehensive income (loss) before reclassifications, net of tax	(51)	76	1,325
Losses (gains) reclassified from AOCI to net income	(154)	(145)	(36)
Income tax expense (benefit)	38	49	9
Net losses (gains) reclassified from AOCI to net income	(116)	(96)	(27)
Ending balance	$ 1,660	$ 1,827	$ 1,847

VARIABLE INTEREST ENTITIES (Det

VARIABLE INTEREST ENTITIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Variable Interest Entity [Line Items]
Income from continuing operations attributable to noncontrolling interest	$ 46	$ 51	$ 41
Cash paid for capital expenditures including deposits	695	646	943
Inventories	5,094	4,460
Property, plant and equipment, net	9,942	8,895	$ 9,070
Accounts payable	(2,008)	(2,099)
Noncontrolling interests	(233)	(235)
Variable Interest Entity, Primary Beneficiary | SunCoke Middletown
Variable Interest Entity [Line Items]
Income from continuing operations attributable to noncontrolling interest		52
Cash paid for capital expenditures including deposits	24	25
Inventories	27	29
Property, plant and equipment, net	288	288
Accounts payable	(19)	(26)
Other assets (liabilities), net	(47)	(39)
Noncontrolling interests	$ (249)	$ (252)

EARNINGS PER SHARE - Earnings P

EARNINGS PER SHARE - Earnings Per Share Computation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ (708)	$ 449	$ 1,373
Income from continuing operations attributable to noncontrolling interest	46	51	41
Net income (loss) from continuing operations attributable to Cliffs shareholders	(754)	398	1,332
Income from discontinued operations, net of tax	0	1	3
Net income (loss) attributable to Cliffs shareholders	$ (754)	$ 399	$ 1,335
Weighted average number of shares:
Basic (in shares)	480	510	519
Convertible senior notes (in shares)	0	0	2
Employee stock plans (in shares)	0	1	3
Diluted (in shares)	480	511	524
Earnings per common share attributable to Cliffs common shareholders - basic
Continuing operations (in dollars per share)	$ (1.57)	$ 0.78	$ 2.57
Discontinued operations (in dollars per share)	0	0	0
Earnings (loss) per common share attributable to Cliffs common shareholders - basic (in dollars per share)	(1.57)	0.78	2.57
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted:
Continuing operations (in dollars per share)	(1.57)	0.78	2.55
Discontinued operations (in dollars per share)	0	0	0
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted (in dollars per share)	$ (1.57)	$ 0.78	$ 2.55

EARNINGS PER SHARE - Anti-Dilut

EARNINGS PER SHARE - Anti-Dilutive Securities (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Payment Arrangement
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted earnings per share (in shares)	2	2	0

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Commitments Under Take-Or-Pay Obligations (Details) $ in Millions	Dec. 31, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2025	$ 3,073
2026	1,618
2027	1,439
2028	1,044
2029	913
Thereafter	$ 4,694

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Millions	Dec. 31, 2024 USD ($)
Letter of Credit
Other Commitments [Line Items]
Credit facility, amount outstanding	$ 62
Surety Bond
Other Commitments [Line Items]
Surety-backed letters of credit and surety bonds outstanding	$ 271

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - Senior Notes Due 2031 - Subsequent Event - Senior notes $ in Millions	Feb. 06, 2025 USD ($)
Subsequent Event [Line Items]
Debt issued	$ 850
Stated interest rate	7.50%