Cleveland-Cliffs (CLF) 10-K 11 Feb 22 2021 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 10, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
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
Entity Shell Company	false
Entity Public Float			$ 10,636,421,962
Entity Common Stock, Shares Outstanding		525,409,705
Entity Central Index Key	0000764065
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Documents Incorporated by Reference [Text Block]	Portions of the registrant’s proxy statement for its 2022 annual meeting of shareholders are incorporated by reference into Part III.

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Cleveland, Ohio

Statements of Consolidated Fina

Statements of Consolidated Financial Position - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 48	$ 112
Accounts receivable, net	2,154	1,169
Inventories	5,188	3,828
Other current assets	263	189
Total current assets	7,653	5,298
Non-current assets:
Property, plant and equipment, net	9,186	8,743
Goodwill	1,116	1,406
Other non-current assets	1,020	1,324
TOTAL ASSETS	18,975	16,771
Current liabilities:
Accounts payable	2,073	1,575
Accrued employment costs	585	460
State and local taxes	138	147
Other current liabilities	765	747
Total current liabilities	3,561	2,929
Non-current liabilities:
Long-term debt	5,238	5,390
Pension liability, non-current	578	1,224
OPEB liability, non-current	2,383	2,889
Other non-current liabilities	1,441	1,260
TOTAL LIABILITIES	13,201	13,692
Commitments and contingencies (See Note 20)
Series B Participating Redeemable Preferred Stock - no par value. Authorized, Issued and Outstanding - no shares (2020 - 583,273 shares)	0	738
Equity:
Common Shares - par value $0.125 per share, Authorized - 1,200,000,000 shares (2020 - 600,000,000 shares); Issued - 506,832,537 shares (2020 - 506,832,537) shares); Outstanding - 500,158,955 shares (2020 - 477,517,372) shares)	63	63
Capital in excess of par value of shares	4,892	5,431
Retained deficit	(1)	(2,989)
Cost of 6,673,582 common shares in treasury (2020 - 29,315,165 shares)	(82)	(354)
Accumulated other comprehensive income (loss)	618	(133)
Total Cliffs shareholders' equity	5,490	2,018
Noncontrolling interest	284	323
TOTAL EQUITY	5,774	2,341
TOTAL LIABILITIES, REDEEMABLE PREFERRED STOCK AND EQUITY	$ 18,975	$ 16,771

Statements of Consolidated Fi_2

Statements of Consolidated Financial Position (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Redeemable preferred stock, par value (in dollars per share)	$ 0	$ 0
Redeemable preferred stock, authorized (in shares)	0	583,273
Redeemable preferred stock, issued (in shares)	0	583,273
Redeemable preferred stock, outstanding (in shares)	0	583,273
Common shares, par value (in dollars per share)	$ 0.125	$ 0.125
Common shares, authorized (in shares)	1,200,000,000	600,000,000
Common shares, issued (in shares)	506,832,537	506,832,537
Common shares, outstanding (in shares)	500,158,955	477,517,372
Common shares in treasury (in shares)	6,673,582	29,315,165

Statements Of Consolidated Oper

Statements Of Consolidated Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenues	$ 20,444	$ 5,354	$ 1,990
Operating costs:
Cost of goods sold	(15,910)	(5,102)	(1,414)
Selling, general and administrative expenses	(422)	(244)	(113)
Acquisition-related costs	(20)	(90)	(7)
Miscellaneous – net	(80)	(60)	(27)
Total operating costs	(16,432)	(5,496)	(1,561)
Operating income (loss)	4,012	(142)	429
Other income (expense):
Interest expense, net	(337)	(238)	(101)
Gain (loss) on extinguishment of debt	(88)	130	(18)
Net periodic benefit credits (costs) other than service cost component	210	54	(1)
Other non-operating income	6	3	4
Total other expense	(209)	(51)	(116)
Income (loss) from continuing operations before income taxes	3,803	(193)	313
Income tax benefit (expense)	(773)	111	(18)
Income (loss) from continuing operations	3,030	(82)	295
Income (loss) from discontinued operations, net of tax	3	1	(2)
Net income (loss)	3,033	(81)	293
Income attributable to noncontrolling interest	(45)	(41)	0
Net income (loss) attributable to Cliffs shareholders	$ 2,988	$ (122)	$ 293
Earnings (loss) per common share attributable to Cliffs shareholders - basic
Continuing operations (in dollars per share)	$ 5.62	$ (0.32)	$ 1.07
Discontinued operations (in dollars per share)	0.01	0	(0.01)
Earnings (loss) per common share attributable to Cliffs common shareholders - basic (in dollars per share)	5.63	(0.32)	1.06
Earnings (loss) per common share attributable to Cliffs shareholders - diluted
Continuing operations (in dollars per share)	5.35	(0.32)	1.04
Discontinued operations (in dollars per share)	0.01	0	(0.01)
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted (in dollars per share)	$ 5.36	$ (0.32)	$ 1.03

Statements Of Consolidated Comp

Statements Of Consolidated Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 3,033	$ (81)	$ 293
Other comprehensive income (loss):
Changes in pension and OPEB, net of tax	684	181	(35)
Changes in foreign currency translation	(2)	3	0
Changes in derivative financial instruments, net of tax	69	2	0
Total other comprehensive income (loss)	751	186	(35)
Comprehensive income	3,784	105	258
Comprehensive income attributable to noncontrolling interests	(45)	(41)	0
Comprehensive income attributable to Cliffs shareholders	$ 3,739	$ 64	$ 258

Statements Of Consolidated Cash

Statements Of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
OPERATING ACTIVITIES
Net income (loss)	$ 3,033	$ (81)	$ 293
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation, depletion and amortization	897	308	85
Amortization of inventory step-up	161	96	0
Deferred income taxes	767	(101)	17
Pension and OPEB costs (credits)	(103)	(23)	20
Loss (gain) on extinguishment of debt	88	(130)	18
Other	139	(70)	93
Changes in operating assets and liabilities, net of business combination:
Receivables and other assets	(858)	(42)	255
Inventories	(1,370)	(146)	(136)
Pension and OPEB payments and contributions	(343)	(75)	(20)
Payables, accrued expenses and other liabilities	374	6	(57)
Net cash provided (used) by operating activities	2,785	(258)	568
INVESTING ACTIVITIES
Purchase of property, plant and equipment	(705)	(525)	(656)
Other investing activities	33	10	12
Net cash used by investing activities	(1,379)	(2,042)	(644)
FINANCING ACTIVITIES
Series B Redeemable Preferred Stock redemption	(1,343)	0	0
Proceeds from issuance of common shares	322	0	0
Repurchase of common shares	0	0	(253)
Proceeds from issuance of debt	1,000	1,763	721
Debt issuance costs	(20)	(76)	(7)
Repayments of debt	(1,372)	(1,023)	(729)
Borrowings under credit facilities	5,962	2,060	0
Repayments under credit facilities	(5,889)	(550)	0
Other financing activities	(130)	(115)	(126)
Net cash provided (used) by financing activities	(1,470)	2,059	(394)
Net decrease in cash and cash equivalents	(64)	(241)	(470)
Cash and cash equivalents at beginning of year	112	353	823
Cash and cash equivalents at end of year	48	112	353
Ferrous Processing and Trading
INVESTING ACTIVITIES
Payments to Acquire Businesses, Net of Cash Acquired	(761)	0	0
ArcelorMittal USA
INVESTING ACTIVITIES
Payments to Acquire Businesses, Net of Cash Acquired	54	(658)	0
AK Steel
INVESTING ACTIVITIES
Payments to Acquire Businesses, Net of Cash Acquired	$ 0	$ (869)	$ 0

Statements of Consolidated Chan

Statements of Consolidated Changes in Equity - USD ($) $ in Millions	Total	AK Steel	ArcelorMittal USA	Common Stock	Common StockAK Steel	Common StockArcelorMittal USA	Capital in Excess of Par Value of Shares	Capital in Excess of Par Value of SharesAK Steel	Capital in Excess of Par Value of SharesArcelorMittal USA	Retained Earnings (Deficit)	Common Shares in Treasury	AOCI (Loss)	Non-controlling Interest	Non-controlling InterestAK Steel	Non-controlling InterestArcelorMittal USA
Balance, beginning of period (in shares) at Dec. 31, 2018				293,000,000
Balance, beginning of period at Dec. 31, 2018	$ 424			$ 37			$ 3,917			$ (3,060)	$ (186)	$ (284)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	258									293		(35)	0
Stock and other incentive plans (in shares)				2,000,000
Stock and other incentive plans, APIC							(44)
Stock and other incentive plans	4										48
Common stock repurchases (in shares)				(24,000,000)
Common stock repurchased (value)	(253)										(253)
Common share dividends	(75)									(75)
Balance, end of period (in shares) at Dec. 31, 2019				271,000,000
Balance, end of period at Dec. 31, 2019	$ 358			$ 37			3,873			(2,842)	(391)	(319)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common share dividends (in dollars per share)	$ 0.27
Comprehensive income (loss)	$ 105									(122)		186	41
Stock and other incentive plans (in shares)				2,000,000
Stock and other incentive plans, APIC							(24)
Stock and other incentive plans	13										37
Acquisition (in shares)					127,000,000	78,000,000
Acquisition		$ 948	$ 1,003		$ 16	$ 10		$ 602	$ 980
Acquisition, Noncontrolling interest														$ 330	$ 13
Common share dividends	(25)									(25)
Net distributions to noncontrolling interests	$ (61)												(61)
Balance, end of period (in shares) at Dec. 31, 2020	477,517,372			478,000,000
Balance, end of period at Dec. 31, 2020	$ 2,341			$ 63			5,431			(2,989)	(354)	(133)	323
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common share dividends (in dollars per share)	$ 0.06
Comprehensive income (loss)	$ 3,784									2,988		751	45
Stock and other incentive plans (in shares)				2,000,000
Stock and other incentive plans, APIC							(8)
Stock and other incentive plans	20										28
Issuance of common shares (in shares)				20,000,000
Issuance of common shares	322						78				244
Series B Redeemable Preferred Stock redemption	(604)						(604)
1.500% 2025 Convertible Senior Notes redemption	(5)						(5)
Acquisition of ArcelorMittal USA - Measurement period adjustments			$ (22)												$ (22)
Net distributions to noncontrolling interests	$ (62)												(62)
Balance, end of period (in shares) at Dec. 31, 2021	500,158,955			500,000,000
Balance, end of period at Dec. 31, 2021	$ 5,774			$ 63			$ 4,892			$ (1)	$ (82)	$ 618	$ 284

BASIS OF PRESENTATION AND SIGNI

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2021
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 Cliffs is the largest flat-rolled steel producer in North America. Founded in 1847 as a mine operator, we are also the largest manufacturer of iron ore pellets in North America. We are vertically integrated from mined raw materials, direct reduced iron and ferrous scrap to primary steelmaking and downstream finishing, stamping, tooling and tubing. We serve a diverse range of markets due to our comprehensive offering of flat-rolled steel products and are the largest supplier of steel to the automotive industry in North America. Headquartered in Cleveland, Ohio, we employ approximately 26,000 people across our operations in the United States and Canada. Unless otherwise noted, discussion of our business and results of operations in this Annual Report on Form 10-K refers to our continuing operations. Acquisition of FPT On November 18, 2021, we completed the acquisition of FPT. FPT is a leading prime ferrous scrap processor in the U.S. FPT's operations consist of 22 scrap facilities located primarily in the Midwest region of the United States. 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 condensed 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. As of December 31, 2019, our 23% ownership in Hibbing was recorded as an equity method investment. As a result of the acquisition of ArcelorMittal USA, we acquired an additional 62.3% ownership interest in Hibbing. As of both December 31, 2021 and December 31, 2020, our ownership in the Hibbing joint venture was 85.3% and was fully consolidated within our operating results with a noncontrolling interest. Our investment in affiliates of $128 million and $105 million as of December 31, 2021 and 2020, 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, long-lived assets, inventory, tax assets and 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 engaged independent valuation specialists to assist with the determination of the fair value of assets acquired, liabilities assumed, noncontrolling interest, and goodwill, for the acquisitions. 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 would have 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 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. 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 in accordance with CECL. 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. Refer to NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION for further information. Derivative Financial 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 financial instruments are recognized as either assets or liabilities in 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 (loss) . Amounts recorded in Accumulated other comprehensive income (loss) 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. 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 27 years Refer to NOTE 6 - PROPERTY, PLANT AND EQUIPMENT for further information. 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, but it is assessed for impairment on an annual basis on October 1 (or more frequently if necessary). Refer to NOTE 3 - ACQUISITIONS and NOTE 7 - GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES for further information. Other Intangible Assets and Liabilities Intangible assets and liabilities are subject to periodic amortization on a straight-line basis over their estimated useful lives. Refer to NOTE 3 - ACQUISITIONS and NOTE 7 - GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES for further information. 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. For short-term leases (leases with an initial lease term of 12 months or less), right-of-use assets and lease liabilities are not recognized in the consolidated balance sheet. Operating lease expense is recognized on a straight-line basis over the lease term. Refer to NOTE 13 - LEASE OBLIGATIONS for further information. 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. For the years ended December 31, 2021, 2020 and 2019, no impairment indicators were present that would indicate the carrying value of any of our asset groups may not be recoverable; as a result, no impairment assessments were required. 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. Refer to NOTE 9 - FAIR VALUE OF FINANCIAL INSTRUMENTS and NOTE 10 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information. Pensions 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 (loss) in the Statements of Consolidated Financial Position. The actuarial estimates of the PBO and APBO incorporate various assumptions including the discount rates, the rates of increases in compensation, healthcare cost trend rates, mortality, retirement timing and employee turnover. 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 (costs) other than service cost component. Refer to NOTE 10 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information. Labor Agreements At December 31, 2021, we employed approximately 26,000 people, of which approximately 18,500 were represented by labor unions under various agreements. We have ten agreements that expire in 2022 and three agreements that expire in 2023. Workers at some of our North American facilities are covered by agreements with the USW, UAW and IAM, as well as several other smaller unions that have various expiration dates. Asset Retirement Obligations Asset retirement obligations are recognized when incurred and recorded as liabilities 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 earnings in the period an estimate is revised. Refer to NOTE 14 - ASSET RETIREMENT OBLIGATIONS for further information. Environmental Remediation Costs Certain of 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. Refer to NOTE 20 - COMMITMENTS AND CONTINGENCIES for further information. 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, when title transfers to our customer for product shipped 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. Refer to NOTE 4 - REVENUES for further information. 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. Share-Based Compensation The fair value of each performance share grant is estimated on the date of grant using a Monte Carlo simulation to forecast relative TSR performance. A correlation matrix of historical and projected stock prices was developed for both the Company and its predetermined peer group of mining and metals 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 mining and metals 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. The fair value of the restricted stock units is determined based on the closing price of our common shares on the grant date. Upon vesting of share-based compensation awards, we issue shares from treasury shares before issuing new shares. Forfeitures are recognized when they occur. 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. Refer to NOTE 11 - STOCK COMPENSATION PLANS for additional information. 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 Net income (loss) in the period that includes the enactment date. 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. Refer to NOTE 12 - INCOME TAXES for further information. Foreign Currency Our financial statements are prepared with the U.S. dollar as the reporting currency, and the functional currency of all subsidiaries is the U.S. dollar, except for our European Operations for which the functional currency is the Euro. Earnings Per Share We present both basic and diluted EPS amounts for continuing operations and discontinued operations. Total basic EPS amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders , less the earnings allocated to our Series B Participating Redeemable Preferred Stock, by the weighted average number of common shares outstanding during the period presented. Total diluted EPS amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders by the weighted average number of common shares, common share equivalents under stock plans using the treasury-stock method, common share equivalents of the Series B Participating Redeemable Preferred Stock using the if- converted method and the calculated common share equivalents in excess of the conversion rate related to our 1.500% 2025 Convertible Senior Notes using the treasury-stock method. Common share equivalents are excluded from EPS computations in the periods in which they have an anti-dilutive effect. Refer to NOTE 8 - DEBT AND CREDIT FACILITIES and NOTE 19 - EARNINGS PER SHARE for further information. 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. Refer to NOTE 18 - VARIABLE INTEREST ENTITIES for additional information. Recent Accounting Pronouncements Issued and Not Effective In August 2020, the FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40). This update requires certain convertible instruments to be accounted for as a single liability measured at its amortized cost. Additionally, the update requires the use of the "if-converted" method, removing the treasury stock method, when calculating diluted shares. The two methods of adoption are the full and modified retrospective approaches. We expect to utilize the modified retrospective approach. Using this approach, the guidance shall be applied to transactions outstanding as of the beginning of the fiscal year in which the amendment is adopted. Subsequent to the year ended December 31, 2021, we redeemed all of our outstanding 1.500% 2025 Convertible Senior Notes; therefore, there will be no impact as a result of our adoption of this update as of January 1, 2022. Refer to NOTE 21 - SUBSEQUENT EVENTS for further information.

SUPPLEMENTARY FINANCIAL STATEME

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block [Abstract]
Supplementary Financial Statement Information	NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION Allowance for Credit Losses The following is a roll-forward of our allowance for credit losses associated with Accounts receivable, net : (In Millions) 2021 2020 Allowance for credit losses as of January 1 $ (5) $ — Decrease (increase) in allowance 1 (5) Allowance for credit losses as of December 31 $ (4) $ (5) Inventories The following table presents the detail of our Inventories in the Statements of Consolidated Financial Position: (In Millions) Year Ended December 31, 2021 2020 Product inventories Finished and semi-finished goods $ 2,814 $ 2,125 Raw materials 2,070 1,431 Total product inventories 4,884 3,556 Manufacturing supplies and critical spares 304 272 Inventories $ 5,188 $ 3,828 The excess of current cost over LIFO cost of iron ore inventories was $124 million and $104 million at December 31, 2021 and 2020, respectively. As of December 31, 2021, the product inventory balance for iron ore inventories increased, resulting in a LIFO increment in 2021. The effect of the inventory build was an increase in Inventories of $45 million in the Statements of Consolidated Operations for the year ended December 31, 2021. As of December 31, 2020, the product inventory balance for iron ore inventories decreased, resulting in the liquidation of a LIFO layer. The effect of the inventory reduction was an increase in Cost of goods sold of $30 million in the Statements of Consolidated Operations for the year ended December 31, 2020. Cash Flow Information A reconciliation of capital additions to cash paid for capital expenditures is as follows: (In Millions) Year Ended December 31, 2021 2020 2019 Capital additions $ 857 $ 483 $ 690 Less: Non-cash accruals 102 (86) 15 Right-of-use assets - finance leases 50 44 29 Grants — — (10) Cash paid for capital expenditures including deposits $ 705 $ 525 $ 656 Cash payments (receipts) for interest and income taxes are as follows: (In Millions) 2021 2020 2019 Taxes paid on income $ 166 $ 5 $ — Income tax refunds (16) (120) (118) Interest paid on debt obligations net of capitalized interest 1 299 170 98 1 Capitalized interest was $6 million, $53 million and $25 million for the years ended December 31, 2021, 2020 and 2019, respectively. Other Non-Cash Investing and Financing Activities (In Millions) 2021 2020 2019 Fair value of settlement of a pre-existing relationship as part of consideration in connection with FPT Acquisition $ (20) $ — $ — Fair value of common shares issued as part of consideration in connection with AM USA Transaction — 990 — Fair value of Series B Participating Redeemable Preferred Stock issued as part of consideration in connection with AM USA Transaction — 738 — Fair value of settlement of a pre-existing relationship as part of consideration in connection with AM USA Transaction — 237 — Fair value of common shares issued as consideration in connection with AK Steel Merger — 618 — Fair value of equity awards assumed in connection with AK Steel Merger — 4 —

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Acquisitions	NOTE 3 - ACQUISITIONS In 2020, we acquired two major steelmakers, AK Steel and ArcelorMittal USA, vertically integrating our legacy iron ore business with steel production. In 2021, we also entered into the scrap business with the FPT Acquisition. We are vertically integrated from mined raw materials, direct reduced iron and ferrous scrap to primary steelmaking and downstream finishing, stamping, tooling and tubing. We now have a presence across the entire steel manufacturing process, from mining to pelletizing to the development and production of finished high value steel products. The AK Steel Merger combined Cliffs, a historic producer of iron ore pellets, with AK Steel, a producer of flat-rolled carbon, stainless and electrical steel products, to create a vertically integrated producer of value-added iron ore and steel products. The AM USA Transaction transformed us into a fully-integrated steel enterprise with the size and scale to expand product offerings and improve through-the-cycle margins. The FPT Acquisition gives us a competitive advantage in sourcing prime scrap, a key raw material for our steelmaking facilities. FPT Acquisition Overview On November 18, 2021, pursuant to the FPT Acquisition Agreement, we completed the FPT Acquisition, in which we were the acquirer. Following the FPT Acquisition, the operating results of FPT are included in our consolidated financial statements. For the period subsequent to the FPT Acquisition (November 18, 2021 through December 31, 2021), FPT generated Revenues of $153 million and a loss of $18 million included within Net income (loss) attributable to Cliffs shareholders, which included $22 million related to amortization of the fair value inventory step-up. Additionally, we incurred acquisition-related costs, excluding severance costs, of $1 million for the year ended December 31, 2021 in connection with the FPT Acquisition, which was recorded in Acquisition-related costs on the Statements of Consolidated Operations . The fair value of the total purchase consideration was determined as follows: (In Millions) Cash consideration (subject to customary working capital adjustments) $ 775 Fair value of settlement of a pre-existing relationship (20) Total purchase consideration $ 755 The cash portion of the purchase price is subject to customary working capital adjustments. Additionally, if the Company decides to make any elections under Section 338(h)(10) of the IRC with respect to entities acquired in connection with the FPT Acquisition, the final cash consideration could potentially change. Valuation Assumption and Purchase Price Allocation We estimated fair values at November 18, 2021 for the preliminary allocation of consideration to the net tangible and intangible assets acquired and liabilities assumed in connection with the FPT 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 FPT Acquisition, most notably, inventories, personal and real property, leases, investments, deferred taxes, environmental 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 FPT Acquisition was: (In Millions) Initial Allocation of Consideration Cash and cash equivalents $ 9 Accounts receivable, net 233 Inventories 137 Other current assets 4 Property, plant and equipment 179 Other non-current assets 74 Accounts payable (122) Accrued employment costs (8) State and local taxes (1) Other current liabilities (8) Other non-current liabilities (21) Net identifiable assets acquired 476 Goodwill 279 Total net assets acquired $ 755 The goodwill resulting from the FPT Acquisition primarily represents the incremental benefit of providing substantial access to prime scrap for our vertically integrated steelmaking business, as well as any synergistic benefits to be realized from the FPT Acquisition within our Steelmaking segment. The preliminary purchase price allocated to identifiable intangible assets acquired was: (In Millions) Weighted Average Life (In Years) Customer relationships $ 18 15 Supplier relationships 18 18 Trade names and trademarks 7 15 Total identifiable intangible assets $ 43 16 Intangible assets are classified as Other non-current assets on the Statements of Consolidated Financial Position. Acquisition of ArcelorMittal USA Overview On December 9, 2020, pursuant to the terms of the AM USA Transaction Agreement, we purchased ArcelorMittal USA from ArcelorMittal. In connection with the closing of the AM USA Transaction, as contemplated by the terms of the AM USA Transaction Agreement, ArcelorMittal’s former joint venture partner in Kote and Tek exercised its put right pursuant to the terms of the Kote and Tek joint venture agreements. As a result, we purchased all of such joint venture partner’s interests in Kote and Tek. Following the closing of the AM USA Transaction, we own 100% of the interests in Kote and Tek. We incurred acquisition-related costs, excluding severance costs, of $3 million and $26 million for the years ended December 31, 2021 and 2020, respectively, in connection with the AM USA Transaction, which were recorded in Acquisition-related costs on the Statements of Consolidated Operations. The fair value of the total purchase consideration was determined as follows: (In Millions) Fair value of Cliffs common shares issued $ 990 Fair value of Cliffs Series B Participating Redeemable Preferred Stock issued 738 Fair value of settlement of a pre-existing relationship 237 Cash consideration 639 Total purchase consideration $ 2,604 The fair value of Cliffs common shares issued was calculated as follows: Number of Cliffs common shares issued 78,186,671 Closing price of Cliffs common share as of December 9, 2020 $ 12.66 Fair value of Cliffs common shares issued (in millions) $ 990 The fair value of Cliffs Series B Participating Redeemable Preferred Stock issued was calculated as follows: Number of Cliffs Series B Participating Redeemable Preferred Stock issued 583,273 Redemption price per share as of December 9, 2020 $ 1,266 Fair value of Cliffs Series B Participating Redeemable Preferred Stock issued (in millions) $ 738 The fair value of the cash consideration was comprised of the following: (In Millions) Cash consideration pursuant to the AM USA Transaction Agreement $ 505 Cash consideration for purchase of the remaining JV partner's interest of Kote and Tek 182 Total cash consideration receivable (48) Total cash consideration $ 639 The cash portion of the purchase price was subject to customary working capital adjustments, and the working capital adjustments were finalized during the second quarter of 2021. We made certain elections under Section 338(h)(10) of the IRC with respect to entities acquired in connection with the AM USA Transaction, which did not change the final cash consideration. The fair value of the settlement of a pre-existing relationship was comprised of the following: (In Millions) Accounts receivable $ 97 Freestanding derivative asset from customer supply agreement 140 Total fair value of settlement of a pre-existing relationship $ 237 Valuation Assumption and Purchase Price Allocation The allocation of consideration to the net tangible and intangible assets acquired and liabilities assumed in connection with the AM USA Transaction was based on estimated fair values at December 9, 2020, and was finalized during the quarter ended December 31, 2021. The following is a summary of the purchase price allocation to assets acquired and liabilities assumed in the AM USA Transaction: (In Millions) Initial Allocation of Consideration Measurement Final Allocation Consideration as of December 31, 2021 Cash and cash equivalents $ 35 $ — $ 35 Accounts receivable, net 349 (3) 346 Inventories 2,115 14 2,129 Other current assets 34 2 36 Property, plant and equipment 4,017 387 4,404 Deferred income taxes — 285 285 Other non-current assets 158 7 165 Accounts payable (736) 8 (728) Accrued employment costs (271) 5 (266) State and local taxes (76) — (76) Other current liabilities (453) 23 (430) Pension liability, non-current (730) — (730) OPEB liability, non-current (2,465) — (2,465) Other non-current liabilities (598) (171) (769) Noncontrolling interest (13) 21 8 Net identifiable assets acquired 1,366 578 1,944 Goodwill 1,230 (570) 660 Total net assets acquired $ 2,596 $ 8 $ 2,604 During the period subsequent to the AM USA Transaction, we made certain measurement period adjustments to the acquired assets and liabilities assumed due to clarification of information utilized to determine fair value during the measurement period. The measurement period adjustments related to the revaluation of the Company's previously held equity method investment, which is now being consolidated post-acquisition, resulting in a loss of $31 million, within Miscellaneous – net for the year ended December 31, 2021. The goodwill resulting from the acquisition of ArcelorMittal USA primarily represents the growth opportunities in the automotive, construction, appliances, infrastructure and machinery and equipment markets, as well as any synergistic benefits to be realized from the AM USA Transaction, and was assigned to our flat steel operations within our Steelmaking segment. Acquisition of AK Steel Overview On March 13, 2020, pursuant to the AK Steel Merger Agreement, we completed the acquisition of AK Steel, in which we were the acquirer. As a result of the AK Steel Merger, each share of AK Steel common stock issued and outstanding immediately prior to the effective time of the AK Steel Merger (other than excluded shares) was converted into the right to receive 0.400 Cliffs common shares and, if applicable, cash in lieu of any fractional Cliffs common shares. We incurred acquisition-related costs, excluding severance costs, of $1 million and $26 million for the years ended December 31, 2021 and 2020, respectively, in connection with the AK Steel Merger, which were recorded in Acquisition-related costs on the Statements of Consolidated Operations. The fair value of the total purchase consideration was determined as follows: (In Millions) Fair value of AK Steel debt $ 914 Fair value of Cliffs common shares issued for AK Steel outstanding common stock 618 Other 3 Total purchase consideration $ 1,535 The fair value of Cliffs common shares issued for outstanding shares of AK Steel common stock and with respect to Cliffs common shares underlying converted AK Steel equity awards that vested upon completion of the AK Steel Merger was calculated as follows: (In Millions, Number of shares of AK Steel common stock issued and outstanding 317 Exchange ratio 0.400 Shares of Cliffs common shares issued to AK Steel stockholders 127 Price per share of Cliffs common shares $ 4.87 Fair value of Cliffs common shares issued for outstanding AK Steel common stock $ 618 The fair value of AK Steel's debt included in the consideration was calculated as follows: (In Millions) Credit Facility $ 590 7.500% Senior Secured Notes due July 2023 324 Fair value of debt included in consideration $ 914 Valuation Assumption and Purchase Price Allocation The allocation of consideration to the net tangible and intangible assets acquired and liabilities assumed in connection with the AK Steel Merger was based on estimated fair values at March 13, 2020, and was finalized during the quarter ended March 31, 2021. The following is a summary of the purchase price allocation to assets acquired and liabilities assumed in the AK Steel Merger: (In Millions) Initial Allocation of Consideration Measurement Period Adjustments Final Allocation of Consideration as of March 31, 2021 Cash and cash equivalents $ 38 $ 1 $ 39 Accounts receivable, net 666 (2) 664 Inventories 1,563 (243) 1,320 Other current assets 68 (16) 52 Property, plant and equipment 2,184 90 2,274 Deferred income taxes — 69 69 Other non-current assets 475 (4) 471 Accounts payable (636) (8) (644) Accrued employment costs (94) 1 (93) State and local taxes (35) 4 (31) Other current liabilities (276) 2 (274) Long-term debt (1,179) — (1,179) Pension liability, non-current (473) 10 (463) OPEB liability, non-current (400) (8) (408) Other non-current liabilities (507) 72 (435) Noncontrolling interest — (1) (1) Net identifiable assets acquired 1,394 (33) 1,361 Goodwill 141 33 174 Total net assets acquired $ 1,535 $ — $ 1,535 During the period subsequent to the AK Steel Merger, we made certain measurement period adjustments to the acquired assets and liabilities assumed due to clarification of information utilized to determine fair value during the measurement period. The goodwill resulting from the acquisition of AK Steel was assigned to our downstream Tubular and Tooling and Stamping operating segments. Goodwill is calculated as the excess of the purchase price over the net identifiable assets recognized and primarily represents the growth opportunities in light weighting solutions to automotive customers, as well as any synergistic benefits to be realized. Goodwill from the AK Steel Merger is not expected to be deductible for income tax purposes. The purchase price allocated to identifiable intangible assets and liabilities acquired was: (In Millions) Weighted Average Life (In Years) Intangible assets: Customer relationships $ 77 18 Developed technology 60 17 Trade names and trademarks 11 10 Total identifiable intangible assets $ 148 17 Intangible liabilities: Above-market supply contracts $ (71) 12 Intangible assets are classified as Other non-current assets on the Statements of Consolidated Financial Position. Intangible liabilities are classified as Other non-current liabilities on the Statements of Consolidated Financial Position. The above-market supply contracts relate to the long-term coke and energy supply agreements with SunCoke Energy, which includes SunCoke Middletown, a consolidated VIE. Refer to NOTE 18 - VARIABLE INTEREST ENTITIES for further information. Pro Forma Results 2020 Acquisitions The following table provides unaudited pro forma financial information, prepared in accordance with Topic 805, as if ArcelorMittal USA and AK Steel had been acquired as of January 1, 2019: (In Millions) Year Ended December 31, 2020 2019 Revenues $ 12,837 $ 17,163 Net income (loss) attributable to Cliffs shareholders (520) (11) 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 2020 Acquisitions occurred on January 1, 2019. Significant pro forma adjustments include the following: 1. The elimination of intercompany revenues between Cliffs and ArcelorMittal USA and AK Steel of $844 million and $1,499 million for the years ended December 31, 2020 and 2019, respectively. 2. The 2020 pro forma net loss was adjusted to exclude $96 million of non-recurring inventory acquisition accounting adjustments incurred during the year ended December 31, 2020. The 2019 pro forma net loss was adjusted to include $362 million of non-recurring inventory acquisition accounting adjustments for the year ended December 31, 2019. 3. The elimination of non-recurring transaction costs incurred by Cliffs, AK Steel and ArcelorMittal USA in connection with the 2020 Acquisitions were $93 million for the year ended December 31, 2020. The 2019 pro forma net loss was adjusted to include $93 million of non-recurring transaction cost adjustments for the year ended December 31, 2019. 4. The 2020 pro forma net loss was adjusted to exclude restructuring costs of $1,820 million of non-recurring costs incurred by ArcelorMittal USA prior to the AM USA Transaction. 5. The 2020 and 2019 pro forma net losses were adjusted to exclude $140 million and $129 million for the years ended December 31, 2020 and 2019, respectively, for the impact of reversal of the fees charged for management, financial and legal services under the Industrial Franchise Agreement with the former parent. 6. Total other pro forma adjustments included reduced expenses of $32 million for the year ended December 31, 2020, primarily due to decreased depreciation expense and pension and OPEB expense, offset partially by increased interest and amortization expense. 7. Total other pro forma adjustments included an expense of $76 million for the year ended December 31, 2019, primarily due to increased interest, amortization and pension and OPEB expense, offset partially by decreased depreciation expense. 8. The income tax impact of pro forma transaction adjustments that affect Net income (loss) attributable to Cliffs shareholders at a statutory rate of 24.3% resulted in an increased benefit to Income tax benefit (expense) of $170 million and $117 million for the years ended December 31, 2020 and 2019, respectively. FPT Acquisition The following table provides unaudited pro forma financial information, prepared in accordance with Topic 805, as if FPT had been acquired as of January 1, 2020: (In Millions) Year Ended December 31, 2021 2020 Revenues $ 21,701 $ 13,549 Net income (loss) attributable to Cliffs shareholders 3,074 (526) 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 FPT Acquisition occurred on January 1, 2020. There were no significant pro forma adjustments for the FPT Acquisition. 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 companies. This unaudited pro forma financial information should not be considered indicative of the results that would have actually occurred if the 2020 Acquisitions had been consummated on January 1, 2019, or if the FPT Acquisition had been consummated on January 1, 2020, nor are they indicative of future results.

REVENUES

REVENUES	12 Months Ended
	Dec. 31, 2021
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. Prior to the AM USA Transaction, we had a supply agreement with ArcelorMittal USA, which included supplemental revenue or refunds based on the HRC price in the year the iron ore was consumed in ArcelorMittal USA's blast furnaces. As control transferred prior to consumption, the supplemental revenue was recorded in accordance with Topic 815. All sales occurring subsequent to the AM USA Transaction are intercompany and eliminated in consolidation. Included within Revenues related to Topic 815 for the supplemental revenue portion of the supply agreement is derivative revenue of $122 million and $78 million for the years ended December 31, 2020 and 2019, respectively. The following table represents our Revenues by market: (In Millions) Year Ended December 31, 2021 2020 2019 Steelmaking: Automotive $ 4,726 $ 2,062 $ — Infrastructure and manufacturing 5,380 784 — Distributors and converters 7,671 696 — Steel producers 2,124 1,423 1,990 Total Steelmaking 19,901 4,965 1,990 Other Businesses: Automotive 426 329 — Infrastructure and manufacturing 47 34 — Distributors and converters 70 26 — Total Other Businesses 543 389 — Total revenues $ 20,444 $ 5,354 $ 1,990 The following table represents our Revenues by product line: (Dollars In Millions, Sales Volumes in Thousands) Year Ended December 31, 2021 2020 2019 Revenue Volume 1 Revenue Volume 1 Revenue Volume 1 Steelmaking: Hot-rolled steel $ 5,615 4,886 $ 386 633 $ — — Cold-rolled steel 3,186 2,790 490 682 — — Coated steel 5,864 5,056 1,747 1,911 — — Stainless and electrical steel 1,622 674 868 416 — — Plate 1,316 1,020 46 62 — — Other steel products 1,247 1,460 46 79 — — Other 1,051 N/A 1,382 N/A 1,990 N/A Total steelmaking 19,901 4,965 1,990 Other Businesses: Other 543 N/A 389 N/A — N/A Total revenues $ 20,444 $ 5,354 $ 1,990 1 All product volumes are stated in net tons. Deferred Revenue The table below summarizes our deferred revenue balances: (In Millions) Deferred Revenue (Current) Deferred Revenue (Long-Term) 2021 2020 2021 2020 Opening balance as of January 1 $ 7 $ 22 $ — $ 26 Net increase (decrease) 18 (15) — (26) Closing balance as of December 31 $ 25 $ 7 $ — $ — Prior to the AK Steel Merger, our iron ore pellet sales agreement with Severstal Dearborn, LLC, subsequently assumed by AK Steel, required supplemental payments to be paid by the customer during the period from 2009 through 2013. Installment amounts received under this arrangement in excess of sales were classified as deferred revenue in the Statements of Consolidated Financial Position upon receipt of payment and the revenue was recognized over the term of the supply agreement, which had extended until 2022, in equal annual installments. As a result of the termination of that iron ore pellet sales agreement, we realized $35 million of deferred revenue, which was recognized within Revenues in the Statements of Consolidated Operations during the year ended December 31, 2020.

SEGMENT REPORTING

SEGMENT REPORTING	12 Months Ended
	Dec. 31, 2021
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 the largest flat-rolled steel producer supported by being the largest iron ore pellet producer as well as a leading prime scrap processor in North America, 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. We evaluate 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 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, management 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. Our results by segment are as follows: (In Millions) Year Ended December 31, 2021 2020 2019 Revenues: Steelmaking $ 19,901 $ 4,965 $ 1,990 Other Businesses 543 389 — Total revenues $ 20,444 $ 5,354 $ 1,990 Adjusted EBITDA: Steelmaking $ 5,422 $ 433 $ 636 Other Businesses 9 47 — Corporate and eliminations (169) (127) (111) Total Adjusted EBITDA $ 5,262 $ 353 $ 525 The following table provides a reconciliation of our consolidated Net income (loss) to total Adjusted EBITDA: (In Millions) Year Ended December 31, 2021 2020 2019 Net income (loss) $ 3,033 $ (81) $ 293 Less: Interest expense, net (337) (238) (101) Income tax benefit (expense) (773) 111 (18) Depreciation, depletion and amortization (897) (308) (85) 5,040 354 497 Less: EBITDA from noncontrolling interests 1 75 56 — Gain (loss) on extinguishment of debt (88) 130 (18) Severance costs (15) (38) (2) Acquisition-related costs excluding severance costs (5) (52) (7) Acquisition-related loss on equity method investment (31) — — Amortization of inventory step-up (161) (96) — Impact of discontinued operations 3 1 (1) Total Adjusted EBITDA $ 5,262 $ 353 $ 525 1 EBITDA of noncontrolling interests includes the following: Net income attributable to noncontrolling interests $ 45 $ 41 $ — Depreciation, depletion and amortization 30 15 — EBITDA of noncontrolling interests $ 75 $ 56 $ — The following table summarizes our depreciation, depletion and amortization and capital additions by segment: (In Millions) Year Ended December 31, 2021 2020 2019 Depreciation, depletion and amortization: Steelmaking $ 855 $ 276 $ 80 Other Businesses 37 27 — Corporate 5 5 5 Total depreciation, depletion and amortization $ 897 $ 308 $ 85 Capital additions 1: Steelmaking $ 787 $ 436 $ 687 Other Businesses 52 45 — Corporate 18 2 3 Total capital additions $ 857 $ 483 $ 690 1 Refer to NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION for additional information. The following summarizes our assets by segment: (In Millions) December 31, 2021 2020 Assets: Steelmaking $ 18,326 $ 15,849 Other Businesses 306 239 Total segment assets 18,632 16,088 Corporate 343 683 Total assets $ 18,975 $ 16,771 Included in the consolidated financial statements are the following amounts relating to geographic location based on product destination: (In Millions) 2021 2020 2019 Revenues: United States $ 18,881 $ 4,580 $ 1,505 Canada 803 602 448 Other countries 760 172 37 Total revenues $ 20,444 $ 5,354 $ 1,990 Property, plant and equipment, net: United States $ 9,092 $ 8,647 $ 1,929 Canada 93 91 — Other countries 1 5 — Total property, plant and equipment, net $ 9,186 $ 8,743 $ 1,929

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	12 Months Ended
	Dec. 31, 2021
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: (In Millions) December 31, 2021 2020 Land, land improvements, and mineral rights $ 1,291 $ 1,213 Buildings 889 703 Equipment 8,709 6,786 Other 229 151 Construction in progress 408 1,364 Total property, plant and equipment 1 11,526 10,217 Allowance for depreciation and depletion (2,340) (1,474) Property, plant, and equipment, net $ 9,186 $ 8,743 1 Includes right-of-use assets related to finance leases of $411 million and $361 million as of December 31, 2021 and 2020, respectively. We recorded depreciation expense of $848 million, $298 million and $77 million for the years ended December 31, 2021, 2020 and 2019, respectively. We recorded capitalized interest into property, plant and equipment of $6 million, $53 million and $25 million during the years ended December 31, 2021, 2020 and 2019, respectively. The net book value of the mineral and land rights are as follows: (In Millions) December 31, 2021 2020 Mineral rights: Cost $ 780 $ 773 Depletion (187) (142) Net mineral rights $ 593 $ 631 Land rights $ 406 $ 361 We recorded depletion expense of $46 million, $8 million and $8 million for the years ended December 31, 2021, 2020, and 2019, respectively.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES	12 Months Ended
	Dec. 31, 2021
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: (In Millions) December 31, 2021 2020 Steelmaking $ 942 $ 1,232 Other Businesses 174 174 Total goodwill $ 1,116 $ 1,406 The decrease of $290 million in the balance of Goodwill in our Steelmaking segment as of December 31, 2021, compared to December 31, 2020, is due to the decrease in estimated identified goodwill as a result of measurement period adjustments to the purchase price allocation for the acquisition of ArcelorMittal USA, partially offset by the increase due to the preliminary assignment of Goodwill in 2021 based on the preliminary purchase price allocation for the acquisition of FPT. Refer to NOTE 3 - ACQUISITIONS for further details. Intangible Assets and Liabilities The following is a summary of our intangible assets and liabilities: (In Millions) December 31, 2021 December 31, 2020 Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Intangible assets 1 : Customer relationships $ 95 $ (8) $ 87 $ 77 $ (3) $ 74 Developed technology 60 (6) 54 60 (3) 57 Trade names and trademarks 18 (2) 16 11 (1) 10 Mining permits 72 (26) 46 72 (25) 47 Supplier relationships 18 — 18 — — — Total intangible assets $ 263 $ (42) $ 221 $ 220 $ (32) $ 188 Intangible liabilities 2 : Above-market supply contracts $ (71) $ 14 $ (57) $ (71) $ 7 $ (64) 1 Intangible assets are classified as Other non-current assets . 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 $10 million and $8 million for the years ended December 31, 2021 and 2020, respectively. Estimated future amortization expense related to intangible assets is $13 million annually for the years 2022 through 2026.

DEBT AND CREDIT FACILITIES

DEBT AND CREDIT FACILITIES	12 Months Ended
	Dec. 31, 2021
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) December 31, 2021 Debt Instrument Issuer 1 Annual Effective Interest Rate Total Principal Amount Unamortized Debt Issuance Costs Unamortized Premiums (Discounts) Total Debt Senior Secured Notes: 9.875% 2025 Senior Secured Notes Cliffs 10.57% $ 607 $ (4) $ (13) $ 590 6.750% 2026 Senior Secured Notes Cliffs 6.99% 845 (16) (7) 822 Senior Unsecured Notes: 1.500% 2025 Convertible Senior Notes Cliffs 6.26% 294 (3) (39) 252 7.000% 2027 Senior Notes Cliffs 9.24% 73 — (7) 66 7.000% 2027 AK Senior Notes AK Steel 9.24% 56 — (5) 51 5.875% 2027 Senior Notes Cliffs 6.49% 556 (3) (15) 538 4.625% 2029 Senior Notes Cliffs 4.63% 500 (8) — 492 4.875% 2031 Senior Notes Cliffs 4.88% 500 (8) — 492 6.250% 2040 Senior Notes Cliffs 6.34% 263 (2) (3) 258 IRBs due 2024 to 2028 AK Steel Various 66 — 2 68 ABL Facility 3 Cliffs 2 1.87% 4,500 — — 1,609 Total long-term debt $ 5,238 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 The total principal amount for the ABL Facility is stated at the maximum borrowing capacity. (In Millions) December 31, 2020 Debt Instrument Issuer 1 Annual Effective Interest Rate Total Principal Amount Unamortized Unamortized Premiums (Discounts) Total Debt Senior Secured Notes: 4.875% 2024 Senior Secured Notes Cliffs 5.00% $ 395 $ (3) $ (1) $ 391 9.875% 2025 Senior Secured Notes Cliffs 10.57% 955 (8) (25) 922 6.750% 2026 Senior Secured Notes Cliffs 6.99% 845 (20) (9) 816 Senior Unsecured Notes: 7.625% 2021 AK Senior Notes AK Steel 7.33% 34 — — 34 7.500% 2023 AK Senior Notes AK Steel 6.17% 13 — — 13 6.375% 2025 Senior Notes Cliffs 8.11% 64 — (4) 60 6.375% 2025 AK Senior Notes AK Steel 8.11% 29 — (2) 27 1.500% 2025 Convertible Senior Notes Cliffs 6.26% 296 (4) (49) 243 5.750% 2025 Senior Notes Cliffs 6.01% 396 (3) (4) 389 7.000% 2027 Senior Notes Cliffs 9.24% 73 — (8) 65 7.000% 2027 AK Senior Notes AK Steel 9.24% 56 — (6) 50 5.875% 2027 Senior Notes Cliffs 6.49% 556 (4) (18) 534 6.250% 2040 Senior Notes Cliffs 6.34% 263 (2) (3) 258 IRBs due 2024 to 2028 AK Steel Various 92 — 2 94 EDC Revolving Facility 3 * 3.25% 40 — — 18 ABL Facility 3 Cliffs 2 2.15% 3,500 — — 1,510 Total debt 5,424 Less: current 34 Total long-term debt $ 5,390 *Our subsidiaries, Fleetwood Metal Industries Inc. and The Electromac Group Inc., were the borrowers under the EDC Revolving Facility. 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 The total principal amounts for the indicated credit facilities are stated at their respective maximum borrowing capacities. Outstanding Senior Secured Notes The following represents a summary of our senior secured notes' maturity and interest payable due dates: Debt Instrument Maturity Interest Payable 9.875% 2025 Senior Secured Notes October 17, 2025 April 17 and October 17 6.750% 2026 Senior Secured Notes March 15, 2026 March 15 and September 15 The senior secured notes of each series are jointly and severally and fully and unconditionally guaranteed on a senior secured basis by substantially all of our material domestic subsidiaries and are secured (subject in each case to certain exceptions and permitted liens) by (i) a first-priority lien, on a pari passu basis with the senior secured notes of the other series, on substantially all of our assets and the assets of the guarantors, other than the ABL Collateral (as defined below), and (ii) a second-priority lien on the ABL Collateral, which is junior to a first-priority lien for the benefit of the lenders under our ABL Facility. We may redeem the 9.875% 2025 Senior Secured Notes, 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 of the 9.875% 2025 Senior Secured Notes. The 9.875% 2025 Senior Secured Notes are redeemable prior to October 17, 2022, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. We may also redeem up to 35% of the aggregate principal amount of the 9.875% 2025 Senior Secured Notes prior to October 17, 2022, at a redemption price equal to 109.875% of the principal amount thereof, plus accrued and unpaid interest, if any, to but not including, the date of redemption with the net cash proceeds of one or more equity offerings. On March 11, 2021, we exercised this optional redemption feature when we purchased $322 million aggregate principal amount of the 9.875% 2025 Senior Secured Notes using the net proceeds from the underwritten public offering of 20 million common shares. The 9.875% 2025 Senior Secured Notes are redeemable beginning on October 17, 2022, at a redemption price equal to 107.406% of the principal amount thereof, decreasing on each April 17 thereafter until April 17, 2025, on and after which the 9.875% 2025 Senior Secured Notes are redeemable at par, in each case, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. We may redeem the 6.750% 2026 Senior Secured Notes 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 of the 6.750% 2026 Senior Secured Notes. The 6.750% 2026 Senior Secured Notes are redeemable prior to March 15, 2022, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. We may also redeem up to 35% of the aggregate principal amount of the 6.750% 2026 Senior Secured Notes prior to March 15, 2022, at a redemption price equal to 106.750% of the principal amount thereof, plus accrued and unpaid interest, if any, to but not including, the date of redemption with the net cash proceeds of one or more equity offerings. The 6.750% 2026 Senior Secured Notes are redeemable beginning on March 15, 2022, at a redemption price equal to 105.063% of the principal amount thereof, decreasing on each March 15 thereafter until March 15, 2025, on and after which the 6.750% 2026 Senior Secured Notes are redeemable at par, in each case, 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 senior secured notes, we will be required to offer to purchase 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 purchase. The terms of the senior secured notes contain certain customary covenants; however, there are no financial covenants. Outstanding Senior Unsecured Notes 2021 Issuances On February 17, 2021, we entered into an indenture among Cliffs, the guarantors party thereto and U.S. Bank National Association, as trustee, relating to the issuances of $500 million aggregate principal amount of 4.625% 2029 Senior Notes and $500 million aggregate principal amount of 4.875% 2031 Senior Notes, each issued at par. The 4.625% 2029 Senior Notes and 4.875% 2031 Senior Notes were issued in private placement transactions exempt from the registration requirements of the Securities Act. The 4.625% 2029 Senior Notes and 4.875% 2031 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 4.625% 2029 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 4.625% 2029 Senior Notes and 4.875% 2031 Senior Notes. In addition, if a change in control triggering event, as defined in the indenture, occurs with respect to the 4.625% 2029 Senior Notes and 4.875% 2031 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 4.625% 2029 Senior Notes and 4.875% 2031 Senior Notes contain certain customary covenants; however, there are no financial covenants. 4.625% 2029 Senior Notes The 4.625% 2029 Senior Notes bear interest at a rate of 4.625% per annum, payable semi-annually in arrears on March 1 and September 1 of each year, commencing on September 1, 2021. The 4.625% 2029 Senior Notes will mature on March 1, 2029. 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 following is a summary of redemption prices for our 4.625% 2029 Senior Notes: Redemption Period Redemption Price 1 Restricted Amount Prior to March 1, 2024 - using the proceeds of equity issuance 104.625 % Up to 35% of original aggregate principal Prior to March 1, 2024 2 100.000 Beginning March 1, 2024 102.313 Beginning March 1, 2025 101.156 Beginning on March 1, 2026 and thereafter 100.000 1 Plus accrued and unpaid interest, if any, up to, but excluding, the redemption date. 2 Plus a "make-whole" premium. 4.875% 2031 Senior Notes The 4.875% 2031 Senior Notes bear interest at a rate of 4.875% per annum, payable semi-annually in arrears on March 1 and September 1 of each year, commencing on September 1, 2021. The 4.875% 2031 Senior Notes will mature on March 1, 2031. 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 following is a summary of redemption prices for our 4.875% 2031 Senior Notes: Redemption Period Redemption Price 1 Restricted Amount Prior to March 1, 2026 - using the proceeds of equity issuance 104.875 % Up to 35% of original aggregate principal Prior to March 1, 2026 2 100.000 Beginning March 1, 2026 102.438 Beginning March 1, 2027 101.625 Beginning March 1, 2028 100.813 Beginning on March 1, 2029 and thereafter 100.000 1 Plus accrued and unpaid interest, if any, up to, but excluding, the redemption date. 2 Plus a "make-whole" premium. 1.500% 2025 Convertible Senior Notes The 1.500% 2025 Convertible Senior Notes bear interest at a rate of 1.500% per year, payable semiannually in arrears on January 15 and July 15 of each year. The 1.500% 2025 Convertible Senior Notes mature on January 15, 2025. The 1.500% 2025 Convertible Senior Notes are senior unsecured obligations and rank senior in right of payment to any of our indebtedness that is expressly subordinated in right of payment to the 1.500% 2025 Convertible Senior Notes; equal in right of payment to any of our unsecured indebtedness that is not so subordinated; effectively junior in right of payment to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of our subsidiaries. The terms of the 1.500% 2025 Convertible Senior Notes contain certain customary covenants; however, there are no financial covenants. Holders may convert their 1.500% 2025 Convertible Senior Notes at their option at any time prior to the close of business on the business day immediately preceding July 15, 2024, only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2018, if the last reported sale price of our common shares, par value $0.125 per share, for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five-business day period after any five-consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of 1.500% 2025 Convertible Senior Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our common shares and the conversion rate on each such trading day; (3) if we call the notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events. On or after July 15, 2024 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 1.500% 2025 Convertible Senior Notes at any time, regardless of the foregoing circumstances. Upon conversion, we will pay or deliver, as the case may be, cash, common shares or a combination of cash and common shares, at our election. Upon the issuance of the 1.500% 2025 Convertible Senior Notes the initial conversion rate was 122.4365 common shares per $1,000 principal, with a conversion price of $8.17 per common share. The conversion rate is subject to adjustment in some circumstances, including the payment of dividends on common shares, but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the maturity date, or if we deliver a notice of redemption, we will, in certain circumstances, increase the conversion rate for a holder who elects to convert its 1.500% 2025 Convertible Senior Notes in connection with such a corporate event or notice of redemption, as the case may be. As of December 31, 2021, the conversion rate was 129.2985 common shares per $1,000 principal amount of 1.500% 2025 Convertible Senior Notes. We may not redeem the 1.500% 2025 Convertible Senior Notes prior to January 15, 2022. We may redeem all or any portion of the 1.500% 2025 Convertible Senior Notes, for cash at our option on or after January 15, 2022 if the last reported sale price of our common shares has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30-consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the 1.500% 2025 Convertible Senior Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. If we undergo a fundamental change as defined in the indenture, holders may require us to repurchase for cash all or any portion of their 1.500% 2025 Convertible Senior Notes at a fundamental change repurchase price equal to 100% of the principal amount of the 1.500% 2025 Convertible Senior Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In accounting for the issuance of the notes, we separated the 1.500% 2025 Convertible Senior Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of similar liabilities that did not have associated convertible features. The carrying amount of the equity component of $86 million representing the conversion option was determined by deducting the fair value of the liability component from the par value of the notes. The difference represents the debt discount that is amortized to interest expense over the term of the notes. The equity component is not remeasured as long as it continues to qualify for equity classification. On December 1, 2021, we issued a notice of redemption for all $294 million aggregate principal amount outstanding of the 1.500% 2025 Convertible Senior Notes. Refer to NOTE 21 - SUBSEQUENT EVENTS for further information on the redemption of the 1.500% 2025 Convertible Senior Notes. 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 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 and 5.875% 2027 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 redeemable prior to March 15, 2022, at a redemption price equal to 100% of the principal amount thereof plus a "make-whole" premium set forth in the indenture, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 7.000% 2027 Senior Notes are redeemable beginning on March 15, 2022, at a redemption price equal to 103.500% of the principal amount thereof, decreasing on each March 15 thereafter until March 15, 2025, on and after which the 7.000% 2027 Senior Notes are redeemable at par, in each case, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 5.875% 2027 Senior Notes are redeemable prior to June 1, 2022, at a redemption price equal to 100% of the principal amount thereof plus a “make-whole” premium set forth in the indenture, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. We may also redeem up to 35% of the aggregate principal amount of the 5.875% 2027 Senior Notes prior to June 1, 2022 at a redemption price equal to 105.875% of the principal amount thereof, plus accrued and unpaid interest, if any, to, but not including, the date of redemption with the net cash proceeds of one or more equity offerings. The 5.875% 2027 Senior Notes are redeemable beginning on June 1, 2022, at a redemption price equal to 102.938% of the principal amount thereof, decreasing on each June 1 thereafter until June 1, 2025, on and after which the 5.875% 2027 Senior Notes are redeemable at par, in each case, 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, 2021, 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 redeemable prior to March 15, 2022, at a redemption price equal to 100% of the principal amount thereof plus a “make-whole” premium set forth in the indenture, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. The 7.000% 2027 AK Senior Notes are redeemable beginning on March 15, 2022, at a redemption price equal to 103.500% of the principal amount thereof, decreasing on each March 15 thereafter until March 15, 2025, on and after which the 7.000% 2027 Senior Notes are redeemable at par, in each case, plus accrued and unpaid interest, if any, to, but not including, the date of redemption. ABL Facility On March 13, 2020, in connection with the AK Steel Merger, we entered into a new ABL Facility with various financial institutions to replace and refinance Cliffs’ Former ABL Facility and AK Steel Corporation’s former revolving credit facility. The ABL Facility will mature upon the earlier of March 13, 2025 or 91 days prior to the maturity of certain other material debt and provided for up to $2 billion in borrowings, including a $555 million sublimit for the issuance of letters of credit and a $125 million sublimit for swingline loans. Availability under the ABL Facility is limited to an eligible borrowing base, as applicable, determined by applying customary advance rates to eligible accounts receivable, inventory and certain mobile equipment. On March 27, 2020, we amended our ABL Facility to, among other things, provide for a new FILO tranche B of commitments in the aggregate amount of $150 million by exchanging existing commitments under the ABL Facility. The total commitments under the ABL Facility after giving effect to this first amendment remained at $2 billion. The terms and conditions (other than the pricing) that apply to the FILO tranche were substantially the same as the terms and conditions that apply to the tranche A facility of the ABL Facility immediately prior to the amendment. On December 9, 2020, we entered into the Second ABL Amendment. The Second ABL Amendment modified the ABL Facility to, among other things, increase the amount of tranche A revolver commitments available thereunder by an additional $1.5 billion and increase certain dollar baskets related to certain negative covenants that apply to the ABL Facility. After giving effect to the ABL Amendment, the aggregate principal amount of tranche A revolver commitments under the ABL Facility was $3.35 billion and the aggregate principal amount of FILO tranche B revolver commitments under the ABL Facility remained at $150 million. On December 17, 2021, we entered into the Third ABL Amendment. The Third ABL Amendment modified the ABL Facility to, among other things, increase the amount of tranche A revolver commitments available thereunder by an additional $1 billion and exchange $150 million of tranche B revolver commitments available thereunder for tranche A revolver commitments. After giving effect to the Third ABL Amendment, the aggregate principal amount of tranche A revolver commitments under the ABL Facility is $4.5 billion and there are no remaining tranche B revolver commitments under the ABL Facility. The increase is a result of a larger projected borrowing base driven by more favorable market conditions. 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. Borrowings under the ABL Facility bear interest, at our option, at a base rate or, if certain conditions are met, a LIBOR rate, in each case, plus an applicable margin. We may amend our ABL Facility to replace the LIBOR rate with one or more secured overnight financing based rates or an alternative benchmark rate, giving consideration to any evolving or then-existing convention for similar dollar denominated syndicated credit facilities for such alternative benchmarks. 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. 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. As of December 31, 2021 and 2020, 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 following represents a summary of our borrowing capacity under the ABL Facility: (In Millions) December 31, Available borrowing base on ABL Facility 1 $ 4,500 Borrowings (1,609) Letter of credit obligations 2 (175) Borrowing capacity available $ 2,716 1 As of December 31, 2021, the ABL Facility has a maximum available borrowing base of $4.5 billion. The 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, workers' compensation, employee severance, insurance, operating agreements and environmental obligations. Other Financing Arrangements Industrial Revenue Bonds AK Steel had outstanding $66 million aggregate principal amount of fixed-rate, tax-exempt IRBs as of December 31, 2021. The weighted-average fixed rate of these IRBs is 6.86%. These IRBs are unsecured senior debt obligations that are equal in ranking with AK Steel's senior notes and AK Steel's guarantees of Cliffs' unsubordinated indebtedness. These IRBs are effectively subordinated to AK Steel’s guarantees of Cliffs’ secured indebtedness to the extent of the value of AK Steel’s assets securing such guarantees. These IRBs contain certain customary covenants; however, there are no financial covenants. Debt Extinguishment - 2021 During the fourth quarter of 2021, we paid in full the outstanding balance of our EDC revolving facilities for $55 million in aggregate principal amount and terminated the agreements. Prior to such terminations, the EDC revolving facilities provided for up to $80 million in borrowings. On October 15, 2021, we redeemed $26 million in aggregate principal amount of the IRBs due 2024. During the third quarter of 2021, we repurchased $2 million in aggregate principal amount of 1.500% 2025 Convertible Senior Notes. On June 28, 2021, we redeemed all $396 million aggregate principal amount outstanding of the 5.750% 2025 Senior Notes using available liquidity. During the second quarter of 2021, we also repurchased $25 million aggregate principal amount of 9.875% 2025 Senior Secured Notes. On March 11, 2021, we purchased $322 million aggregate principal amount of the 9.875% 2025 Senior Secured Notes using the net proceeds from the February 11, 2021 issuance of 20 million common shares and cash on hand. On March 12, 2021, we fully redeemed the 4.875% 2024 Senior Secured Notes, 7.625% 2021 AK Senior Notes, 7.50% 2023 AK Senior Notes, 6.375% 2025 Senior Notes and 6.375% 2025 AK Senior Notes, which totaled an aggregate principal amount of $535 million. The following is a summary of the debt extinguished and the respective impact on extinguishment: (In Millions) Year Ended Debt Extinguished (Loss) on Extinguishment 9.875% 2025 Senior Secured Notes $ 347 $ (47) 4.875% 2024 Senior Secured Notes 395 (14) 7.625% 2021 AK Senior Notes 34 — 7.500% 2023 AK Senior Notes 13 — 6.375% 2025 Senior Notes 64 (7) 1.500% 2025 Convertible Senior Notes 2 — 6.375% 2025 AK Senior Notes 29 (3) 5.750% 2025 Senior Notes 396 (17) IRBs due 2024 26 — Total $ 1,306 $ (88) Debt Extinguishment - 2020 During the year ended December 31, 2020, we used the net proceeds from the offering of the additional 9.875% 2025 Senior Secured Notes to repurchase $736 million aggregate principal amount of our outstanding senior notes of various series, which resulted in a net debt reduction of $181 million. We also repurchased an additional $35 million aggregate principal amount of our outstanding senior notes of various series and we redeemed $7 million aggregate principal amount of our outstanding 2020 IRBs, with cash on hand. Additionally, in connection with the AK Steel Merger, we purchased $364 million aggregate principal amount of 7.625% 2021 AK Senior Notes and $311 million aggregate principal amount of 7.500% 2023 AK Senior Notes upon early settlement of tender offers made by Cliffs. The net proceeds from the offering of 6.750% 2026 Senior Secured Notes, along with a portion of the ABL Facility borrowings, were used to fund such purchases. As the 7.625% 2021 AK Senior Notes and 7.500% 2023 AK Senior Notes were recorded at fair value just prior to being purchased, there was no gain or loss on extinguishment. Additionally, in connection with the final settlement of the tender offers, we purchased $9 million aggregate principal amount of the 7.625% 2021 AK Senior Notes and $56 million ag

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	NOTE 9 - FAIR VALUE OF FINANCIAL INSTRUMENTS There were no significant assets or liabilities measured at fair value as of December 31, 2021 or December 31, 2020. 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. Our supply agreement with ArcelorMittal USA contained provisions for supplemental revenue or refunds based on the HRC price in the year the iron ore product was consumed in ArcelorMittal USA’s blast furnaces. We accounted for these provisions as derivative instruments at the time of sale and adjusted the derivative instruments to fair value through Revenues each reporting period until the product was consumed and the amounts were settled. These instruments were classified as Level 3 assets. Upon the completion of the AM USA Transaction, the outstanding derivatives were settled as part of acquisition accounting. The following tables represent a reconciliation of the changes in fair value of financial instruments measured at fair value on a recurring basis using significant unobservable inputs (Level 3): (In Millions) Level 3 Assets 2021 2020 Beginning balance - January 1 $ — $ 45 Total gains included in earnings — 122 Settlements — (27) Settlement of pre-existing relationship — (140) Ending balance - December 31 $ — $ — Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ — $ — 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. A summary of the carrying value and fair value of other financial instruments were as follows: (In Millions) December 31, 2021 December 31, 2020 Classification Carrying Fair Value Carrying Fair Value Senior notes Level 1 $ 3,561 $ 3,911 $ 3,802 $ 4,446 IRBs due 2024 to 2028 Level 1 68 66 94 91 EDC Revolving Facility - outstanding balance Level 2 — — 18 18 ABL Facility - outstanding balance Level 2 1,609 1,609 1,510 1,510 Total $ 5,238 $ 5,586 $ 5,424 $ 6,065

PENSIONS AND OTHER POSTRETIREME

PENSIONS AND OTHER POSTRETIREMENT BENEFITS	12 Months Ended
	Dec. 31, 2021
Postemployment Benefits [Abstract]
PENSION AND OTHER POSTRETIREMENT BENEFITS	NOTE 10 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS We offer 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. As a result of the acquisitions of AK Steel and ArcelorMittal USA, we assumed the obligations under their defined benefit pension plans, OPEB plans, defined contribution plans and commitments to multiemployer pension plans according to collective bargaining agreements that cover certain union-represented employees. The AK Steel defined benefit pension plans and OPEB plans acquired amounted to a benefit obligation, net of assets of $949 million based on a March 13, 2020 measurement. The ArcelorMittal USA defined benefit pension plans and OPEB plans acquired amounted to a benefit obligation, net of assets of $3,294 million based on a December 9, 2020 measurement. 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. OPEB Plans We offer postretirement health care and life insurance benefits to retirees through various 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: 2021 2020 2021 2020 Benefit obligations — beginning of year $ 6,565 $ 1,021 $ 3,757 $ 255 Service cost 56 23 51 8 Interest cost 103 64 74 19 Plan amendments — — 8 — Actuarial loss (gain) (131) 162 (456) 14 Benefits paid (456) (146) (227) (89) Participant contributions — — 47 22 Acquired through business combinations — 5,535 — 3,528 Effect of settlement (101) (94) — — Benefit obligations — end of year $ 6,036 $ 6,565 $ 3,254 $ 3,757 Change in plan assets: Fair value of plan assets — beginning of year $ 5,332 $ 749 $ 783 $ 260 Actual return on plan assets 668 472 29 45 Participant contributions — — 26 17 Employer contributions 155 50 139 30 Benefits paid (454) (146) (165) (88) Acquired through business combinations — 4,301 — 519 Effect of settlement (95) (94) — — Fair value of plan assets — end of year $ 5,606 $ 5,332 $ 812 $ 783 Funded status $ (430) $ (1,233) $ (2,442) $ (2,974) Amounts recognized in Statements of Financial Position: Non-current assets $ 153 $ 3 $ 71 $ 54 Current liabilities (5) (12) (130) (139) Non-current liabilities (578) (1,224) (2,383) (2,889) Total amount recognized $ (430) $ (1,233) $ (2,442) $ (2,974) Amounts recognized in accumulated other comprehensive loss (income): Net actuarial loss (gain) $ (286) $ 164 $ (392) $ 56 Prior service cost (credit) 5 6 4 (6) Net amount recognized $ (281) $ 170 $ (388) $ 50 The accumulated benefit obligation for all defined benefit pension plans was $6,013 million and $6,537 million at December 31, 2021 and 2020, respectively. Components of Net Periodic Benefit Cost (Credit) (In Millions) Pension Benefits OPEB 2021 2020 2019 2021 2020 2019 Service cost $ 56 $ 23 $ 17 $ 51 $ 8 $ 2 Interest cost 103 64 35 74 19 10 Expected return on plan assets (359) (140) (55) (40) (20) (17) Amortization: Net actuarial loss 32 27 24 3 3 5 Prior service costs (credits) 1 1 1 (2) (2) (2) Settlements (22) (6) — — — — Net periodic benefit cost (credit) $ (189) $ (31) $ 22 $ 86 $ 8 $ (2) For 2022, we estimate net periodic benefit cost (credit) as follows: (In Millions) Defined benefit pension plans $ (179) OPEB plans 72 Total $ (107) Components of Accumulated Other Comprehensive Loss (Income) The following includes details on the significant actuarial losses (gains) impacting the benefit obligation: (In Millions) Pension Benefits OPEB 2021 2020 2021 2020 Discount rates $ (224) $ 181 $ (117) $ 44 Demographic updates 76 (3) 3 (11) Mortality 19 (16) 13 (4) Per capita health care costs — — (350) (10) Other (2) — (5) (5) Actuarial loss (gain) on benefit obligation (131) 162 (456) 14 Actual returns on assets under (over) expected (309) (332) 11 (26) Amortization of net actuarial gain (loss) (32) (27) 2 (3) Amortization of prior service credits (costs) (1) (1) (3) 2 Settlements 22 6 — — Other — (27) 8 (2) Total recognized in accumulated other comprehensive income $ (451) $ (219) $ (438) $ (15) Contributions Annual contributions to the pension plans are made within income tax deductibility restrictions in accordance with statutory regulations. OPEB plans are not subject to minimum regulatory funding requirements, but rather amounts are contributed pursuant to bargaining agreements. (In Millions) Pension Benefits 1 Other Benefits 2 Company Contributions & Payments VEBA Direct Total 2020 $ 50 $ — $ 25 $ 25 2021 163 67 113 180 2022 (Expected) 4 28 110 138 1 The 2021 pension contributions include $118 million in deferred 2020 pension contributions in connection with the CARES Act that were paid on January 4, 2021. 2 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, 2021). 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. The amount expected for 2022 in the VEBA column reflects the contribution to be made in February 2022 for earnings in the quarter ended December 31, 2021. We do not include an estimate for contributions beyond that due to the variability of the calculation. Estimated Future Benefit Payments (In Millions) Pension OPEB 2022 $ 475 $ 180 2023 477 171 2024 451 167 2025 428 163 2026 424 163 2027-2031 1,879 823 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. Depending on the plan, we use either company-specific base mortality tables or tables issued by the Society of Actuaries. We use the Pri-2012 mortality tables from the Society of Actuaries with adjustments for blue collar, white collar or no collar depending on the plan. On December 31, 2021, the assumed mortality improvement projection was updated from generational scale MP-2020 to generational scale MP-2021 for the Pri-2012 mortality tables. The following represents weighted-average assumptions used to determine benefit obligations: Pension Benefits OPEB December 31, December 31, 2021 2020 2021 2020 Discount rate 2.75 % 2.34 % 3.01 % 2.71 % Interest crediting rate 5.35 5.25 N/A N/A Compensation rate increase 2.52 2.56 3.00 3.00 The following represents weighted-average assumptions used to determine net benefit cost: Pension Benefits OPEB December 31, December 31, 2021 2020 2019 2021 2020 2019 Obligation discount rate 2.32 % 3.02 % 4.27 % 2.46 % 3.28 % 4.29 % Service cost discount rate 2.78 3.34 4.35 3.28 3.35 4.49 Interest cost discount rate 1.64 2.53 3.92 2.04 2.51 3.94 Interest crediting rate 5.35 5.50 6.00 N/A N/A N/A Expected return on plan assets 6.84 7.69 8.25 5.20 6.82 7.00 Compensation rate increase 2.54 2.56 2.53 3.00 3.00 3.00 The following represents assumed weighted-average health care cost trend rates: December 31, 2021 2020 Health care cost trend rate assumed for next year 2.36 % 6.05 % Ultimate health care cost trend rate 4.50 4.59 Year that the ultimate rate is reached 2031 2031 Plan Assets Our financial objectives with respect to our pension and VEBA assets are to fully fund the actuarial accrued liability for each of the plans, to maximize investment returns within reasonable and prudent levels of risk, and to maintain sufficient liquidity to meet benefit obligations on a timely basis. Our investment objective is to outperform the expected return on assets assumption used in the plans’ actuarial reports over the life of the plans. The expected return on assets takes into account historical returns and estimated future long-term returns based on capital market assumptions applied to the asset allocation strategy. The expected return is net of investment expenses paid by the plans. In addition, investment performance is monitored quarterly by benchmarking to various indices and metrics for the one-, three- and five-year periods. The asset allocation strategy is determined through a detailed analysis of assets and liabilities by plan, which defines the overall risk that is acceptable with regard to the expected level and variability of portfolio returns, surplus (assets compared to liabilities), contributions and pension expense. The asset allocation review process involves simulating capital market behaviors including global asset class performance, inflation and interest rates in order to evaluate various asset allocation scenarios and determine the asset mix with the highest likelihood of meeting financial objectives. The process includes factoring in the current funded status and likely future funded status levels of the plans by taking into account expected growth or decline in the contributions over time. The asset allocation strategy varies by plan. The following table reflects the actual asset allocations for pension and VEBA assets as of December 31, 2021 and 2020, as well as the 2022 weighted average target asset allocations. Equity investments include securities in large-cap, mid-cap and small-cap companies located in the U.S. and worldwide. Fixed income investments primarily include corporate bonds and government debt securities. Pension Assets VEBA Assets Asset Category 2022 Percentage of 2022 Percentage of 2021 2020 2021 2020 Equity securities 46.3 % 47.6 % 51.8 % 21.2 % 22.5 % 22.2 % Fixed income 34.6 34.6 33.8 68.5 66.4 66.4 Hedge funds 2.2 2.2 2.2 1.4 1.8 1.8 Private equity 5.0 2.7 2.1 1.1 — 0.4 Structured credit 5.2 5.6 5.0 1.0 1.2 0.9 Real estate 5.2 5.6 3.3 1.0 2.1 1.8 Absolute return fixed income 1.5 1.7 1.8 5.8 6.0 6.5 Total 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 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 Significant Other Significant Investments Measured at Net Asset Value Total Asset Category 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 Equity securities: U.S. equities $ 1,157 $ 1,163 $ — $ — $ — $ — $ 775 $ 787 $ 1,932 $ 1,950 Global equities 617 615 — — — — 117 195 734 810 Fixed income: U.S. government securities 1 140 141 310 295 — — 50 40 500 476 U.S. corporate bonds 502 512 371 466 — — 503 303 1,376 1,281 Non U.S. and other bonds — — 66 46 — — — — 66 46 Hedge funds — — — — 125 118 — — 125 118 Private equity — — — — 151 114 — — 151 114 Structured credit — — — — 315 264 — — 315 264 Real estate — — — — 313 174 — — 313 174 Absolute return fixed income — — — — — — 94 99 94 99 Total $ 2,416 $ 2,431 $ 747 $ 807 $ 904 $ 670 $ 1,539 $ 1,424 $ 5,606 $ 5,332 1 Includes cash equivalents. 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 fair value of our other benefit plan assets by asset category is as follows: (In Millions) Quoted Prices in Active Significant Other Significant Investments Measured at Net Asset Value Total Asset Category 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 Equity securities: U.S. equities $ 26 $ 26 $ — $ — $ — $ — $ 103 $ 93 $ 129 $ 119 Global equities 6 6 — — — — 48 49 54 55 Fixed income: U.S. government securities 1 111 62 80 94 — — — — 191 156 U.S. corporate bonds 219 237 129 127 — — — — 348 364 Hedge funds — — — — 15 14 — — 15 14 Private equity — — — — — 3 — — — 3 Structured credit — — — — 10 7 — — 10 7 Real estate — — — — 17 14 — — 17 14 Absolute return fixed income — — — — — — 48 51 48 51 Total $ 362 $ 331 $ 209 $ 221 $ 42 $ 38 $ 199 $ 193 $ 812 $ 783 1 Includes cash equivalents. The following represents the fair value measurements of changes in plan assets using significant unobservable inputs (Level 3): (In Millions) Pension Assets VEBA Assets 2021 2020 2021 2020 Beginning balance — January 1 $ 670 $ 212 $ 38 $ 34 Actual return on plan assets: Relating to assets still held at the reporting date 124 8 6 2 Relating to assets sold during the period 8 6 — 1 Purchases 142 195 — — Sales (40) (13) (2) (1) Acquired through business combinations — 262 — 2 Ending balance — December 31 $ 904 $ 670 $ 42 $ 38 Following is a description of the inputs and valuation methodologies used to measure the fair value of our plan assets. Equity Securities Equity securities classified as Level 1 investments include U.S. large-, small- and mid-cap investments and international equities. These investments are comprised of securities listed on an exchange, market or automated quotation system for which quotations are readily available. The valuation of these securities is determined using a market approach and is based upon unadjusted quoted prices for identical assets in active markets. Fixed Income Fixed income securities classified as Level 1 investments include bonds, government debt securities and cash equivalents. These investments are comprised of securities listed on an exchange, market or automated quotation system for which quotations are readily available. The valuation of these securities is determined using a market approach and is based upon unadjusted quoted prices for identical assets in active markets. Also included in fixed income is a portfolio of U.S. Treasury STRIPS, which are zero-coupon bearing fixed income securities backed by the full faith and credit of the U.S. government. The securities sell at a discount to par because there are no incremental coupon payments. STRIPS are not issued directly by the Treasury, but rather are created by a financial institution, government securities broker or government securities dealer. Liquidity on the issue varies depending on various market conditions; however, in general, the STRIPS market is slightly less liquid than that of the U.S. Treasury Bond market. The STRIPS are priced daily through a bond pricing vendor and are classified as Level 2. Hedge Funds Hedge funds are alternative investments comprised of direct or indirect investment in offshore hedge funds with an investment objective to achieve equity-like returns with one half the volatility of equities and moderate correlation. The valuation techniques used to measure fair value attempt to maximize the use of observable inputs and minimize the use of unobservable inputs. Considerable judgment is required to interpret the factors used to develop estimates of fair value. Valuations of the underlying investment funds are obtained and reviewed. The securities that are valued by the funds are interests in the investment funds and not the underlying holdings of such investment funds. Thus, the inputs used to value the investments in each of the underlying funds may differ from the inputs used to value the underlying holdings of such funds. Hedge funds are valued monthly and recorded on a one-month lag. Private Equity Funds Private equity funds are alternative investments that represent direct or indirect investments in partnerships, venture funds or a diversified pool of private investment vehicles (fund of funds). Investment commitments are made in private equity funds based on an asset allocation strategy, and capital calls are made over the life of the funds to fund the commitments. As of December 31, 2021, remaining commitments total $151 million for our pension and OPEB plans. Committed amounts are funded from plan assets when capital calls are made. Investment commitments are not pre-funded in reserve accounts. Private equity investments are valued quarterly and recorded on a one-quarter lag. For private equity investment values reported on a lag, current market information is reviewed for any material changes in values at the reporting date. Capital distributions for the funds do not occur on a regular frequency. Liquidation of these investments would require sale of the partnership interest. Structured Credit Structured credit funds provide flexibility and access to both complex and illiquid premiums by investing across global, public and private residential, commercial, corporate and specialty credit markets that are priced based on valuations provided by independent, third-party pricing agents, if available. Such values generally reflect the last reported sales price if the security is actively traded. The third-party pricing agents may also value structured credit investments at an evaluated bid price by employing methodologies that utilize actual market transactions, broker-supplied valuations or other methodologies designed to identify the market value of such securities. Structured credit investments are valued monthly and certain funds have an initial lock-up period and withdrawal restrictions on a semi-annual and quarterly basis. For structured credit investment values reported on a lag, current market information is reviewed for any material changes in values at the reporting date. Real Estate The real estate portfolio for the pension plans is an alternative investment comprised of funds with strategic categories of real estate investments. All real estate holdings are appraised externally at least annually, and appraisals are conducted by reputable, independent appraisal firms that are members of the Appraisal Institute. All external appraisals are performed in accordance with the Uniform Standards of Professional Appraisal Practices. The property valuations and assumptions about each property are reviewed quarterly by the investment manager and values are adjusted if there has been a significant change in circumstances relating to the property since the last external appraisal. The fair values of the funds are updated on either a monthly or quarterly basis. Redemption requests are considered on a quarterly basis, subject to notice requirements. The real estate fund of funds investment for the VEBA trusts invests in pooled investment vehicles that, in turn, invest in commercial real estate properties. Valuations are performed quarterly and financial statements are prepared on a semi-annual basis, with annual audited statements. Asset values for this fund are reported with a one- quarter lag, and current market information is reviewed for any material changes in values at the reporting date. Withdrawals are permitted on the last business day of each quarter subject to a 95-day prior written notice. Absolute Return Fixed Income Absolute return fixed income investments consist of a global fixed income fund with the investment objective of generating positive absolute returns over a full market cycle. The fund's investments in securities, forward exchange contracts and futures contracts are reported at fair value on a recurring monthly basis. The fund's trustee values securities based upon independent pricing sources and futures contracts are valued at closing settled prices. Redemptions of the fund at NAV are permitted monthly under most circumstances. 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 $55 million, $22 million and $3 million in 2021, 2020 and 2019, respectively. Multiemployer 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 (a) FIP/RP Status Pending/Implemented (b) Contributions Surcharge Imposed (c) Expiration Date of Collective Bargaining Agreement (d) 2021 2020 2021 2020 2019 Steelworkers Pension Trust 23-6648508/499 Green Green No $ 88 $ 14 $ 4 No 9/1/2022 to 09/1/2025 IAM National Pension Fund’s National Pension Plan 51-6031295/002 Red Red Yes 16 16 — Yes 5/31/2022 to 5/15/2023 Other Plans (e) — — — Total $ 104 $ 30 $ 4 (a) The most recent Pension Protection Act zone status available in 2021 and 2020 is for each plan's year-end at December 31, 2020 and 2019. 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". (b) 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. (c) The surcharge represents an additional required contribution due as a result of the critical funding status of the plan. (d) We are a party to five 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. (e) Plans that are not individually significant to our Company are presented in aggregate. With the 2020 Acquisitions, we are one of the largest contributors to the Steelworkers Pension Trust. Our contributions exceeded 5% of total combined contributions in 2021 and 2020. As of January 1, 2021 (the last date for which we have information), the Steelworkers Pension Trust had a total actuarial liability of $5,960 million and assets with a market value of $5,998 million, for a funded ratio of about 101%.

STOCK COMPENSATION PLANS

STOCK COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
STOCK COMPENSATION PLANS	NOTE 11 - STOCK COMPENSATION PLANS At December 31, 2021, we had outstanding awards under three share-based compensation plans: the 2021 Equity Plan, the A&R 2015 Equity Plan and the 2012 Amended Equity Plan. On April 28, 2021, the Company's shareholders approved the 2021 Equity Plan, which succeeded the A&R 2015 Equity Plan and made available 26.0 million new common shares plus 2.5 million shares remaining available under the A&R 2015 Equity Plan. As of December 31, 2021, there were 28.0 million remaining shares available for grant under the 2021 Equity Plan. No additional grants were issued from the 2012 Amended Equity Plan or the A&R 2015 Equity Plan after the date of approval of the 2021 Equity Plan; however, all awards previously granted under the predecessor plans will continue in accordance with the terms of the outstanding awards. On March 13, 2020, the maximum number of shares that may be issued under the A&R 2015 Equity Plan increased by 5.7 million common shares in relation to the outstanding AK Steel stock-based incentive awards that we converted at a 0.400 rate of exchange. The converted stock-based incentive awards include 2.0 million stock options, 1.0 million long-term performance plan awards, 0.5 million performance shares, 0.2 million restricted stock awards and 0.3 million restricted stock units. Stock-Based Compensation Expense The following table summarizes the total compensation expense recognized for stock-based compensation awards: (In Millions, except per Year Ended December 31, 2021 2020 2019 Cost of goods sold $ (2) $ (2) $ (2) Selling, general and administrative expenses (16) (13) (16) Acquisition-related costs — (2) — Stock based compensation expense (18) (17) (18) Income tax benefit 4 4 4 Stock based compensation expense, net of tax $ (14) $ (13) $ (14) Decrease in basic earnings per common share $ (0.03) $ (0.03) $ (0.05) Decrease in diluted earnings per common share $ (0.03) $ (0.03) $ (0.05) The total compensation cost related to outstanding awards not yet recognized is $24 million at December 31, 2021. This expense is expected to be recognized over the remaining weighted-average period of 1.4 years. Performance Shares The following table summarizes the performance award activity: Year Ended December 31, 2021 2020 2019 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 2,452,226 $ 10.34 1,935,878 $ 15.58 1,424,723 $ 14.46 Granted 652,888 25.12 960,637 6.93 572,104 18.31 Granted - replacement awards — — 1,550,216 4.59 — — Distributed (1,279,509) 11.74 (1,938,786) 12.23 — — Performance adjustment 625,355 11.93 549,154 15.63 — — Forfeited/canceled (80,490) 11.27 (604,873) 5.70 (60,949) 15.12 Outstanding at end of year 2,370,470 $ 14.04 2,452,226 $ 10.34 1,935,878 $ 15.58 On March 13, 2020, we granted 1.0 million long-term performance plan awards and 0.5 million performance shares as AK Steel replacement awards. As of December 31, 2021, 0.2 million long-term performance plan awards and 0.1 million performance shares were outstanding as a result of qualifying termination events that triggered accelerated performance share payouts and prorated long-term performance plan awards payouts at target. The long-term performance plan awards are based on a three-year Adjusted EBITDA metric. 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. Restricted Stock Units The following table summarizes the restricted stock units activity: Year Ended December 31, 2021 2020 2019 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 2,143,583 $ 7.12 2,147,183 $ 9.10 4,694,360 $ 4.18 Granted 678,420 17.45 960,637 4.87 572,104 11.24 Granted - replacement awards — — 200,291 4.87 — — Distributed (642,992) 7.31 (1,101,115) 8.58 (3,058,307) 1.95 Forfeited/canceled (56,185) 9.50 (63,413) 7.31 (60,974) 9.31 Outstanding at end of year 2,122,826 $ 10.31 2,143,583 $ 7.12 2,147,183 $ 9.10 On March 13, 2020, we granted 0.2 million restricted stock awards as AK Steel replacement awards. The restricted stock awards relating to AK Steel vest ratably on the first, second and third anniversaries of the grant. We valued the AK Steel replacement rewards at $4.87 per share using the closing price of our common shares on March 13, 2020, the grant date. 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 that were granted in 2021, 2020 and 2019 cliff vest over three years on December 31, 2023, December 31, 2022 and December 31, 2021, respectively. Stock Options The following table summarizes the stock option activity: Year Ended December 31, 2021 2020 2019 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 2,485,808 $ 11.60 563,230 $ 10.42 563,230 $ 10.42 Granted - replacement awards — — 2,010,277 11.86 — — Exercised (1,457,495) 10.36 (79,973) 7.01 — — Forfeited/canceled (26,253) 36.48 (7,726) 41.04 — — Outstanding at end of year 1,002,060 $ 12.75 2,485,808 $ 11.60 563,230 $ 10.42 Exercisable at end of year 904,574 $ 13.35 2,172,052 $ 11.86 563,230 $ 10.42 Stock options granted to date generally vest over a period from one to three years with an expiration date at ten years from the date of grant. On March 13, 2020, we granted 2.0 million options as AK Steel replacement awards. The weighted average fair value of the converted options was $0.51 per share and was calculated using the Black-Scholes option-pricing model. Qualifying termination events resulted in vest date accelerations and reductions to the option expiration date from ten years to three years. The total intrinsic value of options exercised in 2021 was $13 million and the amount in 2020 was immaterial. For options outstanding at December 31, 2021, the weighted-average remaining contractual life was 3.0 years and the aggregate intrinsic value was $10 million. For options exercisable at December 31, 2021, the weighted-average remaining contractual life was 2.6 years and the aggregate intrinsic value was $8 million. Nonemployee Directors Our nonemployee directors are entitled to receive restricted share awards under the Directors’ Plan. For 2021, 2020 and 2019, nonemployee directors were granted a specified number of restricted shares, with a value equal to $120,000, $100,000 and $100,000, respectively. The number of shares is based on the closing price of our common shares on the date of the Annual Meeting. 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. On March 13, 2020, 0.3 million restricted stock units previously awarded to the members of the AK Steel board of directors were distributed per the terms of the AK Steel Merger Agreement. For the last three years, grants of restricted and/or deferred shares have been awarded to elected or re-elected nonemployee directors as follows: Year of Grant Restricted Shares Deferred Shares 2021 58,851 13,078 2020 253,809 54,794 2019 86,477 23,659

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	NOTE 12 - INCOME TAXES Income (loss) from continuing operations before income taxes includes the following components: (In Millions) 2021 2020 2019 United States $ 3,827 $ (201) $ 313 Foreign (24) 8 — $ 3,803 $ (193) $ 313 The components of the income tax provision (benefit) on continuing operations consist of the following: (In Millions) 2021 2020 2019 Current provision (benefit): United States federal $ 14 $ (2) $ (1) United States state & local 55 — — Foreign — (1) — 69 (3) (1) Deferred provision (benefit): United States federal 683 (95) 19 United States state & local 31 (11) — Foreign (10) (2) — Total income tax provision (benefit) from continuing operations $ 773 $ (111) $ 18 Reconciliation of our income tax attributable to continuing operations computed at the U.S. federal statutory rate is as follows: (In Millions) 2021 2020 2019 Tax at U.S. statutory rate $ 799 21 % $ (41) 21 % $ 66 21 % Increase (decrease) due to: Percentage depletion in excess of cost depletion (99) (3) (42) 22 (49) (16) Non-taxable income related to noncontrolling interests (9) — (9) 4 — — Luxembourg legal entity reduction — — — — 846 271 Valuation allowance release: Luxembourg legal entity reduction — — — — (846) (271) State taxes, net 86 2 (11) 6 — — Other items, net (4) — (8) 4 1 1 Provision for income tax expense (benefit) and effective income tax rate including discrete items $ 773 20 % $ (111) 57 % $ 18 6 % The increase in income tax expense in 2021 from income tax benefit in 2020 is directly correlated to the increase in pre-tax book income from the prior period for both federal and state income tax purposes. The increase in income tax benefit from 2019 to 2020 is directly correlated to the decrease in pre-tax book income from the prior period for both federal and state income tax purposes. The Luxembourg legal entity reduction relates to initiatives resulting in the dissolution of certain entities and settlement of related financial instruments in 2019. The 2019 NOL deferred tax asset reduction resulted in tax expense of $846 million, which was fully offset by a decrease in the respective valuation allowance. The components of income taxes for other than continuing operations consisted of the following: (In Millions) 2021 2020 2019 Other comprehensive income (loss): Pension and OPEB $ (206) $ (52) $ 11 Derivative financial instruments (21) (1) — Total $ (227) $ (53) $ 11 Significant components of our deferred tax assets and liabilities are as follows: (In Millions) 2021 2020 Deferred tax assets: Operating loss and other carryforwards $ 379 $ 1,236 Pension and OPEB liabilities 584 228 State and local 109 132 Other liabilities 287 190 Total deferred tax assets before valuation allowance 1,359 1,786 Deferred tax asset valuation allowance (409) (836) Net deferred tax assets 950 950 Deferred tax liabilities: Investment in partnerships (191) (144) Property, plant and equipment and mineral rights (641) (246) Other assets (216) (68) Total deferred tax liabilities (1,048) (458) Net deferred tax assets (liabilities) $ (98) $ 492 We had gross domestic (including states) and foreign NOLs of $2,081 million and $1,407 million, respectively, at December 31, 2021. We had gross domestic and foreign NOLs of $7,444 million and $1,592 million, respectively, at December 31, 2020. The U.S. federal NOLs will begin to expire in 2034 and state NOLs will begin to expire in 2022. The foreign NOLs can be carried forward indefinitely. We had gross interest expense limitation carryforwards of $18 million and $80 million for the years ended December 31, 2021 and 2020, respectively. This interest expense can be carried forward indefinitely. The changes in the valuation allowance are presented below: (In Millions) 2021 2020 2019 Balance at beginning of year $ 836 $ 441 $ 1,287 Change in valuation allowance: Included in income tax benefit (82) (3) (846) Increase (decrease) from acquisitions (345) 398 — Balance at end of year $ 409 $ 836 $ 441 During 2021, we recorded a decrease to the valuation allowance of $345 million related to the election filed with our 2020 federal tax return to waive the pre-acquisition NOLs that are limited under Section 382 of the IRC. An offsetting decrease is recorded in the NOL deferred tax asset in the same period. These amounts relate to a portion of the $398 million valuation allowance recorded during 2020 through opening balance sheet adjustments to reflect the portion of federal and state NOLs that are limited under Section 382 of the IRC acquired through the AK Steel Merger. During 2019, a legal entity reduction initiative was completed in Luxembourg resulting in the dissolution of certain entities and settlement of related financial instruments, triggering the utilization of $1.3 billion of NOL deferred tax asset and reversal of the intercompany notes deferred tax liability of $447 million. The total net deferred tax reduction resulted in an expense of $846 million, which was fully offset by a decrease in the valuation allowance. Our losses in Luxembourg in recent periods represent sufficient negative evidence to require a full valuation allowance against the remaining deferred tax assets in that jurisdiction. We intend to maintain a valuation allowance against the deferred tax assets related to these operating losses until sufficient positive evidence exists to support the realization of such assets. We also have a valuation allowance recorded against certain state NOLs, which are expected to expire before utilization. At December 31, 2021 and 2020, we had a valuation allowance recorded against certain state NOLs of $70 million and $98 million, respectively. At December 31, 2021 and 2020, 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) 2021 2020 2019 Unrecognized tax benefits balance as of January 1 $ 107 $ 29 $ 29 Increase for tax positions in current year 4 7 — Decrease for tax positions of prior year (66) (4) — Lapses in statutes of limitations (10) — — Increases from acquisitions — 75 — Unrecognized tax benefits balance as of December 31 $ 35 $ 107 $ 29 At December 31, 2021 and 2020, we had $35 million and $107 million, respectively, of unrecognized tax benefits recorded. Of this amount, $1 million was recorded in Other current liabilities for the year ended December 31, 2021. Additionally, $34 million and $2 million, were recorded in Other non-current liabilities for the years ended December 31, 2021 and 2020, respectively. An additional $96 million was recorded in Other non-current assets for the year ended December 31, 2020. If the unrecognized tax benefits were recognized, $30 million would impact the effective tax rate. 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 2008 and forward remain subject to examination for Canada.

LEASE OBLIGATIONS

LEASE OBLIGATIONS	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
LEASE OBLIGATIONS	NOTE 13 - LEASE OBLIGATIONS Our operating leases consist primarily of leases for office space, iron ore vessels, rail cars and processing equipment. Our finance leases consist primarily of processing equipment and mining equipment. We use our incremental borrowing rate as the discount rate to determine the present value of the lease payments, as our leases do not have readily determinable implicit discount rates. 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. Lease costs are presented below: (In Millions) Year Ended December 31, 2021 2020 Operating leases $ 70 $ 43 Finance leases: Amortization of lease cost 94 15 Interest on lease liabilities 9 4 Short-term leases 66 13 Total $ 239 $ 75 Other information related to leases was as follows: (In Millions) Year Ended December 31, 2021 2020 Cash paid for amounts included in measurement of lease liabilities: Operating leases within cash flows from operating activities $ 70 $ 43 Finance leases within cash flows from operating activities $ 9 $ 4 Finance leases within cash flows from financing activities $ 94 $ 15 Right-of-use assets obtained in exchange for new finance lease liabilities 1 $ 50 $ 44 Weighted-average remaining lease term - operating leases (in years) 8 8 Weighted-average remaining lease term - finance leases (in years) 5 5 Weighted-average discount rate - operating leases 7 % 8 % Weighted-average discount rate - finance leases 4 % 4 % 1 Right-of-use assets obtained in acquisitions are not included in this figure. Future minimum lease payments under noncancellable finance and operating leases as of December 31, 2021 were as follows: (In Millions) Finance Leases Operating Leases 2022 $ 105 $ 68 2023 96 56 2024 31 47 2025 28 39 2026 19 35 Thereafter 66 133 Total future minimum lease payments 345 378 Less: imputed interest 54 108 Total lease payments 291 270 Less: current portion of lease liabilities 97 50 Long-term lease liabilities $ 194 $ 220 The current and long-term portions of our finance and operating lease liabilities are included in Other current liabilities and Other non-current liabilities

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS	12 Months Ended
	Dec. 31, 2021
Environmental Remediation Obligations [Abstract]
ASSET RETIREMENT OBLIGATIONS	NOTE 14 - ASSET RETIREMENT OBLIGATIONS The following is a summary of our asset retirement obligations: (In Millions) December 31, 2021 2020 Asset retirement obligations 1 $ 449 $ 342 Less: current portion 35 7 Long-term asset retirement obligations $ 414 $ 335 1 Includes $293 million and $190 million related to our active operations as of December 31, 2021 and 2020, respectively. 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. We performed a detailed assessment of our asset retirement obligations related to our active operations most recently in 2020 in accordance with our accounting policy, which requires us to perform an in-depth evaluation of the liability every three years in addition to routine annual assessments. In 2020, we employed third-party specialists to assist in the evaluation. 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. As the majority of our asset retirement obligations at our steelmaking operations have indeterminate settlement dates, asset retirement obligations have been recorded at present values using estimated ranges of the economic lives of the underlying assets. The following is a roll-forward of our asset retirement obligation liability: (In Millions) 2021 2020 Asset retirement obligation as of January 1 $ 342 $ 165 Increase from acquisitions 116 172 Accretion expense 18 14 Remediation payments (29) (9) Revision in estimated cash flows 2 — Asset retirement obligation as of December 31 $ 449 $ 342 The increase from acquisitions for the year ended December 31, 2021 relates to measurement period adjustments as a result of the final purchase price allocation of the AM USA Transaction.

CAPITAL STOCK

CAPITAL STOCK	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
CAPITAL STOCK	NOTE 15 - CAPITAL STOCK Underwritten Public Offering On February 11, 2021, we sold 20 million of our common shares and 40 million common shares were sold by an affiliate of ArcelorMittal in an underwritten public offering. In each case, shares were sold at a price per share of $16.12. Prior to this sale, ArcelorMittal held approximately 78 million of our common shares, which were issued as a part of the consideration in connection with the AM USA Transaction. We did not receive any proceeds from the sale of the 40 million common shares sold on behalf of ArcelorMittal. We used the net proceeds from the offering, plus cash on hand, to redeem $322 million aggregate principal amount of our outstanding 9.875% 2025 Senior Secured Notes. Acquisition of AK Steel As more fully described in NOTE 3 - ACQUISITIONS, we acquired AK Steel on March 13, 2020. At the effective time of the AK Steel Merger, each share of AK Steel common stock issued and outstanding prior to the effective time of the AK Steel Merger was converted into, and became exchangeable for, 0.400 Cliffs common shares, par value $0.125 per share. We issued a total of 127 million common shares in connection with the AK Steel Merger at a fair value of $618 million. Following the closing of the AK Steel Merger, AK Steel's common stock was de-listed from the NYSE. Acquisition of ArcelorMittal USA As more fully described in NOTE 3 - ACQUISITIONS, we acquired ArcelorMittal USA on December 9, 2020. Pursuant to the terms of the AM USA Transaction Agreement, we issued 78,186,671 common shares and 583,273 shares of a new series of our Serial Preferred Stock, Class B, without par value, designated as the “Series B Participating Redeemable Preferred Stock,” in each case to an indirect, wholly owned subsidiary of ArcelorMittal as part of the consideration paid by us in connection with the closing of the AM USA Transaction. Series B Participating Redeemable Preferred Stock Redemption We had 583,273 shares of our Series B Participating Redeemable Preferred Stock issued and outstanding as of December 31, 2020. During the third quarter of 2021, we redeemed all 583,273 shares of our Series B Participating Redeemable Preferred Stock at a redemption price of $1.3 billion using borrowings under our ABL Facility. Amendment to Articles of Incorporation On April 29, 2021, we filed a Certificate of Amendment to our Fourth Amended Articles of Incorporation, as amended, to increase the total number of authorized common shares from 600,000,000 to 1,200,000,000. Preferred Stock We have 3,000,000 shares of Serial Preferred Stock, Class A, without par value, authorized, of which, none are issued or outstanding as of December 31, 2021. We also have 4,000,000 shares of Serial Preferred Stock, Class B, without par value, authorized, of which, none are issued or outstanding as of December 31, 2021. Dividends The below table summarizes our recent dividend activity: Declaration Date Record Date Payment Date Dividend Declared per Common Share 2/18/2020 4/3/2020 4/15/2020 $ 0.06 12/2/2019 1/3/2020 1/15/2020 0.06 Subsequent to the dividend paid on April 15, 2020, our Board suspended future dividends. Share Repurchase Program

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	The components of Accumulated other comprehensive income (loss) within Cliffs shareholders’ equity and related tax effects allocated to each are shown below: (In Millions) Pre-tax Tax Benefit After-tax As of December 31, 2021: Pension and OPEB $ 669 $ (120) $ 549 Foreign currency translation adjustments 1 — 1 Derivative financial instruments 89 (21) 68 $ 759 $ (141) $ 618 As of December 31, 2020: Pension and OPEB $ (221) $ 86 $ (135) Foreign currency translation adjustments 3 — 3 Derivative financial instruments (1) — (1) $ (219) $ 86 $ (133) As of December 31, 2019: Pension and OPEB $ (454) $ 138 $ (316) Derivative financial instruments (4) 1 (3) $ (458) $ 139 $ (319) The following table reflects the changes in Accumulated other comprehensive income (loss) related to Cliffs shareholders’ equity: (In Millions) Postretirement Benefit Liability, Foreign Currency Translation Derivative Financial Instruments, Accumulated Other Comprehensive Income (Loss) December 31, 2018 $ (281) $ — $ (3) $ (284) Other comprehensive loss before reclassifications (57) — (2) (59) Net loss reclassified from AOCI 22 — 2 24 December 31, 2019 (316) — (3) (319) Other comprehensive income (loss) before reclassifications 163 3 (6) 160 Net loss reclassified from AOCI 18 — 8 26 December 31, 2020 (135) 3 (1) (133) Other comprehensive income (loss) before reclassifications 675 (2) 117 790 Net loss (gain) reclassified from AOCI 9 — (48) (39) December 31, 2021 $ 549 $ 1 $ 68 $ 618 The following table reflects the details about Accumulated other comprehensive income (loss) components reclassified from Cliffs shareholders’ equity: (In Millions) Details about Accumulated Other Comprehensive Income (Loss) Components Amount of (Gain)/Loss Affected Line Item in the Statement of Consolidated Operations Year Ended December 31, 2021 2020 2019 Changes in pension and OPEB: Prior service costs 1 $ (1) $ (1) $ (1) Net periodic benefit credits (costs) other than service cost component Net actuarial loss 1 35 30 29 Net periodic benefit credits (costs) other than service cost component Settlements 1 (22) (6) — Net periodic benefit credits (costs) other than service cost component Total before taxes 12 23 28 Income tax benefit (3) (5) (6) Income tax benefit (expense) Net of taxes $ 9 $ 18 $ 22 Changes in derivative financial instruments: Commodity contracts $ (61) $ 10 $ 3 Cost of goods sold Income tax expense (benefit) 13 (2) (1) Income tax benefit (expense) Net of taxes $ (48) $ 8 $ 2 Total reclassifications for the period, net of tax $ (39) $ 26 $ 24 1 See NOTE 10 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information.

RELATED PARTIES

RELATED PARTIES	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
RELATED PARTIES	NOTE 17 - RELATED PARTIES We have certain co-owned joint ventures with companies from the steel and mining industries, including integrated steel companies, their subsidiaries and other downstream users of steel and iron ore products. Hibbing is a co-owned joint venture with U.S. Steel, in which, as of both December 31, 2020 and December 31, 2021, we own 85.3% and U.S. Steel owns 14.7%. As a result of the AM USA Transaction, we acquired an additional 62.3% ownership stake in the Hibbing mine and became the majority owner and mine manager. Prior to the AM USA Transaction, ArcelorMittal was a related party due to its ownership interest in Hibbing. As such, certain long-term contracts with ArcelorMittal resulted in Revenues from related parties, and are included within the below. Revenues from related parties were as follows: (In Millions) Year Ended December 31, 2021 2020 2019 Revenue from related parties $ 139 $ 893 $ 1,015 Revenues $ 20,444 $ 5,354 $ 1,990 Related party revenues as a percent of Revenues 0.7 % 16.7 % 51.0 % Purchases from related parties $ 94 $ 16 $ — The following table presents the classification of related party assets and liabilities in the Statements of Consolidated Financial Position: (In Millions) December 31, Balance Sheet Location of Assets (Liabilities) 2021 2020 Accounts receivable, net $ 3 $ 2 Accounts payable (7) (6)

VARIABLE INTEREST ENTITIES

VARIABLE INTEREST ENTITIES	12 Months Ended
	Dec. 31, 2021
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 and $41 million for the years ended December 31, 2021 and 2020, respectively, which was included in our consolidated Income (loss) from continuing operations before income taxes . 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: (In Millions) December 31, 2021 2020 Cash and cash equivalents $ — $ 5 Inventories 20 21 Property, plant and equipment, net 300 308 Accounts payable (12) (15) Other assets (liabilities), net (12) (10) Noncontrolling interests (296) (309)

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
EARNINGS PER SHARE	The following table summarizes the computation of basic and diluted EPS: (In Millions, Except Per Share Amounts) Year Ended December 31, 2021 2020 2019 Income (loss) from continuing operations $ 3,030 $ (82) $ 295 Income from continuing operations attributable to noncontrolling interest (45) (41) — Net income (loss) from continuing operations attributable to Cliffs shareholders 2,985 (123) 295 Income (loss) from discontinued operations, net of tax 3 1 (2) Net income (loss) attributable to Cliffs shareholders $ 2,988 $ (122) $ 293 Weighted average number of shares: Basic 498 379 277 Redeemable preferred shares 33 — — Convertible senior notes 22 — 4 Employee stock plans 5 — 3 Diluted 558 379 284 Earnings (loss) per common share attributable to Cliffs common shareholders - basic 1 : Continuing operations $ 5.62 $ (0.32) $ 1.07 Discontinued operations 0.01 — (0.01) $ 5.63 $ (0.32) $ 1.06 Earnings (loss) per common share attributable to Continuing operations $ 5.35 $ (0.32) $ 1.04 Discontinued operations 0.01 — (0.01) $ 5.36 $ (0.32) $ 1.03 1 For the year ended December 31, 2021, basic earnings per share was calculated by dividing Net income (loss) attributable to Cliffs shareholders , less $187 million of earnings attributed to Series B Participating Redeemable Preferred Stock, by the weighted average number of basic common shares outstanding during the period presented. The following table summarizes the shares that have been excluded from the diluted earnings per share calculation for the year ended December 31, 2020, as they were anti-dilutive: (In Millions) 2020 Redeemable preferred shares 4 Convertible senior notes 2 Shares related to employee stock plans 1

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2021
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 steel manufacturing 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 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. 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 Although we believe our operating practices have been consistent with prevailing industry standards, hazardous materials may have been released at operating sites or third-party sites in the past, including operating sites that we no longer own. 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, 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: (In Millions) December 31, December 31, Environmental obligations $ 207 $ 135 Less current portion 20 18 Long-term environmental obligations $ 187 $ 117 The increase in environmental obligations as of December 31, 2021, compared to December 31, 2020, related to measurement period adjustments as a result of the purchase price allocation of the AM USA Transaction and the preliminary purchase price allocation of the FPT Acquisition. 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 for the environmental matters discussed below 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 these investigations are still 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. On April 29, 2002, AK Steel entered a mutually agreed-upon administrative order with the consent of the EPA pursuant to Section 122 of CERCLA to perform a RI/FS of the Hamilton plant site located in New Miami, Ohio. The plant ceased operations in 1990 and all of its former structures have been demolished. AK Steel submitted the investigation portion of the RI/FS and completed supplemental studies. Until the RI/FS is complete, we cannot reasonably estimate the additional costs, if any, we may incur for potentially required remediation of the site or when we may incur them. Burns Harbor Water Issues In August 2019, ArcelorMittal Burns Harbor LLC (n/k/a Cleveland-Cliffs Burns Harbor LLC) suffered a loss of the blast furnace cooling water recycle system, which led to the discharge of cyanide and ammonia in excess of the Burns Harbor plant's NPDES permit limits. Since that time, the facility has taken numerous steps to prevent recurrence and maintain compliance with its NPDES permit. We engaged in settlement discussions with the U.S. Department of Justice, the EPA and the State of Indiana to resolve any alleged violations of environmental laws or regulations arising out of the August 2019 event. Later stages of the settlement discussions included the Environmental Law and Policy Center (ELPC) and Hoosier Environmental Council (HEC), which had filed a lawsuit on December 20, 2019 in the U.S. District Court for the Northern District of Indiana alleging violations resulting from the August 2019 event and other Clean Water Act claims. We believe that a consent decree has been finalized and is currently pending final approvals, which requires specified enhancements to the mill's wastewater treatment systems and a $3 million civil penalty, along with other terms and conditions. ELPC and HEC are also proposed signatories to the consent decree. ArcelorMittal Burns Harbor LLC was served with a subpoena on December 5, 2019, from the United States District Court for the Northern District of Indiana, relating to the August 2019 event and has responded to the subpoena requests, including follow-up requests. With the resolution of monetary sanctions and injunctive relief requirements under the pending consent decree, we do not believe that the costs to resolve any other third-party claims, including potential natural resource damages claims, that may arise out of the August 2019 event are likely to have, individually or in the aggregate, a material adverse effect on our consolidated financial condition, results of operations or cash flows. 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 12 - 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 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

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	NOTE 21 - SUBSEQUENT EVENTS On December 1, 2021, we issued a notice of redemption for all $294 million in aggregate principal amount outstanding of the 1.500% 2025 Convertible Senior Notes. The 1.500% 2025 Convertible Senior Notes were redeemed on January 18, 2022, through a combination settlement, with the aggregate principal amount of $294 million paid in cash, and 24 million common shares, with a fair value of $499 million, delivered to noteholders in settlement of the premium due per the terms of the indenture, plus cash in respect of the accrued and unpaid interest on the 1.500% 2025 Convertible Senior Notes to, but not including, the redemption date per the terms of the indenture. On February 10, 2022, our Board of Directors authorized a program to repurchase 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 billion. We are not obligated to make any purchases and the program may be suspended or discontinued at any time. The share repurchase program does not have a specific expiration date.

BASIS OF PRESENTATION AND SIG_2

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Consolidation	Basis of Consolidation The condensed 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. As of December 31, 2019, our 23% ownership in Hibbing was recorded as an equity method investment. As a result of the acquisition of ArcelorMittal USA, we acquired an additional 62.3% ownership interest in Hibbing. As of both December 31, 2021 and December 31, 2020, our ownership in the Hibbing joint venture was 85.3% and was fully consolidated within our operating results with a noncontrolling interest. Our investment in affiliates of $128 million and $105 million as of December 31, 2021 and 2020, 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
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 engaged independent valuation specialists to assist with the determination of the fair value of assets acquired, liabilities assumed, noncontrolling interest, and goodwill, for the acquisitions. 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 would have 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 and Cash Equivalents 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.
Trade Accounts Receivable and Allowance for Credit Loss	Trade Accounts Receivable and Allowance for Credit LossTrade 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 in accordance with CECL. 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. Refer to NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION for further information.
Derivative Financial Instruments and Hedging Activities	Derivative Financial 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 financial instruments are recognized as either assets or liabilities in 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 (loss) . Amounts recorded in Accumulated other comprehensive income (loss) 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. 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 27 years Refer to NOTE 6 - PROPERTY, PLANT AND EQUIPMENT for further information.
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, but it is assessed for impairment on an annual basis on October 1 (or more frequently if necessary). Refer to NOTE 3 - ACQUISITIONS and NOTE 7 - GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES for further information. Other Intangible Assets and Liabilities Intangible assets and liabilities are subject to periodic amortization on a straight-line basis over their estimated useful lives. Refer to NOTE 3 - ACQUISITIONS and NOTE 7 - GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES for further information.
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. For short-term leases (leases with an initial lease term of 12 months or less), right-of-use assets and lease liabilities are not recognized in the consolidated balance sheet. Operating lease expense is recognized on a straight-line basis over the lease term. Refer to NOTE 13 - LEASE OBLIGATIONS for further information.
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. For the years ended December 31, 2021, 2020 and 2019, no impairment indicators were present that would indicate the carrying value of any of our asset groups may not be recoverable; as a result, no impairment assessments were required.
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. Refer to NOTE 9 - FAIR VALUE OF FINANCIAL INSTRUMENTS and NOTE 10 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information.
Pension and Other Postretirement Plans	Pensions 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 (loss) in the Statements of Consolidated Financial Position. The actuarial estimates of the PBO and APBO incorporate various assumptions including the discount rates, the rates of increases in compensation, healthcare cost trend rates, mortality, retirement timing and employee turnover. 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 (costs) other than service cost component. Refer to NOTE 10 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information.
Labor Agreements	Labor Agreements At December 31, 2021, we employed approximately 26,000 people, of which approximately 18,500 were represented by labor unions under various agreements. We have ten agreements that expire in 2022 and three agreements that expire in 2023. Workers at some of our North American facilities are covered by agreements with the USW, UAW and IAM, as well as several other smaller unions that have various expiration dates.
Asset Retirement Obligations	Asset Retirement Obligations Asset retirement obligations are recognized when incurred and recorded as liabilities 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 earnings in the period an estimate is revised. Refer to NOTE 14 - ASSET RETIREMENT OBLIGATIONS for further information.
Environmental Remediation Costs	Environmental Remediation Costs Certain of 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. Refer to NOTE 20 - COMMITMENTS AND CONTINGENCIES for further information.
Revenue Recognition	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, when title transfers to our customer for product shipped 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. Refer to NOTE 4 - REVENUES for further information.
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.
Share-based Compensation	Share-Based Compensation The fair value of each performance share grant is estimated on the date of grant using a Monte Carlo simulation to forecast relative TSR performance. A correlation matrix of historical and projected stock prices was developed for both the Company and its predetermined peer group of mining and metals 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 mining and metals 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. The fair value of the restricted stock units is determined based on the closing price of our common shares on the grant date. Upon vesting of share-based compensation awards, we issue shares from treasury shares before issuing new shares. Forfeitures are recognized when they occur. 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. Refer to NOTE 11 - STOCK COMPENSATION PLANS for additional information.
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 Net income (loss) in the period that includes the enactment date. 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. Refer to NOTE 12 - INCOME TAXES for further information.
Foreign Currency	Foreign Currency Our financial statements are prepared with the U.S. dollar as the reporting currency, and the functional currency of all subsidiaries is the U.S. dollar, except for our European Operations for which the functional currency is the Euro.
Earnings Per Share	Earnings Per Share We present both basic and diluted EPS amounts for continuing operations and discontinued operations. Total basic EPS amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders , less the earnings allocated to our Series B Participating Redeemable Preferred Stock, by the weighted average number of common shares outstanding during the period presented. Total diluted EPS amounts are calculated by dividing Net income (loss) attributable to Cliffs shareholders by the weighted average number of common shares, common share equivalents under stock plans using the treasury-stock method, common share equivalents of the Series B Participating Redeemable Preferred Stock using the if- converted method and the calculated common share equivalents in excess of the conversion rate related to our 1.500% 2025 Convertible Senior Notes using the treasury-stock method. Common share equivalents are excluded from EPS computations in the periods in which they have an anti-dilutive effect. Refer to NOTE 8 - DEBT AND CREDIT FACILITIES and NOTE 19 - EARNINGS PER SHARE for further information.
Variable Interest Entities	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. Refer to NOTE 18 - VARIABLE INTEREST ENTITIES for additional information.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Issued and Not Effective In August 2020, the FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40). This update requires certain convertible instruments to be accounted for as a single liability measured at its amortized cost. Additionally, the update requires the use of the "if-converted" method, removing the treasury stock method, when calculating diluted shares. The two methods of adoption are the full and modified retrospective approaches. We expect to utilize the modified retrospective approach. Using this approach, the guidance shall be applied to transactions outstanding as of the beginning of the fiscal year in which the amendment is adopted. Subsequent to the year ended December 31, 2021, we redeemed all of our outstanding 1.500% 2025 Convertible Senior Notes; therefore, there will be no impact as a result of our adoption of this update as of January 1, 2022. Refer to NOTE 21 - SUBSEQUENT EVENTS for further information.

BASIS OF PRESENTATION AND SIG_3

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2021
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 27 years The following table indicates the carrying value of each of the major classes of our depreciable assets: (In Millions) December 31, 2021 2020 Land, land improvements, and mineral rights $ 1,291 $ 1,213 Buildings 889 703 Equipment 8,709 6,786 Other 229 151 Construction in progress 408 1,364 Total property, plant and equipment 1 11,526 10,217 Allowance for depreciation and depletion (2,340) (1,474) Property, plant, and equipment, net $ 9,186 $ 8,743 1 Includes right-of-use assets related to finance leases of $411 million and $361 million as of December 31, 2021 and 2020, respectively. The net book value of the mineral and land rights are as follows: (In Millions) December 31, 2021 2020 Mineral rights: Cost $ 780 $ 773 Depletion (187) (142) Net mineral rights $ 593 $ 631 Land rights $ 406 $ 361

SUPPLEMENTARY FINANCIAL STATE_2

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block [Abstract]
Roll-forward of Allowance for Credit Losses	The following is a roll-forward of our allowance for credit losses associated with Accounts receivable, net : (In Millions) 2021 2020 Allowance for credit losses as of January 1 $ (5) $ — Decrease (increase) in allowance 1 (5) Allowance for credit losses as of December 31 $ (4) $ (5)
Schedule Of Inventories	The following table presents the detail of our Inventories in the Statements of Consolidated Financial Position: (In Millions) Year Ended December 31, 2021 2020 Product inventories Finished and semi-finished goods $ 2,814 $ 2,125 Raw materials 2,070 1,431 Total product inventories 4,884 3,556 Manufacturing supplies and critical spares 304 272 Inventories $ 5,188 $ 3,828
Schedule of Cash Flow, Supplemental Disclosures	A reconciliation of capital additions to cash paid for capital expenditures is as follows: (In Millions) Year Ended December 31, 2021 2020 2019 Capital additions $ 857 $ 483 $ 690 Less: Non-cash accruals 102 (86) 15 Right-of-use assets - finance leases 50 44 29 Grants — — (10) Cash paid for capital expenditures including deposits $ 705 $ 525 $ 656 Cash payments (receipts) for interest and income taxes are as follows: (In Millions) 2021 2020 2019 Taxes paid on income $ 166 $ 5 $ — Income tax refunds (16) (120) (118) Interest paid on debt obligations net of capitalized interest 1 299 170 98 1 Capitalized interest was $6 million, $53 million and $25 million for the years ended December 31, 2021, 2020 and 2019, respectively.
Schedule of Noncash or Part Noncash Acquisitions	Other Non-Cash Investing and Financing Activities (In Millions) 2021 2020 2019 Fair value of settlement of a pre-existing relationship as part of consideration in connection with FPT Acquisition $ (20) $ — $ — Fair value of common shares issued as part of consideration in connection with AM USA Transaction — 990 — Fair value of Series B Participating Redeemable Preferred Stock issued as part of consideration in connection with AM USA Transaction — 738 — Fair value of settlement of a pre-existing relationship as part of consideration in connection with AM USA Transaction — 237 — Fair value of common shares issued as consideration in connection with AK Steel Merger — 618 — Fair value of equity awards assumed in connection with AK Steel Merger — 4 —

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Schedule of Fair Value of Purchase Consideration	The fair value of the total purchase consideration was determined as follows: (In Millions) Cash consideration (subject to customary working capital adjustments) $ 775 Fair value of settlement of a pre-existing relationship (20) Total purchase consideration $ 755 The preliminary purchase price allocation to assets acquired and liabilities assumed in the FPT Acquisition was: (In Millions) Initial Allocation of Consideration Cash and cash equivalents $ 9 Accounts receivable, net 233 Inventories 137 Other current assets 4 Property, plant and equipment 179 Other non-current assets 74 Accounts payable (122) Accrued employment costs (8) State and local taxes (1) Other current liabilities (8) Other non-current liabilities (21) Net identifiable assets acquired 476 Goodwill 279 Total net assets acquired $ 755 The fair value of the total purchase consideration was determined as follows: (In Millions) Fair value of Cliffs common shares issued $ 990 Fair value of Cliffs Series B Participating Redeemable Preferred Stock issued 738 Fair value of settlement of a pre-existing relationship 237 Cash consideration 639 Total purchase consideration $ 2,604 The fair value of Cliffs common shares issued was calculated as follows: Number of Cliffs common shares issued 78,186,671 Closing price of Cliffs common share as of December 9, 2020 $ 12.66 Fair value of Cliffs common shares issued (in millions) $ 990 The fair value of Cliffs Series B Participating Redeemable Preferred Stock issued was calculated as follows: Number of Cliffs Series B Participating Redeemable Preferred Stock issued 583,273 Redemption price per share as of December 9, 2020 $ 1,266 Fair value of Cliffs Series B Participating Redeemable Preferred Stock issued (in millions) $ 738 The fair value of the cash consideration was comprised of the following: (In Millions) Cash consideration pursuant to the AM USA Transaction Agreement $ 505 Cash consideration for purchase of the remaining JV partner's interest of Kote and Tek 182 Total cash consideration receivable (48) Total cash consideration $ 639 The cash portion of the purchase price was subject to customary working capital adjustments, and the working capital adjustments were finalized during the second quarter of 2021. We made certain elections under Section 338(h)(10) of the IRC with respect to entities acquired in connection with the AM USA Transaction, which did not change the final cash consideration. The fair value of the settlement of a pre-existing relationship was comprised of the following: (In Millions) Accounts receivable $ 97 Freestanding derivative asset from customer supply agreement 140 Total fair value of settlement of a pre-existing relationship $ 237 The fair value of the total purchase consideration was determined as follows: (In Millions) Fair value of AK Steel debt $ 914 Fair value of Cliffs common shares issued for AK Steel outstanding common stock 618 Other 3 Total purchase consideration $ 1,535 The fair value of AK Steel's debt included in the consideration was calculated as follows: (In Millions) Credit Facility $ 590 7.500% Senior Secured Notes due July 2023 324 Fair value of debt included in consideration $ 914
Summary of Purchase Price Allocated to Identifiable Intangible Assets and Liabilities Acquired	The preliminary purchase price allocated to identifiable intangible assets acquired was: (In Millions) Weighted Average Life (In Years) Customer relationships $ 18 15 Supplier relationships 18 18 Trade names and trademarks 7 15 Total identifiable intangible assets $ 43 16 The purchase price allocated to identifiable intangible assets and liabilities acquired was: (In Millions) Weighted Average Life (In Years) Intangible assets: Customer relationships $ 77 18 Developed technology 60 17 Trade names and trademarks 11 10 Total identifiable intangible assets $ 148 17 Intangible liabilities: Above-market supply contracts $ (71) 12
Summary of the Purchase Price Allocation to Assets Acquired and Liabilities Assumed	The following is a summary of the purchase price allocation to assets acquired and liabilities assumed in the AM USA Transaction: (In Millions) Initial Allocation of Consideration Measurement Final Allocation Consideration as of December 31, 2021 Cash and cash equivalents $ 35 $ — $ 35 Accounts receivable, net 349 (3) 346 Inventories 2,115 14 2,129 Other current assets 34 2 36 Property, plant and equipment 4,017 387 4,404 Deferred income taxes — 285 285 Other non-current assets 158 7 165 Accounts payable (736) 8 (728) Accrued employment costs (271) 5 (266) State and local taxes (76) — (76) Other current liabilities (453) 23 (430) Pension liability, non-current (730) — (730) OPEB liability, non-current (2,465) — (2,465) Other non-current liabilities (598) (171) (769) Noncontrolling interest (13) 21 8 Net identifiable assets acquired 1,366 578 1,944 Goodwill 1,230 (570) 660 Total net assets acquired $ 2,596 $ 8 $ 2,604 (In Millions) Initial Allocation of Consideration Measurement Period Adjustments Final Allocation of Consideration as of March 31, 2021 Cash and cash equivalents $ 38 $ 1 $ 39 Accounts receivable, net 666 (2) 664 Inventories 1,563 (243) 1,320 Other current assets 68 (16) 52 Property, plant and equipment 2,184 90 2,274 Deferred income taxes — 69 69 Other non-current assets 475 (4) 471 Accounts payable (636) (8) (644) Accrued employment costs (94) 1 (93) State and local taxes (35) 4 (31) Other current liabilities (276) 2 (274) Long-term debt (1,179) — (1,179) Pension liability, non-current (473) 10 (463) OPEB liability, non-current (400) (8) (408) Other non-current liabilities (507) 72 (435) Noncontrolling interest — (1) (1) Net identifiable assets acquired 1,394 (33) 1,361 Goodwill 141 33 174 Total net assets acquired $ 1,535 $ — $ 1,535
Schedule of Common Shares Issues upon Completion of Merger	The fair value of Cliffs common shares issued for outstanding shares of AK Steel common stock and with respect to Cliffs common shares underlying converted AK Steel equity awards that vested upon completion of the AK Steel Merger was calculated as follows: (In Millions, Number of shares of AK Steel common stock issued and outstanding 317 Exchange ratio 0.400 Shares of Cliffs common shares issued to AK Steel stockholders 127 Price per share of Cliffs common shares $ 4.87 Fair value of Cliffs common shares issued for outstanding AK Steel common stock $ 618
Summary of Unaudited Pro Forma Financial Information	The following table provides unaudited pro forma financial information, prepared in accordance with Topic 805, as if ArcelorMittal USA and AK Steel had been acquired as of January 1, 2019: (In Millions) Year Ended December 31, 2020 2019 Revenues $ 12,837 $ 17,163 Net income (loss) attributable to Cliffs shareholders (520) (11) The following table provides unaudited pro forma financial information, prepared in accordance with Topic 805, as if FPT had been acquired as of January 1, 2020: (In Millions) Year Ended December 31, 2021 2020 Revenues $ 21,701 $ 13,549 Net income (loss) attributable to Cliffs shareholders 3,074 (526)

REVENUES (Tables)

REVENUES (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Summary of Revenue by market and product line	The following table represents our Revenues by market: (In Millions) Year Ended December 31, 2021 2020 2019 Steelmaking: Automotive $ 4,726 $ 2,062 $ — Infrastructure and manufacturing 5,380 784 — Distributors and converters 7,671 696 — Steel producers 2,124 1,423 1,990 Total Steelmaking 19,901 4,965 1,990 Other Businesses: Automotive 426 329 — Infrastructure and manufacturing 47 34 — Distributors and converters 70 26 — Total Other Businesses 543 389 — Total revenues $ 20,444 $ 5,354 $ 1,990 The following table represents our Revenues by product line: (Dollars In Millions, Sales Volumes in Thousands) Year Ended December 31, 2021 2020 2019 Revenue Volume 1 Revenue Volume 1 Revenue Volume 1 Steelmaking: Hot-rolled steel $ 5,615 4,886 $ 386 633 $ — — Cold-rolled steel 3,186 2,790 490 682 — — Coated steel 5,864 5,056 1,747 1,911 — — Stainless and electrical steel 1,622 674 868 416 — — Plate 1,316 1,020 46 62 — — Other steel products 1,247 1,460 46 79 — — Other 1,051 N/A 1,382 N/A 1,990 N/A Total steelmaking 19,901 4,965 1,990 Other Businesses: Other 543 N/A 389 N/A — N/A Total revenues $ 20,444 $ 5,354 $ 1,990 1 All product volumes are stated in net tons.
Summary of Deferred Revenue	The table below summarizes our deferred revenue balances: (In Millions) Deferred Revenue (Current) Deferred Revenue (Long-Term) 2021 2020 2021 2020 Opening balance as of January 1 $ 7 $ 22 $ — $ 26 Net increase (decrease) 18 (15) — (26) Closing balance as of December 31 $ 25 $ 7 $ — $ —

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Summary of Results by Segment	Our results by segment are as follows: (In Millions) Year Ended December 31, 2021 2020 2019 Revenues: Steelmaking $ 19,901 $ 4,965 $ 1,990 Other Businesses 543 389 — Total revenues $ 20,444 $ 5,354 $ 1,990 Adjusted EBITDA: Steelmaking $ 5,422 $ 433 $ 636 Other Businesses 9 47 — Corporate and eliminations (169) (127) (111) Total Adjusted EBITDA $ 5,262 $ 353 $ 525 The following table provides a reconciliation of our consolidated Net income (loss) to total Adjusted EBITDA: (In Millions) Year Ended December 31, 2021 2020 2019 Net income (loss) $ 3,033 $ (81) $ 293 Less: Interest expense, net (337) (238) (101) Income tax benefit (expense) (773) 111 (18) Depreciation, depletion and amortization (897) (308) (85) 5,040 354 497 Less: EBITDA from noncontrolling interests 1 75 56 — Gain (loss) on extinguishment of debt (88) 130 (18) Severance costs (15) (38) (2) Acquisition-related costs excluding severance costs (5) (52) (7) Acquisition-related loss on equity method investment (31) — — Amortization of inventory step-up (161) (96) — Impact of discontinued operations 3 1 (1) Total Adjusted EBITDA $ 5,262 $ 353 $ 525 1 EBITDA of noncontrolling interests includes the following: Net income attributable to noncontrolling interests $ 45 $ 41 $ — Depreciation, depletion and amortization 30 15 — EBITDA of noncontrolling interests $ 75 $ 56 $ — The following table summarizes our depreciation, depletion and amortization and capital additions by segment: (In Millions) Year Ended December 31, 2021 2020 2019 Depreciation, depletion and amortization: Steelmaking $ 855 $ 276 $ 80 Other Businesses 37 27 — Corporate 5 5 5 Total depreciation, depletion and amortization $ 897 $ 308 $ 85 Capital additions 1: Steelmaking $ 787 $ 436 $ 687 Other Businesses 52 45 — Corporate 18 2 3 Total capital additions $ 857 $ 483 $ 690 1 Refer to NOTE 2 - SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION for additional information.
Summary of Assets by Segment	The following summarizes our assets by segment: (In Millions) December 31, 2021 2020 Assets: Steelmaking $ 18,326 $ 15,849 Other Businesses 306 239 Total segment assets 18,632 16,088 Corporate 343 683 Total assets $ 18,975 $ 16,771
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: (In Millions) 2021 2020 2019 Revenues: United States $ 18,881 $ 4,580 $ 1,505 Canada 803 602 448 Other countries 760 172 37 Total revenues $ 20,444 $ 5,354 $ 1,990 Property, plant and equipment, net: United States $ 9,092 $ 8,647 $ 1,929 Canada 93 91 — Other countries 1 5 — Total property, plant and equipment, net $ 9,186 $ 8,743 $ 1,929

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2021
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 27 years The following table indicates the carrying value of each of the major classes of our depreciable assets: (In Millions) December 31, 2021 2020 Land, land improvements, and mineral rights $ 1,291 $ 1,213 Buildings 889 703 Equipment 8,709 6,786 Other 229 151 Construction in progress 408 1,364 Total property, plant and equipment 1 11,526 10,217 Allowance for depreciation and depletion (2,340) (1,474) Property, plant, and equipment, net $ 9,186 $ 8,743 1 Includes right-of-use assets related to finance leases of $411 million and $361 million as of December 31, 2021 and 2020, respectively. The net book value of the mineral and land rights are as follows: (In Millions) December 31, 2021 2020 Mineral rights: Cost $ 780 $ 773 Depletion (187) (142) Net mineral rights $ 593 $ 631 Land rights $ 406 $ 361

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill by Segment	The following is a summary of Goodwill by segment: (In Millions) December 31, 2021 2020 Steelmaking $ 942 $ 1,232 Other Businesses 174 174 Total goodwill $ 1,116 $ 1,406
Summary of Intangible Assets and Liabilities	The following is a summary of our intangible assets and liabilities: (In Millions) December 31, 2021 December 31, 2020 Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Intangible assets 1 : Customer relationships $ 95 $ (8) $ 87 $ 77 $ (3) $ 74 Developed technology 60 (6) 54 60 (3) 57 Trade names and trademarks 18 (2) 16 11 (1) 10 Mining permits 72 (26) 46 72 (25) 47 Supplier relationships 18 — 18 — — — Total intangible assets $ 263 $ (42) $ 221 $ 220 $ (32) $ 188 Intangible liabilities 2 : Above-market supply contracts $ (71) $ 14 $ (57) $ (71) $ 7 $ (64) 1 Intangible assets are classified as Other non-current assets . 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, 2021
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	The following represents a summary of our long-term debt: (In Millions) December 31, 2021 Debt Instrument Issuer 1 Annual Effective Interest Rate Total Principal Amount Unamortized Debt Issuance Costs Unamortized Premiums (Discounts) Total Debt Senior Secured Notes: 9.875% 2025 Senior Secured Notes Cliffs 10.57% $ 607 $ (4) $ (13) $ 590 6.750% 2026 Senior Secured Notes Cliffs 6.99% 845 (16) (7) 822 Senior Unsecured Notes: 1.500% 2025 Convertible Senior Notes Cliffs 6.26% 294 (3) (39) 252 7.000% 2027 Senior Notes Cliffs 9.24% 73 — (7) 66 7.000% 2027 AK Senior Notes AK Steel 9.24% 56 — (5) 51 5.875% 2027 Senior Notes Cliffs 6.49% 556 (3) (15) 538 4.625% 2029 Senior Notes Cliffs 4.63% 500 (8) — 492 4.875% 2031 Senior Notes Cliffs 4.88% 500 (8) — 492 6.250% 2040 Senior Notes Cliffs 6.34% 263 (2) (3) 258 IRBs due 2024 to 2028 AK Steel Various 66 — 2 68 ABL Facility 3 Cliffs 2 1.87% 4,500 — — 1,609 Total long-term debt $ 5,238 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 The total principal amount for the ABL Facility is stated at the maximum borrowing capacity. (In Millions) December 31, 2020 Debt Instrument Issuer 1 Annual Effective Interest Rate Total Principal Amount Unamortized Unamortized Premiums (Discounts) Total Debt Senior Secured Notes: 4.875% 2024 Senior Secured Notes Cliffs 5.00% $ 395 $ (3) $ (1) $ 391 9.875% 2025 Senior Secured Notes Cliffs 10.57% 955 (8) (25) 922 6.750% 2026 Senior Secured Notes Cliffs 6.99% 845 (20) (9) 816 Senior Unsecured Notes: 7.625% 2021 AK Senior Notes AK Steel 7.33% 34 — — 34 7.500% 2023 AK Senior Notes AK Steel 6.17% 13 — — 13 6.375% 2025 Senior Notes Cliffs 8.11% 64 — (4) 60 6.375% 2025 AK Senior Notes AK Steel 8.11% 29 — (2) 27 1.500% 2025 Convertible Senior Notes Cliffs 6.26% 296 (4) (49) 243 5.750% 2025 Senior Notes Cliffs 6.01% 396 (3) (4) 389 7.000% 2027 Senior Notes Cliffs 9.24% 73 — (8) 65 7.000% 2027 AK Senior Notes AK Steel 9.24% 56 — (6) 50 5.875% 2027 Senior Notes Cliffs 6.49% 556 (4) (18) 534 6.250% 2040 Senior Notes Cliffs 6.34% 263 (2) (3) 258 IRBs due 2024 to 2028 AK Steel Various 92 — 2 94 EDC Revolving Facility 3 * 3.25% 40 — — 18 ABL Facility 3 Cliffs 2 2.15% 3,500 — — 1,510 Total debt 5,424 Less: current 34 Total long-term debt $ 5,390 *Our subsidiaries, Fleetwood Metal Industries Inc. and The Electromac Group Inc., were the borrowers under the EDC Revolving Facility. 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 The total principal amounts for the indicated credit facilities are stated at their respective maximum borrowing capacities.
Debt Instrument Redemption	The following is a summary of redemption prices for our 4.625% 2029 Senior Notes: Redemption Period Redemption Price 1 Restricted Amount Prior to March 1, 2024 - using the proceeds of equity issuance 104.625 % Up to 35% of original aggregate principal Prior to March 1, 2024 2 100.000 Beginning March 1, 2024 102.313 Beginning March 1, 2025 101.156 Beginning on March 1, 2026 and thereafter 100.000 1 Plus accrued and unpaid interest, if any, up to, but excluding, the redemption date. 2 Plus a "make-whole" premium. Redemption Period Redemption Price 1 Restricted Amount Prior to March 1, 2026 - using the proceeds of equity issuance 104.875 % Up to 35% of original aggregate principal Prior to March 1, 2026 2 100.000 Beginning March 1, 2026 102.438 Beginning March 1, 2027 101.625 Beginning March 1, 2028 100.813 Beginning on March 1, 2029 and thereafter 100.000 1 Plus accrued and unpaid interest, if any, up to, but excluding, the redemption date. 2 Plus a "make-whole" premium.
Summary of Borrowing Capacity Under the ABL Facility	The following represents a summary of our borrowing capacity under the ABL Facility: (In Millions) December 31, Available borrowing base on ABL Facility 1 $ 4,500 Borrowings (1,609) Letter of credit obligations 2 (175) Borrowing capacity available $ 2,716 1 As of December 31, 2021, the ABL Facility has a maximum available borrowing base of $4.5 billion. The 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, workers' compensation, employee severance, insurance, operating agreements and environmental obligations.
Summary of Debt Extinguished	The following is a summary of the debt extinguished and the respective impact on extinguishment: (In Millions) Year Ended Debt Extinguished (Loss) on Extinguishment 9.875% 2025 Senior Secured Notes $ 347 $ (47) 4.875% 2024 Senior Secured Notes 395 (14) 7.625% 2021 AK Senior Notes 34 — 7.500% 2023 AK Senior Notes 13 — 6.375% 2025 Senior Notes 64 (7) 1.500% 2025 Convertible Senior Notes 2 — 6.375% 2025 AK Senior Notes 29 (3) 5.750% 2025 Senior Notes 396 (17) IRBs due 2024 26 — Total $ 1,306 $ (88) The following is a summary of the debt extinguished and the respective impact on extinguishment: (In Millions) Year Ended Debt Extinguished Gain (Loss) on Extinguishment 7.625% 2021 AK Senior Notes $ 373 $ — 7.500% 2023 AK Senior Notes 367 3 4.875% 2024 Senior Secured Notes 6 1 6.375% 2025 Senior Notes 168 21 1.500% 2025 Convertible Senior Notes 20 1 5.750% 2025 Senior Notes 77 16 7.000% 2027 Senior Notes 262 27 5.875% 2027 Senior Notes 195 49 6.250% 2040 Senior Notes 36 13 6.375% 2025 AK Senior Notes 9 (1) Total $ 1,513 $ 130 The following is a summary of the debt extinguished and the respective impact on extinguishment: (In Millions) Year Ended Debt Extinguished (Loss) on Extinguishment 4.875% 2021 Senior Notes $ 124 $ (5) 5.750% 2025 Senior Notes 600 (13) Total $ 724 $ (18)
Summary of Debt Instrument Maturities	The following represents a summary of our debt instrument maturities based on the principal amounts outstanding at December 31, 2021: (In Millions) Maturities of Debt 2022 $ — 2023 — 2024 36 2025 2,510 2026 845 Thereafter 1,978 Total maturities of debt $ 5,369

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Reconciliation of Changes in Fair Value of Financial Instruments Measured on a Recurring Basis	The following tables represent a reconciliation of the changes in fair value of financial instruments measured at fair value on a recurring basis using significant unobservable inputs (Level 3): (In Millions) Level 3 Assets 2021 2020 Beginning balance - January 1 $ — $ 45 Total gains included in earnings — 122 Settlements — (27) Settlement of pre-existing relationship — (140) Ending balance - December 31 $ — $ — Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ — $ —
Summary of Carrying Value and Fair Value of Other Financial Instruments	A summary of the carrying value and fair value of other financial instruments were as follows: (In Millions) December 31, 2021 December 31, 2020 Classification Carrying Fair Value Carrying Fair Value Senior notes Level 1 $ 3,561 $ 3,911 $ 3,802 $ 4,446 IRBs due 2024 to 2028 Level 1 68 66 94 91 EDC Revolving Facility - outstanding balance Level 2 — — 18 18 ABL Facility - outstanding balance Level 2 1,609 1,609 1,510 1,510 Total $ 5,238 $ 5,586 $ 5,424 $ 6,065

PENSIONS AND OTHER POSTRETIRE_2

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Tables)	12 Months Ended
	Dec. 31, 2021
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: 2021 2020 2021 2020 Benefit obligations — beginning of year $ 6,565 $ 1,021 $ 3,757 $ 255 Service cost 56 23 51 8 Interest cost 103 64 74 19 Plan amendments — — 8 — Actuarial loss (gain) (131) 162 (456) 14 Benefits paid (456) (146) (227) (89) Participant contributions — — 47 22 Acquired through business combinations — 5,535 — 3,528 Effect of settlement (101) (94) — — Benefit obligations — end of year $ 6,036 $ 6,565 $ 3,254 $ 3,757 Change in plan assets: Fair value of plan assets — beginning of year $ 5,332 $ 749 $ 783 $ 260 Actual return on plan assets 668 472 29 45 Participant contributions — — 26 17 Employer contributions 155 50 139 30 Benefits paid (454) (146) (165) (88) Acquired through business combinations — 4,301 — 519 Effect of settlement (95) (94) — — Fair value of plan assets — end of year $ 5,606 $ 5,332 $ 812 $ 783 Funded status $ (430) $ (1,233) $ (2,442) $ (2,974) Amounts recognized in Statements of Financial Position: Non-current assets $ 153 $ 3 $ 71 $ 54 Current liabilities (5) (12) (130) (139) Non-current liabilities (578) (1,224) (2,383) (2,889) Total amount recognized $ (430) $ (1,233) $ (2,442) $ (2,974) Amounts recognized in accumulated other comprehensive loss (income): Net actuarial loss (gain) $ (286) $ 164 $ (392) $ 56 Prior service cost (credit) 5 6 4 (6) Net amount recognized $ (281) $ 170 $ (388) $ 50 Annual contributions to the pension plans are made within income tax deductibility restrictions in accordance with statutory regulations. OPEB plans are not subject to minimum regulatory funding requirements, but rather amounts are contributed pursuant to bargaining agreements. (In Millions) Pension Benefits 1 Other Benefits 2 Company Contributions & Payments VEBA Direct Total 2020 $ 50 $ — $ 25 $ 25 2021 163 67 113 180 2022 (Expected) 4 28 110 138 1 The 2021 pension contributions include $118 million in deferred 2020 pension contributions in connection with the CARES Act that were paid on January 4, 2021. 2 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, 2021). 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. The amount expected for 2022 in the VEBA column reflects the contribution to be made in February 2022 for earnings in the quarter ended December 31, 2021. We do not include an estimate for contributions beyond that due to the variability of the calculation.
Components Of Net Periodic Benefit Cost	Components of Net Periodic Benefit Cost (Credit) (In Millions) Pension Benefits OPEB 2021 2020 2019 2021 2020 2019 Service cost $ 56 $ 23 $ 17 $ 51 $ 8 $ 2 Interest cost 103 64 35 74 19 10 Expected return on plan assets (359) (140) (55) (40) (20) (17) Amortization: Net actuarial loss 32 27 24 3 3 5 Prior service costs (credits) 1 1 1 (2) (2) (2) Settlements (22) (6) — — — — Net periodic benefit cost (credit) $ (189) $ (31) $ 22 $ 86 $ 8 $ (2) For 2022, we estimate net periodic benefit cost (credit) as follows: (In Millions) Defined benefit pension plans $ (179) OPEB plans 72 Total $ (107)
Components of Accumulated Other Comprehensive Income (Loss)	The following includes details on the significant actuarial losses (gains) impacting the benefit obligation: (In Millions) Pension Benefits OPEB 2021 2020 2021 2020 Discount rates $ (224) $ 181 $ (117) $ 44 Demographic updates 76 (3) 3 (11) Mortality 19 (16) 13 (4) Per capita health care costs — — (350) (10) Other (2) — (5) (5) Actuarial loss (gain) on benefit obligation (131) 162 (456) 14 Actual returns on assets under (over) expected (309) (332) 11 (26) Amortization of net actuarial gain (loss) (32) (27) 2 (3) Amortization of prior service credits (costs) (1) (1) (3) 2 Settlements 22 6 — — Other — (27) 8 (2) Total recognized in accumulated other comprehensive income $ (451) $ (219) $ (438) $ (15)
Estimated Future Benefit Payments	Estimated Future Benefit Payments (In Millions) Pension OPEB 2022 $ 475 $ 180 2023 477 171 2024 451 167 2025 428 163 2026 424 163 2027-2031 1,879 823
Defined Benefit Plan, Assumptions	The following represents weighted-average assumptions used to determine benefit obligations: Pension Benefits OPEB December 31, December 31, 2021 2020 2021 2020 Discount rate 2.75 % 2.34 % 3.01 % 2.71 % Interest crediting rate 5.35 5.25 N/A N/A Compensation rate increase 2.52 2.56 3.00 3.00 The following represents weighted-average assumptions used to determine net benefit cost: Pension Benefits OPEB December 31, December 31, 2021 2020 2019 2021 2020 2019 Obligation discount rate 2.32 % 3.02 % 4.27 % 2.46 % 3.28 % 4.29 % Service cost discount rate 2.78 3.34 4.35 3.28 3.35 4.49 Interest cost discount rate 1.64 2.53 3.92 2.04 2.51 3.94 Interest crediting rate 5.35 5.50 6.00 N/A N/A N/A Expected return on plan assets 6.84 7.69 8.25 5.20 6.82 7.00 Compensation rate increase 2.54 2.56 2.53 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, 2021 2020 Health care cost trend rate assumed for next year 2.36 % 6.05 % Ultimate health care cost trend rate 4.50 4.59 Year that the ultimate rate is reached 2031 2031
Plan Assets and Asset Allocation	The following table reflects the actual asset allocations for pension and VEBA assets as of December 31, 2021 and 2020, as well as the 2022 weighted average target asset allocations. Equity investments include securities in large-cap, mid-cap and small-cap companies located in the U.S. and worldwide. Fixed income investments primarily include corporate bonds and government debt securities. Pension Assets VEBA Assets Asset Category 2022 Percentage of 2022 Percentage of 2021 2020 2021 2020 Equity securities 46.3 % 47.6 % 51.8 % 21.2 % 22.5 % 22.2 % Fixed income 34.6 34.6 33.8 68.5 66.4 66.4 Hedge funds 2.2 2.2 2.2 1.4 1.8 1.8 Private equity 5.0 2.7 2.1 1.1 — 0.4 Structured credit 5.2 5.6 5.0 1.0 1.2 0.9 Real estate 5.2 5.6 3.3 1.0 2.1 1.8 Absolute return fixed income 1.5 1.7 1.8 5.8 6.0 6.5 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 Significant Other Significant Investments Measured at Net Asset Value Total Asset Category 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 Equity securities: U.S. equities $ 1,157 $ 1,163 $ — $ — $ — $ — $ 775 $ 787 $ 1,932 $ 1,950 Global equities 617 615 — — — — 117 195 734 810 Fixed income: U.S. government securities 1 140 141 310 295 — — 50 40 500 476 U.S. corporate bonds 502 512 371 466 — — 503 303 1,376 1,281 Non U.S. and other bonds — — 66 46 — — — — 66 46 Hedge funds — — — — 125 118 — — 125 118 Private equity — — — — 151 114 — — 151 114 Structured credit — — — — 315 264 — — 315 264 Real estate — — — — 313 174 — — 313 174 Absolute return fixed income — — — — — — 94 99 94 99 Total $ 2,416 $ 2,431 $ 747 $ 807 $ 904 $ 670 $ 1,539 $ 1,424 $ 5,606 $ 5,332 1 Includes cash equivalents. (In Millions) Quoted Prices in Active Significant Other Significant Investments Measured at Net Asset Value Total Asset Category 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 Equity securities: U.S. equities $ 26 $ 26 $ — $ — $ — $ — $ 103 $ 93 $ 129 $ 119 Global equities 6 6 — — — — 48 49 54 55 Fixed income: U.S. government securities 1 111 62 80 94 — — — — 191 156 U.S. corporate bonds 219 237 129 127 — — — — 348 364 Hedge funds — — — — 15 14 — — 15 14 Private equity — — — — — 3 — — — 3 Structured credit — — — — 10 7 — — 10 7 Real estate — — — — 17 14 — — 17 14 Absolute return fixed income — — — — — — 48 51 48 51 Total $ 362 $ 331 $ 209 $ 221 $ 42 $ 38 $ 199 $ 193 $ 812 $ 783 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): (In Millions) Pension Assets VEBA Assets 2021 2020 2021 2020 Beginning balance — January 1 $ 670 $ 212 $ 38 $ 34 Actual return on plan assets: Relating to assets still held at the reporting date 124 8 6 2 Relating to assets sold during the period 8 6 — 1 Purchases 142 195 — — Sales (40) (13) (2) (1) Acquired through business combinations — 262 — 2 Ending balance — December 31 $ 904 $ 670 $ 42 $ 38
Multiemployer Plan	Information with respect to multiemployer plans in which we participate follows: Pension Fund EIN/Pension Plan Number Pension Protection Act Zone Status (a) FIP/RP Status Pending/Implemented (b) Contributions Surcharge Imposed (c) Expiration Date of Collective Bargaining Agreement (d) 2021 2020 2021 2020 2019 Steelworkers Pension Trust 23-6648508/499 Green Green No $ 88 $ 14 $ 4 No 9/1/2022 to 09/1/2025 IAM National Pension Fund’s National Pension Plan 51-6031295/002 Red Red Yes 16 16 — Yes 5/31/2022 to 5/15/2023 Other Plans (e) — — — Total $ 104 $ 30 $ 4 (a) The most recent Pension Protection Act zone status available in 2021 and 2020 is for each plan's year-end at December 31, 2020 and 2019. 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". (b) 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. (c) The surcharge represents an additional required contribution due as a result of the critical funding status of the plan. (d) We are a party to five 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. (e) 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, 2021
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: (In Millions, except per Year Ended December 31, 2021 2020 2019 Cost of goods sold $ (2) $ (2) $ (2) Selling, general and administrative expenses (16) (13) (16) Acquisition-related costs — (2) — Stock based compensation expense (18) (17) (18) Income tax benefit 4 4 4 Stock based compensation expense, net of tax $ (14) $ (13) $ (14) Decrease in basic earnings per common share $ (0.03) $ (0.03) $ (0.05) Decrease in diluted earnings per common share $ (0.03) $ (0.03) $ (0.05)
Summary of Performance Award Activity	The following table summarizes the performance award activity: Year Ended December 31, 2021 2020 2019 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 2,452,226 $ 10.34 1,935,878 $ 15.58 1,424,723 $ 14.46 Granted 652,888 25.12 960,637 6.93 572,104 18.31 Granted - replacement awards — — 1,550,216 4.59 — — Distributed (1,279,509) 11.74 (1,938,786) 12.23 — — Performance adjustment 625,355 11.93 549,154 15.63 — — Forfeited/canceled (80,490) 11.27 (604,873) 5.70 (60,949) 15.12 Outstanding at end of year 2,370,470 $ 14.04 2,452,226 $ 10.34 1,935,878 $ 15.58
Summary of Restricted Stock Unit Activity	The following table summarizes the restricted stock units activity: Year Ended December 31, 2021 2020 2019 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 2,143,583 $ 7.12 2,147,183 $ 9.10 4,694,360 $ 4.18 Granted 678,420 17.45 960,637 4.87 572,104 11.24 Granted - replacement awards — — 200,291 4.87 — — Distributed (642,992) 7.31 (1,101,115) 8.58 (3,058,307) 1.95 Forfeited/canceled (56,185) 9.50 (63,413) 7.31 (60,974) 9.31 Outstanding at end of year 2,122,826 $ 10.31 2,143,583 $ 7.12 2,147,183 $ 9.10
Summary of Stock Option Activity	The following table summarizes the stock option activity: Year Ended December 31, 2021 2020 2019 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 2,485,808 $ 11.60 563,230 $ 10.42 563,230 $ 10.42 Granted - replacement awards — — 2,010,277 11.86 — — Exercised (1,457,495) 10.36 (79,973) 7.01 — — Forfeited/canceled (26,253) 36.48 (7,726) 41.04 — — Outstanding at end of year 1,002,060 $ 12.75 2,485,808 $ 11.60 563,230 $ 10.42 Exercisable at end of year 904,574 $ 13.35 2,172,052 $ 11.86 563,230 $ 10.42
Summary of Grants of Restricted and/or Deferred Shares to Nonemployee Directors	For the last three years, grants of restricted and/or deferred shares have been awarded to elected or re-elected nonemployee directors as follows: Year of Grant Restricted Shares Deferred Shares 2021 58,851 13,078 2020 253,809 54,794 2019 86,477 23,659

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2021
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: (In Millions) 2021 2020 2019 United States $ 3,827 $ (201) $ 313 Foreign (24) 8 — $ 3,803 $ (193) $ 313
Components of the Income Tax Provision (Benefit) on Continuing Operations	The components of the income tax provision (benefit) on continuing operations consist of the following: (In Millions) 2021 2020 2019 Current provision (benefit): United States federal $ 14 $ (2) $ (1) United States state & local 55 — — Foreign — (1) — 69 (3) (1) Deferred provision (benefit): United States federal 683 (95) 19 United States state & local 31 (11) — Foreign (10) (2) — Total income tax provision (benefit) from continuing operations $ 773 $ (111) $ 18 The components of income taxes for other than continuing operations consisted of the following: (In Millions) 2021 2020 2019 Other comprehensive income (loss): Pension and OPEB $ (206) $ (52) $ 11 Derivative financial instruments (21) (1) — Total $ (227) $ (53) $ 11
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) 2021 2020 2019 Tax at U.S. statutory rate $ 799 21 % $ (41) 21 % $ 66 21 % Increase (decrease) due to: Percentage depletion in excess of cost depletion (99) (3) (42) 22 (49) (16) Non-taxable income related to noncontrolling interests (9) — (9) 4 — — Luxembourg legal entity reduction — — — — 846 271 Valuation allowance release: Luxembourg legal entity reduction — — — — (846) (271) State taxes, net 86 2 (11) 6 — — Other items, net (4) — (8) 4 1 1 Provision for income tax expense (benefit) and effective income tax rate including discrete items $ 773 20 % $ (111) 57 % $ 18 6 %
Significant Components of Deferred Tax Assets and Liabilities	Significant components of our deferred tax assets and liabilities are as follows: (In Millions) 2021 2020 Deferred tax assets: Operating loss and other carryforwards $ 379 $ 1,236 Pension and OPEB liabilities 584 228 State and local 109 132 Other liabilities 287 190 Total deferred tax assets before valuation allowance 1,359 1,786 Deferred tax asset valuation allowance (409) (836) Net deferred tax assets 950 950 Deferred tax liabilities: Investment in partnerships (191) (144) Property, plant and equipment and mineral rights (641) (246) Other assets (216) (68) Total deferred tax liabilities (1,048) (458) Net deferred tax assets (liabilities) $ (98) $ 492
Summary of Changes in the Valuation Allowance	The changes in the valuation allowance are presented below: (In Millions) 2021 2020 2019 Balance at beginning of year $ 836 $ 441 $ 1,287 Change in valuation allowance: Included in income tax benefit (82) (3) (846) Increase (decrease) from acquisitions (345) 398 — Balance at end of year $ 409 $ 836 $ 441
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) 2021 2020 2019 Unrecognized tax benefits balance as of January 1 $ 107 $ 29 $ 29 Increase for tax positions in current year 4 7 — Decrease for tax positions of prior year (66) (4) — Lapses in statutes of limitations (10) — — Increases from acquisitions — 75 — Unrecognized tax benefits balance as of December 31 $ 35 $ 107 $ 29

LEASE OBLIGATIONS (Tables)

LEASE OBLIGATIONS (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Summary of Lease Costs	Lease costs are presented below: (In Millions) Year Ended December 31, 2021 2020 Operating leases $ 70 $ 43 Finance leases: Amortization of lease cost 94 15 Interest on lease liabilities 9 4 Short-term leases 66 13 Total $ 239 $ 75 Other information related to leases was as follows: (In Millions) Year Ended December 31, 2021 2020 Cash paid for amounts included in measurement of lease liabilities: Operating leases within cash flows from operating activities $ 70 $ 43 Finance leases within cash flows from operating activities $ 9 $ 4 Finance leases within cash flows from financing activities $ 94 $ 15 Right-of-use assets obtained in exchange for new finance lease liabilities 1 $ 50 $ 44 Weighted-average remaining lease term - operating leases (in years) 8 8 Weighted-average remaining lease term - finance leases (in years) 5 5 Weighted-average discount rate - operating leases 7 % 8 % Weighted-average discount rate - finance leases 4 % 4 % 1 Right-of-use assets obtained in acquisitions are not included in this figure.
Summary of Future Minimum Lease Payments under Noncellable Finance and Operating Leases	Future minimum lease payments under noncancellable finance and operating leases as of December 31, 2021 were as follows: (In Millions) Finance Leases Operating Leases 2022 $ 105 $ 68 2023 96 56 2024 31 47 2025 28 39 2026 19 35 Thereafter 66 133 Total future minimum lease payments 345 378 Less: imputed interest 54 108 Total lease payments 291 270 Less: current portion of lease liabilities 97 50 Long-term lease liabilities $ 194 $ 220

ASSET RETIREMENT OBLIGATIONS (T

ASSET RETIREMENT OBLIGATIONS (Tables)	12 Months Ended
	Dec. 31, 2021
Environmental Remediation Obligations [Abstract]
Schedule of Asset Retirement Obligations	The following is a summary of our asset retirement obligations: (In Millions) December 31, 2021 2020 Asset retirement obligations 1 $ 449 $ 342 Less: current portion 35 7 Long-term asset retirement obligations $ 414 $ 335 1 Includes $293 million and $190 million related to our active operations as of December 31, 2021 and 2020, respectively.
Roll-forward of Asset Retirement Obligation Liability	The following is a roll-forward of our asset retirement obligation liability: (In Millions) 2021 2020 Asset retirement obligation as of January 1 $ 342 $ 165 Increase from acquisitions 116 172 Accretion expense 18 14 Remediation payments (29) (9) Revision in estimated cash flows 2 — Asset retirement obligation as of December 31 $ 449 $ 342

CAPITAL STOCK (Tables)

CAPITAL STOCK (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Summary of Recent Dividend Activity	The below table summarizes our recent dividend activity: Declaration Date Record Date Payment Date Dividend Declared per Common Share 2/18/2020 4/3/2020 4/15/2020 $ 0.06 12/2/2019 1/3/2020 1/15/2020 0.06

ACCUMULATED OTHERCOMPREHENSIVE

ACCUMULATED OTHERCOMPREHENSIVE INCOME (LOSS) (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Components of Accumulated Other Comprehensive Income (Loss)	The components of Accumulated other comprehensive income (loss) within Cliffs shareholders’ equity and related tax effects allocated to each are shown below: (In Millions) Pre-tax Tax Benefit After-tax As of December 31, 2021: Pension and OPEB $ 669 $ (120) $ 549 Foreign currency translation adjustments 1 — 1 Derivative financial instruments 89 (21) 68 $ 759 $ (141) $ 618 As of December 31, 2020: Pension and OPEB $ (221) $ 86 $ (135) Foreign currency translation adjustments 3 — 3 Derivative financial instruments (1) — (1) $ (219) $ 86 $ (133) As of December 31, 2019: Pension and OPEB $ (454) $ 138 $ (316) Derivative financial instruments (4) 1 (3) $ (458) $ 139 $ (319) The following table reflects the changes in Accumulated other comprehensive income (loss) related to Cliffs shareholders’ equity: (In Millions) Postretirement Benefit Liability, Foreign Currency Translation Derivative Financial Instruments, Accumulated Other Comprehensive Income (Loss) December 31, 2018 $ (281) $ — $ (3) $ (284) Other comprehensive loss before reclassifications (57) — (2) (59) Net loss reclassified from AOCI 22 — 2 24 December 31, 2019 (316) — (3) (319) Other comprehensive income (loss) before reclassifications 163 3 (6) 160 Net loss reclassified from AOCI 18 — 8 26 December 31, 2020 (135) 3 (1) (133) Other comprehensive income (loss) before reclassifications 675 (2) 117 790 Net loss (gain) reclassified from AOCI 9 — (48) (39) December 31, 2021 $ 549 $ 1 $ 68 $ 618
Reclassification out of Accumulated Other Comprehensive Income	The following table reflects the details about Accumulated other comprehensive income (loss) components reclassified from Cliffs shareholders’ equity: (In Millions) Details about Accumulated Other Comprehensive Income (Loss) Components Amount of (Gain)/Loss Affected Line Item in the Statement of Consolidated Operations Year Ended December 31, 2021 2020 2019 Changes in pension and OPEB: Prior service costs 1 $ (1) $ (1) $ (1) Net periodic benefit credits (costs) other than service cost component Net actuarial loss 1 35 30 29 Net periodic benefit credits (costs) other than service cost component Settlements 1 (22) (6) — Net periodic benefit credits (costs) other than service cost component Total before taxes 12 23 28 Income tax benefit (3) (5) (6) Income tax benefit (expense) Net of taxes $ 9 $ 18 $ 22 Changes in derivative financial instruments: Commodity contracts $ (61) $ 10 $ 3 Cost of goods sold Income tax expense (benefit) 13 (2) (1) Income tax benefit (expense) Net of taxes $ (48) $ 8 $ 2 Total reclassifications for the period, net of tax $ (39) $ 26 $ 24 1 See NOTE 10 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS for further information.

RELATED PARTIES (Tables)

RELATED PARTIES (Tables)	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Summary Of Related Party Transactions	Revenues from related parties were as follows: (In Millions) Year Ended December 31, 2021 2020 2019 Revenue from related parties $ 139 $ 893 $ 1,015 Revenues $ 20,444 $ 5,354 $ 1,990 Related party revenues as a percent of Revenues 0.7 % 16.7 % 51.0 % Purchases from related parties $ 94 $ 16 $ — The following table presents the classification of related party assets and liabilities in the Statements of Consolidated Financial Position: (In Millions) December 31, Balance Sheet Location of Assets (Liabilities) 2021 2020 Accounts receivable, net $ 3 $ 2 Accounts payable (7) (6)

VARIABLE INTEREST ENTITIES (Tab

VARIABLE INTEREST ENTITIES (Tables)	12 Months Ended
	Dec. 31, 2021
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: (In Millions) December 31, 2021 2020 Cash and cash equivalents $ — $ 5 Inventories 20 21 Property, plant and equipment, net 300 308 Accounts payable (12) (15) Other assets (liabilities), net (12) (10) Noncontrolling interests (296) (309)

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share Computation	The following table summarizes the computation of basic and diluted EPS: (In Millions, Except Per Share Amounts) Year Ended December 31, 2021 2020 2019 Income (loss) from continuing operations $ 3,030 $ (82) $ 295 Income from continuing operations attributable to noncontrolling interest (45) (41) — Net income (loss) from continuing operations attributable to Cliffs shareholders 2,985 (123) 295 Income (loss) from discontinued operations, net of tax 3 1 (2) Net income (loss) attributable to Cliffs shareholders $ 2,988 $ (122) $ 293 Weighted average number of shares: Basic 498 379 277 Redeemable preferred shares 33 — — Convertible senior notes 22 — 4 Employee stock plans 5 — 3 Diluted 558 379 284 Earnings (loss) per common share attributable to Cliffs common shareholders - basic 1 : Continuing operations $ 5.62 $ (0.32) $ 1.07 Discontinued operations 0.01 — (0.01) $ 5.63 $ (0.32) $ 1.06 Earnings (loss) per common share attributable to Continuing operations $ 5.35 $ (0.32) $ 1.04 Discontinued operations 0.01 — (0.01) $ 5.36 $ (0.32) $ 1.03 1 For the year ended December 31, 2021, basic earnings per share was calculated by dividing Net income (loss) attributable to Cliffs shareholders , less $187 million of earnings attributed to Series B Participating Redeemable Preferred Stock, by the weighted average number of basic common shares outstanding during the period presented.
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table summarizes the shares that have been excluded from the diluted earnings per share calculation for the year ended December 31, 2020, as they were anti-dilutive: (In Millions) 2020 Redeemable preferred shares 4 Convertible senior notes 2 Shares related to employee stock plans 1

COMMITMENT AND CONTINGENCIES (T

COMMITMENT AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Environmental Obligations	The following is a summary of our environmental obligations: (In Millions) December 31, December 31, Environmental obligations $ 207 $ 135 Less current portion 20 18 Long-term environmental obligations $ 187 $ 117

BASIS OF PRESENTATION AND SIG_4

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)employeesegment	Nov. 18, 2021segment	Dec. 31, 2020USD ($)	Dec. 09, 2020	Dec. 31, 2019
Basis of Presentation and Significant Accounting Policies [Line Items]
Number of employees | employee	26,000
Number of operating segments	4
Number of reportable segments	1
Other Noncurrent Assets
Basis of Presentation and Significant Accounting Policies [Line Items]
Investment in affiliates | $	$ 128		$ 105
Ferrous Processing and Trading
Basis of Presentation and Significant Accounting Policies [Line Items]
Number of facilities acquired		22
Hibbing
Basis of Presentation and Significant Accounting Policies [Line Items]
Ownership interest, equity method investment	85.30%		85.30%	62.30%	23.00%
Workforce represented by labor unions
Basis of Presentation and Significant Accounting Policies [Line Items]
Number of employees | employee	18,500

BASIS OF PRESENTATION AND SIG_5

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Depreciation Methods and Useful Lives (Details)	12 Months Ended
	Dec. 31, 2021
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	27 years

SUPPLEMENTARY FINANCIAL STATE_3

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses as of January 1	$ (5)	$ 0
Decrease (increase) in allowance	1	(5)
Allowance for credit losses as of December 31	$ (4)	$ (5)

SUPPLEMENTARY FINANCIAL STATE_4

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Inventory (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Text Block [Abstract]
Finished and semi-finished goods	$ 2,814	$ 2,125
Raw materials	2,070	1,431
Total product inventories	4,884	3,556
Manufacturing supplies and critical spares	304	272
Inventories	5,188	3,828
Excess of current cost over LIFO cost of iron ore inventories	124	104
Effect of inventory build	$ 45
Effect of inventory reduction		$ 30

SUPPLEMENTARY FINANCIAL STATE_5

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Text Block [Abstract]
Capital additions	$ 857	$ 483	$ 690
Non-cash accruals	102	(86)	15
Right-of-use assets - finance leases	50	44	29
Grants	0	0	(10)
Cash paid for capital expenditures including deposits	705	525	656
Taxes paid on income	166	5	0
Income tax refunds	(16)	(120)	(118)
Interest paid on debt obligations net of capitalized interest	299	170	98
Interest capitalized	$ 6	$ 53	$ 25

SUPPLEMENTARY FINANCIAL STATE_6

SUPPLEMENTARY FINANCIAL STATEMENT INFORMATION - Non-cash Investing and Financing Activities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Ferrous Processing and Trading
Noncash or Part Noncash Acquisitions [Line Items]
Fair value of settlement of a pre-existing relationship as part of consideration in connection with transaction	$ (20)	$ 0	$ 0
ArcelorMittal USA
Noncash or Part Noncash Acquisitions [Line Items]
Fair value of settlement of a pre-existing relationship as part of consideration in connection with transaction	0	(237)	0
ArcelorMittal USA | Common Stock
Noncash or Part Noncash Acquisitions [Line Items]
Fair value of other consideration given	0	990	0
ArcelorMittal USA | Series B Preferred Stock
Noncash or Part Noncash Acquisitions [Line Items]
Fair value of other consideration given	0	738	0
AK Steel | Common Stock
Noncash or Part Noncash Acquisitions [Line Items]
Fair value of other consideration given	0	618	0
Share-based Payment Arrangement | AK Steel
Noncash or Part Noncash Acquisitions [Line Items]
Fair value of other consideration given	$ 0	$ 4	$ 0

ACQUISITIONS - Narrative (Detai

ACQUISITIONS - Narrative (Details) $ in Millions	Mar. 13, 2020	Dec. 31, 2021USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2021USD ($)
Business Acquisition [Line Items]
Number of businesses acquired | segment				2
Revenues			$ 20,444	$ 5,354	$ 1,990
Net loss attributable to acquisition			2,988	(122)	293
Amortization of inventory step-up			161	96	0
Acquisition-related costs			20	90	$ 7
Ferrous Processing and Trading
Business Acquisition [Line Items]
Revenues		$ 153
Net loss attributable to acquisition		18
Amortization of inventory step-up		$ 22
Acquisition-related costs			1
ArcelorMittal USA
Business Acquisition [Line Items]
Acquisition-related costs			3	26
Revaluation of equity method investment						$ 31
AK Steel
Business Acquisition [Line Items]
Acquisition-related costs			$ 1	$ 26
Exchange ratio	0.400

ACQUISITIONS - Consideration (D

ACQUISITIONS - Consideration (Details) $ / shares in Units, $ in Millions	Nov. 18, 2021USD ($)	Dec. 09, 2020USD ($)$ / sharesshares	Mar. 13, 2020USD ($)$ / sharesshares	Dec. 31, 2021shares	Dec. 31, 2020shares
Business Acquisition [Line Items]
Cash consideration		$ 639
Common shares, outstanding (in shares) | shares				500,158,955	477,517,372
Series B Preferred Stock
Business Acquisition [Line Items]
Fair value of Cliffs issued stock		738
Ferrous Processing and Trading
Business Acquisition [Line Items]
Fair value of settlement of a pre-existing relationship	$ (20)
Cash consideration	775
Total purchase consideration	$ 755
ArcelorMittal USA
Business Acquisition [Line Items]
Fair value of settlement of a pre-existing relationship		(237)
Cash consideration		639
Total purchase consideration		2,604
Cash consideration pursuant to the AM USA Transaction Agreement		505
Cash consideration for purchase of the remaining JV partner's interest of Kote and Tek		182
Total cash consideration receivable		(48)
Accounts receivable		97
Freestanding derivative asset from customer supply agreement		140
ArcelorMittal USA | Common Stock
Business Acquisition [Line Items]
Fair value of Cliffs issued stock		$ 990
Number of shares issued (in shares) | shares		78,186,671
Share price (in dollars per share) | $ / shares		$ 12.66
ArcelorMittal USA | Series B Preferred Stock
Business Acquisition [Line Items]
Number of shares issued (in shares) | shares		583,273		583,273
Share price (in dollars per share) | $ / shares		$ 1,266
AK Steel
Business Acquisition [Line Items]
Total purchase consideration			$ 1,535
Share price (in dollars per share) | $ / shares			$ 4.87
Fair value of AK Steel debt			$ 914
Common shares, outstanding (in shares) | shares			317,000,000
Exchange ratio			0.400
Shares of Cliffs common shares issued to AK Steel stockholders (in shares) | shares			127,000,000
AK Steel | Common Stock
Business Acquisition [Line Items]
Number of shares issued (in shares) | shares				127,000,000
Other consideration transferred			$ 3
Exchange ratio				0.400
Fair value of Cliffs common shares issued for outstanding AK Steel common stock			618
AK Steel | ABL Facility
Business Acquisition [Line Items]
Fair value of AK Steel debt			590
AK Steel | 7.500% 2023 AK Senior Notes
Business Acquisition [Line Items]
Fair value of AK Steel debt			$ 324

ACQUISITIONS - Preliminary purc

ACQUISITIONS - Preliminary purchase price allocation (Details) - USD ($) $ in Millions	13 Months Ended
	Dec. 31, 2021	Mar. 31, 2021	Nov. 18, 2021	Dec. 31, 2020	Dec. 09, 2020	Mar. 13, 2020
Business Acquisition [Line Items]
Goodwill	$ 1,116			$ 1,406
Measurement Period Adjustments, Other non-current liabilities		$ (72)
Ferrous Processing and Trading
Business Acquisition [Line Items]
Cash and cash equivalents			$ 9
Accounts receivable, net			233
Inventories			137
Other current assets			4
Property, plant and equipment			179
Other non-current assets			74
Accounts payable			(122)
Accrued employment costs			(8)
State and local taxes			(1)
Other current liabilities			(8)
Other non-current liabilities			(21)
Net identifiable assets acquired			476
Goodwill			279
Total net assets acquired			$ 755
ArcelorMittal USA
Business Acquisition [Line Items]
Cash and cash equivalents	35				$ 35
Accounts receivable, net	346				349
Inventories	2,129				2,115
Other current assets	36				34
Property, plant and equipment	4,404				4,017
Deferred income taxes	285				0
Other non-current assets	165				158
Accounts payable	(728)				(736)
Accrued employment costs	(266)				(271)
State and local taxes	(76)				(76)
Other current liabilities	(430)				(453)
Pension liability, non-current	(730)				(730)
OPEB liability, non-current	(2,465)				(2,465)
Other non-current liabilities	(769)				(598)
Noncontrolling interest	(8)				(13)
Net identifiable assets acquired	1,944				1,366
Goodwill	660				1,230
Total net assets acquired	2,604				$ 2,596
Measurement Period Adjustments, Cash and cash equivalents	0
Measurement Period Adjustments, Accounts receivable, net	(3)
Measurement Period Adjustments, Inventories	14
Measurement Period Adjustments, Other current assets	2
Measurement Period Adjustments, Property, plant and equipment	387
Measurement Period Adjustments, Deferred income taxes	285
Measurement Period Adjustments, Other non-current assets	7
Measurement Period Adjustments, Accounts payable	8
Measurement Period Adjustments, Accrued employment costs	5
Measurement Period Adjustments, State and local taxes	0
Measurement Period Adjustments, Other current liabilities	23
Measurement Period Adjustments, Pension liability, non-current	0
Measurement Period Adjustments, OPEB liability, non-current	0
Measurement Period Adjustments, Other non-current liabilities	(171)
Measurement Period Adjustments, Noncontrolling interest	21
Measurement Period Adjustments, Net identifiable assets acquired	578
Measurement Period Adjustments, Goodwill	(570)
Measurement Period Adjustments, Total net assets acquired	$ 8
AK Steel
Business Acquisition [Line Items]
Cash and cash equivalents		39				$ 38
Accounts receivable, net		664				666
Inventories		1,320				1,563
Other current assets		52				68
Property, plant and equipment		2,274				2,184
Deferred income taxes		69				0
Other non-current assets		471				475
Accounts payable		(644)				(636)
Accrued employment costs		(93)				(94)
State and local taxes		(31)				(35)
Other current liabilities		(274)				(276)
Long-term debt		(1,179)				(1,179)
Pension liability, non-current		(463)				(473)
OPEB liability, non-current		(408)				(400)
Other non-current liabilities		(435)				(507)
Noncontrolling interest		(1)				0
Net identifiable assets acquired		1,361				1,394
Goodwill		174				141
Total net assets acquired		1,535				$ 1,535
Measurement Period Adjustments, Cash and cash equivalents		1
Measurement Period Adjustments, Accounts receivable, net		(2)
Measurement Period Adjustments, Inventories		243
Measurement Period Adjustments, Other current assets		16
Measurement Period Adjustments, Property, plant and equipment		90
Measurement Period Adjustments, Deferred income taxes		69
Measurement Period Adjustments, Other non-current assets		4
Measurement Period Adjustments, Accounts payable		8
Measurement Period Adjustments, Accrued employment costs		1
Measurement Period Adjustments, State and local taxes		4
Measurement Period Adjustments, Other current liabilities		2
Measurement Period Adjustments, Long-term debt		0
Measurement Period Adjustments, Pension liability, non-current		10
Measurement Period Adjustments, OPEB liability, non-current		(8)
Measurement Period Adjustments, Noncontrolling interest		1
Measurement Period Adjustments, Net identifiable assets acquired		(33)
Measurement Period Adjustments, Goodwill		33
Measurement Period Adjustments, Total net assets acquired		$ 0

ACQUISITIONS - Intangible asset

ACQUISITIONS - Intangible assets and liabilities (Details) - USD ($) $ in Millions	Nov. 18, 2021	Mar. 13, 2020
Ferrous Processing and Trading
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 43
Weighted average life, finite-lived intangible assets	16 years
Ferrous Processing and Trading | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 18
Weighted average life, finite-lived intangible assets	15 years
Ferrous Processing and Trading | Supplier relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 18
Weighted average life, finite-lived intangible assets	18 years
Ferrous Processing and Trading | Trade names and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 7
Weighted average life, finite-lived intangible assets	15 years
AK Steel
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		$ 148
Weighted average life, finite-lived intangible assets		17 years
Finite-lived intangible liability assumed		$ (71)
Weighted average life, finite-lived intangible liabilities		12 years
AK Steel | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		$ 77
Weighted average life, finite-lived intangible assets		18 years
AK Steel | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		$ 60
Weighted average life, finite-lived intangible assets		17 years
AK Steel | Trade names and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		$ 11
Weighted average life, finite-lived intangible assets		10 years

ACQUISITIONS - Pro Forma (Detai

ACQUISITIONS - Pro Forma (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
ArcelorMittal USA and AK Steel
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues, pro forma		$ 12,837	$ 17,163
Net income (loss) attributable to Cliffs shareholders, pro forma		(520)	(11)
Expenses, pro forma		$ 32	76
Statutory tax rate, pro forma		24.30%
Income tax benefit (expense), pro forma		$ 170	117
ArcelorMittal USA and AK Steel | Intersegment Eliminations
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues, pro forma		844	1,499
Ferrous Processing and Trading
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues, pro forma	$ 21,701	13,549
Net income (loss) attributable to Cliffs shareholders, pro forma	$ 3,074	(526)
Franchise | ArcelorMittal USA and AK Steel
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net income (loss) attributable to Cliffs shareholders, pro forma		140	129
Fair Value Adjustment to Inventory | ArcelorMittal USA and AK Steel
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net income (loss) attributable to Cliffs shareholders, pro forma		96	362
Acquisition-related costs | ArcelorMittal USA and AK Steel
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net income (loss) attributable to Cliffs shareholders, pro forma		93	$ 93
Restructuring Costs | ArcelorMittal USA
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net income (loss) attributable to Cliffs shareholders, pro forma		$ 1,820

REVENUES - By Market and Produc

REVENUES - By Market and Product Line (Details) T in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)T	Dec. 31, 2020USD ($)T	Dec. 31, 2019USD ($)T
Disaggregation of Revenue [Line Items]
Revenues	$ 20,444	$ 5,354	$ 1,990
Customer Supply Agreements | Sales
Disaggregation of Revenue [Line Items]
Derivative revenue		122	78
Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	19,901	4,965	1,990
Steelmaking | Hot-rolled steel
Disaggregation of Revenue [Line Items]
Revenues	$ 5,615	$ 386	$ 0
Sales volume (in net tons) | T	4,886	633	0
Steelmaking | Cold-rolled steel
Disaggregation of Revenue [Line Items]
Revenues	$ 3,186	$ 490	$ 0
Sales volume (in net tons) | T	2,790	682	0
Steelmaking | Coated steel
Disaggregation of Revenue [Line Items]
Revenues	$ 5,864	$ 1,747	$ 0
Sales volume (in net tons) | T	5,056	1,911	0
Steelmaking | Stainless and electrical steel
Disaggregation of Revenue [Line Items]
Revenues	$ 1,622	$ 868	$ 0
Sales volume (in net tons) | T	674	416	0
Steelmaking | Plate
Disaggregation of Revenue [Line Items]
Revenues	$ 1,316	$ 46	$ 0
Sales volume (in net tons) | T	1,020	62	0
Steelmaking | Other steel products
Disaggregation of Revenue [Line Items]
Revenues	$ 1,247	$ 46	$ 0
Sales volume (in net tons) | T	1,460	79	0
Steelmaking | Other
Disaggregation of Revenue [Line Items]
Revenues	$ 1,051	$ 1,382	$ 1,990
Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	543	389	0
Other Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues	543	389	0
Automotive | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	4,726	2,062	0
Automotive | Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	426	329	0
Infrastructure and manufacturing | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	5,380	784	0
Infrastructure and manufacturing | Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	47	34	0
Distributors and converters | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	7,671	696	0
Distributors and converters | Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	70	26	0
Steel producers | Steelmaking
Disaggregation of Revenue [Line Items]
Revenues	$ 2,124	$ 1,423	$ 1,990

REVENUES - Deferred Revenue (De

REVENUES - Deferred Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred Revenue Arrangement [Line Items]
Realization of deferred revenue		$ 35
Other Current Liabilities
Deferred Revenue Arrangement [Line Items]
Deferred Revenue (Current)	$ 25	7	$ 22
Net Increase (Decrease)	18	(15)
Other Noncurrent Liabilities
Deferred Revenue Arrangement [Line Items]
Net Increase (Decrease)	0	(26)
Deferred Revenue (Long-Term)	$ 0	$ 0	$ 26

SEGMENT REPORTING - Schedule Of

SEGMENT REPORTING - Schedule Of Segment Reporting Information, By Segment (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)segment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment	4
Number of reportable segments | segment	1
Revenues	$ 20,444	$ 5,354	$ 1,990
Adjusted EBITDA	5,262	353	525
Steelmaking
Segment Reporting Information [Line Items]
Revenues	19,901	4,965	1,990
Adjusted EBITDA	5,422	433	636
Other Businesses
Segment Reporting Information [Line Items]
Revenues	543	389	0
Adjusted EBITDA	9	47	0
Corporate and eliminations
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ (169)	$ (127)	$ (111)

SEGMENT REPORTING - Reconciliat

SEGMENT REPORTING - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net income (loss)	$ 3,033	$ (81)	$ 293
Interest expense, net	(337)	(238)	(101)
Income tax benefit (expense)	773	(111)	18
Depreciation, depletion and amortization	897	308	85
Gain (loss) on extinguishment of debt	(88)	130	(18)
Amortization of inventory step-up	(161)	(96)	0
Total Adjusted EBITDA	5,262	353	525
Net income attributable to noncontrolling interests	(45)	(41)	0
EBITDA Calculation
Segment Reporting Information [Line Items]
Net income (loss)	3,033	(81)	293
Interest expense, net	(337)	(238)	(101)
Income tax benefit (expense)	773	(111)	18
Depreciation, depletion and amortization	897	308	85
EBITDA	5,040	354	497
Adjusted EBITDA Calculation
Segment Reporting Information [Line Items]
EBITDA of noncontrolling interests	75	56	0
Gain (loss) on extinguishment of debt	(88)	130	(18)
Severance costs	(15)	(38)	(2)
Acquisition-related costs excluding severance costs	(5)	(52)	(7)
Acquisition-related loss on equity method investment	(31)	0	0
Amortization of inventory step-up	(161)	(96)	0
Impact of discontinued operations	(3)	(1)	1
Total Adjusted EBITDA	5,262	353	525
Net income attributable to noncontrolling interests	(45)	(41)	0
Depreciation, depletion and amortization	$ 30	$ 15	$ 0

SEGMENT REPORTING - Depreciatio

SEGMENT REPORTING - Depreciation, Depletion and Amortization and Capital Additions By Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	$ 897	$ 308	$ 85
Capital additions	857	483	690
Steelmaking
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	855	276	80
Capital additions	787	436	687
Other Businesses
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	37	27	0
Capital additions	52	45	0
Corporate and eliminations
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	5	5	5
Capital additions	$ 18	$ 2	$ 3

SEGMENT REPORTING - Summary of

SEGMENT REPORTING - Summary of Assets by Segment (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 18,975	$ 16,771
Operating Segments
Segment Reporting Information [Line Items]
Total assets	18,632	16,088
Steelmaking | Operating Segments
Segment Reporting Information [Line Items]
Total assets	18,326	15,849
Other Businesses | Operating Segments
Segment Reporting Information [Line Items]
Total assets	306	239
Corporate and eliminations
Segment Reporting Information [Line Items]
Total assets	$ 343	$ 683

SEGMENTS REPORTING (Revenues an

SEGMENTS REPORTING (Revenues and Property, Plant and Equipment, Net by Geographical Location) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 20,444	$ 5,354	$ 1,990
Property, plant and equipment, net	9,186	8,743	1,929
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	18,881	4,580	1,505
Property, plant and equipment, net	9,092	8,647	1,929
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	803	602	448
Property, plant and equipment, net	93	91	0
Other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	760	172	37
Property, plant and equipment, net	$ 1	$ 5	$ 0

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, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 11,526	$ 10,217
Allowance for depreciation and depletion	(2,340)	(1,474)
Property, plant and equipment, net	9,186	8,743	$ 1,929
Other Noncurrent Assets
Property, Plant and Equipment [Line Items]
Right-of-use assets related to finance leases	411	361
Land, land improvements, and mineral rights
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,291	1,213
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	889	703
Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	8,709	6,786
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	229	151
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 408	$ 1,364

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation	$ 848	$ 298	$ 77
Interest capitalized	6	53	25
Depletion	$ 46	$ 8	$ 8

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT (Book Value of Land and Mineral Rights Disclosure) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Mineral rights:
Cost	$ 780	$ 773
Depletion	(187)	(142)
Net mineral rights	593	631
Land rights	$ 406	$ 361

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES - Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 1,116	$ 1,406
Steelmaking
Goodwill [Line Items]
Goodwill	942	1,232
Decrease of goodwill	(290)
Other Businesses
Goodwill [Line Items]
Goodwill	$ 174	$ 174

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES - Intangibles (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 263	$ 220
Finite-Lived Intangible Assets, Accumulated Amortization	(42)	(32)
Finite-Lived Intangible Assets, Net	221	188
Finite-Lived Intangible Liability, Gross	(71)	(71)
Finite-Lived Intangible Liability, Accumulated Amortization	14	7
Finite-Lived Intangible Liability, Net	(57)	(64)
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	95	77
Finite-Lived Intangible Assets, Accumulated Amortization	(8)	(3)
Finite-Lived Intangible Assets, Net	87	74
Developed technology
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	60	60
Finite-Lived Intangible Assets, Accumulated Amortization	(6)	(3)
Finite-Lived Intangible Assets, Net	54	57
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	18	11
Finite-Lived Intangible Assets, Accumulated Amortization	(2)	(1)
Finite-Lived Intangible Assets, Net	16	10
Mining permits
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	72	72
Finite-Lived Intangible Assets, Accumulated Amortization	(26)	(25)
Finite-Lived Intangible Assets, Net	46	47
Supplier relationships
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	18	0
Finite-Lived Intangible Assets, Accumulated Amortization	0	0
Finite-Lived Intangible Assets, Net	$ 18	$ 0

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of Intangible Assets	$ 10	$ 8
Finite-Lived Intangible Asset, Expected Amortization, Year One	13
Finite-Lived Intangible Asset, Expected Amortization, Year Two	13
Finite-Lived Intangible Asset, Expected Amortization, Year Three	13
Finite-Lived Intangible Asset, Expected Amortization, Year Four	13
Finite-Lived Intangible Asset, Expected Amortization, Year Five	13
Amortization of Intangible Liability	(7)	$ (7)
Finite-Lived Intangible Liabilities, Amortization Credit, Next Twelve Months	(5)
Finite-Lived Intangible Liabilities, Amortization Credit, Year Two	(5)
Finite-Lived Intangible Liabilities, Amortization Credit, Year Three	(5)
Finite-Lived Intangible Liabilities, Amortization Credit, Year Four	(5)
Finite-Lived Intangible Liabilities, Amortization Credit, Year Five	$ (5)

DEBT AND CREDIT FACILITIES - Sc

DEBT AND CREDIT FACILITIES - Schedule Of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2021	Sep. 30, 2021	Feb. 17, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total Principal Amount	$ 5,369
Total Debt				$ 5,424
Less: current				34
Total long-term debt	5,238			$ 5,390
AK Steel
Debt Instrument [Line Items]
Total Principal Amount	$ 56
4.875% 2024 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				4.875%
Annual Effective Interest Rate				5.00%
Total Principal Amount				$ 395
Unamortized Debt Issuance Costs				(3)
Unamortized Discounts				(1)
Total Debt				$ 391
9.875% 2025 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	9.875%			9.875%
Annual Effective Interest Rate	10.57%			10.57%
Total Principal Amount	$ 607			$ 955
Unamortized Debt Issuance Costs	(4)			(8)
Unamortized Discounts	(13)			(25)
Total Debt	$ 590			$ 922
6.750% 2026 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	6.75%			6.75%
Annual Effective Interest Rate	6.99%			6.99%
Total Principal Amount	$ 845			$ 845
Unamortized Debt Issuance Costs	(16)			(20)
Unamortized Discounts	(7)			(9)
Total Debt	$ 822			$ 816
7.625% 2021 AK Senior Notes | AK Steel
Debt Instrument [Line Items]
Stated interest rate				7.625%
Annual Effective Interest Rate				7.33%
Total Principal Amount				$ 34
Unamortized Debt Issuance Costs				0
Unamortized Discounts				0
Total Debt				$ 34
7.500% 2023 AK Senior Notes | AK Steel
Debt Instrument [Line Items]
Stated interest rate				7.50%
Annual Effective Interest Rate				6.17%
Total Principal Amount				$ 13
Unamortized Debt Issuance Costs				0
Unamortized Discounts				0
Total Debt				$ 13
6.375% 2025 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				6.375%
Annual Effective Interest Rate				8.11%
Total Principal Amount				$ 64
Unamortized Debt Issuance Costs				0
Unamortized Discounts				(4)
Total Debt				$ 60
6.375% 2025 AK Senior Notes | AK Steel
Debt Instrument [Line Items]
Stated interest rate				6.375%
Annual Effective Interest Rate				8.11%
Total Principal Amount				$ 29
Unamortized Debt Issuance Costs				0
Unamortized Discounts				(2)
Total Debt				$ 27
1.500% 2025 Convertible Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	1.50%			1.50%
Annual Effective Interest Rate	6.26%			6.26%
Total Principal Amount	$ 294			$ 296
Unamortized Debt Issuance Costs	(3)			(4)
Unamortized Discounts	(39)			(49)
Total Debt	$ 252			$ 243
5.750% 2025 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate				5.75%
Annual Effective Interest Rate				6.01%
Total Principal Amount				$ 396
Unamortized Debt Issuance Costs				(3)
Unamortized Discounts				(4)
Total Debt				$ 389
7.000% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	7.00%			7.00%
Annual Effective Interest Rate	9.24%			9.24%
Total Principal Amount	$ 73			$ 73
Unamortized Debt Issuance Costs	0			0
Unamortized Discounts	(7)			(8)
Total Debt	$ 66			$ 65
7.000% 2027 AK Senior Notes | AK Steel
Debt Instrument [Line Items]
Stated interest rate	7.00%			7.00%
Annual Effective Interest Rate	9.24%			9.24%
Total Principal Amount	$ 56	$ 80		$ 56
Unamortized Debt Issuance Costs	0			0
Unamortized Discounts	(5)			(6)
Total Debt	$ 51			$ 50
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	5.875%			5.875%
Annual Effective Interest Rate	6.49%			6.49%
Total Principal Amount	$ 556			$ 556	$ 750
Unamortized Debt Issuance Costs	(3)			(4)
Unamortized Discounts	(15)			(18)
Total Debt	$ 538			$ 534
4.625% 2029 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	4.625%
Annual Effective Interest Rate	4.63%
Total Principal Amount	$ 500		$ 500
Unamortized Debt Issuance Costs	(8)
Unamortized Discounts	0
Total Debt	$ 492
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	4.875%
Annual Effective Interest Rate	4.88%
Total Principal Amount	$ 500		$ 500
Unamortized Debt Issuance Costs	(8)
Unamortized Discounts	0
Total Debt	$ 492
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate	6.25%			6.25%
Annual Effective Interest Rate	6.34%			6.34%
Total Principal Amount	$ 263			$ 263
Unamortized Debt Issuance Costs	(2)			(2)
Unamortized Discounts	(3)			(3)
Total Debt	258			258
Industrial Revenue Bonds | AK Steel
Debt Instrument [Line Items]
Total Principal Amount	66			92
Unamortized Debt Issuance Costs	0			0
Unamortized Premiums	2			2
Total Debt	68			$ 94
EDC Revolving Credit Facility | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Annual Effective Interest Rate				3.25%
Credit facility, maximum borrowing capacity				$ 40
Credit facility, amount outstanding				$ 18
ABL Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 1,609
ABL Facility | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Annual Effective Interest Rate	1.87%			2.15%
Credit facility, maximum borrowing capacity	$ 4,500			$ 3,500
Credit facility, amount outstanding	$ 1,609			$ 1,510

DEBT AND CREDIT FACILITIES - De

DEBT AND CREDIT FACILITIES - Debt Issuances and Terms (Details) $ / shares in Units, $ in Millions	Oct. 15, 2021USD ($)	Mar. 11, 2021USD ($)	Apr. 24, 2020USD ($)	Sep. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)	Feb. 17, 2021USD ($)	Feb. 11, 2021shares
Debt Instrument [Line Items]
Debt Extinguished			$ 736			$ 1,306	$ 1,513	$ 724
Common shares, issued (in shares) | shares						506,832,537	506,832,537			20,000,000
Common shares, par value (in dollars per share) | $ / shares						$ 0.125	$ 0.125
Total Principal Amount						$ 5,369
AK Steel
Debt Instrument [Line Items]
Total Principal Amount						56
9.875% 2025 Senior Secured Notes
Debt Instrument [Line Items]
Debt Extinguished		$ 322			$ 25	$ 347
9.875% 2025 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs						101.00%
Stated interest rate						9.875%	9.875%
Total Principal Amount						$ 607	$ 955
6.750% 2026 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate						6.75%	6.75%
Total Principal Amount						$ 845	$ 845
4.625% 2029 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs						101.00%
Stated interest rate						4.625%
Total Principal Amount						$ 500			$ 500
4.875% 2031 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs						101.00%
Stated interest rate						4.875%
Total Principal Amount						$ 500			$ 500
1.500% 2025 Convertible Senior Notes
Debt Instrument [Line Items]
Redemption price, percentage						100.00%
Debt Extinguished				$ 2		$ 2	$ 20
Convertible debt, threshold percentage of stock price trigger, five-day trading						0.98
Conversion ratio						129.2985		122.4365
Convertible debt, initial conversion price (in dollars per share) | $ / shares						$ 8.17
Convertible debt, equity component						$ 86
1.500% 2025 Convertible Senior Notes | Minimum
Debt Instrument [Line Items]
Threshold percentage of stock price trigger						130.00%
1.500% 2025 Convertible Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate						1.50%	1.50%
Total Principal Amount						$ 294	$ 296
7.000% 2027 Senior Notes
Debt Instrument [Line Items]
Debt Extinguished							$ 262
7.000% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate						7.00%	7.00%
Total Principal Amount						$ 73	$ 73
5.875% 2027 Senior Notes
Debt Instrument [Line Items]
Debt Extinguished							$ 195
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs						101.00%
Stated interest rate						5.875%	5.875%
Total Principal Amount						$ 556	$ 556	$ 750
6.250% 2040 Senior Notes
Debt Instrument [Line Items]
Debt Extinguished							$ 36
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs						101.00%
Stated interest rate						6.25%	6.25%
Total Principal Amount						$ 263	$ 263
4.875% 2021 Senior Notes
Debt Instrument [Line Items]
Debt Extinguished								124
6.375% 2025 Senior Notes
Debt Instrument [Line Items]
Debt Extinguished						64	$ 168
6.375% 2025 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate							6.375%
Total Principal Amount							$ 64
5.750% 2025 Senior Notes
Debt Instrument [Line Items]
Debt Extinguished					$ 396	$ 396	$ 77	$ 600
5.750% 2025 Senior Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Repurchase price if triggering event occurs						101.00%
Stated interest rate							5.75%
Total Principal Amount							$ 396
4.875% 2024 Senior Secured Notes
Debt Instrument [Line Items]
Debt Extinguished						$ 395	$ 6
4.875% 2024 Senior Secured Notes | Cleveland-Cliffs Inc.
Debt Instrument [Line Items]
Stated interest rate							4.875%
Total Principal Amount							$ 395
Industrial Revenue Bonds
Debt Instrument [Line Items]
Debt Extinguished	$ 26					26
Industrial Revenue Bonds | AK Steel
Debt Instrument [Line Items]
Total Principal Amount						$ 66	$ 92
Weighted average fixed rate						6.86%

DEBT AND CREDIT FACILITIES - _2

DEBT AND CREDIT FACILITIES - Debt Redemption (Details)	12 Months Ended
	Dec. 31, 2021
9.875% 2025 Senior Secured Notes | Debt Instrument, Redemption, Period One, Upon Equity Issuance | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	109.875%
9.875% 2025 Senior Secured Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%	[1]
9.875% 2025 Senior Secured Notes | Debt Instrument, Redemption, Period Two | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	107.406%
6.750% 2026 Senior Secured Notes | Debt Instrument, Redemption, Period One, Upon Equity Issuance | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	106.75%
6.750% 2026 Senior Secured Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%	[1]
6.750% 2026 Senior Secured Notes | Debt Instrument, Redemption, Period Two | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	105.063%
7.000% 2027 Senior Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%	[1]
7.000% 2027 Senior Notes | Debt Instrument, Redemption, Period Two | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	103.50%
7.000% 2027 AK Senior Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%
7.000% 2027 AK Senior Notes | Debt Instrument, Redemption, Period Two | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	103.50%
1.500% 2025 Convertible Senior Notes
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%
5.875% 2027 Senior Notes | Debt Instrument, Redemption, Period One, Upon Equity Issuance | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	105.875%
5.875% 2027 Senior Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%	[1]
5.875% 2027 Senior Notes | Debt Instrument, Redemption, Period Two | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	102.938%
6.250% 2040 Senior Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period One, Upon Equity Issuance | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	104.625%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%	[1]
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period Two | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	102.313%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period Three | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	101.156%
4.625% 2029 Senior Notes | Debt Instrument, Redemption, Period Four | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period One, Upon Equity Issuance | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	104.875%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period One | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Two | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	102.438%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Three | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	101.625%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Four | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.813%
4.875% 2031 Senior Notes | Debt Instrument, Redemption, Period Five | Cleveland-Cliffs Inc.
Debt Instrument, Redemption [Line Items]
Redemption price, percentage	100.00%
[1]	2 Plus a "make-whole" premium.

DEBT AND CREDIT FACILITIES - AB

DEBT AND CREDIT FACILITIES - ABL Facility (Details) - USD ($)	Dec. 31, 2021	Dec. 17, 2021	Dec. 09, 2020	Mar. 27, 2020	Mar. 13, 2020
ABL Facility | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 4,500,000,000			$ 2,000,000,000
Credit facility, sublimit for swingline loans					125,000,000
Filo tranche commitments			$ 150,000,000	$ 150,000,000
Increase in maximum borrowing capacity, tranche A		1,000,000,000	1,500,000,000
Maximum borrowing capacity, tranche A			$ 3,350,000,000
Exchange of Tranche B revolver commitments for Tranche A revolver commitments		$ 150,000,000
Letter of Credit | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity					$ 555,000,000
ABL Facility
Line of Credit Facility [Line Items]
Available borrowing base on ABL Facility	$ 4,500,000,000
Borrowings and Letter of credit obligations	(1,609,000,000)
Borrowing capacity available	2,716,000,000
Letter of Credit
Line of Credit Facility [Line Items]
Borrowings and Letter of credit obligations	$ (175,000,000)

DEBT AND CREDIT FACILITIES - Ot

DEBT AND CREDIT FACILITIES - Other Financing Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Aggregate principal amount	$ 5,369
AK Steel
Debt Instrument [Line Items]
Aggregate principal amount	56
AK Steel | Industrial Revenue Bonds
Debt Instrument [Line Items]
Aggregate principal amount	$ 66	$ 92
Weighted average fixed rate	6.86%

DEBT AND CREDIT FACILITIES - _3

DEBT AND CREDIT FACILITIES - Debt Extinguishments (Details) - USD ($) $ in Millions	Jan. 18, 2022	Oct. 15, 2021	Mar. 12, 2021	Mar. 11, 2021	Apr. 24, 2020	Mar. 27, 2020	Mar. 13, 2020	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Feb. 11, 2021
Extinguishment of Debt [Line Items]
Repayments under credit facilities											$ 5,889	$ 550	$ 0
Total Principal Amount								$ 5,369			5,369
Debt Extinguished					$ 736						$ 1,306	$ 1,513	724
Common shares, issued (in shares)								506,832,537			506,832,537	506,832,537		20,000,000
Gain (loss) on extinguishment of debt											$ (88)	$ 130	(18)
Reduction of Principal Long-Term Debt					$ 181
AK Steel
Extinguishment of Debt [Line Items]
Total Principal Amount								$ 56			56
Senior notes
Extinguishment of Debt [Line Items]
Debt Extinguished												35
Industrial Revenue Bonds | AK Steel
Extinguishment of Debt [Line Items]
Debt Extinguished												7
EDC Revolving Credit Facility
Extinguishment of Debt [Line Items]
Repayments under credit facilities								55
Industrial Revenue Bonds
Extinguishment of Debt [Line Items]
Debt Extinguished		$ 26									26
Gain (loss) on extinguishment of debt											0
Industrial Revenue Bonds | AK Steel
Extinguishment of Debt [Line Items]
Total Principal Amount								66			66	92
1.500% 2025 Convertible Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished									$ 2		2	20
Gain (loss) on extinguishment of debt											0	1
1.500% 2025 Convertible Senior Notes | Subsequent Event
Extinguishment of Debt [Line Items]
Debt Extinguished	$ 294
1.500% 2025 Convertible Senior Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount								294			294	296
5.750% 2025 Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished										$ 396	396	77	600
Gain (loss) on extinguishment of debt											(17)	16	(13)
5.750% 2025 Senior Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount												396
9.875% 2025 Senior Secured Notes
Extinguishment of Debt [Line Items]
Debt Extinguished				$ 322						$ 25	347
Gain (loss) on extinguishment of debt											(47)
9.875% 2025 Senior Secured Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount								607			607	955
Senior notes
Extinguishment of Debt [Line Items]
Debt Extinguished			$ 535
4.875% 2024 Senior Secured Notes
Extinguishment of Debt [Line Items]
Debt Extinguished											395	6
Gain (loss) on extinguishment of debt											(14)	1
4.875% 2024 Senior Secured Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount												395
7.625% 2021 AK Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished						$ 9	$ 364				34	373
Gain (loss) on extinguishment of debt											0	0
7.625% 2021 AK Senior Notes | AK Steel
Extinguishment of Debt [Line Items]
Total Principal Amount												34
7.500% 2023 AK Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished						$ 56	$ 311				13	367
Gain (loss) on extinguishment of debt											0	3
7.500% 2023 AK Senior Notes | AK Steel
Extinguishment of Debt [Line Items]
Total Principal Amount												13
6.375% 2025 Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished											64	168
Gain (loss) on extinguishment of debt											(7)	21
6.375% 2025 Senior Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount												64
6.375% 2025 AK Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished											29	9
Gain (loss) on extinguishment of debt											(3)	(1)
6.375% 2025 AK Senior Notes | AK Steel
Extinguishment of Debt [Line Items]
Total Principal Amount												29
7.000% 2027 Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished												262
Gain (loss) on extinguishment of debt												27
7.000% 2027 Senior Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount								73			73	73
5.875% 2027 Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished												195
Gain (loss) on extinguishment of debt												49
5.875% 2027 Senior Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount								556			556	556	750
6.250% 2040 Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished												36
Gain (loss) on extinguishment of debt												13
6.250% 2040 Senior Notes | Cleveland-Cliffs Inc.
Extinguishment of Debt [Line Items]
Total Principal Amount								$ 263			$ 263	$ 263
4.875% 2021 Senior Notes
Extinguishment of Debt [Line Items]
Debt Extinguished													124
Gain (loss) on extinguishment of debt													$ (5)

DEBT AND CREDIT FACILITIES - _4

DEBT AND CREDIT FACILITIES - Schedule of Debt Instrument Maturities (Details) $ in Millions	Dec. 31, 2021USD ($)
Debt Disclosure [Abstract]
2022	$ 0
2023	0
2024	36
2025	2,510
2026	845
Thereafter	1,978
Long-term Debt	$ 5,369

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value, Assets and Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance - January 1	$ 0	$ 45
Total gains included in earnings	0	122
Settlements	0	(27)
Settlement of pre-existing relationship	0	(140)
Ending balance - December 31	0	0
Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS - Carrying Value And Fair Value Of Financial Instruments Disclosure (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	$ 5,238	$ 5,424
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	5,586	6,065
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	3,561	3,802
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	3,911	4,446
Industrial Revenue Bonds | 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	68	94
Industrial Revenue Bonds | 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	66	91
Line of Credit | Carrying Value | Significant  Other Observable Inputs (Level 2) | EDC Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	0	18
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	1,609	1,510
Line of Credit | Fair Value | Significant  Other Observable Inputs (Level 2) | EDC Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long-term debt	0	18
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	$ 1,609	$ 1,510

PENSION AND OTHER POSTRETIREMEN

PENSION AND OTHER POSTRETIREMENT BENEFITS - Obligations and Funded Status (Details) - USD ($) $ in Millions	Dec. 09, 2020	Mar. 13, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Amounts recognized in accumulated other comprehensive loss (income):
Accumulated benefit obligation			$ 6,013	$ 6,537
AK Steel
Change in benefit obligations:
Acquired through business combinations		$ 949
ArcelorMittal USA
Change in benefit obligations:
Acquired through business combinations	$ 3,294
Pension Plan
Change in benefit obligations:
Benefit obligations — beginning of year			6,565	1,021
Service cost			56	23	$ 17
Interest cost			103	64	35
Plan amendments			0	0
Actuarial loss (gain)			(131)	162
Benefits paid			(456)	(146)
Participant contributions			0	0
Acquired through business combinations			0	5,535
Effect of settlement			(101)	(94)
Benefit obligations — end of year			6,036	6,565	1,021
Change in plan assets:
Fair value of plan assets — beginning of year			5,332	749
Actual return on plan assets			668	472
Participant contributions			0	0
Employer contributions			155	50
Benefits paid			(454)	(146)
Acquired through business combinations			0	4,301
Effect of settlement			(95)	(94)
Fair value of plan assets — end of year			5,606	5,332	749
Funded status			(430)	(1,233)
Amounts recognized in Statements of Financial Position:
Non-current assets			153	3
Current liabilities			(5)	(12)
Non-current liabilities			(578)	(1,224)
Total amount recognized			(430)	(1,233)
Amounts recognized in accumulated other comprehensive loss (income):
Net actuarial loss (gain)			(286)	164
Prior service cost (credit)			5	6
Net amount recognized			(281)	170
Other Postretirement Benefits Plan
Change in benefit obligations:
Benefit obligations — beginning of year			3,757	255
Service cost			51	8	2
Interest cost			74	19	10
Plan amendments			8	0
Actuarial loss (gain)			(456)	14
Benefits paid			(227)	(89)
Participant contributions			47	22
Acquired through business combinations			0	3,528
Effect of settlement			0	0
Benefit obligations — end of year			3,254	3,757	255
Change in plan assets:
Fair value of plan assets — beginning of year			783	260
Actual return on plan assets			29	45
Participant contributions			26	17
Employer contributions			139	30
Benefits paid			(165)	(88)
Acquired through business combinations			0	519
Effect of settlement			0	0
Fair value of plan assets — end of year			812	783	$ 260
Funded status			(2,442)	(2,974)
Amounts recognized in Statements of Financial Position:
Non-current assets			71	54
Current liabilities			(130)	(139)
Non-current liabilities			(2,383)	(2,889)
Total amount recognized			(2,442)	(2,974)
Amounts recognized in accumulated other comprehensive loss (income):
Net actuarial loss (gain)			(392)	56
Prior service cost (credit)			4	(6)
Net amount recognized			$ (388)	$ 50

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, 2021	Dec. 31, 2020	Dec. 31, 2019
Amortization:
Net periodic benefit cost (credit)	$ (210)	$ (54)	$ 1
Defined Benefit Plan, Expected Amounts [Abstract]
Estimated net periodic benefit cost	(107)
Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	56	23	17
Interest cost	103	64	35
Expected return on plan assets	(359)	(140)	(55)
Amortization:
Net actuarial loss	32	27	24
Prior service costs (credits)	1	1	1
Settlements	(22)	(6)	0
Net periodic benefit cost (credit)	(189)	(31)	22
Defined Benefit Plan, Expected Amounts [Abstract]
Estimated net periodic benefit cost	(179)
Other Postretirement Benefits Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	51	8	2
Interest cost	74	19	10
Expected return on plan assets	(40)	(20)	(17)
Amortization:
Net actuarial loss	3	3	5
Prior service costs (credits)	(2)	(2)	(2)
Settlements	0	0	0
Net periodic benefit cost (credit)	86	$ 8	$ (2)
Defined Benefit Plan, Expected Amounts [Abstract]
Estimated net periodic benefit cost	$ 72

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, 2021	Dec. 31, 2020
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	$ (451)	$ (219)
Actual returns on assets under (over) expected	(309)	(332)
Amortization of net actuarial gain (loss)	(32)	(27)
Amortization of prior service credits (costs)	(1)	(1)
Settlements	22	6
Other	0	(27)
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(438)	(15)
Actual returns on assets under (over) expected	11	(26)
Amortization of net actuarial gain (loss)	2	(3)
Amortization of prior service credits (costs)	(3)	2
Settlements	0	0
Other	8	(2)
Discount rates | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(224)	181
Discount rates | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(117)	44
Demographic updates | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	76	(3)
Demographic updates | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	3	(11)
Mortality | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	19	(16)
Mortality | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	13	(4)
Per capita health care costs | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	0	0
Per capita health care costs | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(350)	(10)
Other | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(2)	0
Other | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(5)	(5)
Actuarial loss (gain) on benefit obligation | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	(131)	162
Actuarial loss (gain) on benefit obligation | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain) on benefit obligation	$ (456)	$ 14

PENSIONS AND OTHER POSTRETIRE_4

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Contributions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	$ 155	$ 50
Expected employer contributions, next fiscal year	4
Defined Benefit Plan, Plan Assets, Contributions by Employer	163
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	139	30
Expected employer contributions, next fiscal year	138
Defined Benefit Plan, Plan Assets, Contributions by Employer	180	25
Other Postretirement Benefits Plan | VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions, next fiscal year	28
Defined Benefit Plan, Plan Assets, Contributions by Employer	67	0
Other Postretirement Benefits Plan | Direct Payments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions, next fiscal year	110
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 113	$ 25

PENSION AND OTHER POSTRETIREM_2

PENSION AND OTHER POSTRETIREMENT BENEFITS - Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2021USD ($)
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022	$ 475
2023	477
2024	451
2025	428
2026	424
2027-2031	1,879
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022	180
2023	171
2024	167
2025	163
2026	163
2027-2031	$ 823

PENSIONS AND OTHER POSTRETIRE_5

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Weighted-Average Assumptions Used to Determine Benefit Obligations (Details)	Dec. 31, 2021	Dec. 31, 2020
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.75%	2.34%
Interest crediting rate	5.35%	5.25%
Rate of compensation increase	2.52%	2.56%
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.01%	2.71%
Rate of compensation increase	3.00%	3.00%

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, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Obligation discount rate	2.32%	3.02%	4.27%
Service cost discount rate	2.78%	3.34%	4.35%
Interest cost discount rate	1.64%	2.53%	3.92%
Interest crediting rate	5.35%	5.50%	6.00%
Expected return on plan assets	6.84%	7.69%	8.25%
Compensation rate increase	2.54%	2.56%	2.53%
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Obligation discount rate	2.46%	3.28%	4.29%
Service cost discount rate	3.28%	3.35%	4.49%
Interest cost discount rate	2.04%	2.51%	3.94%
Expected return on plan assets	5.20%	6.82%	7.00%
Compensation rate increase	3.00%	3.00%	3.00%

PENSIONS AND OTHER POSTRETIRE_7

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Assumed Health Care Cost Trend Rates (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Postemployment Benefits [Abstract]
Health care cost trend rate assumed for next year	2.36%	6.05%
Ultimate health care cost trend rate	4.50%	4.59%
Year that the ultimate rate is reached	2031	2031

PENSIONS AND OTHER POSTRETIRE_8

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Target Allocation and Actual Asset Allocations for Pension and VEBA Plan Assets (Details)	Dec. 31, 2021	Dec. 31, 2020
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	100.00%
Percentage of Plan Assets	100.00%	100.00%
Pension Plan | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	46.30%
Percentage of Plan Assets	47.60%	51.80%
Pension Plan | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	34.60%
Percentage of Plan Assets	34.60%	33.80%
Pension Plan | Hedge funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	2.20%
Percentage of Plan Assets	2.20%	2.20%
Pension Plan | Private equity
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	5.00%
Percentage of Plan Assets	2.70%	2.10%
Pension Plan | Structured credit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	5.20%
Percentage of Plan Assets	5.60%	5.00%
Pension Plan | Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	5.20%
Percentage of Plan Assets	5.60%	3.30%
Pension Plan | Absolute return fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	1.50%
Percentage of Plan Assets	1.70%	1.80%
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	100.00%
Percentage of Plan Assets	100.00%	100.00%
Other Postretirement Benefits Plan | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	21.20%
Percentage of Plan Assets	22.50%	22.20%
Other Postretirement Benefits Plan | Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	68.50%
Percentage of Plan Assets	66.40%	66.40%
Other Postretirement Benefits Plan | Hedge funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	1.40%
Percentage of Plan Assets	1.80%	1.80%
Other Postretirement Benefits Plan | Private equity
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	1.10%
Percentage of Plan Assets	0.00%	0.40%
Other Postretirement Benefits Plan | Structured credit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	1.00%
Percentage of Plan Assets	1.20%	0.90%
Other Postretirement Benefits Plan | Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	1.00%
Percentage of Plan Assets	2.10%	1.80%
Other Postretirement Benefits Plan | Absolute return fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2022 Target Allocation	5.80%
Percentage of Plan Assets	6.00%	6.50%

PENSIONS AND OTHER POSTRETIRE_9

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	$ 5,606	$ 5,332	$ 749
Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	812	783	260
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	2,416	2,431
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	362	331
Significant  Other Observable Inputs (Level 2) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	747	807
Significant  Other Observable Inputs (Level 2) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	209	221
Significant Unobservable Inputs (Level 3) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	904	670	$ 212
Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	42	38
Investments Measured at Net Asset Value | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	1,539	1,424
Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	199	193
U.S. equities | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	1,932	1,950
U.S. equities | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	129	119
U.S. equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	1,157	1,163
U.S. equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	26	26
U.S. equities | Significant  Other Observable Inputs (Level 2) | Pension Plan
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) | Other Postretirement Benefits Plan
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 Plan
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) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	775	787
U.S. equities | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	103	93
Global equities | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	734	810
Global equities | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	54	55
Global equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	617	615
Global equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	6	6
Global equities | Significant  Other Observable Inputs (Level 2) | Pension Plan
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) | Other Postretirement Benefits Plan
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 Plan
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) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	117	195
Global equities | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	48	49
U.S. government securities | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	500	476
U.S. government securities | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	191	156
U.S. government securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	140	141
U.S. government securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	111	62
U.S. government securities | Significant  Other Observable Inputs (Level 2) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	310	295
U.S. government securities | Significant  Other Observable Inputs (Level 2) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	80	94
U.S. government securities | Significant Unobservable Inputs (Level 3) | Pension Plan
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) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	50	40
U.S. government securities | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
U.S. corporate bonds | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	1,376	1,281
U.S. corporate bonds | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	348	364
U.S. corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	502	512
U.S. corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	219	237
U.S. corporate bonds | Significant  Other Observable Inputs (Level 2) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	371	466
U.S. corporate bonds | Significant  Other Observable Inputs (Level 2) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	129	127
U.S. corporate bonds | Significant Unobservable Inputs (Level 3) | Pension Plan
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) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	503	303
U.S. corporate bonds | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Non U.S. and other bonds | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	66	46
Non U.S. and other bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
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  Other Observable Inputs (Level 2) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	66	46
Non U.S. and other bonds | Significant Unobservable Inputs (Level 3) | Pension Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Hedge funds | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	125	118
Hedge funds | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	15	14
Hedge funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
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) | Other Postretirement Benefits Plan
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 Plan
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) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	125	118
Hedge funds | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	15	14
Hedge funds | Investments Measured at Net Asset Value | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Hedge funds | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Private equity | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	151	114
Private equity | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	3
Private equity | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Private equity | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
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 Plan
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) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	151	114
Private equity | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	3
Private equity | Investments Measured at Net Asset Value | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Private equity | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Non U.S. and other bonds | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	315	264
Non U.S. and other bonds | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	10	7
Non U.S. and other bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Non U.S. and other bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
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  Other Observable Inputs (Level 2) | Pension Plan
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  Other Observable Inputs (Level 2) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	315	264
Non U.S. and other bonds | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	10	7
Non U.S. and other bonds | Investments Measured at Net Asset Value | Pension Plan
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 | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Real estate | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	313	174
Real estate | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	17	14
Real estate | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
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) | Other Postretirement Benefits Plan
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 Plan
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) | Other Postretirement Benefits Plan
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 Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	313	174
Real estate | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	17	14
Real estate | Investments Measured at Net Asset Value | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Real estate | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Absolute return fixed income | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	94	99
Absolute return fixed income | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	48	51
Absolute return fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Absolute return fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Absolute return fixed income | Significant  Other Observable Inputs (Level 2) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Absolute return fixed income | Significant  Other Observable Inputs (Level 2) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Absolute return fixed income | Significant Unobservable Inputs (Level 3) | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Absolute return fixed income | Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	0	0
Absolute return fixed income | Investments Measured at Net Asset Value | Pension Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	94	99
Absolute return fixed income | Investments Measured at Net Asset Value | Other Postretirement Benefits Plan
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of pension assets by asset category	$ 48	$ 51

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, 2021	Dec. 31, 2020
Pension Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	$ 5,332	$ 749
Actual return on plan assets:
Fair value of plan assets — end of year	5,606	5,332
Pension Plan | 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	114
Actual return on plan assets:
Fair value of plan assets — end of year	151	114
Reserve for investment commitments	151
Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	783	260
Actual return on plan assets:
Fair value of plan assets — end of year	812	783
Other Postretirement Benefits Plan | 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	3
Actual return on plan assets:
Fair value of plan assets — end of year	0	3
Significant Unobservable Inputs (Level 3) | Pension Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	670	212
Actual return on plan assets:
Relating to assets still held at the reporting date	124	8
Relating to assets sold during the period	8	6
Purchases	142	195
Sales	(40)	(13)
Acquired through business combinations	0	262
Fair value of plan assets — end of year	904	670
Significant Unobservable Inputs (Level 3) | Pension Plan | 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	114
Actual return on plan assets:
Fair value of plan assets — end of year	151	114
Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	38
Actual return on plan assets:
Fair value of plan assets — end of year	42	38
Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan | 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	3
Actual return on plan assets:
Fair value of plan assets — end of year	0	3
Significant Unobservable Inputs (Level 3) | Other Postretirement Benefits Plan | Veba Trust
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	38	34
Actual return on plan assets:
Relating to assets still held at the reporting date	6	2
Relating to assets sold during the period	0	1
Purchases	0	0
Sales	(2)	(1)
Acquired through business combinations		2
Fair value of plan assets — end of year	$ 42	$ 38

PENSIONS AND OTHER POSTRETIR_10

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Defined Contribution Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Postemployment Benefits [Abstract]
Defined contribution pension plans	$ 55	$ 22	$ 3

PENSIONS AND OTHER POSTRETIR_11

PENSIONS AND OTHER POSTRETIREMENT BENEFITS - Multiemployer Plan (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Multiemployer Plan [Line Items]
Contributions	$ 104	$ 30	$ 4
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	$ 88	$ 14	4
Surcharge Imposed	No
Total actuarial liability		5,960
Market value of assets		$ 5,998
Funded ratio		1.01
Steelworkers Pension Trust | Minimum
Multiemployer Plan [Line Items]
Expiration Date of Collective Bargaining Agreement	Sep. 1, 2022
Steelworkers Pension Trust | Maximum
Multiemployer Plan [Line Items]
Expiration Date of Collective Bargaining Agreement	Sep. 1, 2025
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	$ 16	$ 16	0
Surcharge Imposed	Yes
IAM National Pension Fund's National Pension Plan | Minimum
Multiemployer Plan [Line Items]
Expiration Date of Collective Bargaining Agreement	May 31, 2022
IAM National Pension Fund's National Pension Plan | Maximum
Multiemployer Plan [Line Items]
Expiration Date of Collective Bargaining Agreement	May 15, 2023
American Maritime Officers Plan
Multiemployer Plan [Line Items]
Contributions	$ 0	$ 0	$ 0

STOCK COMPENSATION PLANS - Narr

STOCK COMPENSATION PLANS - Narrative (Details)	Mar. 13, 2020shares	Dec. 31, 2021shares	Dec. 31, 2020shares	Dec. 31, 2019shares
2021 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized (in shares)		26,000,000
Number of shares authorized (in shares)		28,000,000
A&R 2015 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)		2,500,000
AK Steel
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exchange ratio	0.400
Stock options granted (in shares)	2,000,000	0	2,010,277	0
AK Steel | A&R 2015 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized (in shares)	5,700,000
Long-term Performance Plan | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	1,000,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		652,888	960,637	572,104
Performance Shares | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	500,000	0	1,550,216	0
Restricted Stock | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	200,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		678,420	960,637	572,104
Restricted Stock Units (RSUs) | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	300,000	0	200,291	0

STOCK COMPENSATION PLANS - Stoc

STOCK COMPENSATION PLANS - Stock-Based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs and Expenses	$ (18)	$ (17)	$ (18)
Income tax benefit	4	4	4
Stock based compensation expense, net of tax	$ (14)	$ (13)	$ (14)
Decrease in basic earnings per common share (in dollars per share)	$ 5.63	$ (0.32)	$ 1.06
Decrease in diluted earnings per common share (in dollars per share)	$ 5.36	(0.32)	1.03
Compensation cost related to outstanding awards not yet recognized	$ 24
Expected period of recognition for outstanding awards not yet recognized	1 year 4 months 24 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)	$ (0.03)	(0.03)	(0.05)
Decrease in diluted earnings per common share (in dollars per share)	$ (0.03)	$ (0.03)	$ (0.05)
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs and Expenses	$ (2)	$ (2)	$ (2)
Selling, general and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs and Expenses	(16)	(13)	(16)
Acquisition-related costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs and Expenses	$ 0	$ (2)	$ 0

STOCK COMPENSATION PLANS - Perf

STOCK COMPENSATION PLANS - Performance Shares (Details) - $ / shares	Mar. 13, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Performance Shares
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)		2,452,226	1,935,878	1,424,723
Outstanding at beginning of year, weighted average grant date fair value (in dollars per share)		$ 10.34	$ 15.58	$ 14.46
Granted (in shares)		652,888	960,637	572,104
Granted, weighted average grant date fair value (in dollars per share)		$ 25.12	$ 6.93	$ 18.31
Distributed (in shares)		(1,279,509)	(1,938,786)	0
Distributed, weighted average grant date fair value (in dollars per share)		$ 11.74	$ 12.23	$ 0
Performance adjustment (in shares)		625,355	549,154	0
Performance adjustment, weighted average grant date fair value (in dollars per share)		$ 11.93	$ 15.63	$ 0
Forfeited/canceled (in shares)		(80,490)	(604,873)	(60,949)
Forfeited/canceled, weighted average grant date fair value (in dollars per share)		$ 11.27	$ 5.70	$ 15.12
Outstanding at end of year (in shares)		2,370,470	2,452,226	1,935,878
Outstanding at end of year, weighted average grant date fair value (in dollars per share)		$ 14.04	$ 10.34	$ 15.58
Performance/vesting period		3 years
Performance Shares | 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		0.00%
Performance Shares | 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		200.00%
Performance Shares | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (in shares)	500,000	0	1,550,216	0
Granted, weighted average grant date fair value (in dollars per share)		$ 0	$ 4.59	$ 0
Outstanding at end of year (in shares)		100,000
Long-term Performance Plan | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (in shares)	1,000,000
Outstanding at end of year (in shares)		200,000

STOCK COMPENSATION PLANS - Rest

STOCK COMPENSATION PLANS - Restricted Stock (Details) - $ / shares	Mar. 13, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Stock Units (RSUs)
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)		2,143,583	2,147,183	4,694,360
Outstanding at beginning of year, weighted average grant date fair value (in dollars per share)		$ 7.12	$ 9.10	$ 4.18
Granted (in shares)		678,420	960,637	572,104
Granted, weighted average grant date fair value (in dollars per share)		$ 17.45	$ 4.87	$ 11.24
Distributed (in shares)		(642,992)	(1,101,115)	(3,058,307)
Distributed, weighted average grant date fair value (in dollars per share)		$ 7.31	$ 8.58	$ 1.95
Forfeited/canceled (in shares)		(56,185)	(63,413)	(60,974)
Forfeited/canceled, weighted average grant date fair value (in dollars per share)		$ 9.50	$ 7.31	$ 9.31
Outstanding at end of year (in shares)		2,122,826	2,143,583	2,147,183
Outstanding at end of year, weighted average grant date fair value (in dollars per share)		$ 10.31	$ 7.12	$ 9.10
Performance/vesting period		3 years
Restricted Stock Units (RSUs) | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (in shares)	300,000	0	200,291	0
Granted, weighted average grant date fair value (in dollars per share)		$ 0	$ 4.87	$ 0
Distributed, weighted average grant date fair value (in dollars per share)	$ 4.87
Restricted Stock | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (in shares)	200,000

STOCK COMPENSATION PLANS - St_2

STOCK COMPENSATION PLANS - Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 13, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)		2,485,808	563,230	563,230
Outstanding at beginning of year, weighted average exercise price (in dollars per share)		$ 11.60	$ 10.42	$ 10.42
Exercised (in shares)		(1,457,495)	(79,973)	0
Exercised, weighted average exercise price (in dollars per share)		$ 10.36	$ 7.01	$ 0
Forfeited/canceled (in shares)		(26,253)	(7,726)	0
Forfeitured/canceled, weighted average exercise price (in dollars per share)		$ 36.48	$ 41.04	$ 0
Outstanding at end of year (in shares)		1,002,060	2,485,808	563,230
Outstanding at end of year, weighted average exercise price (in dollars per share)		$ 12.75	$ 11.60	$ 10.42
Exercisable (in shares)		904,574	2,172,052	563,230
Exercisable, weighted average exercise price (in dollars per share)		$ 13.35	$ 11.86	$ 10.42
Intrinsic value of options exercised		$ 13
Weighted-average remaining contractual life of options outstanding		3 years
Aggregate intrinsic value of options outstanding		$ 10
Weighted-average remaining contractual life of options exerciseable		2 years 7 months 6 days
Aggregate intrinsic value of options exerciseable		$ 8
AK Steel
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Granted (in shares)	2,000,000	0	2,010,277	0
Granted, weighted average exercise price (in dollars per share)	$ 0.51	$ 0	$ 11.86	$ 0

STOCK COMPENSATION PLANS - None

STOCK COMPENSATION PLANS - Nonemployee Directors (Details) - USD ($)	Mar. 13, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost related to outstanding awards not yet recognized		$ 24,000,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		678,420	960,637	572,104
Restricted Stock Units (RSUs) | AK Steel
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	300,000	0	200,291	0
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		$ 120,000	$ 100,000	$ 100,000
Granted (in shares)		58,851	253,809	86,477
Share-based Payment Arrangement, Nonemployee | Director | Deferred shares | Directors Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		13,078	54,794	23,659

INCOME TAXES - Schedule of Inco

INCOME TAXES - Schedule of Income Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
United States	$ 3,827	$ (201)	$ 313
Foreign	(24)	8	0
Income (loss) from continuing operations before income taxes	$ 3,803	$ (193)	$ 313

INCOME TAXES - Schedule of Comp

INCOME TAXES - Schedule of Components of Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)	$ 14	$ (2)	$ (1)
Current State and Local Tax Expense (Benefit)	55	0	0
Current Foreign Tax Expense (Benefit)	0	(1)	0
Current Income Tax Expense (Benefit)	69	(3)	(1)
Deferred Federal Income Tax Expense (Benefit)	683	(95)	19
Deferred State and Local Income Tax Expense (Benefit)	31	(11)	0
Deferred Foreign Income Tax Expense (Benefit)	(10)	(2)	0
Income Tax Expense (Benefit)	$ 773	$ (111)	$ 18

INCOME TAXES - Schedule of Effe

INCOME TAXES - Schedule of Effective Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax at U.S. statutory rate	$ 799	$ (41)	$ 66
Percentage depletion in excess of cost depletion	(99)	(42)	(49)
Non-taxable income related to noncontrolling interests	(9)	(9)	0
Luxembourg legal entity reduction	0	0	846
State taxes, net	86	(11)	0
Other items, net	(4)	(8)	1
Income tax benefit (expense)	$ 773	$ (111)	$ 18
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax at U.S. statutory rate, percent	21.00%	21.00%	21.00%
Percentage depletion in excess of depletion, percent	(3.00%)	22.00%	(16.00%)
Non-taxable income related to noncontrolling interests, percent	0.00%	4.00%	0.00%
Luxembourg legal entity reduction, percent	0.00%	0.00%	271.00%
Sales taxes, net, percent	2.00%	6.00%	0.00%
Other items, net, percent	0.00%	4.00%	1.00%
Provision for income tax expense (benefit) and effective income tax rate including discrete items (percent)	20.00%	57.00%	6.00%
Dissolution of entities
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Luxembourg legal entity reduction, valuation release	$ 0	$ 0	$ (846)
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Luxembourg legal entity reduction, valuation allowance release, percent	0.00%	0.00%	(271.00%)

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, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Other comprehensive income (loss), Pension and OPEB	$ (206)	$ (52)	$ 11
Other comprehensive income (loss), Derivative financial instruments	(21)	(1)	0
Other comprehensive income (loss), Total	$ (227)	$ (53)	$ 11

INCOME TAXES - Schedule of Defe

INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Operating loss and other carryforwards	$ 379	$ 1,236
Pension and OPEB liabilities	584	228
State and local	109	132
Other liabilities	287	190
Total deferred tax assets before valuation allowance	1,359	1,786
Deferred tax asset valuation allowance	(409)	(836)	$ (441)	$ (1,287)
Net deferred tax assets	950	950
Deferred tax liabilities:
Investment in partnerships	(191)	(144)
Property, plant and equipment and mineral rights	641	246
Other assets	(216)	(68)
Total deferred tax liabilities	1,048	458
Net deferred tax assets (liabilities)	(98)
Net deferred tax assets (liabilities)		492
Domestic operating loss carryforward	2,081	7,444
Foreign operating loss carryforward	1,407	1,592
Interest expense limitation carryforward	$ 18	$ 80

INCOME TAXES Income Taxes (Sche

INCOME TAXES Income Taxes (Schedule of Valuation Allowance) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Valuation Allowance [Line Items]
Balance at beginning of year	$ 836	$ 441	$ 1,287
Balance at end of year	409	836	441
Included in income tax expense (benefit)
Valuation Allowance [Line Items]
Change in valuation allowance	(82)	(3)	(846)
Increase (decrease) from acquisitions
Valuation Allowance [Line Items]
Change in valuation allowance	$ (345)	$ 398	$ 0

INCOME TAXES (Narrative) (Detai

INCOME TAXES (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Domestic operating loss carryforward	$ 2,081,000,000	$ 7,444,000,000
Foreign operating loss carryforward	1,407,000,000	1,592,000,000
Interest expense limitation carryforward	18,000,000	80,000,000
Deferred tax asset valuation allowance	409,000,000	836,000,000	$ 441,000,000	$ 1,287,000,000
Undistributed earnings of foreign subsidiaries	0	0
Dissolution of entities
Income Tax Contingency [Line Items]
Luxembourg legal entity reduction, valuation release	0	0	(846,000,000)
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Deferred tax asset valuation allowance	$ 70,000,000	$ 98,000,000
LUXEMBOURG | Dissolution of entities
Income Tax Contingency [Line Items]
Change in valuation allowance			(1,300,000,000)
LUXEMBOURG | Intercompany notes
Income Tax Contingency [Line Items]
Change in valuation allowance			$ 447,000,000

INCOME TAXES (Schedule of Unrec

INCOME TAXES (Schedule of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance	$ 107	$ 29	$ 29
Increase for tax positions in current year	4	7	0
Decrease for tax positions of prior year	(66)	(4)	0
Lapses in statutes of limitations	(10)	0	0
Increases from acquisitions	0	75	0
Unrecognized Tax Benefits, Ending Balance	35	107	$ 29
Other Current Liabilities
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Ending Balance	1
Other Noncurrent Liabilities
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance	2
Unrecognized Tax Benefits, Ending Balance	34	2
Other Noncurrent Assets
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance	96
Unrecognized Tax Benefits, Ending Balance		$ 96
Other Liabilities
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits that would impact effective tax rate	$ 30

LEASE OBLIGATIONS - Lease Costs

LEASE OBLIGATIONS - Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating leases	$ 70	$ 43
Finance leases, Amortization of lease cost	94	15
Finance leases, Interest on lease liabilities	9	4
Short-term leases	66	13
Total	$ 239	$ 75

LEASE OBLIGATIONS - Other infor

LEASE OBLIGATIONS - Other information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating leases within cash flows from operating activities	$ 70	$ 43
Finance leases within cash flows from operating activities	9	4
Finance leases within cash flows from financing activities	94	15
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 50	$ 44	$ 29
Weighted-average remaining lease term - operating leases (in years)	8 years	8 years
Weighted-average remaining lease term - finance leases (in years)	5 years	5 years
Weighted-average discount rate - operating leases	7.00%	8.00%
Weighted-average discount rate - finance leases	4.00%	4.00%

LEASE OBLIGATIONS - Future Mini

LEASE OBLIGATIONS - Future Minimum Lease Payments (Details) $ in Millions	Dec. 31, 2021USD ($)
Leases [Abstract]
Finance Lease, Liability, Payments, Due in Next Rolling Twelve Months	$ 105
Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months	68
Finance Lease, Liability, Payments, Due in Rolling Year Two	96
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Two	56
Finance Lease, Liability, Payments, Due in Rolling Year Three	31
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Three	47
Finance Lease, Liability, Payments, Due in Rolling Year Four	28
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Four	39
Finance Lease, Liability, Payments, Due in Rolling Year Five	19
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Five	35
Finance Lease, Liability, Payments, Due in Rolling after Year Five	66
Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five	133
Finance Lease, Liability, Payment, Due	345
Lessee, Operating Lease, Liability, to be Paid	378
Finance Lease, Liability, Undiscounted Excess Amount	54
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	108
Finance Lease, Liability	$ 291
Finance Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities
Operating Lease, Liability	$ 270
Finance Lease, Liability, Current	97
Finance Lease, Liability, Noncurrent	194
Operating Lease, Liability, Current	50
Operating Lease, Liability, Noncurrent	$ 220
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities

ASSET RETIREMENT OBLIGATIONS -

ASSET RETIREMENT OBLIGATIONS - Summary Of Asset Retirement Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	$ 449	$ 342	$ 165
Less: current portion	35	7
Long-term asset retirement obligations	414	335
Total Segment Assets
Environmental Exit Cost [Line Items]
Asset Retirement Obligations, Related to Active Operations	$ 293	$ 190

ASSET RETIREMENT OBLIGATIONS _2

ASSET RETIREMENT OBLIGATIONS - Asset Retirement Obligation Roll-forward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Asset Retirement Obligation [Roll Forward]
Asset Retirement Obligation at Beginning of Year	$ 342	$ 165
Increase from acquisitions	116	172
Accretion expense	18	14
Remediation payments	(29)	(9)
Revision in estimated cash flows	2
Asset Retirement Obligation at End of Year	$ 449	$ 342

CAPITAL STOCK - Narrative (Deta

CAPITAL STOCK - Narrative (Details) $ / shares in Units, $ in Millions	Mar. 11, 2021USD ($)	Dec. 09, 2020shares	Apr. 24, 2020USD ($)	Mar. 13, 2020USD ($)	Sep. 30, 2021USD ($)shares	Jun. 30, 2021USD ($)	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)	Apr. 29, 2021shares	Mar. 31, 2021shares	Feb. 11, 2021$ / sharesshares
Class of Stock [Line Items]
Common shares, issued (in shares)							506,832,537	506,832,537				20,000,000
Common Stock, Shares, Sold												40,000,000
Common stock, shares issued, price per share | $ / shares												$ 16.12
Debt Extinguished | $			$ 736				$ 1,306	$ 1,513	$ 724
Common shares, par value (in dollars per share) | $ / shares							$ 0.125	$ 0.125
Redeemable preferred stock, issued (in shares)							0	583,273
Redeemable preferred stock, outstanding (in shares)							0	583,273
Common shares, authorized (in shares)							1,200,000,000	600,000,000		1,200,000,000	600,000,000
Repurchase of common shares | $							$ 0	$ 0	$ 253
9.875% 2025 Senior Secured Notes
Class of Stock [Line Items]
Debt Extinguished | $	$ 322					$ 25	$ 347
ArcelorMittal
Class of Stock [Line Items]
Common Stock, Shares, Sold												40,000,000
Cleveland-Cliffs Inc. | 9.875% 2025 Senior Secured Notes
Class of Stock [Line Items]
Stated interest rate							9.875%	9.875%
AK Steel
Class of Stock [Line Items]
Exchange ratio				0.400
Common Stock
Class of Stock [Line Items]
Common shares, par value (in dollars per share) | $ / shares							$ 0.125
Stock Repurchased During Period, Shares								24,000,000
Common Stock | ArcelorMittal USA
Class of Stock [Line Items]
Acquisition (in shares)		78,186,671
Common Stock | AK Steel
Class of Stock [Line Items]
Acquisition (in shares)							127,000,000
Exchange ratio							0.400
Fair value of Cliffs common shares issued for outstanding AK Steel common stock | $				$ 618
Series B Preferred Stock
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Shares					583,273
Stock Redeemed or Called During Period, Value | $					$ 1,300
Preferred Stock, Shares Authorized							4,000,000
Preferred Stock, Shares Issued							0
Preferred Stock, Shares Outstanding							0
Series B Preferred Stock | ArcelorMittal USA
Class of Stock [Line Items]
Acquisition (in shares)		583,273					583,273
Series A Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Authorized							3,000,000
Preferred Stock, Shares Issued							0
Preferred Stock, Shares Outstanding							0

CAPITAL STOCK - Dividends Decla

CAPITAL STOCK - Dividends Declared (Details) - $ / shares	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021
Equity [Abstract]
Common stock dividends paid, per share	$ 0.06	$ 0.06

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - AOCI (Loss) and Related Tax Effects (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-tax Amount	$ 759	$ (219)	$ (458)
Tax Benefit (Expense)	(141)	86	139
After-tax Amount	618	(133)	(319)	$ (284)
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-tax Amount	669	(221)	(454)
Tax Benefit (Expense)	(120)	86	138
After-tax Amount	549	(135)	(316)	(281)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-tax Amount	1	3
Tax Benefit (Expense)	0	0
After-tax Amount	1	3	0	0
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-tax Amount	89	(1)	(4)
Tax Benefit (Expense)	(21)	0	1
After-tax Amount	$ 68	$ (1)	$ (3)	$ (3)

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Accumulated Other Comprehensive Income (Loss) Changes in Equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	$ (133)	$ (319)	$ (284)
Other comprehensive loss before reclassifications	790	160	(59)
Net loss reclassified from AOCI	(39)	26	24
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	618	(133)	(319)
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(135)	(316)	(281)
Other comprehensive loss before reclassifications	675	163	(57)
Net loss reclassified from AOCI	9	18	22
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	549	(135)	(316)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	3	0	0
Other comprehensive loss before reclassifications	(2)	3	0
Net loss reclassified from AOCI	0	0	0
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	1	3	0
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(1)	(3)	(3)
Other comprehensive loss before reclassifications	117	(6)	(2)
Net loss reclassified from AOCI	(48)	8	2
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	$ 68	$ (1)	$ (3)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Details of AOCI (Loss) Components Reclassified from Equity (Details) - Reclassification out of Accumulated Other Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Prior service costs	$ (1)	$ (1)	$ (1)
Net actuarial loss	(35)	(30)	(29)
Settlements	22	6	0
Total before taxes	12	23	28
Income tax expense	(3)	(5)	(6)
Net of taxes	9	18	22
Commodity contracts	(61)	10	3
Income tax expense	13	(2)	(1)
Net of taxes	(48)	8	2
Total reclassifications for the period, net of tax	$ (39)	$ 26	$ 24

RELATED PARTIES - Narrative (De

RELATED PARTIES - Narrative (Details) - Hibbing	Dec. 31, 2021	Dec. 31, 2020	Dec. 09, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Ownership interest, equity method investment	85.30%	85.30%	62.30%	23.00%
ArcelorMittal USA
Related Party Transaction [Line Items]
Ownership interest, equity method investment			62.30%
U. S. Steel Canada [Member]
Related Party Transaction [Line Items]
Ownership interest, equity method investment	14.70%

RELATED PARTIES - Summary Of Re

RELATED PARTIES - Summary Of Related Party Transactions Table Disclosure (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Related Party Transactions [Abstract]
Revenue from related parties	$ 139	$ 893	$ 1,015
Revenues	$ 20,444	$ 5,354	$ 1,990
Related party revenues as a percent of Revenues	0.70%	16.70%	51.00%
Purchases from related parties	$ 94	$ 16	$ 0

RELATED PARTIES - Classificatio

RELATED PARTIES - Classification of Related Party Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Related Party Transactions [Abstract]
Accounts receivable, net	$ 3	$ 2
Accounts payable	$ (7)	$ (6)

VARIABLE INTEREST ENTITIES (Det

VARIABLE INTEREST ENTITIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Income from continuing operations attributable to noncontrolling interest	$ 45	$ 41	$ 0
Cash and cash equivalents	48	112
Inventories	5,188	3,828
Property, plant and equipment, net	9,186	8,743	$ 1,929
Accounts payable	(2,073)	(1,575)
Noncontrolling interests	(284)	(323)
Variable Interest Entity, Primary Beneficiary | SunCoke Middletown
Variable Interest Entity [Line Items]
Income from continuing operations attributable to noncontrolling interest	52	41
Cash and cash equivalents	0	5
Inventories	20	21
Property, plant and equipment, net	300	308
Accounts payable	(12)	(15)
Other assets (liabilities), net	(12)	(10)
Noncontrolling interests	$ (296)	$ (309)

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, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 3,030	$ (82)	$ 295
Income from continuing operations attributable to noncontrolling interest	45	41	0
Net income (loss) from continuing operations attributable to Cliffs shareholders	2,985	(123)	295
Income (loss) from discontinued operations, net of tax	3	1	(2)
Net income (loss) attributable to Cliffs shareholders	$ 2,988	$ (122)	$ 293
Weighted average number of shares:
Basic (in shares)	498	379	277
Redeemable preferred shares (in shares)	33	0	0
Convertible senior notes (in shares)	22	0	4
Employee stock plans (in shares)	5	0	3
Diluted (in shares)	558	379	284
Earnings (loss) per common share attributable to Cliffs common shareholders - basic1:
Continuing operations (in dollars per share)	$ 5.62	$ (0.32)	$ 1.07
Discontinued operations (in dollars per share)	0.01	0	(0.01)
Earnings (loss) per common share attributable to Cliffs common shareholders - basic (in dollars per share)	5.63	(0.32)	1.06
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted:
Continuing operations (in dollars per share)	5.35	(0.32)	1.04
Discontinued operations (in dollars per share)	0.01	0	(0.01)
Earnings (loss) per common share attributable to Cliffs common shareholders - diluted (in dollars per share)	$ 5.36	$ (0.32)	$ 1.03
Earnings attributed to Series B Participating Redeemable Preferred Stock	$ 187

EARNINGS PER SHARE - Anti-Dilut

EARNINGS PER SHARE - Anti-Dilutive Securities (Details) shares in Millions	12 Months Ended
	Dec. 31, 2021shares
Series B Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted earnings per share (in shares)	4
Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted earnings per share (in shares)	2
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)	1

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Environmental Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Environmental obligations	$ 207	$ 135
Less current portion	20	18
Long-term environmental obligations	$ 187	$ 117

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Millions	Dec. 31, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Civil penalty	$ 3

SUBSEQUENT EVENTS SUBSEQUENT EV

SUBSEQUENT EVENTS SUBSEQUENT EVENTS (Details) - USD ($) shares in Millions, $ in Millions	Jan. 18, 2022	Apr. 24, 2020	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Feb. 10, 2022
Subsequent Event [Line Items]
Debt Extinguished		$ 736		$ 1,306	$ 1,513	$ 724
1.500% 2025 Convertible Senior Notes redemption				(5)
Subsequent Event
Subsequent Event [Line Items]
Authorized amount of stock repurchase							$ 1,000
1.500% 2025 Convertible Senior Notes
Subsequent Event [Line Items]
Debt Extinguished			$ 2	$ 2	$ 20
1.500% 2025 Convertible Senior Notes | Subsequent Event
Subsequent Event [Line Items]
Debt Extinguished	$ 294
Repayments of Debt	294
1.500% 2025 Convertible Senior Notes redemption	$ 499
Common Stock | Subsequent Event
Subsequent Event [Line Items]
Conversion of convertible securities (in shares)	24