Cleveland-Cliffs (CLF) 10-Q 25 Apr 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 24, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	CLEVELAND-CLIFFS INC.
Entity Central Index Key	0000764065
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		282,845,060
Trading Symbol	clf
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Current Reporting Status	Yes

Statements Of Unaudited Condens

Statements Of Unaudited Condensed Consolidated Financial Position - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
CURRENT ASSETS
Cash and cash equivalents	$ 430.2	$ 823.2
Accounts receivable, net	20.1	226.7
Inventories	312.7	87.9
Supplies and other inventories	97.3	93.2
Derivative assets	107.4	91.5
Income tax receivable, current	117.3	117.3
Other current assets	41	39.8
TOTAL CURRENT ASSETS	1,126	1,479.6
PROPERTY, PLANT AND EQUIPMENT, NET	1,410.3	1,286
OTHER ASSETS
Deposits for property, plant and equipment	68.3	83
Income tax receivable, non-current	121.3	121.3
Deferred income tax assets	466.6	464.8
Other non-current assets	113.8	94.9
TOTAL OTHER ASSETS	770	764
TOTAL ASSETS	3,306.3	3,529.6
CURRENT LIABILITIES
Accounts payable	171.7	186.8
Accrued employment costs	42.1	74
Accrued interest	23	38.4
Partnership distribution payable	43.8	43.5
Other current liabilities	113.4	125.5
TOTAL CURRENT LIABILITIES	394	468.2
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	244.2	248.7
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	174.4	172
LONG-TERM DEBT	2,087	2,092.9
OTHER LIABILITIES	145	123.6
TOTAL LIABILITIES	3,044.6	3,105.4
COMMITMENTS AND CONTINGENCIES (REFER TO NOTE 20)
SHAREHOLDERS' EQUITY
Common Shares - par value $0.125 per share, Authorized - 600,000,000 shares (2018 - 600,000,000 shares); Issued - 301,886,794 shares (2018 - 301,886,794 shares); Outstanding - 298,839,140 shares (2018 - 292,611,569 shares)	37.7	37.7
Capital in excess of par value of shares	3,860.2	3,916.7
Retained deficit	(3,096.8)	(3,060.2)
Cost of 19,047,654 common shares in treasury (2018 - 9,275,225 shares)	(263.9)	(186.1)
Accumulated other comprehensive loss	(275.5)	(283.9)
TOTAL EQUITY	261.7	424.2
TOTAL LIABILITIES AND EQUITY	$ 3,306.3	$ 3,529.6

Statements Of Condensed Consoli

Statements Of Condensed Consolidated Financial Position (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Preferred stock, par value	$ 0	$ 0
Common Stock, Par or Stated Value Per Share	$ 0.125	$ 0.125
Common shares, authorized (in shares)	600,000,000	600,000,000
Common shares, issued (in shares)	301,886,794	301,886,794
Common shares, outstanding	298,007,453	292,611,569
Common shares in treasury	3,879,341	9,275,225
Preferred Class A [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	3,000,000	3,000,000
Preferred Class B [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	4,000,000	4,000,000

Statements Of Unaudited Conde_2

Statements Of Unaudited Condensed Consolidated Operations - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
REVENUES FROM PRODUCT SALES AND SERVICES
Revenue from Contract with Customer, Including Assessed Tax	$ 145.4	$ 169.2
Freight Revenue	11.6	10.8
TOTAL REVENUES	157	180
COST OF GOODS SOLD	(126.1)	(118.5)
SALES MARGIN	30.9	61.5
OTHER OPERATING EXPENSE
Selling, general and administrative expenses	(28.1)	(25.1)
Miscellaneous - net	(3.6)	(6.1)
Other operating expense	31.7	31.2
OPERATING INCOME (LOSS)	(0.8)	30.3
OTHER INCOME (EXPENSE)
Interest expense, net	(25.1)	(32.4)
Other non-operating income	0.1	4.4
TOTAL OTHER INCOME (EXPENSE)	(25)	(28)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(25.8)	2.3
INCOME TAX BENEFIT (EXPENSE)	3.7	(15.7)
LOSS FROM CONTINUING OPERATIONS	(22.1)	(13.4)
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	0	(70.9)
NET INCOME (LOSS)	$ (22.1)	$ (84.3)
LOSS PER COMMON SHARE – BASIC
Continuing operations (in dollars per share)	$ (0.08)	$ (0.05)
Discontinued operations (in dollars per share)	0	(0.24)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share)	(0.08)	(0.29)
LOSS PER COMMON SHARE – DILUTED
Continuing operations (in dollars per share)	(0.08)	(0.05)
Discontinued operations (in dollars per share)	0	(0.24)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share)	$ (0.08)	$ (0.29)
AVERAGE NUMBER OF SHARES (IN THOUSANDS)
Basic	289,525	297,266
Diluted	289,525	297,266

Statements Of Unaudited Conde_3

Statements Of Unaudited Condensed Consolidated Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
NET INCOME (LOSS)	$ (22.1)	$ (84.3)
OTHER COMPREHENSIVE INCOME
Changes in pension and other post-retirement benefits, net of tax	5.7	6.7
Changes in foreign currency translation	0	0.7
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	2.7	0.3
OTHER COMPREHENSIVE INCOME	8.4	7.7
TOTAL COMPREHENSIVE LOSS	$ (13.7)	$ (76.6)

Statements Of Unaudited Conde_4

Statements Of Unaudited Condensed Consolidated Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
OPERATING ACTIVITIES
NET INCOME (LOSS)	$ (22.1)	$ (84.3)
Adjustments to reconcile net loss to net cash used by operating activities:
Depreciation, depletion and amortization	19.9	23.9
Gain on derivatives	(5.7)	(40.8)
Other	9.8	25.9
Changes in operating assets and liabilities:
Receivables and other assets	199.9	196.3
Inventories	(224.8)	(193)
Payables, accrued expenses and other liabilities	(88.2)	(70.9)
Net cash used by operating activities	(111.2)	(142.9)
INVESTING ACTIVITIES
Purchase of property, plant and equipment	(132.7)	(12.4)
Deposits for property, plant and equipment	(1.4)	(59)
Other investing activities	8.5	0
Net cash used by investing activities	(125.6)	(71.4)
FINANCING ACTIVITIES
Repurchase of common shares	(124.3)	0
Dividends paid	(14.8)	0
Repurchase of debt	(10.3)	0
Other financing activities	(8.4)	(7)
Net cash used by financing activities	(157.8)	(7)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	0	0.2
Increase/Decrease in Cash and Cash Equivalents, Including Cash Classified Within Other Current Assets Related to Discontinued Operations	(394.6)	(221.1)
Increase/Decrease in Cash and Cash Equivalents from Discontinued Operations, Classified within Other Current Assets	1.6	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS	(393)	(221.1)
CASH AND CASH EQUIVALENTS AT START OF PERIOD	823.2	978.3
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 430.2	$ 757.2

Statements of Unaudited Conde_5

Statements of Unaudited Condensed Consolidated Changes in Equity Statement - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]
Balance, beginning of period (in shares) at Dec. 31, 2017		297,400,000
Balance, beginning of period PY at Dec. 31, 2017	$ (444.1)	$ 37.7	$ 3,933.9	$ (4,207.3)	$ (169.6)	$ (39)	$ 0.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	34			34
NET INCOME (LOSS)	(84.3)			(84.3)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent						7.7
Other Comprehensive Income (Loss), Net of Tax	7.7
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(76.6)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		300,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	1.9		(15.8)		17.7
Balance, end of period (in shares) at Mar. 31, 2018		297,700,000
Balance, end of period PY at Mar. 31, 2018	(484.8)	$ 37.7	3,918.1	(4,257.6)	(151.9)	(31.3)	$ 0.2
Balance, beginning of period at Dec. 31, 2018	$ 424.2	$ 37.7	3,916.7	(3,060.2)	(186.1)	(283.9)
Balance, beginning of period (in shares) at Dec. 31, 2018	292,611,569	292,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME (LOSS)	$ (22.1)			(22.1)
Other Comprehensive Income (Loss), Net of Tax	8.4					8.4
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		1,700,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	$ (10)		(56.5)		46.5
Stock Repurchased During Period, Shares	(11,500,000)	(11,500,000)
Repurchase of common shares	$ (124.3)				(124.3)
Dividends, Common Stock	(14.5)			(14.5)
Balance, end of period at Mar. 31, 2019	$ 261.7	$ 37.7	$ 3,860.2	$ (3,096.8)	$ (263.9)	$ (275.5)
Balance, end of period (in shares) at Mar. 31, 2019	298,007,453	282,800,000

BASIS OF PRESENTATION AND SIGNI

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	NOTE 1 - BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with SEC rules and regulations and, in the opinion of management, include all adjustments (consisting of normal recurring adjustments) necessary to present fairly the financial position, results of operations, comprehensive loss and cash flows for the periods presented. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Management bases its estimates on various assumptions and historical experience, which are believed to be reasonable; however, due to the inherent nature of estimates, actual results may differ significantly due to changed conditions or assumptions. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of results to be expected for the year ending December 31, 2019 or any other future period. These unaudited condensed consolidated financial statements should be read in conjunction with the financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2018 . As more fully described in the Form 10-K for the year ended December 31, 2018 , in 2018 we committed to a course of action leading to the permanent closure of the Asia Pacific Iron Ore mining operations and, as planned, completed our final shipment in June 2018. Factors considered in this decision included increasingly discounted prices for lower-iron-content ore and the quality of the remaining iron ore reserves. During 2018, we sold all of the assets of our Asia Pacific Iron Ore business through a series of sales to third parties. As a result of our planned exit, management determined that our Asia Pacific Iron Ore operating segment met the criteria to be classified as held for sale and a discontinued operation under ASC Topic 205, Presentation of Financial Statements . As such, all Asia Pacific Iron Ore operating segment results are classified within discontinued operations. Refer to NOTE 14 - DISCONTINUED OPERATIONS for further information. We have two reportable segments - the Mining and Pelletizing segment and the Metallics segment. Unless otherwise noted, discussion of our business and results of operations in this Quarterly Report on Form 10-Q refers to our continuing operations. Basis of Consolidation The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, including the following operations as of March 31, 2019 : Name Location Business Segment Status of Operations Northshore Minnesota Mining and Pelletizing Active United Taconite Minnesota Mining and Pelletizing Active Tilden Michigan Mining and Pelletizing Active Empire Michigan Mining and Pelletizing Indefinitely Idled Toledo HBI Ohio Metallics Construction Stage Intercompany transactions and balances are eliminated upon consolidation. Equity Method Investments Our 23% ownership interest in Hibbing is recorded as an equity method investment. As of March 31, 2019 and December 31, 2018 , our investment in Hibbing was $10.8 million and $15.4 million , respectively, classified as Other liabilities in the Statements of Unaudited Condensed Consolidated Financial Position . Significant Accounting Policies A detailed description of our significant accounting policies can be found in the audited financial statements for the fiscal year ended December 31, 2018 included in our Annual Report on Form 10-K filed with the SEC. There have been no material changes in our significant accounting policies and estimates from those disclosed therein.

NEW ACCOUNTING STANDARDS

NEW ACCOUNTING STANDARDS	3 Months Ended
	Mar. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
NEW ACCOUNTING STANDARDS	NOTE 2 - NEW ACCOUNTING STANDARDS Issued and Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) . The new standard requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases except for short-term leases. For lessees, leases will be classified as either operating or finance leases in the Statements of Unaudited Condensed Consolidated Operations . We adopted this standard on its effective date of January 1, 2019 using the optional alternative approach, which requires application of the new guidance at the beginning of the standard's effective date. Adoption of the updated standard did not have a material effect on our consolidated financial statements. Issued and Not Effective In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments–Credit Losses (Topic 326), which introduces a new accounting model, CECL. CECL requires earlier recognition of credit losses, while also providing additional transparency about credit risk. The CECL model utilizes a lifetime expected credit loss measurement objective for the recognition of credit losses for receivables at the time the financial asset is originated or acquired. The expected credit losses are adjusted each period for changes in expected lifetime credit losses. We plan to adopt this standard on its effective date of January 1, 2020, and are currently evaluating the impact of this standard on our financial statements.

SEGMENT REPORTING

SEGMENT REPORTING	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	NOTE 3 - SEGMENT REPORTING In alignment with our strategic goals, our Company’s continuing operations are organized and managed in two operating segments according to our differentiated products. Our Mining and Pelletizing segment is a major supplier of iron ore pellets to the North American steel industry from our mines and pellet plants located in Michigan and Minnesota. In our Metallics segment, we are currently constructing an HBI production plant in Toledo, Ohio. We expect to complete construction and begin production in 2020. We evaluate performance based on sales margin, defined as revenues less cost of goods sold identifiable to each segment. Additionally, we evaluate performance on a segment basis, as well as a consolidated basis, based on EBITDA and Adjusted EBITDA. These measures allow management and investors to focus on our ability to service our debt as well as illustrate how the business is performing. Additionally, EBITDA and Adjusted EBITDA assist management and investors in their analysis and forecasting as these measures approximate the cash flows associated with operational earnings. The following tables present a summary of our reportable segments including a reconciliation of segment sales margin to Income (loss) from Continuing Operations Before Income Taxes and a reconciliation of Net loss to EBITDA and Adjusted EBITDA: (In Millions) Three Months Ended 2019 2018 Revenues from product sales and services: Mining and Pelletizing $ 157.0 $ 180.0 Sales margin: Mining and Pelletizing $ 30.9 $ 61.5 Other operating expense (31.7 ) (31.2 ) Other expense (25.0 ) (28.0 ) Income (loss) from continuing operations before income taxes $ (25.8 ) $ 2.3 (In Millions) Three Months Ended 2019 2018 Net loss $ (22.1 ) $ (84.3 ) Less: Interest expense, net (25.1 ) (33.5 ) Income tax benefit (expense) 3.7 (15.7 ) Depreciation, depletion and amortization (19.9 ) (23.9 ) EBITDA $ 19.2 $ (11.2 ) Less: Foreign exchange remeasurement $ 0.1 $ (0.4 ) Impact of discontinued operations — (63.1 ) Loss on extinguishment of debt (0.3 ) — Severance costs (1.7 ) — Adjusted EBITDA $ 21.1 $ 52.3 EBITDA: Mining and Pelletizing $ 42.8 $ 72.5 Metallics (0.8 ) (0.3 ) Corporate and Other (including discontinued operations) (22.8 ) (83.4 ) Total EBITDA $ 19.2 $ (11.2 ) Adjusted EBITDA: Mining and Pelletizing $ 47.5 $ 77.1 Metallics (0.8 ) (0.3 ) Corporate (25.6 ) (24.5 ) Total Adjusted EBITDA $ 21.1 $ 52.3 The following table summarizes our depreciation, depletion and amortization expense and capital additions: (In Millions) Three Months Ended 2019 2018 Depreciation, depletion and amortization: Mining and Pelletizing $ 18.5 $ 15.8 Corporate 1.4 1.4 Total depreciation, depletion and amortization $ 19.9 $ 17.2 Capital additions 1 : Mining and Pelletizing $ 46.8 $ 18.7 Metallics 82.4 60.0 Corporate 0.1 0.2 Total capital additions $ 129.3 $ 78.9 1 Refer to NOTE 17 - CASH FLOW INFORMATION for additional information. A summary of assets by segment is as follows: (In Millions) March 31, December 31, Assets: Mining and Pelletizing $ 1,774.5 $ 1,694.1 Metallics 350.0 265.9 Total segment assets 2,124.5 1,960.0 Corporate and Other (including discontinued operations) 1,181.8 1,569.6 Total assets $ 3,306.3 $ 3,529.6

REVENUE

REVENUE	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	NOTE 4 - REVENUE We sell primarily a single product, iron ore pellets, in the North American market. Revenue is recognized generally when iron ore is delivered to our customers. Revenue is measured at the point that control transfers and represents the amount of consideration we expect to receive in exchange for transferring goods. We offer standard payment terms to our customers, generally requiring settlement within 30 days. We enter into supply contracts of varying lengths to provide customers iron ore pellets to use in their blast furnaces. Blast furnaces run continuously with a constant feed of iron ore and, once shut down, cannot easily be restarted. As a result, we ship iron ore in large quantities for storage and use by customers at a later date. Customers do not simultaneously receive and consume the iron ore. Based on our assessment of the factors that indicate the pattern of satisfaction, we transfer control of the iron ore at a point in time upon shipment or delivery of the product. The customer is able to direct the use of, and obtain substantially all of the benefits from, the product at the time the product is delivered. Most of our customer supply agreements specify a provisional price, which is used for initial billing and cash collection. Revenue recorded in accordance with Topic 606 is calculated using the expected revenue rate at the point when control transfers. The final settlement includes market inputs for a specified period of time, which may vary by customer, but typically include one or more of the following published rates: Platts 62% Price, Atlantic Basin pellet premiums, Platts international indexed freight rates and changes in specified Producer Price Indices, including industrial commodities, fuel and steel. Changes in the expected revenue rate from the date control transfers through final settlement of contract terms is recorded in accordance with Topic 815. Refer to NOTE 13 - DERIVATIVE INSTRUMENTS for further information on how our estimated and final revenue rates are determined. A supply agreement with a customer provides for supplemental revenue or refunds based on the average annual daily market price for hot-rolled coil steel in the year the iron ore is consumed in the customer’s blast furnaces. As control transfers prior to consumption, the supplemental revenue is recorded in accordance with ASC Topic 815. Refer to NOTE 13 - DERIVATIVE INSTRUMENTS for further information on supplemental revenue or refunds. Included within Revenues from product sales and services is derivative revenue related to Topic 815 of $5.5 million and $43.8 million , for three months ended March 31, 2019 and 2018 , respectively. Deferred Revenue The table below summarizes our deferred revenue balances: (In Millions) Deferred Revenue (Current) Deferred Revenue (Long-Term) 2019 2018 2019 2018 Opening balance as of January 1 $ 21.0 $ 23.8 $ 38.5 $ 51.4 Closing balance as of March 31 18.1 31.0 38.5 51.4 Increase (decrease) $ (2.9 ) $ 7.2 $ — $ — The terms of one of our pellet supply agreements required supplemental payments to be paid by the customer during the period 2009 through 2012. Installment amounts received under this arrangement in excess of sales were classified as Other current liabilities and Other liabilities in the Statements of Unaudited Condensed Consolidated Financial Position upon receipt of payment. Revenue is recognized over the life of the supply agreement, which extends until 2022, in equal annual installments. As of March 31, 2019 and December 31, 2018 , installment amounts received in excess of sales totaled $51.4 million related to this agreement. As of March 31, 2019 and December 31, 2018 , deferred revenue of $12.9 million was recorded in Other current liabilities and $38.5 million was recorded as long-term in Other liabilities in the Statements of Unaudited Condensed Consolidated Financial Position , related to this agreement. Due to the payment terms and the timing of cash receipts near a period end, cash receipts can exceed shipments for certain customers. Revenue recognized on these transactions totaling $5.3 million and $8.2 million was deferred and included in Other current liabilities in the Statements of Unaudited Condensed Consolidated Financial Position as of March 31, 2019 and December 31, 2018 , respectively.

INVENTORIES

INVENTORIES	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Inventories	NOTE 5 - INVENTORIES The following table presents the detail of our Inventories in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) March 31, 2019 December 31, 2018 Finished goods $ 287.7 $ 77.8 Work-in-process 25.0 10.1 Total inventories $ 312.7 $ 87.9

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	3 Months Ended
	Mar. 31, 2019
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) March 31, December 31, Land rights and mineral rights $ 549.6 $ 549.6 Office and information technology 70.5 70.0 Buildings 87.4 87.2 Mining equipment 568.4 548.5 Processing equipment 660.9 645.8 Electric power facilities 58.7 58.7 Land improvements 23.8 23.8 Asset retirement obligation 14.8 14.8 Other 25.5 25.2 Construction-in-progress 392.0 284.8 2,451.6 2,308.4 Allowance for depreciation and depletion (1,041.3 ) (1,022.4 ) $ 1,410.3 $ 1,286.0 We recorded capitalized interest of $4.0 million and $1.0 million into construction-in-progress during the three months ended March 31, 2019 and 2018 , respectively.

DEBT AND CREDIT FACILITIES

DEBT AND CREDIT FACILITIES	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
DEBT AND CREDIT FACILITIES	NOTE 7 - DEBT AND CREDIT FACILITIES The following represents a summary of our long-term debt: (In Millions) March 31, 2019 Debt Instrument Annual Effective Interest Rate Total Principal Amount Debt Issuance Costs Unamortized Discounts Total Debt Secured Notes: $400 Million 4.875% 2024 Senior Notes 5.00% $ 400.0 $ (5.5 ) $ (2.1 ) $ 392.4 Unsecured Notes: $700 Million 4.875% 2021 Senior Notes 4.89% 114.0 (0.2 ) — 113.8 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (5.3 ) (73.0 ) 238.0 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,073.3 (9.5 ) (14.1 ) 1,049.7 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.2 ) (3.3 ) 292.9 ABL Facility N/A 450.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 0.2 Long-term debt $ 2,087.0 (In Millions) December 31, 2018 Debt Instrument Annual Effective Interest Rate Total Principal Amount Debt Issuance Costs Unamortized Discounts Total Debt Secured Notes: $400 Million 4.875% 2024 Senior Notes 5.00% $ 400.0 $ (5.7 ) $ (2.2 ) $ 392.1 Unsecured Notes: $700 Million 4.875% 2021 Senior Notes 4.89% 124.0 (0.2 ) — 123.8 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (5.5 ) (75.6 ) 235.2 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,073.3 (9.9 ) (14.6 ) 1,048.8 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.3 ) (3.3 ) 292.8 ABL Facility N/A 450.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 0.2 Long-term debt $ 2,092.9 Debt Extinguishment The following is a summary of the debt extinguished with cash and the respective loss on extinguishment: (In Millions) Three Months Ended March 31, 2019 Debt Instrument Debt Extinguished Loss on Extinguishment $700 Million 4.875% 2021 Senior Notes $ 10.0 $ 0.3 $ 10.0 $ 0.3 Debt Maturities The following represents a summary of our maturities of debt instruments based on the principal amounts outstanding at March 31, 2019 : (In Millions) Maturities of Debt 2019 $ — 2020 — 2021 114.0 2022 — 2023 — 2024 400.0 2025 and thereafter 1,688.0 Total maturities of debt $ 2,202.0 ABL Facility The following represents a summary of our borrowing capacity under the ABL Facility: (In Millions) March 31, 2019 December 31, 2018 Available borrowing base on ABL Facility 1 $ 305.4 $ 323.7 Letter of credit obligations and other commitments 2 (65.4 ) (55.0 ) Borrowing capacity available 3 $ 240.0 $ 268.7 1 The ABL Facility has a maximum borrowing base of $450 million, 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, environmental obligations and certain Metallics' contracts. 3 As of March 31, 2019 and December 31, 2018, we had no loans drawn under the ABL Facility.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	NOTE 8 - FAIR VALUE MEASUREMENTS The following represents the assets and liabilities measured at fair value: (In Millions) March 31, 2019 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash equivalents $ — $ 357.6 $ — $ 357.6 Derivative assets — 0.7 106.7 107.4 Total $ — $ 358.3 $ 106.7 $ 465.0 Liabilities: Derivative liabilities $ — $ 0.7 $ 9.8 $ 10.5 Total $ — $ 0.7 $ 9.8 $ 10.5 (In Millions) December 31, 2018 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash equivalents $ 0.8 $ 542.6 $ — $ 543.4 Derivative assets — 0.1 91.4 91.5 Total $ 0.8 $ 542.7 $ 91.4 $ 634.9 Liabilities: Derivative liabilities $ — $ 3.7 $ — $ 3.7 Total $ — $ 3.7 $ — $ 3.7 Financial assets classified in Level 1 included money market funds. The valuation of these instruments is based upon unadjusted quoted prices for identical assets in active markets. The valuation of financial assets and liabilities classified in Level 2 is determined using a market approach based upon quoted prices for similar assets and liabilities in active markets, or other inputs that are observable. Level 2 assets include commercial paper, certificates of deposit and commodity hedge contracts. Level 2 liabilities include commodity hedge contracts. The Level 3 assets and liabilities include derivative assets that consist of freestanding derivative instruments related to a certain supply agreement and derivative assets and liabilities related to certain provisional pricing arrangements with our customers. The supply agreement included in our Level 3 assets contains provisions for supplemental revenue or refunds based on the average annual daily market price for hot-rolled coil steel in the year the iron ore product is consumed in the customer’s blast furnaces. We account for these provisions as derivative instruments at the time of sale and adjust the derivative instruments to fair value through Product revenues each reporting period until the product is consumed and the amounts are settled. We had assets of $106.4 million and $89.3 million at March 31, 2019 and December 31, 2018 , respectively, related to this supply agreement. The provisional pricing arrangements included in our Level 3 assets/liabilities specify provisional price calculations, where the pricing mechanisms generally are based on market pricing, with the final revenue rate to be based on market inputs at a specified point in time in the future, per the terms of the supply agreements. The difference between the estimated final revenue rate at the date of sale and the estimated final revenue rate at the measurement date is characterized as a derivative and is required to be accounted for separately once the revenue has been recognized. The derivative instruments are adjusted to fair value through Product revenues each reporting period based upon current market data and forward-looking estimates provided by management until the final revenue rates are determined. We had assets of $0.3 million and liabilities of $9.8 million related to provisional pricing arrangements at March 31, 2019 compared to assets of $2.1 million related to provisional pricing arrangements at December 31, 2018 . The following table illustrates information about quantitative inputs and assumptions for the assets and liabilities categorized in Level 3 of the fair value hierarchy: Qualitative/Quantitative Information About Level 3 Fair Value Measurements (In Millions) Fair Value at March 31, 2019 Balance Sheet Location Valuation Technique Unobservable Input Range or Point Estimate (Weighted Average) Customer supply agreement $ 106.4 Derivative assets Market Approach Management's Estimate of Market Hot-Rolled Coil Steel per net ton $735 Provisional pricing arrangements $ 9.8 Other current liabilities Market Approach PPI Estimates 180 - 240 Management's Estimate of Platts 62% Price per dry metric ton for respective contract period $80 The significant unobservable input used in the fair value measurement of our customer supply agreement is a forward-looking estimate of the average annual daily market price for hot-rolled coil steel determined by management. The significant unobservable inputs used in the fair value measurement of our provisional pricing arrangements include estimates for PPI data and management’s estimate of Platts 62% Price based upon current market data and index pricing, which include forward-looking estimates determined by management. 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 Three Months Ended 2019 2018 Beginning balance $ 91.4 $ 49.5 Total gains included in earnings 15.3 44.3 Settlements — (0.2 ) Ending balance - March 31 $ 106.7 $ 93.6 Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ 15.3 $ 44.5 (In Millions) Level 3 Liabilities Three Months Ended 2019 2018 Beginning balance $ — $ (1.7 ) Total losses included in earnings (9.8 ) (0.5 ) Settlements — 2.2 Ending balance - March 31 $ (9.8 ) $ — Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (9.8 ) $ — The carrying values of certain financial instruments (e.g., Accounts receivable, net , Accounts payable and Other current liabilities ) approximates 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) March 31, 2019 December 31, 2018 Classification Carrying Value Fair Value Carrying Value Fair Value Long-term debt: Secured Notes $400 Million 4.875% 2024 Senior Notes Level 1 $ 392.4 $ 398.0 $ 392.1 $ 370.2 Unsecured Notes $700 Million 4.875% 2021 Senior Notes Level 1 113.8 115.7 123.8 122.3 $316.25 Million 1.50% 2025 Convertible Senior Notes Level 1 238.0 432.5 235.2 352.4 $1.075 Billion 5.75% 2025 Senior Notes Level 1 1,049.7 1,035.5 1,048.8 962.0 $800 Million 6.25% 2040 Senior Notes Level 1 292.9 255.0 292.8 232.8 ABL Facility Level 2 — — — — Fair value adjustment to interest rate hedge Level 2 0.2 0.2 0.2 0.2 Total long-term debt $ 2,087.0 $ 2,236.9 $ 2,092.9 $ 2,039.9 The fair value of long-term debt was determined using quoted market prices.

PENSIONS AND OTHER POSTRETIREME

PENSIONS AND OTHER POSTRETIREMENT BENEFITS	3 Months Ended
	Mar. 31, 2019
Postemployment Benefits [Abstract]
PENSIONS AND OTHER POSTRETIREMENT BENEFITS	NOTE 9 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS We offer defined benefit pension plans, defined contribution pension plans and OPEB plans, primarily consisting of retiree healthcare benefits, to most employees as part of a total compensation and benefits program. The defined benefit pension plans are noncontributory and benefits generally are based on a minimum formula or employees’ years of service and average earnings for a defined period prior to retirement. The following are the components of defined benefit pension and OPEB costs: Defined Benefit Pension Costs (In Millions) Three Months Ended 2019 2018 Service cost $ 4.1 $ 4.7 Interest cost 8.7 7.6 Expected return on plan assets (13.6 ) (15.0 ) Amortization: Prior service costs 0.3 0.5 Net actuarial loss 5.9 5.3 Net periodic benefit cost $ 5.4 $ 3.1 Other Postretirement Benefits Credits (In Millions) Three Months Ended 2019 2018 Service cost $ 0.4 $ 0.5 Interest cost 2.3 2.1 Expected return on plan assets (4.2 ) (4.6 ) Amortization: Prior service credits (0.5 ) (0.8 ) Net actuarial loss 1.3 1.2 Net periodic benefit credit $ (0.7 ) $ (1.6 ) Based on funding requirements, we made pension contributions of $3.2 million for the three months ended March 31, 2019 , compared to pension contributions of $2.3 million for the three months ended March 31, 2018 . OPEB contributions are typically made on an annual basis in the first quarter of each year, but due to plan funding requirements being met, no OPEB contributions were required or made for the three months ended March 31, 2019 and 2018 .

STOCK COMPENSATION PLANS

STOCK COMPENSATION PLANS	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Compensation Plans	NOTE 10 - STOCK COMPENSATION PLANS Employees’ Plans On February 19, 2019, the Compensation Committee approved grants under the A&R 2015 Equity Plan to certain officers and employees for the 2019 to 2021 performance period. Shares granted under the awards consisted of 0.6 million restricted stock units and 0.6 million performance shares. Restricted stock units granted during 2019 are subject to continued employment, are retention based and are payable in common shares. The outstanding restricted stock units that were granted in 2019 cliff vest on December 31, 2021. Performance shares are subject to continued employment, and each performance share, if earned, entitles the holder to be paid out in common shares. Performance is measured on the basis of relative TSR for the period of January 1, 2019 to December 31, 2021 and measured against the constituents of the SPDR S&P Metals and Mining ETF Index at the beginning of the relevant performance period. The final payouts for the outstanding performance period grants will vary from zero to 200% of the original grant depending on whether and to what extent the Company achieves certain objectives and performance goals as established by the Compensation Committee. Determination of Fair Value 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 historic and projected stock prices was developed for both the Company and our predetermined peer group of mining and metals companies. The fair value assumes that the 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 life of the performance period. The following assumptions were utilized to estimate the fair value for the 2019 performance share grant: Grant Date Grant Date Market Price Average Expected Term (Years) Expected Volatility Risk-Free Interest Rate Dividend Yield Fair Value Fair Value (Percent of Grant Date Market Price) February 19, 2019 $ 11.24 2.87 67.5% 2.55% —% $ 18.31 162.90%

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 11 - INCOME TAXES Our 2019 estimated annual effective tax rate before discrete items is 12.9% . The estimated annual effective tax rate differs from the U.S. statutory rate of 21.0% primarily due to the deductions for percentage depletion in excess of cost depletion related to U.S. operations. The 2018 estimated annual effective tax rate before discrete items at March 31, 2018 was 0.1% . The rate in the comparable prior-year period was significantly lower due to the reversal of valuation allowance in the same period. For the three months ended March 31, 2019 and 2018, we recorded discrete items that resulted in an income tax benefit of $0.4 million and expense of $15.7 million , respectively. The prior-year period expense of $15.7 million primarily relates to the $14.5 million reduction of the refundable AMT credit recorded in Income tax receivable, non-current in our Statements of Unaudited Condensed Consolidated Financial Position based on the sequestration guidance issued by the Internal Revenue Service during the first quarter of 2018. This position was subsequently reversed by the Internal Revenue Service during the fourth quarter of 2018. The prior-year period expense was a $15.7 million reduction of an asset and did not result in a cash tax outlay.

ENVIRONMENTAL AND MINE CLOSURE

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	3 Months Ended
	Mar. 31, 2019
Environmental Remediation Obligations [Abstract]
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	NOTE 12 - ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS The following is a summary of our environmental and mine closure obligations: (In Millions) March 31, December 31, Environmental $ 2.4 $ 2.5 Mine closure 1 174.9 172.4 Total environmental and mine closure obligations 177.3 174.9 Less current portion 2.9 2.9 Long-term environmental and mine closure obligations $ 174.4 $ 172.0 1 Includes our active operating mines, our indefinitely idled Empire mine and a closed mine formerly operating as LTVSMC. Mine Closure The accrued closure obligation for our active mining operations provides for contractual and legal obligations associated with the eventual closure of the mining operations. The closure date for each of our active operating mine sites was determined based on the exhaustion date of the remaining iron ore reserves. 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. The amortization of the related asset and accretion of the liability is recognized over the estimated mine lives for our active operations. The following represents a roll forward of our mine closure obligation liability for the three months ended March 31, 2019 and for the year ended December 31, 2018: (In Millions) March 31, December 31, Asset retirement obligation at beginning of period $ 172.4 $ 168.4 Accretion expense 2.6 9.5 Remediation payments (0.1 ) (1.0 ) Revision in estimated cash flows — (4.5 ) Asset retirement obligation at end of period $ 174.9 $ 172.4

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	NOTE 13 - DERIVATIVE INSTRUMENTS The following table presents the fair value of our derivative instruments and the classification of each in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) Derivative Assets Derivative Liabilities March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Derivative Instrument Balance Sheet Location Fair Value Balance Sheet Location Fair Value Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments under ASC 815: Commodity contracts Derivative assets $ 0.7 Derivative assets $ 0.1 Other current liabilities $ 0.7 Other current liabilities $ 3.7 Derivatives not designated as hedging instruments under ASC 815: Customer supply agreement Derivative assets $ 106.4 Derivative assets $ 89.3 $ — $ — Provisional pricing arrangements Derivative assets 0.3 Derivative assets 2.1 Other current liabilities 9.8 — Total derivatives not designated as hedging instruments under ASC 815 $ 106.7 $ 91.4 $ 9.8 $ — Total derivatives $ 107.4 $ 91.5 $ 10.5 $ 3.7 Derivatives Designated as Hedging Instruments - Cash Flow Hedges Commodity Contracts The following table presents our outstanding hedge contracts: (In Millions) March 31, 2019 December 31, 2018 Notional Amount Unit of Measure Varying Maturity Dates Notional Amount Unit of Measure Varying Maturity Dates Natural gas 4.0 MMBtu April 2019 - February 2020 1.8 MMBtu January 2019 - August 2019 Diesel 7.5 Gallons April 2019 - December 2019 11.0 Gallons January 2019 - December 2019 Derivatives Not Designated as Hedging Instruments Customer Supply Agreement A supply agreement with one customer provides for supplemental revenue or refunds to the customer based on the average annual daily steel market price for hot-rolled coil steel at the time the iron ore product is consumed in the customer’s blast furnace. The supplemental pricing is characterized as a freestanding derivative and is required to be accounted for separately once control transfers to the customer. The derivative instrument, which is finalized based on a future price, is adjusted to fair value through Product revenues each reporting period based upon current market data and forward-looking estimates provided by management until the pellets are consumed and the amounts are settled. Provisional Pricing Arrangements Certain of our supply agreements specify provisional price calculations, where the pricing mechanisms generally are based on market pricing, with the final revenue rate based on certain market inputs at a specified period in time in the future, per the terms of the supply agreements. Market inputs are tied to indexed price adjustment factors that are integral to the iron ore supply contracts and vary based on the agreement. The pricing mechanisms typically include adjustments based upon changes in the Platts 62% Price, Atlantic Basin pellet premiums, Platts international indexed freight rates and changes in specified Producer Price Indices, including those for industrial commodities, fuel and steel. The pricing adjustments generally operate in the same manner, with each factor typically comprising a portion of the price adjustment, although the weighting of each factor varies based upon the specific terms of each agreement. The price adjustment factors have been evaluated to determine if they qualify as embedded derivatives. The price adjustment factors share the same economic characteristics and risks as the host contract and are integral to the host contract as inflation adjustments; accordingly, they have not been separately valued as derivative instruments. Revenue is recognized generally upon delivery to our customers. Revenue is measured at the point that control transfers and represents the amount of consideration we expect to receive in exchange for transferring goods. Changes in the expected revenue rate from the date that control transfers through final settlement of contract terms is recorded in accordance with ASC Topic 815 and is characterized as a derivative and accounted for separately. Subsequently, the derivative instruments are adjusted to fair value through Product revenues each reporting period based upon current market data and forward-looking estimates provided by management until the final revenue rate is determined. The provisional amounts represent the difference between the amount we expect to receive when revenue was initially measured at the point control transfers and our subsequent estimate of the final revenue rate based on the price calculation established in the supply agreements. The following summarizes the effect of our derivatives that are not designated as hedging instruments in the Statements of Unaudited Condensed Consolidated Operations : (In Millions) Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivatives Three Months Ended 2019 2018 Customer supply agreements Product revenues $ 17.1 $ 41.9 Provisional pricing arrangements Product revenues (11.6 ) 1.9 Total $ 5.5 $ 43.8 Refer to NOTE 8 - FAIR VALUE MEASUREMENTS for additional information.

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	3 Months Ended
	Mar. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
DISCONTINUED OPERATIONS	NOTE 14 - DISCONTINUED OPERATIONS The information below sets forth selected financial information related to operating results of our businesses classified as discontinued operations, which include our former Asia Pacific Iron Ore, North American Coal and Canadian operations. While the reclassification of revenues and expenses related to discontinued operations from prior periods have no impact upon previously reported net income, the Statements of Unaudited Condensed Consolidated Operations present the revenues and expenses that were reclassified from the specified line items to discontinued operations and the Statements of Unaudited Condensed Consolidated Financial Position present the assets and liabilities that were reclassified from the specified line items to assets and liabilities of discontinued operations. The charts below provide an asset group breakout for each financial statement line impacted by discontinued operations. (In Millions) Three Months Ended 2019 2018 Income (loss) from discontinued operations, net of tax Asia Pacific Iron Ore $ (0.5 ) $ (71.3 ) North American Coal 0.5 0.4 $ — $ (70.9 ) (In Millions) Three Months Ended 2019 2018 Net cash used by operating activities Asia Pacific Iron Ore $ (0.8 ) $ (21.2 ) $ (0.8 ) $ (21.2 ) Net cash provided (used) by investing activities Asia Pacific Iron Ore $ 0.1 $ (0.1 ) $ 0.1 $ (0.1 ) Asia Pacific Iron Ore Operations Background In January 2018, we announced that we would accelerate the time frame for the planned closure of our Asia Pacific Iron Ore mining operations in Australia. In April 2018, we committed to a course of action leading to the permanent closure of the Asia Pacific Iron Ore mining operations and, as planned, completed our final shipment in June 2018. Factors considered in this decision included increasingly discounted prices for lower-iron-content ore and the quality of the remaining iron ore reserves. During 2018, we sold all of the assets of our Asia Pacific Iron Ore business through a series of sales to third parties. As a result of our planned exit, management determined that our Asia Pacific Iron Ore operating segment met the criteria to be classified as held for sale and a discontinued operation under ASC Topic 205, Presentation of Financial Statements . As such, all Asia Pacific Iron Ore operating segment results are classified within discontinued operations. Loss from Discontinued Operations (In Millions) Three Months Ended Loss from Discontinued Operations 2019 2018 Revenues from product sales and services $ — $ 59.0 Cost of goods sold and operating expenses — (124.1 ) Sales margin — (65.1 ) Other operating expense (0.4 ) (2.5 ) Other expense (0.1 ) (1.1 ) Impairment of long-lived assets — (2.6 ) Loss from discontinued operations, net of tax $ (0.5 ) $ (71.3 )

CAPITAL STOCK

CAPITAL STOCK	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
CAPITAL STOCK	NOTE 15 - CAPITAL STOCK Share Repurchase Program In November 2018, our Board of Directors authorized a program to repurchase outstanding common shares in the open market or in privately negotiated transactions, up to a maximum of $200 million . We are not obligated to make any purchase and the program may be suspended or discontinued at any time. During the three months ended March 31, 2019 , we repurchased 11.5 million common shares at a cost of $124.3 million in the aggregate, including commissions and fees. As of March 31, 2019 , there was $28.6 million remaining under the authorization. The share repurchase program is active until December 31, 2019. Dividends On February 19, 2019, the Board of Directors declared a quarterly cash dividend on our common shares of $0.05 per share. As a result, we have $14.7 million in Other current liabilities in the Statements of Unaudited Condensed Consolidated Financial Position as of March 31, 2019 . Subsequent to quarter end on April 15, 2019, the cash dividend was paid to shareholders of record as of the close of business on April 5, 2019. On October 18, 2018, the Board of Directors declared a quarterly cash dividend on our common shares of $0.05 per share. On January 15, 2019, the cash dividend was paid to shareholders of record as of the close of business on January 4, 2019.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Comprehensive Income (Loss) Note [Text Block]	NOTE 16 - ACCUMULATED OTHER COMPREHENSIVE LOSS The following tables reflect the changes in Accumulated other comprehensive loss related to shareholders’ equity (deficit): (In Millions) Postretirement Benefit Liability, net of tax Derivative Financial Instruments, net of tax Accumulated Other Comprehensive Loss December 31, 2018 $ (281.1 ) $ (2.8 ) $ (283.9 ) Other comprehensive income before reclassifications 0.2 2.5 2.7 Net loss reclassified from accumulated other comprehensive loss 5.5 0.2 5.7 March 31, 2019 $ (275.4 ) $ (0.1 ) $ (275.5 ) (In Millions) Postretirement Benefit Liability, net of tax Foreign Currency Translation Derivative Financial Instruments, net of tax Accumulated Other Comprehensive Loss December 31, 2017 $ (263.9 ) $ 225.4 $ (0.5 ) $ (39.0 ) Other comprehensive income before reclassifications 0.5 0.7 0.4 1.6 Net loss (gain) reclassified from accumulated other comprehensive loss 6.2 — (0.1 ) 6.1 March 31, 2018 $ (257.2 ) $ 226.1 $ (0.2 ) $ (31.3 ) The following table reflects the details about Accumulated other comprehensive loss components related to Cliffs shareholders’ equity (deficit): (In Millions) Details about Accumulated Other Comprehensive Loss Components Amount of (Gain)/Loss Reclassified into Income, Net of Tax Affected Line Item in the Statement of Unaudited Condensed Consolidated Operations Three Months Ended 2019 2018 Amortization of pension and OPEB liability: Prior service credits $ (0.2 ) $ (0.3 ) Other non-operating income Net actuarial loss 7.2 6.5 Other non-operating income $ 7.0 $ 6.2 (1.5 ) — Income tax benefit (expense) $ 5.5 $ 6.2 Net of taxes Unrealized loss (gain) on derivative financial instruments: Commodity contracts $ 0.3 $ (0.1 ) Cost of goods sold (0.1 ) — Income tax benefit (expense) $ 0.2 $ (0.1 ) Net of taxes Total reclassifications for the period, net of tax $ 5.7 $ 6.1

CASH FLOW INFORMATION

CASH FLOW INFORMATION	3 Months Ended
	Mar. 31, 2019
Supplemental Cash Flow Information [Abstract]
Cash Flow Information	NOTE 17 - CASH FLOW INFORMATION A reconciliation of capital additions to cash paid for capital expenditures is as follows: (In Millions) Three Months Ended March 31, 2019 2018 Capital additions $ 129.3 $ 78.9 Less: Non-cash accruals (11.5 ) 7.5 Right-of-use assets – finance leases 15.1 — Grants (8.4 ) — Cash paid for capital expenditures including deposits $ 134.1 $ 71.4 Non-Cash Financing Activities - Declared Dividends On February 19, 2019, the Board of Directors declared a quarterly cash dividend on our common shares of $0.05 per share. The cash dividend of $14.7 million was paid on April 15, 2019 to shareholders of record as of the close of business on April 5, 2019.

RELATED PARTIES

RELATED PARTIES	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
RELATED PARTIES	NOTE 18 - RELATED PARTIES One of our four operating mines, Hibbing, is a co-owned joint venture with companies that are integrated steel producers or their subsidiaries. We are the manager of Hibbing and rely on our joint venture partners to make their required capital contributions and to pay for their share of the iron ore pellets that we produce. The following is a summary of the mine ownership of the co-owned iron ore mine at March 31, 2019 : Mine Cleveland-Cliffs Inc. ArcelorMittal U.S. Steel Hibbing 23.0 % 62.3 % 14.7 % Product revenues from related parties were as follows: (In Millions) Three Months Ended 2019 2018 Product revenues from related parties $ 41.1 $ 62.1 Total product revenues $ 145.4 $ 169.2 Related party product revenue as a percent of total product revenue 28.3 % 36.7 % The following table presents the classification of related party assets and liabilities in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) Balance Sheet Location March 31, 2019 December 31, 2018 Accounts receivable, net $ 15.3 $ 176.0 Derivative assets 106.4 89.3 Partnership distribution payable (43.8 ) (43.5 ) Other current liabilities (0.5 ) (1.8 ) $ 77.4 $ 220.0 A supply agreement with one customer provides for supplemental revenue or refunds to the customer based on the average annual daily market price for hot-rolled coil steel at the time the product is consumed in the customer’s blast furnace. The supplemental pricing is characterized as a freestanding derivative. Refer to NOTE 13 - DERIVATIVE INSTRUMENTS for further information. During 2017, our ownership interest in Empire increased to 100% as we reached an agreement to distribute the noncontrolling interest net assets of $132.7 million to ArcelorMittal, in exchange for its interest in Empire. The net assets were agreed to be distributed in three installments of $44.2 million each, the first of which was paid upon the execution of the agreement, the second of which was paid in August 2018 and the final of which is due in August 2019. The remaining installment is reflected in Partnership distribution payable in the Statements of Unaudited Condensed Consolidated Financial Position as of March 31, 2019 .

EARNINGS PER SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
EPS AND OTHER NON-GAAP FINANCIAL MEASURES	NOTE 19 - EARNINGS PER SHARE The following table summarizes the computation of basic and diluted earnings per share: (In Millions, Except Per Share Amounts) Three Months Ended 2019 2018 Loss from continuing operations $ (22.1 ) $ (13.4 ) Loss from discontinued operations, net of tax — (70.9 ) Net loss $ (22.1 ) $ (84.3 ) Weighted average number of shares: Basic 289.5 297.3 $316.25 million 1.50% 2025 Convertible Senior Notes — — Employee stock plans — — Diluted 289.5 297.3 Loss per common share - basic: Continuing operations $ (0.08 ) $ (0.05 ) Discontinued operations — (0.24 ) $ (0.08 ) $ (0.29 ) Loss per common share - diluted: Continuing operations $ (0.08 ) $ (0.05 ) Discontinued operations — (0.24 ) $ (0.08 ) $ (0.29 ) The following table summarizes the shares that have been excluded from the diluted earnings per share calculation as they were anti-dilutive: (In Millions) Three Months Ended 2019 2018 $316.25 million 1.50% 2025 Convertible Senior Notes 7.3 — Employee stock plans 4.2 3.8 Total number of anti-dilutive shares 11.5 3.8

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	NOTE 20 - COMMITMENTS AND CONTINGENCIES Purchase Commitments In 2017, we began to incur capital commitments related to the construction of our HBI production plant in Toledo, Ohio. In total, we expect to spend approximately $830 million on the HBI production plant, exclusive of construction-related contingencies and capitalized interest through 2020. Through March 31, 2019 , we have entered into contracts and purchase orders for approximately $780 million of the total capital investment for the HBI production plant, of which a total of approximately $265 million has been expended project-to-date, including deposits. We expect expenditures of approximately $290 million during the remaining nine months of 2019. Of the remaining committed capital, expenditures of approximately $275 million are expected to be made during 2020. Contingencies We are currently the subject of, or party to, various claims and legal proceedings incidental to our operations. If management believes that a loss arising from these matters is probable and can reasonably be estimated, we record the amount of the loss or the minimum estimated liability when the loss is estimated using a range, and no point within the range is more probable than another. As additional information becomes available, any potential liability related to these matters is assessed and the estimates are revised, if necessary. Based on currently available information, management believes that the ultimate outcome of these matters, individually and in the aggregate, will not have a material effect on our financial position, results of operations or cash flows. However, 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 impact on the financial position and results of operations for the period in which the ruling occurs or future periods. However, we do not believe that any pending claims or legal proceedings will result in a material liability in relation to our consolidated financial statements.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	NOTE 21 - SUBSEQUENT EVENTS We have evaluated subsequent events through the date of financial statement issuance. On April 24, 2019, the Company’s Board of Directors authorized the Company to repurchase common shares in an additional amount of up to a maximum of $100 million . On November 24, 2018, the Company’s Board of Directors previously authorized share repurchases of up to a maximum amount of $200 million , and approximately $29 million of this earlier authorization remains available as of April 25, 2019. When combined with the additional amount of share repurchase authorization, the Company now has authorization to repurchase common shares up to a maximum of approximately $129 million as of April 25, 2019. Such share repurchases may be made via acquisitions in the open market or privately negotiated transactions, including through accelerated share repurchases or pursuant to the terms of a Rule 10b5-1 plan. The Company is not obligated to make any purchases and the program may be suspended or discontinued at any time. The authorization is active until December 31, 2019.

SUPPLEMENTARY GUARANTOR INFORMA

SUPPLEMENTARY GUARANTOR INFORMATION	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Guarantor Information [Text Block]	NOTE 22 - SUPPLEMENTARY GUARANTOR INFORMATION The accompanying unaudited condensed consolidating financial information has been prepared and presented pursuant to SEC Regulation S-X, Rule 3-10, “Financial Statements of Guarantors and Issuers of Guaranteed Securities Registered or Being Registered.” Certain of our subsidiaries (the "Guarantors") have guaranteed the obligations under the $1.075 billion 5.75% 2025 Senior Notes issued by Cleveland-Cliffs Inc. See NOTE 7 - DEBT AND CREDIT FACILITIES for further information. The following presents the unaudited condensed consolidating financial information for: (i) the Parent Company and the Issuer of the guaranteed obligations (Cleveland-Cliffs Inc.); (ii) the Guarantor subsidiaries, on a combined basis; (iii) the non-guarantor subsidiaries, on a combined basis; (iv) consolidating eliminations; and (v) Cleveland-Cliffs Inc. and subsidiaries on a consolidated basis. Each Guarantor subsidiary is 100% owned by the Parent Company as of March 31, 2019 and December 31, 2018 . The unaudited condensed consolidating financial information is presented as if the Guarantor structure at March 31, 2019 existed for all periods presented. Each of the Guarantor subsidiaries fully and unconditionally guarantee, on a joint and several basis, the obligations of Cleveland-Cliffs Inc. under the $1.075 billion 5.75% 2025 Senior Notes. The guarantee of a Guarantor subsidiary will be automatically and unconditionally released and discharged, and such Guarantor subsidiary’s obligations under the guarantee and the related indenture governing the $1.075 billion 5.75% 2025 Senior Notes (the “Indenture”) will be automatically and unconditionally released and discharged, upon: (a) any sale, exchange, transfer or disposition of such Guarantor subsidiary (by merger, consolidation, or the sale of) or the capital stock of such Guarantor subsidiary after which the applicable Guarantor subsidiary is no longer a subsidiary of the Company or the sale of all or substantially all of such Guarantor subsidiary’s assets (other than by lease); (b) upon designation of any Guarantor subsidiary as an “excluded subsidiary” (as defined in the Indenture); or (c) upon defeasance or satisfaction and discharge of the Indenture. Each entity in the unaudited consolidating financial information follows the same accounting policies as described in the consolidated financial statements. The accompanying unaudited condensed consolidating financial information has been presented on the equity method of accounting for all periods presented. Under this method, investments in subsidiaries are recorded at cost and adjusted for the subsidiaries’ cumulative results of operations, capital contributions and distributions, and other changes in equity. Elimination entries include consolidating and eliminating entries for investments in subsidiaries, and intra-entity activity and balances. Unaudited Condensed Consolidating Statement of Financial Position As of March 31, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 426.8 $ 0.7 $ 2.7 $ — $ 430.2 Accounts receivable, net 7.6 16.2 0.3 (4.0 ) 20.1 Inventories — 312.7 — — 312.7 Supplies and other inventories — 97.3 — — 97.3 Derivative assets 0.7 106.7 — — 107.4 Income tax receivable, current 117.3 — — — 117.3 Other current assets 8.6 21.1 11.3 — 41.0 TOTAL CURRENT ASSETS 561.0 554.7 14.3 (4.0 ) 1,126.0 PROPERTY, PLANT AND EQUIPMENT, NET 12.0 1,347.5 50.8 — 1,410.3 OTHER ASSETS Deposits for property, plant and equipment — 53.6 14.7 — 68.3 Income tax receivable, non-current 117.2 4.1 — — 121.3 Deferred income taxes 465.4 — 1.2 — 466.6 Investment in subsidiaries 1,448.5 30.1 — (1,478.6 ) — Long-term intercompany notes — — 121.3 (121.3 ) — Other non-current assets 16.6 95.8 1.4 — 113.8 TOTAL OTHER ASSETS 2,047.7 183.6 138.6 (1,599.9 ) 770.0 TOTAL ASSETS $ 2,620.7 $ 2,085.8 $ 203.7 $ (1,603.9 ) $ 3,306.3 LIABILITIES CURRENT LIABILITIES Accounts payable $ 5.2 $ 166.4 $ 4.1 $ (4.0 ) $ 171.7 Accrued employment costs 9.4 32.6 0.1 — 42.1 Accrued interest 23.0 — — — 23.0 Partnership distribution payable — 43.8 — — 43.8 Other current liabilities 27.9 78.4 7.1 — 113.4 TOTAL CURRENT LIABILITIES 65.5 321.2 11.3 (4.0 ) 394.0 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 64.1 414.8 (234.7 ) — 244.2 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 154.6 19.8 — 174.4 LONG-TERM DEBT 2,087.0 — — — 2,087.0 LONG-TERM INTERCOMPANY NOTES 121.3 — — (121.3 ) — OTHER LIABILITIES 21.1 116.0 7.9 — 145.0 TOTAL LIABILITIES 2,359.0 1,006.6 (195.7 ) (125.3 ) 3,044.6 EQUITY TOTAL EQUITY 261.7 1,079.2 399.4 (1,478.6 ) 261.7 TOTAL LIABILITIES AND EQUITY $ 2,620.7 $ 2,085.8 $ 203.7 $ (1,603.9 ) $ 3,306.3 Unaudited Condensed Consolidating Statement of Financial Position As of December 31, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 819.8 $ 0.7 $ 2.7 $ — $ 823.2 Accounts receivable, net 9.2 221.3 0.3 (4.1 ) 226.7 Inventories — 87.9 — — 87.9 Supplies and other inventories — 93.2 — — 93.2 Derivative assets 0.1 91.4 — — 91.5 Income tax receivable, current 117.3 — — — 117.3 Other current assets 10.0 16.9 12.9 — 39.8 TOTAL CURRENT ASSETS 956.4 511.4 15.9 (4.1 ) 1,479.6 PROPERTY, PLANT AND EQUIPMENT, NET 13.3 1,221.9 50.8 — 1,286.0 OTHER ASSETS Deposits for property, plant and equipment — 68.4 14.6 — 83.0 Income tax receivable, non-current 117.2 4.1 — — 121.3 Deferred income taxes 463.6 — 1.2 — 464.8 Investment in subsidiaries 1,262.3 50.8 — (1,313.1 ) — Long-term intercompany notes — — 121.3 (121.3 ) — Other non-current assets 8.0 85.4 1.5 — 94.9 TOTAL OTHER ASSETS 1,851.1 208.7 138.6 (1,434.4 ) 764.0 TOTAL ASSETS $ 2,820.8 $ 1,942.0 $ 205.3 $ (1,438.5 ) $ 3,529.6 LIABILITIES CURRENT LIABILITIES Accounts payable $ 5.3 $ 181.4 $ 4.2 $ (4.1 ) $ 186.8 Accrued employment costs 28.5 45.4 0.1 — 74.0 Accrued interest 38.4 — — — 38.4 Partnership distribution payable — 43.5 — — 43.5 Other current liabilities 30.6 86.7 8.2 — 125.5 TOTAL CURRENT LIABILITIES 102.8 357.0 12.5 (4.1 ) 468.2 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 64.3 414.4 (230.0 ) — 248.7 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 152.1 19.9 — 172.0 LONG-TERM DEBT 2,092.9 — — — 2,092.9 LONG-TERM INTERCOMPANY NOTES 121.3 — — (121.3 ) — OTHER LIABILITIES 15.3 99.5 8.8 — 123.6 TOTAL LIABILITIES 2,396.6 1,023.0 (188.8 ) (125.4 ) 3,105.4 EQUITY TOTAL EQUITY 424.2 919.0 394.1 (1,313.1 ) 424.2 TOTAL LIABILITIES AND EQUITY $ 2,820.8 $ 1,942.0 $ 205.3 $ (1,438.5 ) $ 3,529.6 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended March 31, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 145.4 $ — $ — $ 145.4 Freight — 11.6 — — 11.6 — 157.0 — — 157.0 COST OF GOODS SOLD — (126.1 ) — — (126.1 ) SALES MARGIN — 30.9 — — 30.9 OTHER OPERATING EXPENSE Selling, general and administrative expenses (22.8 ) (5.2 ) (0.1 ) — (28.1 ) Miscellaneous – net — (3.4 ) (0.2 ) — (3.6 ) (22.8 ) (8.6 ) (0.3 ) — (31.7 ) OPERATING INCOME (LOSS) (22.8 ) 22.3 (0.3 ) — (0.8 ) OTHER INCOME (EXPENSE) Interest expense, net (24.7 ) (0.5 ) 0.1 — (25.1 ) Other non-operating income (expense) (1.4 ) (3.2 ) 4.7 — 0.1 (26.1 ) (3.7 ) 4.8 — (25.0 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (48.9 ) 18.6 4.5 — (25.8 ) INCOME TAX BENEFIT (EXPENSE) 3.9 (0.1 ) (0.1 ) — 3.7 EQUITY IN INCOME OF SUBSIDIARIES 22.9 4.4 — (27.3 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS (22.1 ) 22.9 4.4 (27.3 ) (22.1 ) INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX — (0.1 ) 0.1 — — NET INCOME (LOSS) $ (22.1 ) $ 22.8 $ 4.5 $ (27.3 ) $ (22.1 ) OTHER COMPREHENSIVE INCOME 8.4 6.7 — (6.7 ) 8.4 TOTAL COMPREHENSIVE INCOME (LOSS) $ (13.7 ) $ 29.5 $ 4.5 $ (34.0 ) $ (13.7 ) Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended March 31, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 169.2 $ — $ — $ 169.2 Freight — 10.8 — — 10.8 — 180.0 — — 180.0 COST OF GOODS SOLD — (118.5 ) — — (118.5 ) SALES MARGIN — 61.5 — — 61.5 OTHER OPERATING EXPENSE Selling, general and administrative expenses (20.1 ) (4.7 ) (0.3 ) — (25.1 ) Miscellaneous – net (0.2 ) (5.3 ) (0.6 ) — (6.1 ) (20.3 ) (10.0 ) (0.9 ) — (31.2 ) OPERATING INCOME (LOSS) (20.3 ) 51.5 (0.9 ) — 30.3 OTHER INCOME (EXPENSE) Interest expense, net (31.9 ) (0.8 ) 0.3 — (32.4 ) Other non-operating income (expense) (0.9 ) 0.5 4.8 — 4.4 (32.8 ) (0.3 ) 5.1 — (28.0 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (53.1 ) 51.2 4.2 — 2.3 INCOME TAX EXPENSE (15.6 ) (0.1 ) — — (15.7 ) EQUITY IN INCOME (LOSS) OF SUBSIDIARIES (15.7 ) 4.5 — 11.2 — INCOME (LOSS) FROM CONTINUING OPERATIONS (84.4 ) 55.6 4.2 11.2 (13.4 ) INCOME (LOSS) FROM DISCONTINUED OPERATIONS, net of tax 0.1 0.2 (71.2 ) — (70.9 ) NET INCOME (LOSS) $ (84.3 ) $ 55.8 $ (67.0 ) $ 11.2 $ (84.3 ) OTHER COMPREHENSIVE INCOME 7.7 5.9 0.8 (6.7 ) 7.7 TOTAL COMPREHENSIVE INCOME (LOSS) $ (76.6 ) $ 61.7 $ (66.2 ) $ 4.5 $ (76.6 ) Unaudited Condensed Consolidating Statement of Cash Flows For the Three Months Ended March 31, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash used by operating activities $ (71.6 ) $ (38.4 ) $ (1.2 ) $ — $ (111.2 ) INVESTING ACTIVITIES Purchase of property, plant and equipment (0.3 ) (132.4 ) — — (132.7 ) Deposits for property, plant and equipment — (1.3 ) (0.1 ) — (1.4 ) Intercompany investing (157.6 ) (0.4 ) — 158.0 — Other investing activities — 8.4 0.1 — 8.5 Net cash used by investing activities (157.9 ) (125.7 ) — 158.0 (125.6 ) FINANCING ACTIVITIES Repurchase of common shares (124.3 ) — — — (124.3 ) Dividends paid (14.8 ) — — — (14.8 ) Repurchase of debt (10.3 ) — — — (10.3 ) Intercompany financing — 157.5 0.5 (158.0 ) — Other financing activities (14.1 ) 6.6 (0.9 ) — (8.4 ) Net cash provided (used) by financing activities (163.5 ) 164.1 (0.4 ) (158.0 ) (157.8 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (393.0 ) — (1.6 ) — (394.6 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — (1.6 ) — (1.6 ) NET DECREASE IN CASH AND CASH EQUIVALENTS (393.0 ) — — — (393.0 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 819.8 0.7 2.7 — 823.2 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 426.8 $ 0.7 $ 2.7 $ — $ 430.2 Unaudited Condensed Consolidating Statement of Cash Flows For the Three Months Ended March 31, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash used by operating activities $ (54.7 ) $ (64.7 ) $ (23.5 ) $ — $ (142.9 ) INVESTING ACTIVITIES Purchase of property, plant and equipment — (12.3 ) (0.1 ) — (12.4 ) Deposits for property, plant and equipment — (54.4 ) (4.6 ) — (59.0 ) Intercompany investing (137.7 ) (4.8 ) — 142.5 — Net cash used by investing activities (137.7 ) (71.5 ) (4.7 ) 142.5 (71.4 ) FINANCING ACTIVITIES Intercompany financing — 135.6 6.9 (142.5 ) — Other financing activities (2.9 ) (0.5 ) (3.6 ) — (7.0 ) Net cash provided (used) by financing activities (2.9 ) 135.1 3.3 (142.5 ) (7.0 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — 0.2 — 0.2 DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (195.3 ) (1.1 ) (24.7 ) — (221.1 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — — — — NET DECREASE IN CASH AND CASH EQUIVALENTS (195.3 ) (1.1 ) (24.7 ) — (221.1 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 948.9 2.1 27.3 — 978.3 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 753.6 $ 1.0 $ 2.6 $ — $ 757.2

BASIS OF PRESENTATION AND SIG_2

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule Of Subsidiaries	Basis of Consolidation The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, including the following operations as of March 31, 2019 : Name Location Business Segment Status of Operations Northshore Minnesota Mining and Pelletizing Active United Taconite Minnesota Mining and Pelletizing Active Tilden Michigan Mining and Pelletizing Active Empire Michigan Mining and Pelletizing Indefinitely Idled Toledo HBI Ohio Metallics Construction Stage Intercompany transactions and balances are eliminated upon consolidation.
Equity Method Investments	Equity Method Investments Our 23% ownership interest in Hibbing is recorded as an equity method investment. As of March 31, 2019 and December 31, 2018 , our investment in Hibbing was $10.8 million and $15.4 million , respectively, classified as Other liabilities in the Statements of Unaudited Condensed Consolidated Financial Position .
Significant Accounting Policies	Significant Accounting Policies A detailed description of our significant accounting policies can be found in the audited financial statements for the fiscal year ended December 31, 2018 included in our Annual Report on Form 10-K filed with the SEC. There have been no material changes in our significant accounting policies and estimates from those disclosed therein.

BASIS OF PRESENTATION AND SIG_3

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule Of Subsidiaries	Basis of Consolidation The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, including the following operations as of March 31, 2019 : Name Location Business Segment Status of Operations Northshore Minnesota Mining and Pelletizing Active United Taconite Minnesota Mining and Pelletizing Active Tilden Michigan Mining and Pelletizing Active Empire Michigan Mining and Pelletizing Indefinitely Idled Toledo HBI Ohio Metallics Construction Stage Intercompany transactions and balances are eliminated upon consolidation.

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Schedule Of Segment Reporting Information, By Segment	The following tables present a summary of our reportable segments including a reconciliation of segment sales margin to Income (loss) from Continuing Operations Before Income Taxes and a reconciliation of Net loss to EBITDA and Adjusted EBITDA: (In Millions) Three Months Ended 2019 2018 Revenues from product sales and services: Mining and Pelletizing $ 157.0 $ 180.0 Sales margin: Mining and Pelletizing $ 30.9 $ 61.5 Other operating expense (31.7 ) (31.2 ) Other expense (25.0 ) (28.0 ) Income (loss) from continuing operations before income taxes $ (25.8 ) $ 2.3 (In Millions) Three Months Ended 2019 2018 Net loss $ (22.1 ) $ (84.3 ) Less: Interest expense, net (25.1 ) (33.5 ) Income tax benefit (expense) 3.7 (15.7 ) Depreciation, depletion and amortization (19.9 ) (23.9 ) EBITDA $ 19.2 $ (11.2 ) Less: Foreign exchange remeasurement $ 0.1 $ (0.4 ) Impact of discontinued operations — (63.1 ) Loss on extinguishment of debt (0.3 ) — Severance costs (1.7 ) — Adjusted EBITDA $ 21.1 $ 52.3 EBITDA: Mining and Pelletizing $ 42.8 $ 72.5 Metallics (0.8 ) (0.3 ) Corporate and Other (including discontinued operations) (22.8 ) (83.4 ) Total EBITDA $ 19.2 $ (11.2 ) Adjusted EBITDA: Mining and Pelletizing $ 47.5 $ 77.1 Metallics (0.8 ) (0.3 ) Corporate (25.6 ) (24.5 ) Total Adjusted EBITDA $ 21.1 $ 52.3 The following table summarizes our depreciation, depletion and amortization expense and capital additions: (In Millions) Three Months Ended 2019 2018 Depreciation, depletion and amortization: Mining and Pelletizing $ 18.5 $ 15.8 Corporate 1.4 1.4 Total depreciation, depletion and amortization $ 19.9 $ 17.2 Capital additions 1 : Mining and Pelletizing $ 46.8 $ 18.7 Metallics 82.4 60.0 Corporate 0.1 0.2 Total capital additions $ 129.3 $ 78.9 1 Refer to NOTE 17 - CASH FLOW INFORMATION for additional information.
Reconciliation of Assets from Segment to Consolidated [Table Text Block]	A summary of assets by segment is as follows: (In Millions) March 31, December 31, Assets: Mining and Pelletizing $ 1,774.5 $ 1,694.1 Metallics 350.0 265.9 Total segment assets 2,124.5 1,960.0 Corporate and Other (including discontinued operations) 1,181.8 1,569.6 Total assets $ 3,306.3 $ 3,529.6

REVENUE (Tables)

REVENUE (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset and Liability	The table below summarizes our deferred revenue balances: (In Millions) Deferred Revenue (Current) Deferred Revenue (Long-Term) 2019 2018 2019 2018 Opening balance as of January 1 $ 21.0 $ 23.8 $ 38.5 $ 51.4 Closing balance as of March 31 18.1 31.0 38.5 51.4 Increase (decrease) $ (2.9 ) $ 7.2 $ — $ —

INVENTORIES (Tables)

INVENTORIES (Tables)	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Schedule Of Inventories	The following table presents the detail of our Inventories in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) March 31, 2019 December 31, 2018 Finished goods $ 287.7 $ 77.8 Work-in-process 25.0 10.1 Total inventories $ 312.7 $ 87.9

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	3 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Value Of Each Of The Major Classes Of Consolidated Depreciable Assets	The following table indicates the carrying value of each of the major classes of our depreciable assets: (In Millions) March 31, December 31, Land rights and mineral rights $ 549.6 $ 549.6 Office and information technology 70.5 70.0 Buildings 87.4 87.2 Mining equipment 568.4 548.5 Processing equipment 660.9 645.8 Electric power facilities 58.7 58.7 Land improvements 23.8 23.8 Asset retirement obligation 14.8 14.8 Other 25.5 25.2 Construction-in-progress 392.0 284.8 2,451.6 2,308.4 Allowance for depreciation and depletion (1,041.3 ) (1,022.4 ) $ 1,410.3 $ 1,286.0

DEBT AND CREDIT FACILITIES (Tab

DEBT AND CREDIT FACILITIES (Tables)	3 Months Ended
	Mar. 31, 2019
Line of Credit Facility [Line Items]
Schedule of Line of Credit Facilities [Table Text Block]	The following represents a summary of our borrowing capacity under the ABL Facility: (In Millions) March 31, 2019 December 31, 2018 Available borrowing base on ABL Facility 1 $ 305.4 $ 323.7 Letter of credit obligations and other commitments 2 (65.4 ) (55.0 ) Borrowing capacity available 3 $ 240.0 $ 268.7 1 The ABL Facility has a maximum borrowing base of $450 million, 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, environmental obligations and certain Metallics' contracts. 3 As of March 31, 2019 and December 31, 2018, we had no loans drawn under the ABL Facility.
Schedule Of Long-Term Debt	The following represents a summary of our long-term debt: (In Millions) March 31, 2019 Debt Instrument Annual Effective Interest Rate Total Principal Amount Debt Issuance Costs Unamortized Discounts Total Debt Secured Notes: $400 Million 4.875% 2024 Senior Notes 5.00% $ 400.0 $ (5.5 ) $ (2.1 ) $ 392.4 Unsecured Notes: $700 Million 4.875% 2021 Senior Notes 4.89% 114.0 (0.2 ) — 113.8 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (5.3 ) (73.0 ) 238.0 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,073.3 (9.5 ) (14.1 ) 1,049.7 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.2 ) (3.3 ) 292.9 ABL Facility N/A 450.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 0.2 Long-term debt $ 2,087.0 (In Millions) December 31, 2018 Debt Instrument Annual Effective Interest Rate Total Principal Amount Debt Issuance Costs Unamortized Discounts Total Debt Secured Notes: $400 Million 4.875% 2024 Senior Notes 5.00% $ 400.0 $ (5.7 ) $ (2.2 ) $ 392.1 Unsecured Notes: $700 Million 4.875% 2021 Senior Notes 4.89% 124.0 (0.2 ) — 123.8 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (5.5 ) (75.6 ) 235.2 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,073.3 (9.9 ) (14.6 ) 1,048.8 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.3 ) (3.3 ) 292.8 ABL Facility N/A 450.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 0.2 Long-term debt $ 2,092.9
Extinguishment of Debt, Amount	The following is a summary of the debt extinguished with cash and the respective loss on extinguishment: (In Millions) Three Months Ended March 31, 2019 Debt Instrument Debt Extinguished Loss on Extinguishment $700 Million 4.875% 2021 Senior Notes $ 10.0 $ 0.3 $ 10.0 $ 0.3
Schedule of Maturities of Long-term Debt	Debt Maturities The following represents a summary of our maturities of debt instruments based on the principal amounts outstanding at March 31, 2019 : (In Millions) Maturities of Debt 2019 $ — 2020 — 2021 114.0 2022 — 2023 — 2024 400.0 2025 and thereafter 1,688.0 Total maturities of debt $ 2,202.0

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	The following represents the assets and liabilities measured at fair value: (In Millions) March 31, 2019 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash equivalents $ — $ 357.6 $ — $ 357.6 Derivative assets — 0.7 106.7 107.4 Total $ — $ 358.3 $ 106.7 $ 465.0 Liabilities: Derivative liabilities $ — $ 0.7 $ 9.8 $ 10.5 Total $ — $ 0.7 $ 9.8 $ 10.5 (In Millions) December 31, 2018 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash equivalents $ 0.8 $ 542.6 $ — $ 543.4 Derivative assets — 0.1 91.4 91.5 Total $ 0.8 $ 542.7 $ 91.4 $ 634.9 Liabilities: Derivative liabilities $ — $ 3.7 $ — $ 3.7 Total $ — $ 3.7 $ — $ 3.7
Fair Value, Recurring and Nonrecurring, Valuation Techniques	The provisional pricing arrangements included in our Level 3 assets/liabilities specify provisional price calculations, where the pricing mechanisms generally are based on market pricing, with the final revenue rate to be based on market inputs at a specified point in time in the future, per the terms of the supply agreements.
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation	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 Three Months Ended 2019 2018 Beginning balance $ 91.4 $ 49.5 Total gains included in earnings 15.3 44.3 Settlements — (0.2 ) Ending balance - March 31 $ 106.7 $ 93.6 Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ 15.3 $ 44.5
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	(In Millions) Level 3 Liabilities Three Months Ended 2019 2018 Beginning balance $ — $ (1.7 ) Total losses included in earnings (9.8 ) (0.5 ) Settlements — 2.2 Ending balance - March 31 $ (9.8 ) $ — Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (9.8 ) $ —
Schedule Of Carrying Value And Fair Value Of Financial Instruments	A summary of the carrying value and fair value of other financial instruments were as follows: (In Millions) March 31, 2019 December 31, 2018 Classification Carrying Value Fair Value Carrying Value Fair Value Long-term debt: Secured Notes $400 Million 4.875% 2024 Senior Notes Level 1 $ 392.4 $ 398.0 $ 392.1 $ 370.2 Unsecured Notes $700 Million 4.875% 2021 Senior Notes Level 1 113.8 115.7 123.8 122.3 $316.25 Million 1.50% 2025 Convertible Senior Notes Level 1 238.0 432.5 235.2 352.4 $1.075 Billion 5.75% 2025 Senior Notes Level 1 1,049.7 1,035.5 1,048.8 962.0 $800 Million 6.25% 2040 Senior Notes Level 1 292.9 255.0 292.8 232.8 ABL Facility Level 2 — — — — Fair value adjustment to interest rate hedge Level 2 0.2 0.2 0.2 0.2 Total long-term debt $ 2,087.0 $ 2,236.9 $ 2,092.9 $ 2,039.9

PENSIONS AND OTHER POSTRETIRE_2

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Tables)	3 Months Ended
	Mar. 31, 2019
Postemployment Benefits [Abstract]
Schedule of Net Benefit Costs	The following are the components of defined benefit pension and OPEB costs: Defined Benefit Pension Costs (In Millions) Three Months Ended 2019 2018 Service cost $ 4.1 $ 4.7 Interest cost 8.7 7.6 Expected return on plan assets (13.6 ) (15.0 ) Amortization: Prior service costs 0.3 0.5 Net actuarial loss 5.9 5.3 Net periodic benefit cost $ 5.4 $ 3.1 Other Postretirement Benefits Credits (In Millions) Three Months Ended 2019 2018 Service cost $ 0.4 $ 0.5 Interest cost 2.3 2.1 Expected return on plan assets (4.2 ) (4.6 ) Amortization: Prior service credits (0.5 ) (0.8 ) Net actuarial loss 1.3 1.2 Net periodic benefit credit $ (0.7 ) $ (1.6 )

STOCK COMPENSATION PLANS (Table

STOCK COMPENSATION PLANS (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]	The following assumptions were utilized to estimate the fair value for the 2019 performance share grant: Grant Date Grant Date Market Price Average Expected Term (Years) Expected Volatility Risk-Free Interest Rate Dividend Yield Fair Value Fair Value (Percent of Grant Date Market Price) February 19, 2019 $ 11.24 2.87 67.5% 2.55% —% $ 18.31 162.90%

ENVIRONMENTAL AND MINE CLOSUR_2

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Tables)	3 Months Ended
	Mar. 31, 2019
Environmental Remediation Obligations [Abstract]
Summary Of Mine Closure Obligations	The following is a summary of our environmental and mine closure obligations: (In Millions) March 31, December 31, Environmental $ 2.4 $ 2.5 Mine closure 1 174.9 172.4 Total environmental and mine closure obligations 177.3 174.9 Less current portion 2.9 2.9 Long-term environmental and mine closure obligations $ 174.4 $ 172.0 1 Includes our active operating mines, our indefinitely idled Empire mine and a closed mine formerly operating as LTVSMC.
Asset Retirement Obligation Disclosure	The following represents a roll forward of our mine closure obligation liability for the three months ended March 31, 2019 and for the year ended December 31, 2018: (In Millions) March 31, December 31, Asset retirement obligation at beginning of period $ 172.4 $ 168.4 Accretion expense 2.6 9.5 Remediation payments (0.1 ) (1.0 ) Revision in estimated cash flows — (4.5 ) Asset retirement obligation at end of period $ 174.9 $ 172.4

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative [Line Items]
Schedule Of Derivative Instruments In Statement Of Financial Position, Fair Value	The following table presents the fair value of our derivative instruments and the classification of each in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) Derivative Assets Derivative Liabilities March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Derivative Instrument Balance Sheet Location Fair Value Balance Sheet Location Fair Value Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments under ASC 815: Commodity contracts Derivative assets $ 0.7 Derivative assets $ 0.1 Other current liabilities $ 0.7 Other current liabilities $ 3.7 Derivatives not designated as hedging instruments under ASC 815: Customer supply agreement Derivative assets $ 106.4 Derivative assets $ 89.3 $ — $ — Provisional pricing arrangements Derivative assets 0.3 Derivative assets 2.1 Other current liabilities 9.8 — Total derivatives not designated as hedging instruments under ASC 815 $ 106.7 $ 91.4 $ 9.8 $ — Total derivatives $ 107.4 $ 91.5 $ 10.5 $ 3.7
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	The following table presents our outstanding hedge contracts: (In Millions) March 31, 2019 December 31, 2018 Notional Amount Unit of Measure Varying Maturity Dates Notional Amount Unit of Measure Varying Maturity Dates Natural gas 4.0 MMBtu April 2019 - February 2020 1.8 MMBtu January 2019 - August 2019 Diesel 7.5 Gallons April 2019 - December 2019 11.0 Gallons January 2019 - December 2019
Schedule Of Derivatives Not Designated As Hedging Instruments Statements Of Financial Performance Location Table	The following summarizes the effect of our derivatives that are not designated as hedging instruments in the Statements of Unaudited Condensed Consolidated Operations : (In Millions) Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivatives Three Months Ended 2019 2018 Customer supply agreements Product revenues $ 17.1 $ 41.9 Provisional pricing arrangements Product revenues (11.6 ) 1.9 Total $ 5.5 $ 43.8

DISCONTINUED OPERATIONS (Tables

DISCONTINUED OPERATIONS (Tables)	3 Months Ended
	Mar. 31, 2019
Schedule of Disposal Groups, including Discontinued Operations, Income Statement [Line Items]
Schedule of Disposal Groups, Including Discontinued Operations	The charts below provide an asset group breakout for each financial statement line impacted by discontinued operations. (In Millions) Three Months Ended 2019 2018 Income (loss) from discontinued operations, net of tax Asia Pacific Iron Ore $ (0.5 ) $ (71.3 ) North American Coal 0.5 0.4 $ — $ (70.9 ) (In Millions) Three Months Ended 2019 2018 Net cash used by operating activities Asia Pacific Iron Ore $ (0.8 ) $ (21.2 ) $ (0.8 ) $ (21.2 ) Net cash provided (used) by investing activities Asia Pacific Iron Ore $ 0.1 $ (0.1 ) $ 0.1 $ (0.1 )
Schedule of Disposal Groups, including Discontinued Operations, Income Statement	Loss from Discontinued Operations (In Millions) Three Months Ended Loss from Discontinued Operations 2019 2018 Revenues from product sales and services $ — $ 59.0 Cost of goods sold and operating expenses — (124.1 ) Sales margin — (65.1 ) Other operating expense (0.4 ) (2.5 ) Other expense (0.1 ) (1.1 ) Impairment of long-lived assets — (2.6 ) Loss from discontinued operations, net of tax $ (0.5 ) $ (71.3 )

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables reflect the changes in Accumulated other comprehensive loss related to shareholders’ equity (deficit): (In Millions) Postretirement Benefit Liability, net of tax Derivative Financial Instruments, net of tax Accumulated Other Comprehensive Loss December 31, 2018 $ (281.1 ) $ (2.8 ) $ (283.9 ) Other comprehensive income before reclassifications 0.2 2.5 2.7 Net loss reclassified from accumulated other comprehensive loss 5.5 0.2 5.7 March 31, 2019 $ (275.4 ) $ (0.1 ) $ (275.5 ) (In Millions) Postretirement Benefit Liability, net of tax Foreign Currency Translation Derivative Financial Instruments, net of tax Accumulated Other Comprehensive Loss December 31, 2017 $ (263.9 ) $ 225.4 $ (0.5 ) $ (39.0 ) Other comprehensive income before reclassifications 0.5 0.7 0.4 1.6 Net loss (gain) reclassified from accumulated other comprehensive loss 6.2 — (0.1 ) 6.1 March 31, 2018 $ (257.2 ) $ 226.1 $ (0.2 ) $ (31.3 )
Details of Accumulated Other Comprehensive Income (Loss) Components	The following table reflects the details about Accumulated other comprehensive loss components related to Cliffs shareholders’ equity (deficit): (In Millions) Details about Accumulated Other Comprehensive Loss Components Amount of (Gain)/Loss Reclassified into Income, Net of Tax Affected Line Item in the Statement of Unaudited Condensed Consolidated Operations Three Months Ended 2019 2018 Amortization of pension and OPEB liability: Prior service credits $ (0.2 ) $ (0.3 ) Other non-operating income Net actuarial loss 7.2 6.5 Other non-operating income $ 7.0 $ 6.2 (1.5 ) — Income tax benefit (expense) $ 5.5 $ 6.2 Net of taxes Unrealized loss (gain) on derivative financial instruments: Commodity contracts $ 0.3 $ (0.1 ) Cost of goods sold (0.1 ) — Income tax benefit (expense) $ 0.2 $ (0.1 ) Net of taxes Total reclassifications for the period, net of tax $ 5.7 $ 6.1

CASH FLOW INFORMATION (Tables)

CASH FLOW INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Disclosures	A reconciliation of capital additions to cash paid for capital expenditures is as follows: (In Millions) Three Months Ended March 31, 2019 2018 Capital additions $ 129.3 $ 78.9 Less: Non-cash accruals (11.5 ) 7.5 Right-of-use assets – finance leases 15.1 — Grants (8.4 ) — Cash paid for capital expenditures including deposits $ 134.1 $ 71.4

RELATED PARTIES (Tables)

RELATED PARTIES (Tables)	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Summary Of Other Ownership Interests	The following is a summary of the mine ownership of the co-owned iron ore mine at March 31, 2019 : Mine Cleveland-Cliffs Inc. ArcelorMittal U.S. Steel Hibbing 23.0 % 62.3 % 14.7 %
Summary Of Related Party Transactions Table Disclosure	Product revenues from related parties were as follows: (In Millions) Three Months Ended 2019 2018 Product revenues from related parties $ 41.1 $ 62.1 Total product revenues $ 145.4 $ 169.2 Related party product revenue as a percent of total product revenue 28.3 % 36.7 %
Summary of Balance Sheet Presentation	The following table presents the classification of related party assets and liabilities in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) Balance Sheet Location March 31, 2019 December 31, 2018 Accounts receivable, net $ 15.3 $ 176.0 Derivative assets 106.4 89.3 Partnership distribution payable (43.8 ) (43.5 ) Other current liabilities (0.5 ) (1.8 ) $ 77.4 $ 220.0

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
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 as they were anti-dilutive: (In Millions) Three Months Ended 2019 2018 $316.25 million 1.50% 2025 Convertible Senior Notes 7.3 — Employee stock plans 4.2 3.8 Total number of anti-dilutive shares 11.5 3.8
Earnings Per Share Computation	The following table summarizes the computation of basic and diluted earnings per share: (In Millions, Except Per Share Amounts) Three Months Ended 2019 2018 Loss from continuing operations $ (22.1 ) $ (13.4 ) Loss from discontinued operations, net of tax — (70.9 ) Net loss $ (22.1 ) $ (84.3 ) Weighted average number of shares: Basic 289.5 297.3 $316.25 million 1.50% 2025 Convertible Senior Notes — — Employee stock plans — — Diluted 289.5 297.3 Loss per common share - basic: Continuing operations $ (0.08 ) $ (0.05 ) Discontinued operations — (0.24 ) $ (0.08 ) $ (0.29 ) Loss per common share - diluted: Continuing operations $ (0.08 ) $ (0.05 ) Discontinued operations — (0.24 ) $ (0.08 ) $ (0.29 )

SUPPLEMENTARY GUARANTOR INFOR_2

SUPPLEMENTARY GUARANTOR INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Supplemental Condensed Consolidating Financial Position	Unaudited Condensed Consolidating Statement of Financial Position As of March 31, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 426.8 $ 0.7 $ 2.7 $ — $ 430.2 Accounts receivable, net 7.6 16.2 0.3 (4.0 ) 20.1 Inventories — 312.7 — — 312.7 Supplies and other inventories — 97.3 — — 97.3 Derivative assets 0.7 106.7 — — 107.4 Income tax receivable, current 117.3 — — — 117.3 Other current assets 8.6 21.1 11.3 — 41.0 TOTAL CURRENT ASSETS 561.0 554.7 14.3 (4.0 ) 1,126.0 PROPERTY, PLANT AND EQUIPMENT, NET 12.0 1,347.5 50.8 — 1,410.3 OTHER ASSETS Deposits for property, plant and equipment — 53.6 14.7 — 68.3 Income tax receivable, non-current 117.2 4.1 — — 121.3 Deferred income taxes 465.4 — 1.2 — 466.6 Investment in subsidiaries 1,448.5 30.1 — (1,478.6 ) — Long-term intercompany notes — — 121.3 (121.3 ) — Other non-current assets 16.6 95.8 1.4 — 113.8 TOTAL OTHER ASSETS 2,047.7 183.6 138.6 (1,599.9 ) 770.0 TOTAL ASSETS $ 2,620.7 $ 2,085.8 $ 203.7 $ (1,603.9 ) $ 3,306.3 LIABILITIES CURRENT LIABILITIES Accounts payable $ 5.2 $ 166.4 $ 4.1 $ (4.0 ) $ 171.7 Accrued employment costs 9.4 32.6 0.1 — 42.1 Accrued interest 23.0 — — — 23.0 Partnership distribution payable — 43.8 — — 43.8 Other current liabilities 27.9 78.4 7.1 — 113.4 TOTAL CURRENT LIABILITIES 65.5 321.2 11.3 (4.0 ) 394.0 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 64.1 414.8 (234.7 ) — 244.2 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 154.6 19.8 — 174.4 LONG-TERM DEBT 2,087.0 — — — 2,087.0 LONG-TERM INTERCOMPANY NOTES 121.3 — — (121.3 ) — OTHER LIABILITIES 21.1 116.0 7.9 — 145.0 TOTAL LIABILITIES 2,359.0 1,006.6 (195.7 ) (125.3 ) 3,044.6 EQUITY TOTAL EQUITY 261.7 1,079.2 399.4 (1,478.6 ) 261.7 TOTAL LIABILITIES AND EQUITY $ 2,620.7 $ 2,085.8 $ 203.7 $ (1,603.9 ) $ 3,306.3 Unaudited Condensed Consolidating Statement of Financial Position As of December 31, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 819.8 $ 0.7 $ 2.7 $ — $ 823.2 Accounts receivable, net 9.2 221.3 0.3 (4.1 ) 226.7 Inventories — 87.9 — — 87.9 Supplies and other inventories — 93.2 — — 93.2 Derivative assets 0.1 91.4 — — 91.5 Income tax receivable, current 117.3 — — — 117.3 Other current assets 10.0 16.9 12.9 — 39.8 TOTAL CURRENT ASSETS 956.4 511.4 15.9 (4.1 ) 1,479.6 PROPERTY, PLANT AND EQUIPMENT, NET 13.3 1,221.9 50.8 — 1,286.0 OTHER ASSETS Deposits for property, plant and equipment — 68.4 14.6 — 83.0 Income tax receivable, non-current 117.2 4.1 — — 121.3 Deferred income taxes 463.6 — 1.2 — 464.8 Investment in subsidiaries 1,262.3 50.8 — (1,313.1 ) — Long-term intercompany notes — — 121.3 (121.3 ) — Other non-current assets 8.0 85.4 1.5 — 94.9 TOTAL OTHER ASSETS 1,851.1 208.7 138.6 (1,434.4 ) 764.0 TOTAL ASSETS $ 2,820.8 $ 1,942.0 $ 205.3 $ (1,438.5 ) $ 3,529.6 LIABILITIES CURRENT LIABILITIES Accounts payable $ 5.3 $ 181.4 $ 4.2 $ (4.1 ) $ 186.8 Accrued employment costs 28.5 45.4 0.1 — 74.0 Accrued interest 38.4 — — — 38.4 Partnership distribution payable — 43.5 — — 43.5 Other current liabilities 30.6 86.7 8.2 — 125.5 TOTAL CURRENT LIABILITIES 102.8 357.0 12.5 (4.1 ) 468.2 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 64.3 414.4 (230.0 ) — 248.7 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 152.1 19.9 — 172.0 LONG-TERM DEBT 2,092.9 — — — 2,092.9 LONG-TERM INTERCOMPANY NOTES 121.3 — — (121.3 ) — OTHER LIABILITIES 15.3 99.5 8.8 — 123.6 TOTAL LIABILITIES 2,396.6 1,023.0 (188.8 ) (125.4 ) 3,105.4 EQUITY TOTAL EQUITY 424.2 919.0 394.1 (1,313.1 ) 424.2 TOTAL LIABILITIES AND EQUITY $ 2,820.8 $ 1,942.0 $ 205.3 $ (1,438.5 ) $ 3,529.6
Schedule of Supplemental Statements of Condensed Consolidating Operations and Comprehensive Income (Loss)	Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended March 31, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 145.4 $ — $ — $ 145.4 Freight — 11.6 — — 11.6 — 157.0 — — 157.0 COST OF GOODS SOLD — (126.1 ) — — (126.1 ) SALES MARGIN — 30.9 — — 30.9 OTHER OPERATING EXPENSE Selling, general and administrative expenses (22.8 ) (5.2 ) (0.1 ) — (28.1 ) Miscellaneous – net — (3.4 ) (0.2 ) — (3.6 ) (22.8 ) (8.6 ) (0.3 ) — (31.7 ) OPERATING INCOME (LOSS) (22.8 ) 22.3 (0.3 ) — (0.8 ) OTHER INCOME (EXPENSE) Interest expense, net (24.7 ) (0.5 ) 0.1 — (25.1 ) Other non-operating income (expense) (1.4 ) (3.2 ) 4.7 — 0.1 (26.1 ) (3.7 ) 4.8 — (25.0 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (48.9 ) 18.6 4.5 — (25.8 ) INCOME TAX BENEFIT (EXPENSE) 3.9 (0.1 ) (0.1 ) — 3.7 EQUITY IN INCOME OF SUBSIDIARIES 22.9 4.4 — (27.3 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS (22.1 ) 22.9 4.4 (27.3 ) (22.1 ) INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX — (0.1 ) 0.1 — — NET INCOME (LOSS) $ (22.1 ) $ 22.8 $ 4.5 $ (27.3 ) $ (22.1 ) OTHER COMPREHENSIVE INCOME 8.4 6.7 — (6.7 ) 8.4 TOTAL COMPREHENSIVE INCOME (LOSS) $ (13.7 ) $ 29.5 $ 4.5 $ (34.0 ) $ (13.7 ) Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended March 31, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 169.2 $ — $ — $ 169.2 Freight — 10.8 — — 10.8 — 180.0 — — 180.0 COST OF GOODS SOLD — (118.5 ) — — (118.5 ) SALES MARGIN — 61.5 — — 61.5 OTHER OPERATING EXPENSE Selling, general and administrative expenses (20.1 ) (4.7 ) (0.3 ) — (25.1 ) Miscellaneous – net (0.2 ) (5.3 ) (0.6 ) — (6.1 ) (20.3 ) (10.0 ) (0.9 ) — (31.2 ) OPERATING INCOME (LOSS) (20.3 ) 51.5 (0.9 ) — 30.3 OTHER INCOME (EXPENSE) Interest expense, net (31.9 ) (0.8 ) 0.3 — (32.4 ) Other non-operating income (expense) (0.9 ) 0.5 4.8 — 4.4 (32.8 ) (0.3 ) 5.1 — (28.0 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (53.1 ) 51.2 4.2 — 2.3 INCOME TAX EXPENSE (15.6 ) (0.1 ) — — (15.7 ) EQUITY IN INCOME (LOSS) OF SUBSIDIARIES (15.7 ) 4.5 — 11.2 — INCOME (LOSS) FROM CONTINUING OPERATIONS (84.4 ) 55.6 4.2 11.2 (13.4 ) INCOME (LOSS) FROM DISCONTINUED OPERATIONS, net of tax 0.1 0.2 (71.2 ) — (70.9 ) NET INCOME (LOSS) $ (84.3 ) $ 55.8 $ (67.0 ) $ 11.2 $ (84.3 ) OTHER COMPREHENSIVE INCOME 7.7 5.9 0.8 (6.7 ) 7.7 TOTAL COMPREHENSIVE INCOME (LOSS) $ (76.6 ) $ 61.7 $ (66.2 ) $ 4.5 $ (76.6 )
Schedule of Supplemental Statements of Condensed Consolidating Cash Flows	Unaudited Condensed Consolidating Statement of Cash Flows For the Three Months Ended March 31, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash used by operating activities $ (71.6 ) $ (38.4 ) $ (1.2 ) $ — $ (111.2 ) INVESTING ACTIVITIES Purchase of property, plant and equipment (0.3 ) (132.4 ) — — (132.7 ) Deposits for property, plant and equipment — (1.3 ) (0.1 ) — (1.4 ) Intercompany investing (157.6 ) (0.4 ) — 158.0 — Other investing activities — 8.4 0.1 — 8.5 Net cash used by investing activities (157.9 ) (125.7 ) — 158.0 (125.6 ) FINANCING ACTIVITIES Repurchase of common shares (124.3 ) — — — (124.3 ) Dividends paid (14.8 ) — — — (14.8 ) Repurchase of debt (10.3 ) — — — (10.3 ) Intercompany financing — 157.5 0.5 (158.0 ) — Other financing activities (14.1 ) 6.6 (0.9 ) — (8.4 ) Net cash provided (used) by financing activities (163.5 ) 164.1 (0.4 ) (158.0 ) (157.8 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (393.0 ) — (1.6 ) — (394.6 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — (1.6 ) — (1.6 ) NET DECREASE IN CASH AND CASH EQUIVALENTS (393.0 ) — — — (393.0 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 819.8 0.7 2.7 — 823.2 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 426.8 $ 0.7 $ 2.7 $ — $ 430.2 Unaudited Condensed Consolidating Statement of Cash Flows For the Three Months Ended March 31, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash used by operating activities $ (54.7 ) $ (64.7 ) $ (23.5 ) $ — $ (142.9 ) INVESTING ACTIVITIES Purchase of property, plant and equipment — (12.3 ) (0.1 ) — (12.4 ) Deposits for property, plant and equipment — (54.4 ) (4.6 ) — (59.0 ) Intercompany investing (137.7 ) (4.8 ) — 142.5 — Net cash used by investing activities (137.7 ) (71.5 ) (4.7 ) 142.5 (71.4 ) FINANCING ACTIVITIES Intercompany financing — 135.6 6.9 (142.5 ) — Other financing activities (2.9 ) (0.5 ) (3.6 ) — (7.0 ) Net cash provided (used) by financing activities (2.9 ) 135.1 3.3 (142.5 ) (7.0 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — 0.2 — 0.2 DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (195.3 ) (1.1 ) (24.7 ) — (221.1 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — — — — NET DECREASE IN CASH AND CASH EQUIVALENTS (195.3 ) (1.1 ) (24.7 ) — (221.1 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 948.9 2.1 27.3 — 978.3 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 753.6 $ 1.0 $ 2.6 $ — $ 757.2

BASIS OF PRESENTATION AND SIG_4

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Schedule Of Subsidiaries) (Details)	3 Months Ended
	Mar. 31, 2019
Northshore
Related Party Transaction [Line Items]
Entity Address, State or Province	Minnesota
United Taconite
Related Party Transaction [Line Items]
Entity Address, State or Province	Minnesota
Tilden
Related Party Transaction [Line Items]
Entity Address, State or Province	Michigan
Empire
Related Party Transaction [Line Items]
Entity Address, State or Province	Michigan
Metallics [Member]
Related Party Transaction [Line Items]
Entity Address, State or Province	Ohio

BASIS OF PRESENTATION AND SIG_5

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) - Hibbing [Member] - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Investments in Ventures [Member]
Related Party Transaction [Line Items]
Ownership interest, equity method investment	23.00%	23.00%
Other Noncurrent Liabilities [Member]
Related Party Transaction [Line Items]
Equity Method Investments	$ 10.8	$ 15.4

SEGMENT REPORTING (Schedule of

SEGMENT REPORTING (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 157	$ 180
SALES MARGIN	30.9	61.5
Other operating expense	(31.7)	(31.2)
TOTAL OTHER INCOME (EXPENSE)	(25)	(28)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(25.8)	2.3
NET INCOME (LOSS)	(22.1)	(84.3)
Interest expense, net	(25.1)	(32.4)
Income Tax Expense (Benefit)	(3.7)	15.7
Depreciation, depletion and amortization	19.9	23.9
EBITDA	19.2	(11.2)
Foreign currency transaction gain (loss), before tax	0.1	(0.4)
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	0	(70.9)
Gain (loss) on extinguishment of debt	(0.3)	0
Severance Costs	(1.7)	0
Adjusted EBITDA	21.1	52.3
Depreciation, Depletion and Amortization excluding Depreciation, Amortization and Depletion expense for Discontinued Operations	19.9	17.2
Property, Plant and Equipment, Additions	129.3	78.9
Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
Revenues	157	180
SALES MARGIN	30.9	61.5
Depreciation, depletion and amortization	18.5	15.8
EBITDA	42.8	72.5
Adjusted EBITDA	47.5	77.1
Property, Plant and Equipment, Additions	46.8	18.7
Metallics [Member]
Segment Reporting Information [Line Items]
EBITDA	(0.8)	(0.3)
Adjusted EBITDA	(0.8)	(0.3)
Property, Plant and Equipment, Additions	82.4	60
Other segments
Segment Reporting Information [Line Items]
EBITDA	(22.8)	(83.4)
Adjusted EBITDA	(25.6)	(24.5)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	1.4	1.4
Property, Plant and Equipment, Additions	0.1	0.2
EBITDA Calculation [Member]
Segment Reporting Information [Line Items]
Interest expense, net	(25.1)	(33.5)
Income Tax Expense (Benefit)	3.7	(15.7)
Depreciation, depletion and amortization	19.9	23.9
Adjusted EBITDA Calculation [Member]
Segment Reporting Information [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ 0	$ (63.1)

SEGMENT REPORTING (Summary of A

SEGMENT REPORTING (Summary of Assets by Segment) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 3,306.3	$ 3,529.6
Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	1,774.5	1,694.1
Metallics [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	350	265.9
Operating Segments [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	2,124.5	1,960
Corporate and Other [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 1,181.8	$ 1,569.6

SEGMENT REPORTING (Narrative) (

SEGMENT REPORTING (Narrative) (Details)	3 Months Ended
	Mar. 31, 2019unit
Segment Reporting Information [Line Items]
Number of Reporting Units	2

REVENUE (Deferred Revenue) (Det

REVENUE (Deferred Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]
Contract with Customer, Liability, Current	$ 18.1	$ 31	$ 21	$ 23.8
Other Liabilities [Member]
Deferred Revenue Arrangement [Line Items]
Contract with Customer, Liability, Noncurrent	38.5	51.4	$ 38.5	$ 51.4
Other Current Liabilities [Member]
Deferred Revenue Arrangement [Line Items]
Contract With Customer, Liability, Period Increase (Decrease)	(2.9)	7.2
Other Noncurrent Liabilities [Member]
Deferred Revenue Arrangement [Line Items]
Contract With Customer, Liability, Period Increase (Decrease)	$ 0	$ 0

REVENUE (Narrative) (Details)

REVENUE (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Contract with Customer, Liability, Revenue Recognized			$ 51.4
Other current liabilities	$ 113.4		125.5
Take or Pay Contracts [Member]
Contract with Customer, Liability	5.3		8.2
Not Designated as Hedging Instrument [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	5.5	$ 43.8
Other Current Liabilities [Member]
Contract with Customer, Liability	12.9		12.9
Other Liabilities [Member]
Contract with Customer, Liability, Noncurrent	$ 38.5	$ 51.4	$ 38.5	$ 51.4

INVENTORIES (Schedule Of Invent

INVENTORIES (Schedule Of Inventories) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Inventory, Net [Abstract]
Total inventories	$ 312.7	$ 87.9
Mining and Pelletizing [Member]
Inventory, Net [Abstract]
Finished goods	287.7	77.8
Work-in-process	$ 25	$ 10.1

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT (Value Of Each Of The Major Classes Of Consolidated Depreciable Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,451.6	$ 2,308.4
Allowance for depreciation and depletion	(1,041.3)	(1,022.4)
Property, plant and equipment, net	1,410.3	1,286
Land rights and mineral rights
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	549.6	549.6
Office and information technology
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	70.5	70
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	87.4	87.2
Mining equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	568.4	548.5
Processing equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	660.9	645.8
Electric power facilities
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	58.7	58.7
Land improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	23.8	23.8
Asset retirement obligation
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	14.8	14.8
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	25.5	25.2
Construction-in-progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 392	$ 284.8

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Property, Plant and Equipment [Abstract]
Interest Costs Capitalized	$ 4	$ 1

DEBT AND CREDIT FACILITIES DEBT

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES - BORROWING CAPACITY (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 305,400,000	$ 323,700,000
Long-term Line of Credit	0	0
Line of Credit Facility, Remaining Borrowing Capacity	240,000,000	268,700,000
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit	$ 65,400,000	$ 55,000,000

DEBT AND CREDIT FACILITIES (Sch

DEBT AND CREDIT FACILITIES (Schedule Of Long-Term Debt) (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
LONG-TERM DEBT	$ 2,087,000,000	$ 2,092,900,000
$400 Million 4.875% 2024 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.00%	5.00%
Debt Instrument, Par Value	$ 400,000,000	$ 400,000,000
Unamortized Debt Issuance Expense	(5,500,000)	(5,700,000)
Debt Instrument, Unamortized Discount	(2,100,000)	(2,200,000)
Long-term Debt	$ 392,400,000	$ 392,100,000
$700 Million 4.875% 2021 Senior Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	4.89%	4.89%
Debt Instrument, Par Value	$ 114,000,000	$ 124,000,000
Unamortized Debt Issuance Expense	(200,000)	(200,000)
Debt Instrument, Unamortized Discount	0	0
Long-term Debt	$ 113,800,000	$ 123,800,000
$316 Million 1.5% 2025 Senior Notes [Domain]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.26%	6.26%
Debt Instrument, Par Value	$ 316,300,000	$ 316,300,000
Unamortized Debt Issuance Expense	(5,300,000)	(5,500,000)
Debt Instrument, Unamortized Discount	(73,000,000)	(75,600,000)
Long-term Debt	$ 238,000,000	$ 235,200,000
$1.075 Billion 5.75% 2025 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.01%	6.01%
Debt Instrument, Par Value	$ 1,073,300,000	$ 1,073,300,000
Unamortized Debt Issuance Expense	(9,500,000)	(9,900,000)
Debt Instrument, Unamortized Discount	(14,100,000)	(14,600,000)
Long-term Debt	$ 1,049,700,000	$ 1,048,800,000
$800 Million 6.25% 2040 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.34%	6.34%
Debt Instrument, Par Value	$ 298,400,000	$ 298,400,000
Unamortized Debt Issuance Expense	(2,200,000)	(2,300,000)
Debt Instrument, Unamortized Discount	(3,300,000)	(3,300,000)
Long-term Debt	292,900,000	292,800,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	450,000,000	450,000,000
Credit facility, amount outstanding	0	0
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Fair Value Adjustment to Interest Rate Hedge	$ 200,000	$ 200,000

DEBT AND CREDIT FACILITIES DE_2

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES (Schedule of Extinguishment of Debt) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	$ 10
Gain (loss) on extinguishment of debt	(0.3)	$ 0
$700 Million 4.875% 2021 Senior Note [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	10
Gain (loss) on extinguishment of debt	$ (0.3)

DEBT AND CREDIT FACILITIES (S_2

DEBT AND CREDIT FACILITIES (Schedule of Debt Maturities) (Details) $ in Millions	Mar. 31, 2019USD ($)
Debt Disclosure [Abstract]
Debt Maturities 2019	$ 0
Debt Maturities 2020	0
Debt Maturities 2021	114
Debt Maturities 2022	0
Debt Maturities 2023	0
Debt Maturities 2024	400
2025 and thereafter	1,688
Total maturities of debt	$ 2,202

FAIR VALUE MEASUREMENTS (Fair V

FAIR VALUE MEASUREMENTS (Fair Value of Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	$ 357.6	$ 543.4
Derivative assets	107.4	91.5
Total Asset	465	634.9
Derivative liability	10.5	3.7
Total Liability	10.5	3.7
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0.8
Derivative assets	0	0
Total Asset	0	0.8
Derivative liability	0	0
Total Liability	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	357.6	542.6
Derivative assets	0.7	0.1
Total Asset	358.3	542.7
Derivative liability	0.7	3.7
Total Liability	0.7	3.7
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Derivative assets	106.7	91.4
Total Asset	106.7	91.4
Derivative liability		0
Total Liability	$ 9.8	$ 0

FAIR VALUE MEASUREMENTS (Schedu

FAIR VALUE MEASUREMENTS (Schedule Of Quantitative Inputs And Assumptions For Level 3 Assets And Liabilities) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	$ 107,400,000	$ 91,500,000
Derivative assets	107,400,000	91,500,000
Derivative liability	10,500,000	3,700,000
Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	106,700,000	91,400,000
Derivative liability	9,800,000	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	106,700,000	91,400,000
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member] | Managements Estimate Of 62% Fee [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement with unobservable inputs derivative asset range	80,000,000
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member] | PPI Estimates [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement with unobservable inputs derivative asset range	180
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member] | PPI Estimates [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement with unobservable inputs derivative asset range	240
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | PPI Estimates [Member] | Managements Estimate Of 62% Fee [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement with unobservable inputs derivative asset range	208
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Customer Supply Agreement [Member] | Customer's Hot-Rolled Steel Estimate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement with unobservable inputs derivative asset range	735
Other Current Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	300,000	2,100,000
Derivative liability		0
Other Current Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Customer Supply Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	106,400,000	$ 89,300,000
Other Current Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability	$ 9,800,000

FAIR VALUE MEASUREMENTS (Fair_2

FAIR VALUE MEASUREMENTS (Fair Value, Assets and Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 91.4	$ 49.5
Total gains
Included in earnings	15.3	44.3
Settlements	0	(0.2)
Ending balance - March 31	106.7	93.6
Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date	15.3	44.5
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	0	(1.7)
Total losses
Included in earnings	(9.8)	(0.5)
Settlements	0	2.2
Ending balance - March 31	(9.8)	0
Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date	$ (9.8)	$ 0

FAIR VALUE MEASUREMENTS (Carryi

FAIR VALUE MEASUREMENTS (Carrying Value And Fair Value Of Financial Instruments Disclosure) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Adjustment to Interest Rate Hedge	$ 0.2	$ 0.2
Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	2,236.9	2,039.9
Fair Value [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Adjustment to Interest Rate Hedge	0.2	0.2
Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	2,087	2,092.9
Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Adjustment to Interest Rate Hedge	0.2	0.2
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 4.875% 2024 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	398	370.2
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Note [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	115.7	122.3
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316 Million 1.5% 2025 Senior Notes [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	432.5	352.4
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $1.075 Billion 5.75% 2025 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	1,035.5	962
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $800 Million 6.25% 2040 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	255	232.8
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 4.875% 2024 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	392.4	392.1
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Note [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	113.8	123.8
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316 Million 1.5% 2025 Senior Notes [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	238	235.2
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $1.075 Billion 5.75% 2025 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	1,049.7	1,048.8
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $800 Million 6.25% 2040 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	292.9	292.8
Line of Credit [Member] | Fair Value [Member] | Fair Value, Inputs, Level 2 [Member] | Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	0	0
Line of Credit [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member] | Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	$ 0	$ 0

FAIR VALUE MEASUREMENTS (Narrat

FAIR VALUE MEASUREMENTS (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	$ 107.4	$ 91.5
Derivative liability	10.5	3.7
Derivative Asset	107.4	91.5
Derivative Liability	10.5	3.7
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	0	0
Derivative Liability	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	0.7	0.1
Derivative Liability	0.7	3.7
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	106.7	91.4
Derivative Liability		0
Not Designated as Hedging Instrument [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative liability	9.8	0
Derivative Asset	106.7	91.4
Other Current Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative liability	9.8
Derivative Liability	9.8
Other Current Assets [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Customer Supply Agreement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative Asset	106.4	89.3
Other Current Assets [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative liability		0
Derivative Asset	$ 0.3	$ 2.1

PENSIONS AND OTHER POSTRETIRE_3

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Estimated Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 4.1	$ 4.7
Interest cost	8.7	7.6
Expected return on plan assets	(13.6)	(15)
Prior service credits	0.3	0.5
Net actuarial loss	5.9	5.3
Net periodic benefit credit	5.4	3.1
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.4	0.5
Interest cost	2.3	2.1
Expected return on plan assets	(4.2)	(4.6)
Prior service credits	(0.5)	(0.8)
Net actuarial loss	1.3	1.2
Net periodic benefit credit	$ (0.7)	$ (1.6)

PENSIONS AND OTHER POSTRETIRE_4

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Plans, Defined Benefit [Member]
Definted Benefit Plan Disclosure [Line Items]
Payment for Pension Benefits	$ 3.2	$ 2.3
Other Postretirement Benefit Plans, Defined Benefit [Member]
Definted Benefit Plan Disclosure [Line Items]
OPEB Contributions	$ 0	$ 0

STOCK COMPENSATION PLANS (Assum

STOCK COMPENSATION PLANS (Assumptions Utilized to Estimate Fair Value for Performance Share Grants) (Details)	3 Months Ended
	Mar. 31, 2019$ / shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Grant Date Market Price	$ 11.24
Average Expected Term	2 years 10 months 12 days
Expected Volatility	67.52%
Risk-Free Interest Rate	2.55%
Dividend Yield	0.00%
Fair Value	$ 18.31
Fair Value (Percent of Grant Date Market Price)	162.90%

STOCK COMPENSATION PLANS (Narra

STOCK COMPENSATION PLANS (Narrative) (Details) - 2015 Equity Plan [Member] - shares shares in Millions	Mar. 31, 2019	Mar. 31, 2019
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted shares granted		0.6
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted shares granted		0.6
2019 to 2021 Performance Period [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Payout Rate	0.00%
2019 to 2021 Performance Period [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Payout Rate	200.00%

INCOME TAXES (Narrative) (Detai

INCOME TAXES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent	12.90%	0.10%
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ (0.4)	$ 15.7
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Change in refundable AMT, amount		$ 14.5

ENVIRONMENTAL AND MINE CLOSUR_3

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Summary Of Mine Closure Obligations) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Environmental	$ 2.4	$ 2.5
Asset Retirement Obligation	174.9	172.4	$ 168.4
Environmental Loss Contingency And Mine Reclamation And Closing Liability Current And Noncurrent	177.3	174.9
Environmental Loss Contingency And Mine Reclamation And Closing Liability Current	2.9	2.9
Environmental Loss Contingency And Mine Reclamation And Closing Liability Noncurrent	174.4	172
Mining and Pelletizing [Member]
Loss Contingencies [Line Items]
Asset Retirement Obligation	$ 174.9	$ 172.4

ENVIRONMENTAL AND MINE CLOSUR_4

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Asset Retirement Obligation Disclosure) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation [Roll Forward]
Asset retirement obligation at beginning of period	$ 172.4	$ 168.4
Accretion expense	2.6	9.5
Remediation payments	(0.1)	(1)
Revision in estimated cash flows	0	(4.5)
Asset retirement obligation at end of period	$ 174.9	$ 172.4

DERIVATIVE INSTRUMENTS (Schedul

DERIVATIVE INSTRUMENTS (Schedule Of Derivative Instruments In Statement Of Financial Position, Fair Value) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 107.4	$ 91.5
Derivative liability	10.5	3.7
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	106.7	91.4
Derivative liability	9.8	0
Fair Value, Inputs, Level 3 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Derivative Financial Instruments, Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	0.7	0.1
Fair Value, Inputs, Level 3 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability	0.7	3.7
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	106.4	89.3
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability	9.8
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 0.3	2.1
Derivative liability		$ 0

DERIVATIVE INSTRUMENTS (Sched_2

DERIVATIVE INSTRUMENTS (Schedule Of Derivatives Not Designated As Hedging Instruments) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 5.5	$ 43.8
Customer Supply Agreement [Member] | Revenue from Contract with Customer [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in income on derivative	17.1	41.9
Provisional Pricing Arrangements [Member] | Revenue from Contract with Customer [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in income on derivative	$ (11.6)	$ 1.9

DERIVATIVE INSTRUMENTS (Narrati

DERIVATIVE INSTRUMENTS (Narrative) (Details) gal in Millions, MMcf in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)galMMcf	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)galMMcf
Derivative [Line Items]
Derivative assets	$ 107.4		$ 91.5
Derivative liability	$ 10.5		$ 3.7
Natural Gas [Member]
Derivative [Line Items]
Investment Contract Volume | MMcf	4		1.8
Diesel [Member]
Derivative [Line Items]
Investment Contract Volume | gal	7.5		11
Customer Supply Agreement [Member] | Not Designated as Hedging Instrument [Member] | Revenue from Contract with Customer [Member]
Derivative [Line Items]
Amount of gain/(loss) recognized in income on derivative	$ 17.1	$ 41.9
Provisional Pricing Arrangements [Member] | Not Designated as Hedging Instrument [Member] | Revenue from Contract with Customer [Member]
Derivative [Line Items]
Amount of gain/(loss) recognized in income on derivative	$ (11.6)	$ 1.9

DISCONTINUED OPERATIONS (Schedu

DISCONTINUED OPERATIONS (Schedule of Disposal Groups, Including Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ 0	$ (70.9)
Net cash provided (used) by operating activities	(111.2)	(142.9)
Net cash used by investing activities	(125.6)	(71.4)
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.5)	(71.3)
North American Coal [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	0.5	0.4
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash provided (used) by operating activities	(0.8)	(21.2)
Net cash used by investing activities	0.1	(0.1)
Discontinued Operations [Member] | Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash provided (used) by operating activities	(0.8)	(21.2)
Net cash used by investing activities	$ 0.1	$ (0.1)

DISCONTINUED OPERATIONS (Sche_2

DISCONTINUED OPERATIONS (Schedule of Disposal Groups, including Discontinued Operations, Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 0	$ (70.9)
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues from product sales and services	0	59
Cost of goods sold and operating expenses	0	124.1
Sales margin	0	(65.1)
Other operating expense	(0.4)	(2.5)
Other expense	(0.1)	(1.1)
Impairment of long-lived assets	0	(2.6)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ (0.5)	$ (71.3)

CAPITAL STOCK (Details)

CAPITAL STOCK (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended
	Mar. 31, 2019	Feb. 19, 2019	Nov. 26, 2018	Oct. 18, 2018
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount			$ 200,000,000
Stock Repurchased During Period, Shares	11.5
Repurchase of common shares	$ 124,300,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	28,600,000
Dividends Payable	$ 14,700,000
Common Stock [Member]
Class of Stock [Line Items]
Dividends payable, per share		$ 0.05		$ 0.05

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	$ 424.2
Balance, beginning of period PY		$ (444.1)
Balance, end of period	261.7
Balance, end of period PY		(484.8)
Changes in Pension and Other Post-Retirement Benefits, net of tax [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(281.1)
Balance, beginning of period PY		(263.9)
Other comprehensive income (loss) before reclassifications	0.2	0.5
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5.5	6.2
Balance, end of period	(275.4)
Balance, end of period PY		(257.2)
Unrealized Net Gain (Loss) on Foreign Currency Translation [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period PY		225.4
Other comprehensive income (loss) before reclassifications		0.7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0
Balance, end of period PY		226.1
Net Unrealized Gain (Loss) on Derivative Financial Instruments, net of tax [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(2.8)
Balance, beginning of period PY		(0.5)
Other comprehensive income (loss) before reclassifications	2.5	0.4
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.2	(0.1)
Balance, end of period	(0.1)
Balance, end of period PY		(0.2)
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(283.9)
Balance, beginning of period PY		(39)
Other comprehensive income (loss) before reclassifications	2.7	1.6
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5.7	6.1
Balance, end of period	$ (275.5)
Balance, end of period PY		$ (31.3)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details of Accumulated Other Comprehensive Income (Loss) Components) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0.3	$ (0.1)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5.7	6.1
Realized Gain Loss On Derivatives [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
TaxOnDerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoEarnings	(0.1)	0
Amount of gain/(loss) recognized in income on derivative	0.2	(0.1)
Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5.5	6.2
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Prior service credits	(0.2)	(0.3)
Net actuarial loss	7.2	6.5
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	7	6.2
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	(1.5)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	$ 5.5	$ 6.2

CASH FLOW INFORMATION (Narrativ

CASH FLOW INFORMATION (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 31, 2019	Feb. 19, 2019	Oct. 18, 2018
Dividends Payable [Line Items]
Dividends Payable	$ 14.7
Common Stock [Member]
Dividends Payable [Line Items]
Dividends payable, per share		$ 0.05	$ 0.05

CASH FLOW INFORMATION (Reconcil

CASH FLOW INFORMATION (Reconciliation Of Capital Additions To Cash Paid For Capital Expenditures) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Supplemental Cash Flow Information [Abstract]
Property, Plant and Equipment, Additions, Including Discontinued Operations	$ 129.3	$ 78.9
Non-cash accruals	11.5	(7.5)
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	15.1
Capital leases		0
Government grant rebate	(8.4)	0
Payments To Acquire Property Plant And Equipment Net	$ 134.1	$ 71.4

RELATED PARTIES (Summary Of Oth

RELATED PARTIES (Summary Of Other Ownership Interests) (Details) - Hibbing [Member]	Mar. 31, 2019	Dec. 31, 2018
Arcelor Mittal [Member]
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%
Investments in Ventures [Member]
Related Party Transaction [Line Items]
Ownership interest, equity method investment	23.00%	23.00%

RELATED PARTIES (Summary Of Rel

RELATED PARTIES (Summary Of Related Party Transactions Table Disclosure) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Related Party Transactions [Abstract]
Product revenues from related parties	$ 41.1	$ 62.1
Revenue from Contract with Customer, Including Assessed Tax	$ 145.4	$ 169.2
Related party product revenue as a percent of total product revenue	28.30%	36.70%

RELATED PARTIES (Summary of Bal

RELATED PARTIES (Summary of Balance Sheet Presentation) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Partnership distribution payable	$ 43.8	$ 43.5
Related Party Transaction, Due from (to) Related Party	77.4	220
Trade Accounts Receivable [Member]
Related Party Transaction [Line Items]
Due from Related Parties, Current	15.3	176
Derivative [Member]
Related Party Transaction [Line Items]
Due from Related Parties, Current	106.4	89.3
Other Current Liabilities [Member]
Related Party Transaction [Line Items]
Due to Related Parties, Current	$ (0.5)	$ (1.8)

RELATED PARTIES (Narrative) (De

RELATED PARTIES (Narrative) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019USD ($)Facility	Dec. 31, 2017USD ($)	Dec. 31, 2018
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
Number of mines (in number of facilities) | Facility	4
Empire
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent		100.00%
Purchase of Noncontrolling Interest | $		$ 132.7
Other Liabilities [Member] | Empire
Segment Reporting Information [Line Items]
Noncontrolling Interest Purchase, Installment Amount | $	$ 44.2
Hibbing [Member] | Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
Number of mines (in number of facilities) | Facility	1
Hibbing [Member] | Investments in Ventures [Member]
Segment Reporting Information [Line Items]
Ownership interest, equity method investment	23.00%		23.00%

EARNINGS PER SHARE (Earnings Pe

EARNINGS PER SHARE (Earnings Per Share Computation) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Loss from continuing operations	$ (22.1)	$ (13.4)
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	0	(70.9)
NET INCOME (LOSS)	$ (22.1)	$ (84.3)
Weighted average number of shares:
Basic	289,525	297,266
316.25 million 1.50% 2025 Convertible Senior Notes	0	0
Employee stock plans	0	0
Diluted	289,525	297,266
Loss per common share - basic:
Continuing operations (in dollars per share)	$ (0.08)	$ (0.05)
Discontinued operations (in dollars per share)	0	(0.24)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share)	(0.08)	(0.29)
Loss per common share - diluted:
Continuing operations (in dollars per share)	(0.08)	(0.05)
Discontinued operations (in dollars per share)	0	(0.24)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share)	$ (0.08)	$ (0.29)

EARNINGS PER SHARE EARNINGS PER

EARNINGS PER SHARE EARNINGS PER SHARE (Antidilutive Securities Excluded from Computation) (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Incremental Common Shares Excluded and Attributable to Share-based Payment Arrangements	4.2	3.8
316.25 million 1.50% 2025 Convertible Senior Notes	7.3	0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	11.5	3.8

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Purchase Commitments) (Details) - Capital Commitments [Member] $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
Capital commitments, amount expected	$ 830
Amount expended project-to-date, including deposits	265
Capital commitments, amount expected in remaining nine months of 2019	290
Capital commitments, amount expected in 2020	$ 275

SUBSEQUENT EVENTS (Narrative) (

SUBSEQUENT EVENTS (Narrative) (Details) - USD ($)	Apr. 24, 2019	Mar. 31, 2019	Nov. 26, 2018
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount			$ 200,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 28,600,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount	$ 100,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 129,000,000

SUPPLEMENTARY GUARANTOR INFOR_3

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Financial Position) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 430.2	$ 823.2	$ 757.2	$ 978.3
Accounts receivable, net	20.1	226.7
Inventories	312.7	87.9
Supplies and other inventories	97.3	93.2
Derivative assets	107.4	91.5
Income tax receivable, current	117.3	117.3
Other current assets	41	39.8
TOTAL CURRENT ASSETS	1,126	1,479.6
PROPERTY, PLANT AND EQUIPMENT, NET	1,410.3	1,286
Deposits for property, plant and equipment	68.3	83
Income tax receivable, non-current	121.3	121.3
Deferred income tax assets	466.6	464.8
Investment in subsidiaries	0	0
Long-term intercompany notes	0	0
Other non-current assets	113.8	94.9
TOTAL OTHER ASSETS	770	764
TOTAL ASSETS	3,306.3	3,529.6
Accounts payable	171.7	186.8
Accrued employment costs	42.1	74
Accrued interest	23	38.4
Partnership distribution payable	43.8	43.5
Other current liabilities	113.4	125.5
TOTAL CURRENT LIABILITIES	394	468.2
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	244.2	248.7
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	174.4	172
LONG-TERM DEBT	2,087	2,092.9
LONG-TERM INTERCOMPANY NOTES	0	0
OTHER LIABILITIES	145	123.6
TOTAL LIABILITIES	3,044.6	3,105.4
Stockholders' Equity Attributable to Parent	261.7	424.2
TOTAL LIABILITIES AND EQUITY	3,306.3	3,529.6
Consolidation, Eliminations [Member]
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	(4)	(4.1)
Inventories	0	0
Supplies and other inventories	0	0
Derivative assets	0	0
Income tax receivable, current	0	0
Other current assets	0	0
TOTAL CURRENT ASSETS	(4)	(4.1)
PROPERTY, PLANT AND EQUIPMENT, NET	0	0
Deposits for property, plant and equipment	0	0
Income tax receivable, non-current	0	0
Deferred income tax assets	0	0
Investment in subsidiaries	(1,478.6)	(1,313.1)
Long-term intercompany notes	(121.3)	(121.3)
Other non-current assets	0	0
TOTAL OTHER ASSETS	(1,599.9)	(1,434.4)
TOTAL ASSETS	(1,603.9)	(1,438.5)
Accounts payable	(4)	(4.1)
Accrued employment costs	0	0
Accrued interest	0	0
Partnership distribution payable	0	0
Other current liabilities	0	0
TOTAL CURRENT LIABILITIES	(4)	(4.1)
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	0	0
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	0	0
LONG-TERM DEBT	0	0
LONG-TERM INTERCOMPANY NOTES	(121.3)	(121.3)
OTHER LIABILITIES	0	0
TOTAL LIABILITIES	(125.3)	(125.4)
Stockholders' Equity Attributable to Parent	(1,478.6)	(1,313.1)
TOTAL LIABILITIES AND EQUITY	(1,603.9)	(1,438.5)
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Cash and cash equivalents	2.7	2.7	2.6	27.3
Accounts receivable, net	0.3	0.3
Inventories	0	0
Supplies and other inventories	0	0
Derivative assets	0	0
Income tax receivable, current	0	0
Other current assets	11.3	12.9
TOTAL CURRENT ASSETS	14.3	15.9
PROPERTY, PLANT AND EQUIPMENT, NET	50.8	50.8
Deposits for property, plant and equipment	14.7	14.6
Income tax receivable, non-current	0	0
Deferred income tax assets	1.2	1.2
Investment in subsidiaries	0	0
Long-term intercompany notes	121.3	121.3
Other non-current assets	1.4	1.5
TOTAL OTHER ASSETS	138.6	138.6
TOTAL ASSETS	203.7	205.3
Accounts payable	4.1	4.2
Accrued employment costs	0.1	0.1
Accrued interest	0	0
Partnership distribution payable	0	0
Other current liabilities	7.1	8.2
TOTAL CURRENT LIABILITIES	11.3	12.5
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	(234.7)	(230)
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	19.8	19.9
LONG-TERM DEBT	0	0
LONG-TERM INTERCOMPANY NOTES	0	0
OTHER LIABILITIES	7.9	8.8
TOTAL LIABILITIES	(195.7)	(188.8)
Stockholders' Equity Attributable to Parent	399.4	394.1
TOTAL LIABILITIES AND EQUITY	203.7	205.3
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Cash and cash equivalents	0.7	0.7	1	2.1
Accounts receivable, net	16.2	221.3
Inventories	312.7	87.9
Supplies and other inventories	97.3	93.2
Derivative assets	106.7	91.4
Income tax receivable, current	0	0
Other current assets	21.1	16.9
TOTAL CURRENT ASSETS	554.7	511.4
PROPERTY, PLANT AND EQUIPMENT, NET	1,347.5	1,221.9
Deposits for property, plant and equipment	53.6	68.4
Income tax receivable, non-current	4.1	4.1
Deferred income tax assets	0	0
Investment in subsidiaries	30.1	50.8
Long-term intercompany notes	0	0
Other non-current assets	95.8	85.4
TOTAL OTHER ASSETS	183.6	208.7
TOTAL ASSETS	2,085.8	1,942
Accounts payable	166.4	181.4
Accrued employment costs	32.6	45.4
Accrued interest	0	0
Partnership distribution payable	43.8	43.5
Other current liabilities	78.4	86.7
TOTAL CURRENT LIABILITIES	321.2	357
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	414.8	414.4
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	154.6	152.1
LONG-TERM DEBT	0	0
LONG-TERM INTERCOMPANY NOTES	0	0
OTHER LIABILITIES	116	99.5
TOTAL LIABILITIES	1,006.6	1,023
Stockholders' Equity Attributable to Parent	1,079.2	919
TOTAL LIABILITIES AND EQUITY	2,085.8	1,942
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Cash and cash equivalents	426.8	819.8	$ 753.6	$ 948.9
Accounts receivable, net	7.6	9.2
Inventories	0	0
Supplies and other inventories	0	0
Derivative assets	0.7	0.1
Income tax receivable, current	117.3	117.3
Other current assets	8.6	10
TOTAL CURRENT ASSETS	561	956.4
PROPERTY, PLANT AND EQUIPMENT, NET	12	13.3
Deposits for property, plant and equipment	0	0
Income tax receivable, non-current	117.2	117.2
Deferred income tax assets	465.4	463.6
Investment in subsidiaries	1,448.5	1,262.3
Long-term intercompany notes	0	0
Other non-current assets	16.6	8
TOTAL OTHER ASSETS	2,047.7	1,851.1
TOTAL ASSETS	2,620.7	2,820.8
Accounts payable	5.2	5.3
Accrued employment costs	9.4	28.5
Accrued interest	23	38.4
Partnership distribution payable	0	0
Other current liabilities	27.9	30.6
TOTAL CURRENT LIABILITIES	65.5	102.8
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	64.1	64.3
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	0	0
LONG-TERM DEBT	2,087	2,092.9
LONG-TERM INTERCOMPANY NOTES	121.3	121.3
OTHER LIABILITIES	21.1	15.3
TOTAL LIABILITIES	2,359	2,396.6
Stockholders' Equity Attributable to Parent	261.7	424.2
TOTAL LIABILITIES AND EQUITY	$ 2,620.7	$ 2,820.8

SUPPLEMENTARY GUARANTOR INFOR_4

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Operations and Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue from Contract with Customer, Including Assessed Tax	$ 145.4	$ 169.2
Freight Revenue	11.6	10.8
Revenues	157	180
COST OF GOODS SOLD	(126.1)	(118.5)
SALES MARGIN	30.9	61.5
Selling, general and administrative expenses	(28.1)	(25.1)
Miscellaneous - net	(3.6)	(6.1)
Other operating expense	(31.7)	(31.2)
OPERATING INCOME	(0.8)	30.3
Interest expense, net	(25.1)	(32.4)
Gain (loss) on extinguishment of debt	(0.3)	0
Other non-operating income	0.1	4.4
TOTAL OTHER INCOME (EXPENSE)	(25)	(28)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(25.8)	2.3
Income Tax Expense (Benefit)	3.7	(15.7)
Equity in income (loss) of subsidiaries	0	0
LOSS FROM CONTINUING OPERATIONS	(22.1)	(13.4)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	(70.9)
NET INCOME (LOSS)	(22.1)	(84.3)
Other Comprehensive Income (Loss), Net of Tax	8.4	7.7
TOTAL COMPREHENSIVE LOSS	(13.7)	(76.6)
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Freight Revenue	0	0
Revenues	0	0
COST OF GOODS SOLD	0	0
SALES MARGIN	0	0
Selling, general and administrative expenses	(22.8)	(20.1)
Miscellaneous - net	0	(0.2)
Other operating expense	(22.8)	(20.3)
OPERATING INCOME	(22.8)	(20.3)
Interest expense, net	(24.7)	(31.9)
Other non-operating income	(1.4)	(0.9)
TOTAL OTHER INCOME (EXPENSE)	(26.1)	(32.8)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(48.9)	(53.1)
Income Tax Expense (Benefit)	3.9	(15.6)
Equity in income (loss) of subsidiaries	22.9	(15.7)
LOSS FROM CONTINUING OPERATIONS	(22.1)	(84.4)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0.1
NET INCOME (LOSS)	(22.1)	(84.3)
Other Comprehensive Income (Loss), Net of Tax	8.4	7.7
TOTAL COMPREHENSIVE LOSS	(13.7)	(76.6)
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Revenue from Contract with Customer, Including Assessed Tax	145.4	169.2
Freight Revenue	11.6	10.8
Revenues	157	180
COST OF GOODS SOLD	(126.1)	(118.5)
SALES MARGIN	30.9	61.5
Selling, general and administrative expenses	(5.2)	(4.7)
Miscellaneous - net	(3.4)	(5.3)
Other operating expense	(8.6)	(10)
OPERATING INCOME	22.3	51.5
Interest expense, net	(0.5)	(0.8)
Other non-operating income	(3.2)	0.5
TOTAL OTHER INCOME (EXPENSE)	(3.7)	(0.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	18.6	51.2
Income Tax Expense (Benefit)	(0.1)	(0.1)
Equity in income (loss) of subsidiaries	4.4	4.5
LOSS FROM CONTINUING OPERATIONS	22.9	55.6
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(0.1)	0.2
NET INCOME (LOSS)	22.8	55.8
Other Comprehensive Income (Loss), Net of Tax	6.7	5.9
TOTAL COMPREHENSIVE LOSS	29.5	61.7
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Freight Revenue	0	0
Revenues	0	0
COST OF GOODS SOLD	0	0
SALES MARGIN	0	0
Selling, general and administrative expenses	(0.1)	(0.3)
Miscellaneous - net	(0.2)	(0.6)
Other operating expense	(0.3)	(0.9)
OPERATING INCOME	(0.3)	(0.9)
Interest expense, net	0.1	0.3
Other non-operating income	4.7	4.8
TOTAL OTHER INCOME (EXPENSE)	4.8	5.1
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	4.5	4.2
Income Tax Expense (Benefit)	(0.1)	0
Equity in income (loss) of subsidiaries	0	0
LOSS FROM CONTINUING OPERATIONS	4.4	4.2
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0.1	(71.2)
NET INCOME (LOSS)	4.5	(67)
Other Comprehensive Income (Loss), Net of Tax	0	0.8
TOTAL COMPREHENSIVE LOSS	4.5	(66.2)
Consolidation, Eliminations [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Freight Revenue	0	0
Revenues	0	0
COST OF GOODS SOLD	0	0
SALES MARGIN	0	0
Selling, general and administrative expenses	0	0
Miscellaneous - net	0	0
Other operating expense	0	0
OPERATING INCOME	0	0
Interest expense, net	0	0
Other non-operating income	0	0
TOTAL OTHER INCOME (EXPENSE)	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	0	0
Income Tax Expense (Benefit)	0	0
Equity in income (loss) of subsidiaries	(27.3)	11.2
LOSS FROM CONTINUING OPERATIONS	(27.3)	11.2
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0
NET INCOME (LOSS)	(27.3)	11.2
Other Comprehensive Income (Loss), Net of Tax	(6.7)	(6.7)
TOTAL COMPREHENSIVE LOSS	$ (34)	$ 4.5

SUPPLEMENTARY GUARANTOR INFOR_5

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Repurchase of common shares	$ (124.3)	$ 0
Net cash provided (used) by operating activities	(111.2)	(142.9)
Purchase of property, plant and equipment	(132.7)	(12.4)
Deposits for property, plant and equipment	(1.4)	(59)
Intercompany investing	0	0
Other investing activities	8.5	0
Net cash used by investing activities	(125.6)	(71.4)
Dividends paid	(14.8)	0
Repurchase of debt	(10.3)	0
Intercompany financing	0	0
Other financing activities	(8.4)	(7)
Net cash used by financing activities	(157.8)	(7)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	0	0.2
Increase/Decrease in Cash and Cash Equivalents, Including Cash Classified Within Other Current Assets Related to Discontinued Operations	(394.6)	(221.1)
Increase/Decrease in Cash and Cash Equivalents from Discontinued Operations, Classified within Other Current Assets	1.6	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(393)	(221.1)
Cash and cash equivalents	430.2	757.2	$ 823.2	$ 978.3
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Repurchase of common shares	(124.3)
Net cash provided (used) by operating activities	(71.6)	(54.7)
Purchase of property, plant and equipment	(0.3)	0
Deposits for property, plant and equipment	0	0
Intercompany investing	(157.6)	(137.7)
Other investing activities	0
Net cash used by investing activities	(157.9)	(137.7)
Dividends paid	(14.8)
Repurchase of debt	(10.3)
Intercompany financing	0	0
Other financing activities	(14.1)	(2.9)
Net cash used by financing activities	(163.5)	(2.9)
EFFECT OF EXCHANGE RATE CHANGES ON CASH		0
Increase/Decrease in Cash and Cash Equivalents, Including Cash Classified Within Other Current Assets Related to Discontinued Operations	(393)	(195.3)
Increase/Decrease in Cash and Cash Equivalents from Discontinued Operations, Classified within Other Current Assets	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(393)	(195.3)
Cash and cash equivalents	426.8	753.6	819.8	948.9
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Repurchase of common shares	0
Net cash provided (used) by operating activities	(38.4)	(64.7)
Purchase of property, plant and equipment	(132.4)	(12.3)
Deposits for property, plant and equipment	(1.3)	(54.4)
Intercompany investing	(0.4)	(4.8)
Other investing activities	8.4
Net cash used by investing activities	(125.7)	(71.5)
Dividends paid	0
Repurchase of debt	0
Intercompany financing	157.5	135.6
Other financing activities	6.6	(0.5)
Net cash used by financing activities	164.1	135.1
EFFECT OF EXCHANGE RATE CHANGES ON CASH		0
Increase/Decrease in Cash and Cash Equivalents, Including Cash Classified Within Other Current Assets Related to Discontinued Operations	0	(1.1)
Increase/Decrease in Cash and Cash Equivalents from Discontinued Operations, Classified within Other Current Assets	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	(1.1)
Cash and cash equivalents	0.7	1	0.7	2.1
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Repurchase of common shares	0
Net cash provided (used) by operating activities	(1.2)	(23.5)
Purchase of property, plant and equipment	0	(0.1)
Deposits for property, plant and equipment	(0.1)	(4.6)
Intercompany investing	0	0
Other investing activities	0.1
Net cash used by investing activities	0	(4.7)
Dividends paid	0
Repurchase of debt	0
Intercompany financing	0.5	6.9
Other financing activities	(0.9)	(3.6)
Net cash used by financing activities	(0.4)	3.3
EFFECT OF EXCHANGE RATE CHANGES ON CASH		0.2
Increase/Decrease in Cash and Cash Equivalents, Including Cash Classified Within Other Current Assets Related to Discontinued Operations	(1.6)	(24.7)
Increase/Decrease in Cash and Cash Equivalents from Discontinued Operations, Classified within Other Current Assets	1.6	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	(24.7)
Cash and cash equivalents	2.7	2.6	2.7	27.3
Consolidation, Eliminations [Member]
Repurchase of common shares	0
Net cash provided (used) by operating activities	0	0
Purchase of property, plant and equipment	0	0
Deposits for property, plant and equipment	0	0
Intercompany investing	158	142.5
Other investing activities	0
Net cash used by investing activities	158	142.5
Dividends paid	0
Repurchase of debt	0
Intercompany financing	(158)	(142.5)
Other financing activities	0	0
Net cash used by financing activities	(158)	(142.5)
EFFECT OF EXCHANGE RATE CHANGES ON CASH		0
Increase/Decrease in Cash and Cash Equivalents, Including Cash Classified Within Other Current Assets Related to Discontinued Operations	0	0
Increase/Decrease in Cash and Cash Equivalents from Discontinued Operations, Classified within Other Current Assets	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	0
Cash and cash equivalents	$ 0	$ 0	$ 0	$ 0

SUPPLEMENTARY GUARANTOR INFOR_6

SUPPLEMENTARY GUARANTOR INFORMATION (Narrative) (Details) $ in Millions	Mar. 31, 2019USD ($)
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
$1.075 Billion 5.75% 2025 Senior Notes [Member]
Debt Instrument, Par Value	$ 1,075
Debt Instrument, Interest Rate, Stated Percentage	5.75%

Uncategorized Items - clf-20190

Label	Element	Value
Capital Addition Purchase Commitments [Member]
Recorded Unconditional Purchase Obligation	us-gaap_RecordedUnconditionalPurchaseObligation	$ 780,000,000