Cleveland-Cliffs (CLF) 10-Q 23 Oct 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 21, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	1-8944
Entity Registrant Name	CLEVELAND-CLIFFS INC.
Entity Incorporation, State or Country Code	OH
Entity Tax Identification Number	34-1464672
Entity Address, Address Line One	200 Public Square,
Entity Address, City or Town	Cleveland,
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44114-2315
City Area Code	216
Local Phone Number	694-5700
Title of 12(b) Security	Common shares, par value $0.125 per share
Trading Symbol	CLF
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		270,082,088
Entity Central Index Key	0000764065
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false

Statements Of Unaudited Condens

Statements Of Unaudited Condensed Consolidated Financial Position - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
CURRENT ASSETS
Cash and cash equivalents	$ 399.3	$ 823.2
Accounts receivable, net	164.9	226.7
Finished goods inventories	162.2	77.8
Work-in-process inventories	55.2	10.1
Supplies and other inventories	110.8	93.2
Derivative assets	72.8	91.5
Income tax receivable, current	58.7	117.3
Other current assets	40.7	39.8
TOTAL CURRENT ASSETS	1,064.6	1,479.6
PROPERTY, PLANT AND EQUIPMENT, NET	1,769.9	1,286
OTHER ASSETS
Deposits for property, plant and equipment	41.6	83
Income tax receivable, non-current	62.7	121.3
Deferred income taxes	437.5	464.8
Other non-current assets	114.9	94.9
TOTAL OTHER ASSETS	656.7	764
TOTAL ASSETS	3,491.2	3,529.6
CURRENT LIABILITIES
Accounts payable	212.8	186.8
Accrued employment costs	57.3	74
Accrued interest	34.1	38.4
Derivative liabilities	32.6	3.7
Partnership distribution payable	0	43.5
Other current liabilities	121.7	121.8
TOTAL CURRENT LIABILITIES	458.5	468.2
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	233.2	248.7
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	179.1	172
LONG-TERM DEBT	2,109.1	2,092.9
OTHER LIABILITIES	151.4	123.6
TOTAL LIABILITIES	3,131.3	3,105.4
COMMITMENTS AND CONTINGENCIES (REFER TO NOTE 19)
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 - 270,075,445 shares (2018 - 292,611,569 shares)	37.7	37.7
Capital in excess of par value of shares	3,867.7	3,916.7
Retained deficit	(2,889)	(3,060.2)
Cost of 31,811,349 common shares in treasury (2018 - 9,275,225 shares)	(390.9)	(186.1)
Accumulated other comprehensive loss	(265.6)	(283.9)
TOTAL EQUITY	359.9	424.2
TOTAL LIABILITIES AND EQUITY	$ 3,491.2	$ 3,529.6

Statements Of Condensed Consoli

Statements Of Condensed Consolidated Financial Position (Parenthetical) - $ / shares	Sep. 30, 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	270,075,445	292,611,569
Common shares in treasury	31,811,349	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						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
REVENUES FROM PRODUCT SALES AND SERVICES
TOTAL REVENUES	$ 555.6			$ 741.8			$ 1,455.8	$ 1,636.1
COST OF GOODS SOLD	(400.7)			(480.2)			(1,007)	(1,028.5)
SALES MARGIN	154.9			261.6			448.8	607.6
OTHER OPERATING EXPENSE
Selling, general and administrative expenses	(25.5)			(29.1)			(82.2)	(78.9)
Miscellaneous - net	(7.8)			(7)			(19)	(18.7)
Other operating expense	(33.3)			(36.1)			(101.2)	(97.6)
OPERATING INCOME	121.6			225.5			347.6	510
OTHER INCOME (EXPENSE)
Interest expense, net	(25.3)			(29.5)			(76.5)	(93.1)
Gain (loss) on extinguishment of debt				0			(18.2)	0.2
Other non-operating income	0.3			4.3			1.3	13.1
TOTAL OTHER INCOME (EXPENSE)	(25)			(25.2)			(93.4)	(79.8)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	96.6			200.3			254.2	430.2
INCOME TAX EXPENSE	(4.8)			(0.5)			(23.1)	(14.4)
INCOME FROM CONTINUING OPERATIONS	91.8			199.8			231.1	415.8
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.9)			238			(1.5)	102.8
NET INCOME	$ 90.9	$ 160.8	$ (22.1)	$ 437.8	$ 165.1	$ (84.3)	$ 229.6	$ 518.6
EARNINGS (LOSS) PER COMMON SHARE – BASIC
Continuing operations (in dollars per share)	$ 0.34			$ 0.67			$ 0.83	$ 1.40
Discontinued operations (in dollars per share)	0			0.80			(0.01)	0.35
Earnings (Loss) per Common Share - Basic (in dollars per share)	0.34			1.47			0.82	1.75
EARNINGS (LOSS) PER COMMON SHARE – DILUTED
Continuing operations (in dollars per share)	0.33			0.64			0.80	1.37
Discontinued operations (in dollars per share)	0			0.77			0	0.34
Earnings (Loss) per Common Share - Diluted (in dollars per share)	$ 0.33			$ 1.41			$ 0.80	$ 1.71
AVERAGE NUMBER OF SHARES (IN THOUSANDS)
Basic	269,960			297,878			278,418	297,587
Diluted	276,578			310,203			287,755	303,518
Product [Member]
REVENUES FROM PRODUCT SALES AND SERVICES
TOTAL REVENUES	$ 515			$ 684.7			$ 1,357.8	$ 1,525.9
Freight [Member]
REVENUES FROM PRODUCT SALES AND SERVICES
TOTAL REVENUES	$ 40.6			$ 57.1			$ 98	$ 110.2

Statements Of Unaudited Conde_3

Statements Of Unaudited Condensed Consolidated Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 90.9	$ 437.8	$ 229.6	$ 518.6
OTHER COMPREHENSIVE INCOME (LOSS)
Changes in pension and other post-retirement benefits, net of tax	5.8	6.8	17.3	20.2
Changes in foreign currency translation	0	(228.3)	0	(225.4)
Changes in derivative financial instruments, net of tax	0.4	0.3	1	0.8
OTHER COMPREHENSIVE INCOME (LOSS)	6.2	(221.2)	18.3	(204.4)
TOTAL COMPREHENSIVE INCOME	$ 97.1	$ 216.6	$ 247.9	$ 314.2

Statements Of Unaudited Conde_4

Statements Of Unaudited Condensed Consolidated Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
OPERATING ACTIVITIES
NET INCOME	$ 229.6	$ 518.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	63.1	68.6
Deferred income taxes	22.7	0
Loss (gain) on extinguishment of debt	18.2	(0.2)
Change in derivatives	48.4	(136.4)
Gain on foreign currency translation	0	(228.1)
Other	49.4	5.7
Changes in operating assets and liabilities:
Receivables and other assets	156.5	96.2
Inventories	(129.4)	(57.1)
Payables, accrued expenses and other liabilities	(70.4)	(78.6)
Net cash provided by operating activities	388.1	188.7
INVESTING ACTIVITIES
Purchase of property, plant and equipment	(447.9)	(111.4)
Deposits for property, plant and equipment	(12.8)	(83.3)
Other investing activities	11.2	21
Net cash provided (used) by investing activities	(449.5)	(173.7)
FINANCING ACTIVITIES
Repurchase of common shares	(252.9)	0
Dividends paid	(45.1)	0
Proceeds from issuance of debt	720.9	0
Debt issuance costs	(6.8)	(1.5)
Repurchase of debt	(729.3)	(16.3)
Distributions of partnership equity	(44.2)	(44.2)
Other financing activities	(9.5)	(45.7)
Net cash provided (used) by financing activities	(366.9)	(107.7)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	0	(2.3)
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS	(428.3)	(95)
LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS	(4.4)	(13.8)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(423.9)	(81.2)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	823.2	978.3
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 399.3	$ 897.1

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]
Adoption of accounting standard	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)
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		300,000
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	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 (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]
NET INCOME (LOSS)	518.6
Other Comprehensive Income (Loss), Net of Tax	(204.4)
Balance, end of period (in shares) at Sep. 30, 2018		298,000,000
Balance, end of period PY at Sep. 30, 2018	(86.2)	$ 37.7	3,913.3	(3,654.7)	(139.1)	(243.4)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
TOTAL COMPREHENSIVE LOSS	314.2
Balance, beginning of period (in shares) at Mar. 31, 2018		297,700,000
Balance, beginning of period PY at Mar. 31, 2018	(484.8)	$ 37.7	3,918.1	(4,257.6)	(151.9)	(31.3)	0.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME (LOSS)	165.1			165.1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent						9.1
Other Comprehensive Income (Loss), Net of Tax	9.1
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	174.2
Distributions to noncontrolling interest	(0.2)						(0.2)
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		100,000
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	4.5		0.2		4.3
Balance, end of period (in shares) at Jun. 30, 2018		297,800,000
Balance, end of period PY at Jun. 30, 2018	(306.3)	$ 37.7	3,918.3	(4,092.5)	(147.6)	(22.2)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME (LOSS)	437.8			437.8
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent						(221.2)
Other Comprehensive Income (Loss), Net of Tax	(221.2)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	216.6
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		200,000
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	3.5		(5)		8.5
Balance, end of period (in shares) at Sep. 30, 2018		298,000,000
Balance, end of period PY at Sep. 30, 2018	(86.2)	$ 37.7	3,913.3	(3,654.7)	(139.1)	(243.4)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
TOTAL COMPREHENSIVE LOSS	216.6
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
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		1,700,000
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(10)		(56.5)		46.5
Stock Repurchased During Period, Shares		(11,500,000)
Common Share Repurchases, Value	(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		282,800,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
TOTAL COMPREHENSIVE LOSS	(13.7)
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)	$ 229.6
Other Comprehensive Income (Loss), Net of Tax	$ 18.3
Stock Repurchased During Period, Shares	(24,400,000)
Common Share Repurchases, Value	$ (252.9)
Balance, end of period at Sep. 30, 2019	$ 359.9	$ 37.7	3,867.7	(2,889)	(390.9)	(265.6)
Balance, end of period (in shares) at Sep. 30, 2019	270,075,445	270,100,000
Balance, end of period PY at Sep. 30, 2019						(265.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
TOTAL COMPREHENSIVE LOSS	$ 247.9
Balance, beginning of period at Mar. 31, 2019	261.7	$ 37.7	3,860.2	(3,096.8)	(263.9)	(275.5)
Balance, beginning of period (in shares) at Mar. 31, 2019		282,800,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME (LOSS)	160.8			160.8
Other Comprehensive Income (Loss), Net of Tax	3.7					3.7
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		100,000
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	4.6		3.4		1.2
Stock Repurchased During Period, Shares		(12,900,000)
Common Share Repurchases, Value	(128.6)				(128.6)
Dividends, Common Stock	(16.6)			(16.6)
Balance, end of period at Jun. 30, 2019	285.6	$ 37.7	3,863.6	(2,952.6)	(391.3)	(271.8)
Balance, end of period (in shares) at Jun. 30, 2019		270,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
TOTAL COMPREHENSIVE LOSS	164.5
NET INCOME (LOSS)	90.9			90.9
Other Comprehensive Income (Loss), Net of Tax	6.2					6.2
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		100,000
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	4.5		4.1		0.4
Dividends, Common Stock	(27.3)			(27.3)
Balance, end of period at Sep. 30, 2019	$ 359.9	$ 37.7	$ 3,867.7	$ (2,889)	$ (390.9)	(265.6)
Balance, end of period (in shares) at Sep. 30, 2019	270,075,445	270,100,000
Balance, end of period PY at Sep. 30, 2019						$ (265.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
TOTAL COMPREHENSIVE LOSS	$ 97.1

BASIS OF PRESENTATION AND SIGNI

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 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 income, cash flows and changes in equity 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 and nine months ended September 30, 2019 are not necessarily indicative of results to be expected for the year ending December 31, 2019 or any other future period. Certain prior period amounts have been reclassified to conform with the current year presentation. 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 . 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. 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. As a result of our 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 13 - DISCONTINUED OPERATIONS for further information. 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 September 30, 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 September 30, 2019 and December 31, 2018 , our investment in Hibbing was $14.0 million and $15.4 million , respectively, classified as Other liabilities in the Statements of Unaudited Condensed Consolidated Financial Position . Foreign Currency Our financial statements are prepared with the U.S. dollar as the reporting currency and the functional currency of all subsidiaries is the U.S. dollar. In August 2018, management determined that there were significant changes in economic factors related to our Australian subsidiaries. The change in economic factors was a result of the sale and conveyance of substantially all assets and liabilities of our Australian subsidiaries to third parties, representing a significant change in operations. As such, the functional currency for the Australian subsidiaries changed from the Australian dollar to the U.S. dollar, requiring all remaining Australian denominated monetary balances to be remeasured through the Statements of Unaudited Condensed Consolidated Operations . As a result of the liquidation of the Australian subsidiaries' assets, the historical impact of foreign currency translation recorded in Accumulated other comprehensive loss in the Statements of Unaudited Condensed Consolidated Financial Position of $228.1 million was reclassified and recognized as a gain in Income (loss) from discontinued operations, net of tax in the Statements of Unaudited Condensed Consolidated Operations for the three and nine months ended September 30, 2018. Refer to NOTE 13 - DISCONTINUED OPERATIONS for further information regarding our Australian subsidiaries. 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	9 Months Ended
	Sep. 30, 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 are classified as either operating or finance leases. 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, Current Expected Credit Losses ("CECL"). CECL requires earlier recognition of credit losses, while also providing additional transparency about credit risk. CECL utilizes a lifetime expected credit loss measurement objective for the recognition of credit losses 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 do not expect the standard to have a material effect on our consolidated financial statements.

SEGMENT REPORTING

SEGMENT REPORTING	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Reporting Disclosure	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. Our Metallics segment includes our HBI production plant in Toledo, Ohio, which is currently under construction and expected to be completed during the first half of 2020. During the second quarter of 2019, Northshore mine began supplying DR-grade pellets to our Metallics segment, which will be used as feedstock for the HBI production plant when we begin production in 2020. All intersegment sales were eliminated in consolidation. 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 are used by management, investors, lenders and other external users of our financial statements to assess our operating performance and to compare operating performance to other companies in the iron ore industry. In addition, management believes EBITDA and Adjusted EBITDA are useful measures to assess the earnings power of the business without the impact of capital structure and can be used to assess our ability to service debt and fund future capital expenditures in the business. The following tables present a summary of our reportable segments including a reconciliation of segment revenues to total Revenues from product sales and services , segment sales margin to total Sales margin and a reconciliation of Net income to EBITDA and Adjusted EBITDA: (In Millions) Three Months Ended September 30, 2019 Nine Months Ended Mining and Pelletizing Metallics Total Mining and Pelletizing Metallics Total Operating segment revenues from product sales and services $ 590.6 $ — $ 590.6 $ 1,494.8 $ — $ 1,494.8 Elimination of intersegment revenues (35.0 ) — (35.0 ) (39.0 ) — (39.0 ) Total revenues from product sales and services $ 555.6 $ — $ 555.6 $ 1,455.8 $ — $ 1,455.8 Operating segment sales margin $ 165.8 $ — $ 165.8 $ 461.3 $ — $ 461.3 Elimination of intersegment sales margin (10.9 ) — (10.9 ) (12.5 ) — (12.5 ) Total sales margin $ 154.9 $ — $ 154.9 $ 448.8 $ — $ 448.8 Revenues from product sales and services of $741.8 million and $1,636.1 million , respectively, and sales margin of $261.6 million and $607.6 million , respectively, related to our Mining and Pelletizing segment accounted for all of our consolidated revenues and sales margin for the three and nine months ended September 30, 2018 . (In Millions) Three Months Ended Nine Months Ended 2019 2018 2019 2018 Net income $ 90.9 $ 437.8 $ 229.6 $ 518.6 Less: Interest expense, net (25.4 ) (29.7 ) (76.8 ) (95.5 ) Income tax expense (4.8 ) (0.5 ) (23.1 ) (14.4 ) Depreciation, depletion and amortization (22.2 ) (19.2 ) (63.1 ) (68.6 ) EBITDA $ 143.3 $ 487.2 $ 392.6 $ 697.1 Less: Impact of discontinued operations $ (0.8 ) $ 238.2 $ (1.2 ) $ 120.4 Gain (loss) on extinguishment of debt — — (18.2 ) 0.2 Severance costs — — (1.7 ) — Foreign exchange remeasurement — (0.2 ) — (0.7 ) Impairment of long-lived assets — (1.1 ) — (1.1 ) Adjusted EBITDA $ 144.1 $ 250.3 $ 413.7 $ 578.3 EBITDA: Mining and Pelletizing $ 177.5 $ 273.1 $ 494.9 $ 641.6 Metallics (2.1 ) (1.0 ) (4.0 ) (2.5 ) Corporate and Other (including discontinued operations) (32.1 ) 215.1 (98.3 ) 58.0 Total EBITDA $ 143.3 $ 487.2 $ 392.6 $ 697.1 Adjusted EBITDA: Mining and Pelletizing $ 182.7 $ 279.5 $ 510.7 $ 657.9 Metallics (2.1 ) (1.0 ) (4.0 ) (2.5 ) Corporate (36.5 ) (28.2 ) (93.0 ) (77.1 ) Total Adjusted EBITDA $ 144.1 $ 250.3 $ 413.7 $ 578.3 The following table summarizes our depreciation, depletion and amortization and capital additions: (In Millions) Three Months Ended Nine Months Ended 2019 2018 2019 2018 Depreciation, depletion and amortization: Mining and Pelletizing $ 20.8 $ 17.8 $ 58.9 $ 49.2 Corporate 1.4 1.4 4.2 4.2 Total depreciation, depletion and amortization $ 22.2 $ 19.2 $ 63.1 $ 53.4 Capital additions 1 : Mining and Pelletizing $ 22.1 $ 51.8 $ 104.5 $ 97.2 Metallics 160.5 40.6 398.0 143.6 Corporate 2.1 0.2 3.1 1.1 Total capital additions $ 184.7 $ 92.6 $ 505.6 $ 241.9 1 Refer to NOTE 16 - CASH FLOW INFORMATION for additional information. A summary of assets by segment is as follows: (In Millions) September 30, December 31, Assets: Mining and Pelletizing $ 1,793.9 $ 1,694.1 Metallics 708.5 265.9 Total segment assets 2,502.4 1,960.0 Corporate and Other (including discontinued operations) 988.8 1,569.6 Total assets $ 3,491.2 $ 3,529.6

REVENUE

REVENUE	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	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 PPI, 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 12 - DERIVATIVE INSTRUMENTS for further information on how our estimated and final revenue rates are determined. A supply agreement with one customer provides for supplemental revenue or refunds based on the hot-rolled coil steel price in the year the iron ore is consumed in the customer’s blast furnaces. As control transfers prior to consumption, the supplemental revenue or refunds are recorded in accordance with ASC Topic 815. Refer to NOTE 12 - DERIVATIVE INSTRUMENTS for further information on supplemental revenue or refunds. Included within Revenues from product sales and services related to Topic 815 is a derivative loss of $40.9 million and a derivative gain of $43.4 million for the three and nine months ended September 30, 2019 , respectively, and derivative gains of $135.9 million and $334.4 million for the three and nine months ended September 30, 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 September 30 18.3 16.1 30.0 42.8 Decrease $ (2.7 ) $ (7.7 ) $ (8.5 ) $ (8.6 ) 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 September 30, 2019 and December 31, 2018 , installment amounts received in excess of sales totaled $42.8 million and $51.3 million , respectively, related to this agreement. As of September 30, 2019 and December 31, 2018 , deferred revenue of $12.8 million was recorded in Other current liabilities and $30.0 million and $38.5 million , respectively, 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 $5.5 million and $8.2 million was deferred and included in Other current liabilities in the Statements of Unaudited Condensed Consolidated Financial Position as of September 30, 2019 and December 31, 2018

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	9 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	NOTE 5 - PROPERTY, PLANT AND EQUIPMENT The following table indicates the carrying value of each of the major classes of our depreciable assets: (In Millions) September 30, December 31, Land rights and mineral rights $ 549.7 $ 549.6 Office and information technology 72.9 70.0 Buildings 101.2 87.2 Mining equipment 577.0 548.5 Processing equipment 755.5 645.8 Electric power facilities 58.7 58.7 Land improvements 23.8 23.8 Asset retirement obligation 14.8 14.8 Other 29.2 25.2 Construction-in-progress 668.9 284.8 2,851.7 2,308.4 Allowance for depreciation and depletion (1,081.8 ) (1,022.4 ) $ 1,769.9 $ 1,286.0 We recorded capitalized interest into property, plant and equipment of $7.0 million and $16.9 million for the three and nine months ended September 30, 2019 , respectively, and $1.8 million and $3.9 million for the three and nine months ended September 30, 2018 , respectively.

DEBT AND CREDIT FACILITIES

DEBT AND CREDIT FACILITIES	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
DEBT AND CREDIT FACILITIES	NOTE 6 - DEBT AND CREDIT FACILITIES The following represents a summary of our long-term debt: (In Millions) September 30, 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 $ (4.9 ) $ (1.9 ) $ 393.2 Unsecured Notes: $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (4.8 ) (67.7 ) 243.8 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 473.3 (3.8 ) (5.8 ) 463.7 $750 Million 5.875% 2027 Senior Notes 6.49% 750.0 (6.5 ) (28.0 ) 715.5 $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 — Long-term debt $ 2,109.1 (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 $750 Million 5.875% Senior Notes due 2027 Offering On May 13, 2019, we entered into an indenture among the Company, the guarantors party thereto and U.S. Bank National Association, as trustee, relating to the issuance of $750 million aggregate principal amount of 5.875% 2027 Senior Notes. The 5.875% 2027 Senior Notes were issued at 96.125% of face value. The 5.875% 2027 Senior Notes were issued in a private transaction exempt from the registration requirements of the Securities Act of 1933. Pursuant to the registration rights agreement executed as part of this offering, we agreed to file a registration statement with the SEC with respect to a registered offer to exchange the 5.875% 2027 Senior Notes for publicly registered notes within 365 days of the closing date, with all significant terms and conditions remaining the same. The 5.875% 2027 Senior Notes bear interest at a rate of 5.875% per annum, payable semi-annually in arrears on June 1 and December 1 of each year, commencing on December 1, 2019. The 5.875% 2027 Senior Notes mature on June 1, 2027. The 5.875% 2027 Senior Notes are unsecured obligations and rank equally in right of payment with all of our existing and future unsecured and unsubordinated indebtedness. The 5.875% 2027 Senior Notes are guaranteed on a senior unsecured basis by our material direct and indirect wholly-owned domestic subsidiaries and, therefore, are structurally senior to any of our existing and future indebtedness that is not guaranteed by such guarantors and are structurally subordinated to all existing and future indebtedness and other liabilities of our subsidiaries that do not guarantee the 5.875% 2027 Senior Notes. The 5.875% 2027 Senior Notes may be redeemed, in whole or in part, at any time at our option not less than 30 days nor more than 60 days after prior notice is sent to the holders of the 5.875% 2027 Senior Notes. The following is a summary of redemption prices for our 5.875% 2027 Senior Notes: Redemption Period Redemption Price 1 Restricted Amount Prior to June 1, 2022 - using proceeds of equity issuance 105.875 % Up to 35% of original aggregate principal Prior to June 1, 2022 2 100.000 Beginning on June 1, 2022 102.938 Beginning on June 1, 2023 101.958 Beginning on June 1, 2024 100.979 Beginning on June 1, 2025 and thereafter 100.000 1 Plus accrued and unpaid interest, if any, up to but excluding the redemption date. 2 Plus a "make-whole" premium. In addition, if a change in control triggering event, as defined in the indenture, occurs with respect to the 5.875% 2027 Senior Notes, we will be required to offer to purchase the notes at a purchase price equal to 101% of the aggregate principal amount, plus accrued and unpaid interest, if any, to, but not including, the date of purchase. The terms of the 5.875% 2027 Senior Notes contain certain customary covenants; however, there are no financial covenants. Debt issuance costs of $6.8 million were incurred related to the offering of the 5.875% 2027 Senior Notes and are included in Long-term debt in the Statements of Unaudited Condensed Consolidated Financial Position . Debt Extinguishments - 2019 The net proceeds from the issuance of $750 million aggregate principal amount of 5.875% 2027 Senior Notes, along with cash on hand, were used to redeem in full all of our outstanding 4.875% 2021 Senior Notes and to fund the repurchase of $600 million aggregate principal amount of our outstanding 5.75% 2025 Senior Notes in a tender offer. The following is a summary of the debt extinguished and the respective loss on extinguishment: (In Millions) Nine Months Ended September 30, 2019 Debt Instrument Debt Extinguished (Loss) on Extinguishment $700 Million 4.875% 2021 Senior Notes $ 124.0 $ (5.3 ) $1.075 Billion 5.75% 2025 Senior Notes 600.0 (12.9 ) $ 724.0 $ (18.2 ) Debt Extinguishments - 2018 The following is a summary of the debt extinguished with cash and the respective gain on extinguishment: (In Millions) Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Debt Instrument Debt Extinguished Gain on Extinguishment Debt Extinguished Gain on Extinguishment $400 Million 5.90% 2020 Senior Notes $ — $ — $ 0.5 $ — $500 Million 4.80% 2020 Senior Notes — — 0.1 — $700 Million 4.875% 2021 Senior Notes 1.0 — 14.2 0.1 $1.075 Billion 5.75% 2025 Senior Notes — — 1.7 0.1 $ 1.0 $ — $ 16.5 $ 0.2 Debt Maturities The following represents a summary of our maturities of debt instruments based on the principal amounts outstanding at September 30, 2019 : (In Millions) Maturities of Debt 2019 $ — 2020 — 2021 — 2022 — 2023 — 2024 400.0 2025 and thereafter 1,838.0 Total maturities of debt $ 2,238.0 ABL Facility The following represents a summary of our borrowing capacity under the ABL Facility: (In Millions) September 30, 2019 December 31, 2018 Available borrowing base on ABL Facility 1 $ 400.8 $ 323.7 Letter of credit obligations 2 (34.1 ) (55.0 ) Borrowing capacity available 3 $ 366.7 $ 268.7 1 The ABL Facility has a maximum borrowing base of $450 million. The available borrowing base is determined by applying customary advance rates to eligible accounts receivable, inventory and certain mobile equipment. 2 We issued standby letters of credit with certain financial institutions in order to support business obligations including, but not limited to, workers compensation and environmental obligations. 3 As of September 30, 2019 and December 31, 2018, we had no loans drawn under the ABL Facility.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	NOTE 7 - FAIR VALUE MEASUREMENTS The following represents the assets and liabilities measured at fair value: (In Millions) September 30, 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 $ — $ 272.5 $ — $ 272.5 Derivative assets — — 72.8 72.8 Total $ — $ 272.5 $ 72.8 $ 345.3 Liabilities: Derivative liabilities $ — $ 2.4 $ 30.2 $ 32.6 Total $ — $ 2.4 $ 30.2 $ 32.6 (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 consist of a freestanding derivative instrument 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 hot-rolled coil steel price in the year the iron ore product is consumed in the customer’s blast furnaces. We account for these provisions as a derivative instrument at the time of sale and adjust the derivative instrument to fair value through Product revenues each reporting period until the product is consumed and the amounts are settled. We had assets of $71.2 million and $89.3 million at September 30, 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 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 instrument 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 $1.6 million and $2.1 million related to provisional pricing arrangements at September 30, 2019 and December 31, 2018 , respectively. In addition, we had liabilities of $30.2 million related to provisional pricing arrangements at September 30, 2019 . The following table illustrates information about qualitative and 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 September 30, 2019 Balance Sheet Location Valuation Technique Unobservable Input Range or Point Estimate (Weighted Average) Customer supply agreement $ 71.2 Derivative assets Market Approach Management's Estimate of Hot-Rolled Coil Steel Price per net ton $631 - $700 Provisional pricing arrangements $ 1.6 Derivative assets Market Approach Management's Estimate of Platts 62% Price per dry metric ton for respective contract period $100 Provisional pricing arrangements $ 30.2 Derivative liabilities Market Approach PPI Estimates 172 - 214 Management's Estimate of Platts 62% Price per dry metric ton for respective contract period $87 - $100 Atlantic Basin Pellet Premium per metric ton $59 The significant unobservable input used in the fair value measurement of our customer supply agreement is a forward-looking estimate of the hot-rolled coil steel price determined by management. The significant unobservable inputs used in the fai r value m easurement of our provisional pricing arrangements for our derivative assets and liabilities include management's estimate of Platts 62% Price based upon current market data and index pricing, which includes forward-looking estimates determined by management. Our significant unobservable inputs used in the fair value measurement of our provisional pricing arrangements for our derivative liabilities also include estimates for PPI data and the Atlantic Basin pellet premium. The following tables reconcile 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 Nine Months Ended 2019 2018 2019 2018 Beginning balance $ 118.1 $ 174.6 $ 91.4 $ 49.5 Total gains (losses) included in earnings (6.5 ) 139.0 83.1 341.8 Settlements (38.8 ) (123.0 ) (101.7 ) (200.7 ) Ending balance - September 30 $ 72.8 $ 190.6 $ 72.8 $ 190.6 Total gains (losses) for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ (6.5 ) $ 15.9 $ 81.8 $ 141.0 (In Millions) Level 3 Liabilities Three Months Ended Nine Months Ended 2019 2018 2019 2018 Beginning balance $ — $ (3.0 ) $ — $ (1.7 ) Total losses included in earnings (34.4 ) (3.1 ) (39.7 ) (7.4 ) Settlements 4.2 0.4 9.5 3.4 Ending balance - September 30 $ (30.2 ) $ (5.7 ) $ (30.2 ) $ (5.7 ) Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (30.2 ) $ (2.7 ) $ (30.2 ) $ (5.7 ) 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) September 30, 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 $ 393.2 $ 408.9 $ 392.1 $ 370.2 Unsecured Notes $700 Million 4.875% 2021 Senior Notes Level 1 — — 123.8 122.3 $316.25 Million 1.50% 2025 Convertible Senior Notes Level 1 243.8 345.8 235.2 352.4 $1.075 Billion 5.75% 2025 Senior Notes Level 1 463.7 466.2 1,048.8 962.0 $750 Million 5.875% 2027 Senior Notes Level 1 715.5 712.2 — — $800 Million 6.25% 2040 Senior Notes Level 1 292.9 254.4 292.8 232.8 ABL Facility Level 2 — — — — Fair value adjustment to interest rate hedge Level 2 — — 0.2 0.2 Total long-term debt $ 2,109.1 $ 2,187.5 $ 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	9 Months Ended
	Sep. 30, 2019
Postemployment Benefits [Abstract]
PENSIONS AND OTHER POSTRETIREMENT BENEFITS	NOTE 8 - 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. On August 12, 2019, Cliffs Mining Company, our subsidiary, ceased performing manager duties at Hibbing and transitioned those duties to ArcelorMittal. In connection with this transition, Cliffs Mining Company and ArcelorMittal entered into a transition agreement, pursuant to which the Ore Mining Companies Pension Plan previously sponsored by Cliffs Mining Company is now sponsored by ArcelorMittal Hibbing Management LLC. In connection with the transfer of manager duties at Hibbing, Hibbing employees previously employed by Cliffs Mining Company concluded their employment and became employed by an ArcelorMittal controlled group entity. All non-Hibbing active and retired participants were transferred to our salaried pension plan. This transition did not have a material impact on our consolidated financial statements in the three or nine months ended September 30, 2019 . The following are the components of defined benefit pension and OPEB costs: Defined Benefit Pension Costs (In Millions) Three Months Ended Nine Months Ended 2019 2018 2019 2018 Service cost $ 4.6 $ 4.7 $ 12.9 $ 14.0 Interest cost 8.9 7.6 26.2 22.7 Expected return on plan assets (13.7 ) (15.0 ) (41.0 ) (45.0 ) Amortization: Prior service costs 0.3 0.6 0.9 1.7 Net actuarial loss 5.9 5.3 17.7 15.9 Net periodic benefit cost $ 6.0 $ 3.2 $ 16.7 $ 9.3 Other Postretirement Employment Benefits Credits (In Millions) Three Months Ended Nine Months Ended 2019 2018 2019 2018 Service cost $ 0.5 $ 0.6 $ 1.3 $ 1.6 Interest cost 2.3 2.1 7.0 6.2 Expected return on plan assets (4.2 ) (4.6 ) (12.6 ) (13.8 ) Amortization: Prior service credits (0.5 ) (0.7 ) (1.5 ) (2.2 ) Net actuarial loss 1.3 1.3 3.8 3.8 Net periodic benefit credit $ (0.6 ) $ (1.3 ) $ (2.0 ) $ (4.4 ) Based on funding requirements, we made defined benefit pension contributions of $5.6 million and $12.3 million for the three and nine months ended September 30, 2019 , respectively, compared to defined benefit pension contributions of $18.3 million and $23.9 million for the three and nine months ended September 30, 2018 , respectively. 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 and nine months ended September 30, 2019 and 2018 .

STOCK COMPENSATION PLANS

STOCK COMPENSATION PLANS	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock Compensation Plans	NOTE 9 - 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 historical and projected share 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 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	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 10 - INCOME TAXES Our 2019 estimated annual effective tax rate before discrete items as of September 30, 2019 is 9.6% . The estimated annual effective tax rate differs from the U.S. statutory rate of 21.0% primarily due to the deduction for percentage depletion in excess of cost depletion related to our Mining and Pelletizing segment operations. The 2018 estimated annual effective tax rate before discrete items as of September 30, 2018 was 0.1% , which was significantly lower due to the reversal of valuation allowances in the same period. For the three and nine months ended September 30, 2019 , we recorded discrete items that resulted in an income tax benefit of $0.5 million and $1.3 million , respectively. For the three and nine months ended September 30, 2018, we recorded discrete items that resulted in an income tax expense of $0.2 million and $13.9 million , respectively. The $13.9 million expense relates primarily to a $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

ENVIRONMENTAL AND MINE CLOSURE

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	9 Months Ended
	Sep. 30, 2019
Environmental Remediation Obligations [Abstract]
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	NOTE 11 - ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS The following is a summary of our environmental and mine closure obligations: (In Millions) September 30, December 31, Environmental $ 2.1 $ 2.5 Mine closure 1 179.5 172.4 Total environmental and mine closure obligations 181.6 174.9 Less current portion 2.5 2.9 Long-term environmental and mine closure obligations $ 179.1 $ 172.0 1 Includes our active operating mines, our indefinitely idled Empire mine and a closed mine formerly operating as LTV Steel Mining Company. 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 mine sites was determined based on the exhaustion date of the remaining iron ore reserves. The amortization of the related asset and accretion of the liability is recognized over the estimated mine lives for our active operations. 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 following is a roll forward of our mine closure obligation liability: (In Millions) Nine Months Ended September 30, 2019 Year Ended December 31, 2018 Asset retirement obligation at beginning of period $ 172.4 $ 168.4 Accretion expense 7.6 9.5 Remediation payments (0.5 ) (1.0 ) Revision in estimated cash flows — (4.5 ) Asset retirement obligation at end of period $ 179.5 $ 172.4

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	NOTE 12 - 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 September 30, 2019 December 31, 2018 September 30, 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 $ 0.1 Derivative liabilities $ 2.4 Derivative liabilities $ 3.7 Derivatives not designated as hedging instruments under ASC 815: Customer supply agreement Derivative assets $ 71.2 Derivative assets $ 89.3 $ — $ — Provisional pricing arrangements Derivative assets 1.6 Derivative assets 2.1 Derivative liabilities 30.2 — Total derivatives not designated as hedging instruments under ASC 815 $ 72.8 $ 91.4 $ 30.2 $ — Total derivatives $ 72.8 $ 91.5 $ 32.6 $ 3.7 Derivatives Designated as Hedging Instruments - Cash Flow Hedges Commodity Contracts The following table presents our outstanding hedge contracts: (In Millions) September 30, 2019 December 31, 2018 Notional Amount Unit of Measure Varying Maturity Dates Notional Amount Unit of Measure Varying Maturity Dates Natural gas 7.0 MMBtu October 2019 - November 2020 1.8 MMBtu January 2019 - August 2019 Diesel 2.4 Gallons October 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 hot-rolled coil steel price at the time the iron ore product is consumed in the customer’s blast furnaces. The supplemental pricing is characterized as a freestanding derivative instrument 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 price is 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 PPI, 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 sales contract and are integral to the host sales 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 Topic 815 and is characterized as a derivative instrument 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 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 Nine Months Ended 2019 2018 2019 2018 Customer supply agreements Product revenues $ 7.6 $ 139.7 $ 82.2 $ 337.1 Provisional pricing arrangements Product revenues (48.5 ) (3.8 ) (38.8 ) (2.7 ) Total $ (40.9 ) $ 135.9 $ 43.4 $ 334.4 Refer to NOTE 7 - FAIR VALUE MEASUREMENTS for additional information.

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	NOTE 13 - 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 Income (loss) from discontinued operations, net of tax and the Statements of Unaudited Condensed Consolidated Financial Position present the assets and liabilities that were reclassified from the specified line items to Other current assets , Other current liabilities and Other liabilities . The charts below provide an asset group breakout for each financial statement line impacted by discontinued operations. (In Millions) Three Months Ended September 30, Nine Months Ended 2019 2018 2019 2018 Income (loss) from discontinued operations, net of tax Asia Pacific Iron Ore $ (0.1 ) $ 242.3 $ (1.1 ) $ 117.6 North American Coal (0.8 ) (4.3 ) (0.4 ) (4.2 ) Canadian Operations — — — (10.6 ) $ (0.9 ) $ 238.0 $ (1.5 ) $ 102.8 (In Millions) Nine Months Ended 2019 2018 Net cash used by operating activities Asia Pacific Iron Ore $ (1.9 ) $ (77.0 ) Canadian Operations — (14.6 ) $ (1.9 ) $ (91.6 ) Net cash provided by investing activities Asia Pacific Iron Ore $ 0.1 $ 17.8 $ 0.1 $ 17.8 For the nine months ended September 30, 2018, we had $27.1 million of non-cash financing activities related to the release of asset retirement obligations at Asia Pacific Iron Ore as part of the sale of substantially all remaining assets. 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 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. Income ( Loss) from Discontinued Operations (In Millions) Three Months Ended September 30, Nine Months Ended Income (Loss) from Discontinued Operations 2019 2018 2019 2018 Revenues from product sales and services $ — $ — $ — $ 129.1 Cost of goods sold — (0.5 ) — (230.7 ) Sales margin — (0.5 ) — (101.6 ) Other operating expense — 14.8 (0.8 ) (4.0 ) Other expense (0.1 ) (0.1 ) (0.3 ) (2.3 ) Gain on foreign currency translation — 228.1 — 228.1 Impairment of long-lived assets — — — (2.6 ) Income (loss) from discontinued operations, net of tax $ (0.1 ) $ 242.3 $ (1.1 ) $ 117.6 Gain on Foreign Currency Translation As a result of the liquidation of the Australian subsidiaries' net assets, the historical changes in foreign currency translation recorded in Accumulated other comprehensive loss in the Statements of Unaudited Condensed Consolidated Financial Position totaling $228.1 million was reclassified and recognized as a gain in Income (loss) from discontinued operations, net of tax in the Statements of Unaudited Condensed Consolidated Operations for the three and nine months ended September 30, 2018. Canadian Operations During 2015, we announced that the Bloom Lake Group and the Wabush Group commenced restructuring proceedings in Montreal, Quebec under the CCAA to address the immediate liquidity issues and to preserve and protect their assets for the benefit of all stakeholders while restructuring and/or sale options were explored. The Bloom Lake Group and the Wabush Group filed a joint plan of compromise and arrangement that was approved by the required majorities of each unsecured creditor class and was sanctioned by the Court in June 2018. During July 2018, amendments were made to the plan to address the manner in which certain distributions under the plan would be effected and the plan was implemented. During the third quarter of 2018, under the terms of the amended plan, we and certain of our wholly-owned subsidiaries made a C$19.0 million cash contribution to the Wabush Group pension plans and agreed to contribute into the CCAA estate any remaining distributions or payments we may be entitled to receive as creditors of the Bloom Lake Group and the Wabush Group for distribution to other creditors. The original plan did not resolve certain employee claims asserted against us and certain of our affiliates outside of the CCAA proceedings. The amended plan resolved those employee claims, all claims by the Bloom Lake Group, the Wabush Group and their respective creditors against us as well as all of our claims against the Bloom Lake Group and the Wabush Group.

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
SHAREHOLDERS' EQUITY	NOTE 14 - SHAREHOLDERS' EQUITY Share Repurchase Program On November 26, 2018, we announced a program to repurchase outstanding common shares in the open market or in privately negotiated transactions, up to a maximum of $200 million , excluding commissions and fees. On April 24, 2019, we announced that our Board of Directors increased the common share repurchase authorization by an additional $100 million , excluding commissions and fees. During the nine months ended September 30, 2019 , we repurchased 24.4 million common shares at a cost of $252.9 million in the aggregate, including commissions and fees. As of September 30, 2019 , there was $0.2 million available under the authorization. The share repurchase program is effective until December 31, 2019. Dividends On September 3, 2019, our Board of Directors declared a regular quarterly cash dividend on our common shares of $0.06 per share. In addition, on September 3, 2019, our Board of Directors declared a special cash dividend of $0.04 per share, for a total dividend distribution of $0.10 per share. We have accrued dividends recorded of $28.2 million in Other current liabilities in the Statements of Unaudited Condensed Consolidated Financial Position as of September 30, 2019 . Subsequent to quarter end, on October 15, 2019, both the regular and special cash dividends were paid to shareholders of record as of the close of business on October 4, 2019. On May 31, 2019, our Board of Directors declared a quarterly cash dividend on our common shares of $0.06 per share. The cash dividend was paid on July 15, 2019, to our shareholders of record as of the close of business on July 5, 2019. On each of October 18, 2018 and February 19, 2019, our Board of Directors declared a quarterly cash dividend on our common shares of $0.05 per share. The cash dividends were paid on January 15, 2019 and April 15, 2019, to our shareholders of record as of the close of business on January 4, 2019 and April 5, 2019, respectively.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Comprehensive Income (Loss) Note [Text Block]	NOTE 15 - 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 ) Other comprehensive income (loss) before reclassifications 0.3 (2.3 ) (2.0 ) Net loss reclassified from accumulated other comprehensive loss 5.5 0.2 5.7 June 30, 2019 $ (269.6 ) $ (2.2 ) $ (271.8 ) Other comprehensive income (loss) before reclassifications 0.3 (0.5 ) (0.2 ) Net loss reclassified from accumulated other comprehensive loss 5.5 0.9 6.4 September 30, 2019 $ (263.8 ) $ (1.8 ) $ (265.6 ) (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 ) Other comprehensive income before reclassifications 0.2 2.2 0.2 2.6 Net loss reclassified from accumulated other comprehensive loss 6.5 — — 6.5 June 30, 2018 $ (250.5 ) $ 228.3 $ — $ (22.2 ) Other comprehensive income (loss) before reclassifications 0.3 (0.2 ) 0.2 0.3 Net loss (gain) reclassified from accumulated other comprehensive loss 6.5 (228.1 ) 0.1 (221.5 ) September 30, 2018 $ (243.7 ) $ — $ 0.3 $ (243.4 ) The following table reflects the details about Accumulated other comprehensive loss components related to 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 Nine Months Ended 2019 2018 2019 2018 Amortization of pension and OPEB liability: Prior service credits $ (0.2 ) $ (0.1 ) $ (0.6 ) $ (0.5 ) Other non-operating income Net actuarial loss 7.2 6.6 21.5 19.7 Other non-operating income $ 7.0 $ 6.5 $ 20.9 $ 19.2 (1.5 ) — (4.4 ) — Income tax expense $ 5.5 $ 6.5 $ 16.5 $ 19.2 Net of taxes Changes in foreign currency translation: Gain on foreign currency translation $ — $ (228.1 ) $ — $ (228.1 ) Income (loss) from discontinued operations, net of tax $ — $ (228.1 ) $ — $ (228.1 ) Unrealized loss (gain) on derivative financial instruments: Commodity contracts $ 1.2 $ 0.1 $ 1.7 $ — Cost of goods sold (0.3 ) — (0.4 ) — Income tax expense $ 0.9 $ 0.1 $ 1.3 $ — Net of taxes Total reclassifications for the period, net of tax $ 6.4 $ (221.5 ) $ 17.8 $ (208.9 )

CASH FLOW INFORMATION

CASH FLOW INFORMATION	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Information [Abstract]
Cash Flow Information	NOTE 16 - CASH FLOW INFORMATION A reconciliation of capital additions to cash paid for capital expenditures is as follows: (In Millions) Nine Months Ended September 30, 2019 2018 Capital additions 1 $ 505.6 $ 242.0 Less: Non-cash accruals 26.1 42.2 Right-of-use assets – finance leases 29.3 7.6 Grants (10.5 ) (2.5 ) Cash paid for capital expenditures including deposits $ 460.7 $ 194.7 1 Includes capital additions related to discontinued operations of $0.1 million, for the nine months ended September 30, 2018. Non-Cash Financing Activities - Declared Dividends On September 3, 2019, our Board of Directors declared a regular quarterly and special cash dividend on our common shares, for a total of $0.10 per share. The cash dividend of $27.0 million was paid on Octobe r 15, 2019

RELATED PARTIES

RELATED PARTIES	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
RELATED PARTIES	NOTE 17 - RELATED PARTIES Hibbing is a co-owned joint venture with companies that are integrated steel producers or their subsidiaries. In 2018, we tendered our resignation as the mine manager of the Hibbing mine and we transitioned this role to the majority owner in August 2019. The following is a summary of the mine ownership of the co-owned iron ore mine at September 30, 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 Nine Months Ended 2019 2018 2019 2018 Product revenues from related parties $ 262.0 $ 392.4 $ 718.9 $ 863.8 Total product revenues $ 515.0 $ 684.7 $ 1,357.8 $ 1,525.9 Related party product revenue as a percent of total product revenue 50.9 % 57.3 % 52.9 % 56.6 % 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 September 30, 2019 December 31, 2018 Accounts receivable, net $ 108.7 $ 176.0 Derivative assets 71.2 89.3 Other current assets 0.2 — Derivative liabilities (26.1 ) — Partnership distribution payable — (43.5 ) Other current liabilities (1.4 ) (1.8 ) $ 152.6 $ 220.0 A supply agreement with one customer provides for supplemental revenue or refunds to the customer based on the hot-rolled coil steel price at the time the product is consumed in the customer’s blast furnaces. The supplemental pricing is characterized as a freestanding derivative. Refer to NOTE 12 - 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 balance of which was recorded in Partnership distribution payable in the Statements of Unaudited Condensed Consolidated Financial Position

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
EPS AND OTHER NON-GAAP FINANCIAL MEASURES	NOTE 18 - 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 Nine Months Ended 2019 2018 2019 2018 Income from continuing operations $ 91.8 $ 199.8 $ 231.1 $ 415.8 Income (loss) from discontinued operations, net of tax (0.9 ) 238.0 (1.5 ) 102.8 Net income $ 90.9 $ 437.8 $ 229.6 $ 518.6 Weighted average number of shares: Basic 270.0 297.9 278.4 297.6 Convertible senior notes 3.7 8.0 5.8 1.9 Employee stock plans 2.9 4.3 3.6 4.0 Diluted 276.6 310.2 287.8 303.5 Earnings (loss) per common share - basic: Continuing operations $ 0.34 $ 0.67 $ 0.83 $ 1.40 Discontinued operations — 0.80 (0.01 ) 0.35 $ 0.34 $ 1.47 $ 0.82 $ 1.75 Earnings (loss) per common share - diluted: Continuing operations $ 0.33 $ 0.64 $ 0.80 $ 1.37 Discontinued operations — 0.77 — 0.34 $ 0.33 $ 1.41 $ 0.80 $ 1.71

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	NOTE 19 - COMMITMENTS AND CONTINGENCIES Purchase Commitments HBI production plant In 2017, we began to incur capital commitments related to the construction of our HBI production plant in Toledo, Ohio. We now expect to reach commercial production ahead of schedule, in the first half of 2020. Due to the advanced construction timeline and more certain visibility of the start–up date, a portion of the budgeted contingency has been allocated. In total, we expect to spend approximately $830 million plus a contingency of up to 20% on the HBI production plant, excluding capitalized interest, through 2020. As of September 30, 2019, we have contracts and purchase orders in place for approximately $390 million . We expect cash capital expenditures of approximately $180 million during the remaining three months of 2019 and approximately $245 million during 2020. Contingencies

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	NOTE 20 - SUBSEQUENT EVENTS We have evaluated subsequent events through the date of financial statement issuance.

SUPPLEMENTARY GUARANTOR INFORMA

SUPPLEMENTARY GUARANTOR INFORMATION	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Guarantor Information [Text Block]	NOTE 21 - 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 5.75% 2025 Senior Notes and the 5.875% 2027 Senior Notes issued by Cleveland-Cliffs Inc. See NOTE 6 - 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 September 30, 2019 and December 31, 2018 . The unaudited condensed consolidating financial information is presented as if the Guarantor structure at September 30, 2019 existed for all periods presented. Each of the Guarantor subsidiaries fully and unconditionally guarantees, on a joint and several basis, the obligations of Cleveland-Cliffs Inc. under the 5.75% 2025 Senior Notes and the 5.875% 2027 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 indentures governing the 5.75% 2025 Senior Notes and the 5.875% 2027 Senior Notes (the “Indentures”) 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) designation of any Guarantor subsidiary as an “excluded subsidiary” (as defined in the Indentures); or (c) defeasance or satisfaction and discharge of the Indentures. 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 September 30, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 396.2 $ 0.4 $ 2.7 $ — $ 399.3 Accounts receivable, net 7.4 161.4 0.2 (4.1 ) 164.9 Finished goods inventories — 162.2 — — 162.2 Work-in-process inventories — 55.2 — — 55.2 Supplies and other inventories — 110.8 — — 110.8 Derivative assets — 72.8 — — 72.8 Income tax receivable, current 58.7 — — — 58.7 Other current assets 9.3 22.9 8.5 — 40.7 TOTAL CURRENT ASSETS 471.6 585.7 11.4 (4.1 ) 1,064.6 PROPERTY, PLANT AND EQUIPMENT, NET 12.3 1,706.8 50.8 — 1,769.9 OTHER ASSETS Deposits for property, plant and equipment — 27.1 14.5 — 41.6 Income tax receivable, non-current 58.6 4.1 — — 62.7 Deferred income taxes 436.3 — 1.2 — 437.5 Investment in subsidiaries 1,780.5 39.7 — (1,820.2 ) — Long-term intercompany notes — — 121.3 (121.3 ) — Other non-current assets 15.6 98.0 1.3 — 114.9 TOTAL OTHER ASSETS 2,291.0 168.9 138.3 (1,941.5 ) 656.7 TOTAL ASSETS $ 2,774.9 $ 2,461.4 $ 200.5 $ (1,945.6 ) $ 3,491.2 LIABILITIES CURRENT LIABILITIES Accounts payable $ 4.7 $ 207.8 $ 4.4 $ (4.1 ) $ 212.8 Accrued employment costs 17.1 40.1 0.1 — 57.3 Accrued interest 34.1 — — — 34.1 Derivative liabilities 2.4 30.2 — — 32.6 Partnership distribution payable — — — — — Other current liabilities 38.5 75.9 7.3 — 121.7 TOTAL CURRENT LIABILITIES 96.8 354.0 11.8 (4.1 ) 458.5 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 63.3 414.2 (244.3 ) — 233.2 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 159.7 19.4 — 179.1 LONG-TERM DEBT 2,109.1 — — — 2,109.1 LONG-TERM INTERCOMPANY NOTES 121.3 — — (121.3 ) — OTHER LIABILITIES 24.5 120.8 6.1 — 151.4 TOTAL LIABILITIES 2,415.0 1,048.7 (207.0 ) (125.4 ) 3,131.3 EQUITY TOTAL EQUITY 359.9 1,412.7 407.5 (1,820.2 ) 359.9 TOTAL LIABILITIES AND EQUITY $ 2,774.9 $ 2,461.4 $ 200.5 $ (1,945.6 ) $ 3,491.2 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 Finished goods inventories — 77.8 — — 77.8 Work-in-process inventories — 10.1 — — 10.1 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 Derivative liabilities 3.7 — — — 3.7 Partnership distribution payable — 43.5 — — 43.5 Other current liabilities 26.9 86.7 8.2 — 121.8 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 For the Three Months Ended September 30, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 515.0 $ — $ — $ 515.0 Freight — 40.6 — — 40.6 — 555.6 — — 555.6 COST OF GOODS SOLD — (400.7 ) — — (400.7 ) SALES MARGIN — 154.9 — — 154.9 OTHER OPERATING EXPENSE Selling, general and administrative expenses (20.7 ) (4.7 ) (0.1 ) — (25.5 ) Miscellaneous – net — (7.7 ) (0.1 ) — (7.8 ) (20.7 ) (12.4 ) (0.2 ) — (33.3 ) OPERATING INCOME (LOSS) (20.7 ) 142.5 (0.2 ) — 121.6 OTHER INCOME (EXPENSE) Interest income (expense), net (24.9 ) (0.6 ) 0.2 — (25.3 ) Other non-operating income (expense) (0.9 ) (3.4 ) 4.6 — 0.3 (25.8 ) (4.0 ) 4.8 — (25.0 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (46.5 ) 138.5 4.6 — 96.6 INCOME TAX EXPENSE (4.8 ) — — — (4.8 ) EQUITY IN INCOME OF SUBSIDIARIES 142.2 4.6 — (146.8 ) — INCOME FROM CONTINUING OPERATIONS 90.9 143.1 4.6 (146.8 ) 91.8 LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX — (0.3 ) (0.6 ) — (0.9 ) NET INCOME $ 90.9 $ 142.8 $ 4.0 $ (146.8 ) $ 90.9 OTHER COMPREHENSIVE INCOME 6.2 6.8 — (6.8 ) 6.2 TOTAL COMPREHENSIVE INCOME $ 97.1 $ 149.6 $ 4.0 $ (153.6 ) $ 97.1 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended September 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 684.7 $ — $ — $ 684.7 Freight — 57.1 — — 57.1 — 741.8 — — 741.8 COST OF GOODS SOLD — (480.2 ) — — (480.2 ) SALES MARGIN — 261.6 — — 261.6 OTHER OPERATING EXPENSE Selling, general and administrative expenses (23.1 ) (5.7 ) (0.3 ) — (29.1 ) Miscellaneous – net — (6.5 ) (0.5 ) — (7.0 ) (23.1 ) (12.2 ) (0.8 ) — (36.1 ) OPERATING INCOME (LOSS) (23.1 ) 249.4 (0.8 ) — 225.5 OTHER INCOME (EXPENSE) Interest income (expense), net (29.2 ) (0.4 ) 0.1 — (29.5 ) Other non-operating income (expense) (0.9 ) 0.1 5.1 — 4.3 (30.1 ) (0.3 ) 5.2 — (25.2 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (53.2 ) 249.1 4.4 — 200.3 INCOME TAX EXPENSE (0.3 ) — (0.2 ) — (0.5 ) EQUITY IN INCOME OF SUBSIDIARIES 471.0 4.7 — (475.7 ) — INCOME FROM CONTINUING OPERATIONS 417.5 253.8 4.2 (475.7 ) 199.8 INCOME FROM DISCONTINUED OPERATIONS, net of tax 20.3 12.9 204.8 — 238.0 NET INCOME $ 437.8 $ 266.7 $ 209.0 $ (475.7 ) $ 437.8 OTHER COMPREHENSIVE INCOME (LOSS) (221.2 ) 6.1 (230.5 ) 224.4 (221.2 ) TOTAL COMPREHENSIVE INCOME (LOSS) $ 216.6 $ 272.8 $ (21.5 ) $ (251.3 ) $ 216.6 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income For the Nine Months Ended September 30, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 1,357.8 $ — $ — $ 1,357.8 Freight — 98.0 — — 98.0 — 1,455.8 — — 1,455.8 COST OF GOODS SOLD — (1,007.0 ) — — (1,007.0 ) SALES MARGIN — 448.8 — — 448.8 OTHER OPERATING EXPENSE Selling, general and administrative expenses (67.1 ) (14.7 ) (0.4 ) — (82.2 ) Miscellaneous – net — (17.9 ) (1.1 ) — (19.0 ) (67.1 ) (32.6 ) (1.5 ) — (101.2 ) OPERATING INCOME (LOSS) (67.1 ) 416.2 (1.5 ) — 347.6 OTHER INCOME (EXPENSE) Interest income (expense), net (75.0 ) (1.9 ) 0.4 — (76.5 ) Loss on extinguishment of debt (18.2 ) — — — (18.2 ) Other non-operating income (expense) (3.0 ) (9.8 ) 14.1 — 1.3 (96.2 ) (11.7 ) 14.5 — (93.4 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (163.3 ) 404.5 13.0 — 254.2 INCOME TAX EXPENSE (22.7 ) (0.3 ) (0.1 ) — (23.1 ) EQUITY IN INCOME OF SUBSIDIARIES 415.5 13.3 — (428.8 ) — INCOME FROM CONTINUING OPERATIONS 229.5 417.5 12.9 (428.8 ) 231.1 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX 0.1 (0.3 ) (1.3 ) — (1.5 ) NET INCOME $ 229.6 $ 417.2 $ 11.6 $ (428.8 ) $ 229.6 OTHER COMPREHENSIVE INCOME 18.3 20.1 — (20.1 ) 18.3 TOTAL COMPREHENSIVE INCOME $ 247.9 $ 437.3 $ 11.6 $ (448.9 ) $ 247.9 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Nine Months Ended September 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 1,525.9 $ — $ — $ 1,525.9 Freight — 110.2 — — 110.2 — 1,636.1 — — 1,636.1 COST OF GOODS SOLD — (1,028.5 ) — — (1,028.5 ) SALES MARGIN — 607.6 — — 607.6 OTHER OPERATING EXPENSE Selling, general and administrative expenses (62.9 ) (15.3 ) (0.7 ) — (78.9 ) Miscellaneous – net (0.4 ) (16.9 ) (1.4 ) — (18.7 ) (63.3 ) (32.2 ) (2.1 ) — (97.6 ) OPERATING INCOME (LOSS) (63.3 ) 575.4 (2.1 ) — 510.0 OTHER INCOME (EXPENSE) Interest income (expense), net (91.9 ) (1.8 ) 0.6 — (93.1 ) Gain on extinguishment of debt 0.2 — — — 0.2 Other non-operating income (expense) (2.6 ) 0.8 14.9 — 13.1 (94.3 ) (1.0 ) 15.5 — (79.8 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (157.6 ) 574.4 13.4 — 430.2 INCOME TAX EXPENSE (13.8 ) (0.2 ) (0.4 ) — (14.4 ) EQUITY IN INCOME OF SUBSIDIARIES 665.7 13.8 — (679.5 ) — INCOME FROM CONTINUING OPERATIONS 494.3 588.0 13.0 (679.5 ) 415.8 INCOME FROM DISCONTINUED OPERATIONS, net of tax 24.3 12.8 65.7 — 102.8 NET INCOME $ 518.6 $ 600.8 $ 78.7 $ (679.5 ) $ 518.6 OTHER COMPREHENSIVE INCOME (LOSS) (204.4 ) 18.0 (227.5 ) 209.5 (204.4 ) TOTAL COMPREHENSIVE INCOME (LOSS) $ 314.2 $ 618.8 $ (148.8 ) $ (470.0 ) $ 314.2 Unaudited Condensed Consolidating Statement of Cash Flows For the Nine Months Ended September 30, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (11.0 ) $ 402.8 $ (3.7 ) $ — $ 388.1 INVESTING ACTIVITIES Purchase of property, plant and equipment (1.2 ) (446.7 ) — — (447.9 ) Deposits for property, plant and equipment — (12.3 ) (0.5 ) — (12.8 ) Intercompany investing (83.6 ) (1.2 ) — 84.8 — Other investing activities — 10.4 0.8 — 11.2 Net cash provided (used) by investing activities (84.8 ) (449.8 ) 0.3 84.8 (449.5 ) FINANCING ACTIVITIES Repurchase of common shares (252.9 ) — — — (252.9 ) Dividends paid (45.1 ) — — — (45.1 ) Proceeds from issuance of debt 720.9 — — — 720.9 Debt issuance costs (6.8 ) — — — (6.8 ) Repurchase of debt (729.3 ) — — — (729.3 ) Distributions of partnership equity — (44.2 ) — — (44.2 ) Intercompany financing — 83.1 1.7 (84.8 ) — Other financing activities (14.6 ) 7.8 (2.7 ) — (9.5 ) Net cash provided (used) by financing activities (327.8 ) 46.7 (1.0 ) (84.8 ) (366.9 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (423.6 ) (0.3 ) (4.4 ) — (428.3 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — (4.4 ) — (4.4 ) NET DECREASE IN CASH AND CASH EQUIVALENTS (423.6 ) (0.3 ) — — (423.9 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 819.8 0.7 2.7 — 823.2 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 396.2 $ 0.4 $ 2.7 $ — $ 399.3 Unaudited Condensed Consolidating Statement of Cash Flows For the Nine Months Ended September 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (100.6 ) $ 425.6 $ (136.3 ) $ — $ 188.7 INVESTING ACTIVITIES Purchase of property, plant and equipment (1.1 ) (110.2 ) (0.1 ) — (111.4 ) Deposits for property, plant and equipment — (78.1 ) (5.2 ) — (83.3 ) Intercompany investing 185.7 (6.3 ) 120.7 (300.1 ) — Other investing activities — 3.1 17.9 — 21.0 Net cash provided (used) by investing activities 184.6 (191.5 ) 133.3 (300.1 ) (173.7 ) FINANCING ACTIVITIES Debt issuance costs (1.5 ) — — — (1.5 ) Repurchase of debt (16.3 ) — — — (16.3 ) Distributions of partnership equity — (44.2 ) — — (44.2 ) Intercompany financing (120.7 ) (188.6 ) 9.2 300.1 — Other financing activities (1.9 ) (1.5 ) (42.3 ) — (45.7 ) Net cash used by financing activities (140.4 ) (234.3 ) (33.1 ) 300.1 (107.7 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — (2.3 ) — (2.3 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (56.4 ) (0.2 ) (38.4 ) — (95.0 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — (13.8 ) — (13.8 ) NET DECREASE IN CASH AND CASH EQUIVALENTS (56.4 ) (0.2 ) (24.6 ) — (81.2 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 948.9 2.1 27.3 — 978.3 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 892.5 $ 1.9 $ 2.7 $ — $ 897.1

BASIS OF PRESENTATION AND SIG_2

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Consolidation	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 September 30, 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 September 30, 2019 and December 31, 2018 , our investment in Hibbing was $14.0 million and $15.4 million , respectively, classified as Other liabilities in the Statements of Unaudited Condensed Consolidated Financial Position .
Foreign Currency	Foreign Currency Our financial statements are prepared with the U.S. dollar as the reporting currency and the functional currency of all subsidiaries is the U.S. dollar. In August 2018, management determined that there were significant changes in economic factors related to our Australian subsidiaries. The change in economic factors was a result of the sale and conveyance of substantially all assets and liabilities of our Australian subsidiaries to third parties, representing a significant change in operations. As such, the functional currency for the Australian subsidiaries changed from the Australian dollar to the U.S. dollar, requiring all remaining Australian denominated monetary balances to be remeasured through the Statements of Unaudited Condensed Consolidated Operations . As a result of the liquidation of the Australian subsidiaries' assets, the historical impact of foreign currency translation recorded in Accumulated other comprehensive loss in the Statements of Unaudited Condensed Consolidated Financial Position of $228.1 million was reclassified and recognized as a gain in Income (loss) from discontinued operations, net of tax in the Statements of Unaudited Condensed Consolidated Operations for the three and nine months ended September 30, 2018. Refer to NOTE 13 - DISCONTINUED OPERATIONS for further information regarding our Australian subsidiaries.
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)	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Consolidation	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 September 30, 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)	9 Months Ended
	Sep. 30, 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 revenues to total Revenues from product sales and services , segment sales margin to total Sales margin and a reconciliation of Net income to EBITDA and Adjusted EBITDA: (In Millions) Three Months Ended September 30, 2019 Nine Months Ended Mining and Pelletizing Metallics Total Mining and Pelletizing Metallics Total Operating segment revenues from product sales and services $ 590.6 $ — $ 590.6 $ 1,494.8 $ — $ 1,494.8 Elimination of intersegment revenues (35.0 ) — (35.0 ) (39.0 ) — (39.0 ) Total revenues from product sales and services $ 555.6 $ — $ 555.6 $ 1,455.8 $ — $ 1,455.8 Operating segment sales margin $ 165.8 $ — $ 165.8 $ 461.3 $ — $ 461.3 Elimination of intersegment sales margin (10.9 ) — (10.9 ) (12.5 ) — (12.5 ) Total sales margin $ 154.9 $ — $ 154.9 $ 448.8 $ — $ 448.8 Revenues from product sales and services of $741.8 million and $1,636.1 million , respectively, and sales margin of $261.6 million and $607.6 million , respectively, related to our Mining and Pelletizing segment accounted for all of our consolidated revenues and sales margin for the three and nine months ended September 30, 2018 . (In Millions) Three Months Ended Nine Months Ended 2019 2018 2019 2018 Net income $ 90.9 $ 437.8 $ 229.6 $ 518.6 Less: Interest expense, net (25.4 ) (29.7 ) (76.8 ) (95.5 ) Income tax expense (4.8 ) (0.5 ) (23.1 ) (14.4 ) Depreciation, depletion and amortization (22.2 ) (19.2 ) (63.1 ) (68.6 ) EBITDA $ 143.3 $ 487.2 $ 392.6 $ 697.1 Less: Impact of discontinued operations $ (0.8 ) $ 238.2 $ (1.2 ) $ 120.4 Gain (loss) on extinguishment of debt — — (18.2 ) 0.2 Severance costs — — (1.7 ) — Foreign exchange remeasurement — (0.2 ) — (0.7 ) Impairment of long-lived assets — (1.1 ) — (1.1 ) Adjusted EBITDA $ 144.1 $ 250.3 $ 413.7 $ 578.3 EBITDA: Mining and Pelletizing $ 177.5 $ 273.1 $ 494.9 $ 641.6 Metallics (2.1 ) (1.0 ) (4.0 ) (2.5 ) Corporate and Other (including discontinued operations) (32.1 ) 215.1 (98.3 ) 58.0 Total EBITDA $ 143.3 $ 487.2 $ 392.6 $ 697.1 Adjusted EBITDA: Mining and Pelletizing $ 182.7 $ 279.5 $ 510.7 $ 657.9 Metallics (2.1 ) (1.0 ) (4.0 ) (2.5 ) Corporate (36.5 ) (28.2 ) (93.0 ) (77.1 ) Total Adjusted EBITDA $ 144.1 $ 250.3 $ 413.7 $ 578.3 The following table summarizes our depreciation, depletion and amortization and capital additions: (In Millions) Three Months Ended Nine Months Ended 2019 2018 2019 2018 Depreciation, depletion and amortization: Mining and Pelletizing $ 20.8 $ 17.8 $ 58.9 $ 49.2 Corporate 1.4 1.4 4.2 4.2 Total depreciation, depletion and amortization $ 22.2 $ 19.2 $ 63.1 $ 53.4 Capital additions 1 : Mining and Pelletizing $ 22.1 $ 51.8 $ 104.5 $ 97.2 Metallics 160.5 40.6 398.0 143.6 Corporate 2.1 0.2 3.1 1.1 Total capital additions $ 184.7 $ 92.6 $ 505.6 $ 241.9 1 Refer to NOTE 16 - CASH FLOW INFORMATION for additional information.
Reconciliation of Assets from Segment to Consolidated	A summary of assets by segment is as follows: (In Millions) September 30, December 31, Assets: Mining and Pelletizing $ 1,793.9 $ 1,694.1 Metallics 708.5 265.9 Total segment assets 2,502.4 1,960.0 Corporate and Other (including discontinued operations) 988.8 1,569.6 Total assets $ 3,491.2 $ 3,529.6

REVENUE (Tables)

REVENUE (Tables)	9 Months Ended
	Sep. 30, 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 September 30 18.3 16.1 30.0 42.8 Decrease $ (2.7 ) $ (7.7 ) $ (8.5 ) $ (8.6 )

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	9 Months Ended
	Sep. 30, 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) September 30, December 31, Land rights and mineral rights $ 549.7 $ 549.6 Office and information technology 72.9 70.0 Buildings 101.2 87.2 Mining equipment 577.0 548.5 Processing equipment 755.5 645.8 Electric power facilities 58.7 58.7 Land improvements 23.8 23.8 Asset retirement obligation 14.8 14.8 Other 29.2 25.2 Construction-in-progress 668.9 284.8 2,851.7 2,308.4 Allowance for depreciation and depletion (1,081.8 ) (1,022.4 ) $ 1,769.9 $ 1,286.0

DEBT AND CREDIT FACILITIES (Tab

DEBT AND CREDIT FACILITIES (Tables)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	The following represents a summary of our long-term debt: (In Millions) September 30, 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 $ (4.9 ) $ (1.9 ) $ 393.2 Unsecured Notes: $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (4.8 ) (67.7 ) 243.8 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 473.3 (3.8 ) (5.8 ) 463.7 $750 Million 5.875% 2027 Senior Notes 6.49% 750.0 (6.5 ) (28.0 ) 715.5 $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 — Long-term debt $ 2,109.1 (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 Instrument Redemption	The following is a summary of redemption prices for our 5.875% 2027 Senior Notes: Redemption Period Redemption Price 1 Restricted Amount Prior to June 1, 2022 - using proceeds of equity issuance 105.875 % Up to 35% of original aggregate principal Prior to June 1, 2022 2 100.000 Beginning on June 1, 2022 102.938 Beginning on June 1, 2023 101.958 Beginning on June 1, 2024 100.979 Beginning on June 1, 2025 and thereafter 100.000 1 Plus accrued and unpaid interest, if any, up to but excluding the redemption date. 2 Plus a "make-whole" premium.
Schedule of Extinguishment of Debt	The following is a summary of the debt extinguished and the respective loss on extinguishment: (In Millions) Nine Months Ended September 30, 2019 Debt Instrument Debt Extinguished (Loss) on Extinguishment $700 Million 4.875% 2021 Senior Notes $ 124.0 $ (5.3 ) $1.075 Billion 5.75% 2025 Senior Notes 600.0 (12.9 ) $ 724.0 $ (18.2 )	The following is a summary of the debt extinguished with cash and the respective gain on extinguishment: (In Millions) Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Debt Instrument Debt Extinguished Gain on Extinguishment Debt Extinguished Gain on Extinguishment $400 Million 5.90% 2020 Senior Notes $ — $ — $ 0.5 $ — $500 Million 4.80% 2020 Senior Notes — — 0.1 — $700 Million 4.875% 2021 Senior Notes 1.0 — 14.2 0.1 $1.075 Billion 5.75% 2025 Senior Notes — — 1.7 0.1 $ 1.0 $ — $ 16.5 $ 0.2
Schedule of Maturities of Long-term Debt	The following represents a summary of our maturities of debt instruments based on the principal amounts outstanding at September 30, 2019 : (In Millions) Maturities of Debt 2019 $ — 2020 — 2021 — 2022 — 2023 — 2024 400.0 2025 and thereafter 1,838.0 Total maturities of debt $ 2,238.0
Schedule of Line of Credit Facilities	The following represents a summary of our borrowing capacity under the ABL Facility: (In Millions) September 30, 2019 December 31, 2018 Available borrowing base on ABL Facility 1 $ 400.8 $ 323.7 Letter of credit obligations 2 (34.1 ) (55.0 ) Borrowing capacity available 3 $ 366.7 $ 268.7 1 The ABL Facility has a maximum borrowing base of $450 million. The available borrowing base is determined by applying customary advance rates to eligible accounts receivable, inventory and certain mobile equipment. 2 We issued standby letters of credit with certain financial institutions in order to support business obligations including, but not limited to, workers compensation and environmental obligations. 3 As of September 30, 2019 and December 31, 2018, we had no loans drawn under the ABL Facility.

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	The following represents the assets and liabilities measured at fair value: (In Millions) September 30, 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 $ — $ 272.5 $ — $ 272.5 Derivative assets — — 72.8 72.8 Total $ — $ 272.5 $ 72.8 $ 345.3 Liabilities: Derivative liabilities $ — $ 2.4 $ 30.2 $ 32.6 Total $ — $ 2.4 $ 30.2 $ 32.6 (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 following table illustrates information about qualitative and 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 September 30, 2019 Balance Sheet Location Valuation Technique Unobservable Input Range or Point Estimate (Weighted Average) Customer supply agreement $ 71.2 Derivative assets Market Approach Management's Estimate of Hot-Rolled Coil Steel Price per net ton $631 - $700 Provisional pricing arrangements $ 1.6 Derivative assets Market Approach Management's Estimate of Platts 62% Price per dry metric ton for respective contract period $100 Provisional pricing arrangements $ 30.2 Derivative liabilities Market Approach PPI Estimates 172 - 214 Management's Estimate of Platts 62% Price per dry metric ton for respective contract period $87 - $100 Atlantic Basin Pellet Premium per metric ton $59
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation	The following tables reconcile 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 Nine Months Ended 2019 2018 2019 2018 Beginning balance $ 118.1 $ 174.6 $ 91.4 $ 49.5 Total gains (losses) included in earnings (6.5 ) 139.0 83.1 341.8 Settlements (38.8 ) (123.0 ) (101.7 ) (200.7 ) Ending balance - September 30 $ 72.8 $ 190.6 $ 72.8 $ 190.6 Total gains (losses) for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ (6.5 ) $ 15.9 $ 81.8 $ 141.0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	(In Millions) Level 3 Liabilities Three Months Ended Nine Months Ended 2019 2018 2019 2018 Beginning balance $ — $ (3.0 ) $ — $ (1.7 ) Total losses included in earnings (34.4 ) (3.1 ) (39.7 ) (7.4 ) Settlements 4.2 0.4 9.5 3.4 Ending balance - September 30 $ (30.2 ) $ (5.7 ) $ (30.2 ) $ (5.7 ) Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (30.2 ) $ (2.7 ) $ (30.2 ) $ (5.7 )
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) September 30, 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 $ 393.2 $ 408.9 $ 392.1 $ 370.2 Unsecured Notes $700 Million 4.875% 2021 Senior Notes Level 1 — — 123.8 122.3 $316.25 Million 1.50% 2025 Convertible Senior Notes Level 1 243.8 345.8 235.2 352.4 $1.075 Billion 5.75% 2025 Senior Notes Level 1 463.7 466.2 1,048.8 962.0 $750 Million 5.875% 2027 Senior Notes Level 1 715.5 712.2 — — $800 Million 6.25% 2040 Senior Notes Level 1 292.9 254.4 292.8 232.8 ABL Facility Level 2 — — — — Fair value adjustment to interest rate hedge Level 2 — — 0.2 0.2 Total long-term debt $ 2,109.1 $ 2,187.5 $ 2,092.9 $ 2,039.9

PENSIONS AND OTHER POSTRETIRE_2

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Tables)	9 Months Ended
	Sep. 30, 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 Nine Months Ended 2019 2018 2019 2018 Service cost $ 4.6 $ 4.7 $ 12.9 $ 14.0 Interest cost 8.9 7.6 26.2 22.7 Expected return on plan assets (13.7 ) (15.0 ) (41.0 ) (45.0 ) Amortization: Prior service costs 0.3 0.6 0.9 1.7 Net actuarial loss 5.9 5.3 17.7 15.9 Net periodic benefit cost $ 6.0 $ 3.2 $ 16.7 $ 9.3 Other Postretirement Employment Benefits Credits (In Millions) Three Months Ended Nine Months Ended 2019 2018 2019 2018 Service cost $ 0.5 $ 0.6 $ 1.3 $ 1.6 Interest cost 2.3 2.1 7.0 6.2 Expected return on plan assets (4.2 ) (4.6 ) (12.6 ) (13.8 ) Amortization: Prior service credits (0.5 ) (0.7 ) (1.5 ) (2.2 ) Net actuarial loss 1.3 1.3 3.8 3.8 Net periodic benefit credit $ (0.6 ) $ (1.3 ) $ (2.0 ) $ (4.4 )

STOCK COMPENSATION PLANS (Table

STOCK COMPENSATION PLANS (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [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)	9 Months Ended
	Sep. 30, 2019
Environmental Remediation Obligations [Abstract]
Summary Of Mine Closure Obligations	The following is a summary of our environmental and mine closure obligations: (In Millions) September 30, December 31, Environmental $ 2.1 $ 2.5 Mine closure 1 179.5 172.4 Total environmental and mine closure obligations 181.6 174.9 Less current portion 2.5 2.9 Long-term environmental and mine closure obligations $ 179.1 $ 172.0 1 Includes our active operating mines, our indefinitely idled Empire mine and a closed mine formerly operating as LTV Steel Mining Company.
Asset Retirement Obligation Disclosure	The following is a roll forward of our mine closure obligation liability: (In Millions) Nine Months Ended September 30, 2019 Year Ended December 31, 2018 Asset retirement obligation at beginning of period $ 172.4 $ 168.4 Accretion expense 7.6 9.5 Remediation payments (0.5 ) (1.0 ) Revision in estimated cash flows — (4.5 ) Asset retirement obligation at end of period $ 179.5 $ 172.4

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 2019 December 31, 2018 September 30, 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 $ 0.1 Derivative liabilities $ 2.4 Derivative liabilities $ 3.7 Derivatives not designated as hedging instruments under ASC 815: Customer supply agreement Derivative assets $ 71.2 Derivative assets $ 89.3 $ — $ — Provisional pricing arrangements Derivative assets 1.6 Derivative assets 2.1 Derivative liabilities 30.2 — Total derivatives not designated as hedging instruments under ASC 815 $ 72.8 $ 91.4 $ 30.2 $ — Total derivatives $ 72.8 $ 91.5 $ 32.6 $ 3.7
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	The following table presents our outstanding hedge contracts: (In Millions) September 30, 2019 December 31, 2018 Notional Amount Unit of Measure Varying Maturity Dates Notional Amount Unit of Measure Varying Maturity Dates Natural gas 7.0 MMBtu October 2019 - November 2020 1.8 MMBtu January 2019 - August 2019 Diesel 2.4 Gallons October 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 Nine Months Ended 2019 2018 2019 2018 Customer supply agreements Product revenues $ 7.6 $ 139.7 $ 82.2 $ 337.1 Provisional pricing arrangements Product revenues (48.5 ) (3.8 ) (38.8 ) (2.7 ) Total $ (40.9 ) $ 135.9 $ 43.4 $ 334.4

DISCONTINUED OPERATIONS (Tables

DISCONTINUED OPERATIONS (Tables)	9 Months Ended
	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [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 September 30, Nine Months Ended 2019 2018 2019 2018 Income (loss) from discontinued operations, net of tax Asia Pacific Iron Ore $ (0.1 ) $ 242.3 $ (1.1 ) $ 117.6 North American Coal (0.8 ) (4.3 ) (0.4 ) (4.2 ) Canadian Operations — — — (10.6 ) $ (0.9 ) $ 238.0 $ (1.5 ) $ 102.8 (In Millions) Nine Months Ended 2019 2018 Net cash used by operating activities Asia Pacific Iron Ore $ (1.9 ) $ (77.0 ) Canadian Operations — (14.6 ) $ (1.9 ) $ (91.6 ) Net cash provided by investing activities Asia Pacific Iron Ore $ 0.1 $ 17.8 $ 0.1 $ 17.8
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	NOTE 13 - 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 Income (loss) from discontinued operations, net of tax and the Statements of Unaudited Condensed Consolidated Financial Position present the assets and liabilities that were reclassified from the specified line items to Other current assets , Other current liabilities and Other liabilities . The charts below provide an asset group breakout for each financial statement line impacted by discontinued operations. (In Millions) Three Months Ended September 30, Nine Months Ended 2019 2018 2019 2018 Income (loss) from discontinued operations, net of tax Asia Pacific Iron Ore $ (0.1 ) $ 242.3 $ (1.1 ) $ 117.6 North American Coal (0.8 ) (4.3 ) (0.4 ) (4.2 ) Canadian Operations — — — (10.6 ) $ (0.9 ) $ 238.0 $ (1.5 ) $ 102.8 (In Millions) Nine Months Ended 2019 2018 Net cash used by operating activities Asia Pacific Iron Ore $ (1.9 ) $ (77.0 ) Canadian Operations — (14.6 ) $ (1.9 ) $ (91.6 ) Net cash provided by investing activities Asia Pacific Iron Ore $ 0.1 $ 17.8 $ 0.1 $ 17.8 For the nine months ended September 30, 2018, we had $27.1 million of non-cash financing activities related to the release of asset retirement obligations at Asia Pacific Iron Ore as part of the sale of substantially all remaining assets. 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 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. Income ( Loss) from Discontinued Operations (In Millions) Three Months Ended September 30, Nine Months Ended Income (Loss) from Discontinued Operations 2019 2018 2019 2018 Revenues from product sales and services $ — $ — $ — $ 129.1 Cost of goods sold — (0.5 ) — (230.7 ) Sales margin — (0.5 ) — (101.6 ) Other operating expense — 14.8 (0.8 ) (4.0 ) Other expense (0.1 ) (0.1 ) (0.3 ) (2.3 ) Gain on foreign currency translation — 228.1 — 228.1 Impairment of long-lived assets — — — (2.6 ) Income (loss) from discontinued operations, net of tax $ (0.1 ) $ 242.3 $ (1.1 ) $ 117.6 Gain on Foreign Currency Translation As a result of the liquidation of the Australian subsidiaries' net assets, the historical changes in foreign currency translation recorded in Accumulated other comprehensive loss in the Statements of Unaudited Condensed Consolidated Financial Position totaling $228.1 million was reclassified and recognized as a gain in Income (loss) from discontinued operations, net of tax in the Statements of Unaudited Condensed Consolidated Operations for the three and nine months ended September 30, 2018. Canadian Operations During 2015, we announced that the Bloom Lake Group and the Wabush Group commenced restructuring proceedings in Montreal, Quebec under the CCAA to address the immediate liquidity issues and to preserve and protect their assets for the benefit of all stakeholders while restructuring and/or sale options were explored. The Bloom Lake Group and the Wabush Group filed a joint plan of compromise and arrangement that was approved by the required majorities of each unsecured creditor class and was sanctioned by the Court in June 2018. During July 2018, amendments were made to the plan to address the manner in which certain distributions under the plan would be effected and the plan was implemented. During the third quarter of 2018, under the terms of the amended plan, we and certain of our wholly-owned subsidiaries made a C$19.0 million cash contribution to the Wabush Group pension plans and agreed to contribute into the CCAA estate any remaining distributions or payments we may be entitled to receive as creditors of the Bloom Lake Group and the Wabush Group for distribution to other creditors. The original plan did not resolve certain employee claims asserted against us and certain of our affiliates outside of the CCAA proceedings. The amended plan resolved those employee claims, all claims by the Bloom Lake Group, the Wabush Group and their respective creditors against us as well as all of our claims against the Bloom Lake Group and the Wabush Group.
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Schedule of Disposal Groups, Including Discontinued Operations	Income ( Loss) from Discontinued Operations (In Millions) Three Months Ended September 30, Nine Months Ended Income (Loss) from Discontinued Operations 2019 2018 2019 2018 Revenues from product sales and services $ — $ — $ — $ 129.1 Cost of goods sold — (0.5 ) — (230.7 ) Sales margin — (0.5 ) — (101.6 ) Other operating expense — 14.8 (0.8 ) (4.0 ) Other expense (0.1 ) (0.1 ) (0.3 ) (2.3 ) Gain on foreign currency translation — 228.1 — 228.1 Impairment of long-lived assets — — — (2.6 ) Income (loss) from discontinued operations, net of tax $ (0.1 ) $ 242.3 $ (1.1 ) $ 117.6

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	9 Months Ended
	Sep. 30, 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 ) Other comprehensive income (loss) before reclassifications 0.3 (2.3 ) (2.0 ) Net loss reclassified from accumulated other comprehensive loss 5.5 0.2 5.7 June 30, 2019 $ (269.6 ) $ (2.2 ) $ (271.8 ) Other comprehensive income (loss) before reclassifications 0.3 (0.5 ) (0.2 ) Net loss reclassified from accumulated other comprehensive loss 5.5 0.9 6.4 September 30, 2019 $ (263.8 ) $ (1.8 ) $ (265.6 ) (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 ) Other comprehensive income before reclassifications 0.2 2.2 0.2 2.6 Net loss reclassified from accumulated other comprehensive loss 6.5 — — 6.5 June 30, 2018 $ (250.5 ) $ 228.3 $ — $ (22.2 ) Other comprehensive income (loss) before reclassifications 0.3 (0.2 ) 0.2 0.3 Net loss (gain) reclassified from accumulated other comprehensive loss 6.5 (228.1 ) 0.1 (221.5 ) September 30, 2018 $ (243.7 ) $ — $ 0.3 $ (243.4 )
Details of Accumulated Other Comprehensive Income (Loss) Components	The following table reflects the details about Accumulated other comprehensive loss components related to 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 Nine Months Ended 2019 2018 2019 2018 Amortization of pension and OPEB liability: Prior service credits $ (0.2 ) $ (0.1 ) $ (0.6 ) $ (0.5 ) Other non-operating income Net actuarial loss 7.2 6.6 21.5 19.7 Other non-operating income $ 7.0 $ 6.5 $ 20.9 $ 19.2 (1.5 ) — (4.4 ) — Income tax expense $ 5.5 $ 6.5 $ 16.5 $ 19.2 Net of taxes Changes in foreign currency translation: Gain on foreign currency translation $ — $ (228.1 ) $ — $ (228.1 ) Income (loss) from discontinued operations, net of tax $ — $ (228.1 ) $ — $ (228.1 ) Unrealized loss (gain) on derivative financial instruments: Commodity contracts $ 1.2 $ 0.1 $ 1.7 $ — Cost of goods sold (0.3 ) — (0.4 ) — Income tax expense $ 0.9 $ 0.1 $ 1.3 $ — Net of taxes Total reclassifications for the period, net of tax $ 6.4 $ (221.5 ) $ 17.8 $ (208.9 )

CASH FLOW INFORMATION (Tables)

CASH FLOW INFORMATION (Tables)	9 Months Ended
	Sep. 30, 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) Nine Months Ended September 30, 2019 2018 Capital additions 1 $ 505.6 $ 242.0 Less: Non-cash accruals 26.1 42.2 Right-of-use assets – finance leases 29.3 7.6 Grants (10.5 ) (2.5 ) Cash paid for capital expenditures including deposits $ 460.7 $ 194.7 1 Includes capital additions related to discontinued operations of $0.1 million, for the nine months ended September 30, 2018.

RELATED PARTIES (Tables)

RELATED PARTIES (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 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 Nine Months Ended 2019 2018 2019 2018 Product revenues from related parties $ 262.0 $ 392.4 $ 718.9 $ 863.8 Total product revenues $ 515.0 $ 684.7 $ 1,357.8 $ 1,525.9 Related party product revenue as a percent of total product revenue 50.9 % 57.3 % 52.9 % 56.6 %
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 September 30, 2019 December 31, 2018 Accounts receivable, net $ 108.7 $ 176.0 Derivative assets 71.2 89.3 Other current assets 0.2 — Derivative liabilities (26.1 ) — Partnership distribution payable — (43.5 ) Other current liabilities (1.4 ) (1.8 ) $ 152.6 $ 220.0

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
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 Nine Months Ended 2019 2018 2019 2018 Income from continuing operations $ 91.8 $ 199.8 $ 231.1 $ 415.8 Income (loss) from discontinued operations, net of tax (0.9 ) 238.0 (1.5 ) 102.8 Net income $ 90.9 $ 437.8 $ 229.6 $ 518.6 Weighted average number of shares: Basic 270.0 297.9 278.4 297.6 Convertible senior notes 3.7 8.0 5.8 1.9 Employee stock plans 2.9 4.3 3.6 4.0 Diluted 276.6 310.2 287.8 303.5 Earnings (loss) per common share - basic: Continuing operations $ 0.34 $ 0.67 $ 0.83 $ 1.40 Discontinued operations — 0.80 (0.01 ) 0.35 $ 0.34 $ 1.47 $ 0.82 $ 1.75 Earnings (loss) per common share - diluted: Continuing operations $ 0.33 $ 0.64 $ 0.80 $ 1.37 Discontinued operations — 0.77 — 0.34 $ 0.33 $ 1.41 $ 0.80 $ 1.71

SUPPLEMENTARY GUARANTOR INFOR_2

SUPPLEMENTARY GUARANTOR INFORMATION (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 396.2 $ 0.4 $ 2.7 $ — $ 399.3 Accounts receivable, net 7.4 161.4 0.2 (4.1 ) 164.9 Finished goods inventories — 162.2 — — 162.2 Work-in-process inventories — 55.2 — — 55.2 Supplies and other inventories — 110.8 — — 110.8 Derivative assets — 72.8 — — 72.8 Income tax receivable, current 58.7 — — — 58.7 Other current assets 9.3 22.9 8.5 — 40.7 TOTAL CURRENT ASSETS 471.6 585.7 11.4 (4.1 ) 1,064.6 PROPERTY, PLANT AND EQUIPMENT, NET 12.3 1,706.8 50.8 — 1,769.9 OTHER ASSETS Deposits for property, plant and equipment — 27.1 14.5 — 41.6 Income tax receivable, non-current 58.6 4.1 — — 62.7 Deferred income taxes 436.3 — 1.2 — 437.5 Investment in subsidiaries 1,780.5 39.7 — (1,820.2 ) — Long-term intercompany notes — — 121.3 (121.3 ) — Other non-current assets 15.6 98.0 1.3 — 114.9 TOTAL OTHER ASSETS 2,291.0 168.9 138.3 (1,941.5 ) 656.7 TOTAL ASSETS $ 2,774.9 $ 2,461.4 $ 200.5 $ (1,945.6 ) $ 3,491.2 LIABILITIES CURRENT LIABILITIES Accounts payable $ 4.7 $ 207.8 $ 4.4 $ (4.1 ) $ 212.8 Accrued employment costs 17.1 40.1 0.1 — 57.3 Accrued interest 34.1 — — — 34.1 Derivative liabilities 2.4 30.2 — — 32.6 Partnership distribution payable — — — — — Other current liabilities 38.5 75.9 7.3 — 121.7 TOTAL CURRENT LIABILITIES 96.8 354.0 11.8 (4.1 ) 458.5 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 63.3 414.2 (244.3 ) — 233.2 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 159.7 19.4 — 179.1 LONG-TERM DEBT 2,109.1 — — — 2,109.1 LONG-TERM INTERCOMPANY NOTES 121.3 — — (121.3 ) — OTHER LIABILITIES 24.5 120.8 6.1 — 151.4 TOTAL LIABILITIES 2,415.0 1,048.7 (207.0 ) (125.4 ) 3,131.3 EQUITY TOTAL EQUITY 359.9 1,412.7 407.5 (1,820.2 ) 359.9 TOTAL LIABILITIES AND EQUITY $ 2,774.9 $ 2,461.4 $ 200.5 $ (1,945.6 ) $ 3,491.2 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 Finished goods inventories — 77.8 — — 77.8 Work-in-process inventories — 10.1 — — 10.1 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 Derivative liabilities 3.7 — — — 3.7 Partnership distribution payable — 43.5 — — 43.5 Other current liabilities 26.9 86.7 8.2 — 121.8 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 For the Three Months Ended September 30, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 515.0 $ — $ — $ 515.0 Freight — 40.6 — — 40.6 — 555.6 — — 555.6 COST OF GOODS SOLD — (400.7 ) — — (400.7 ) SALES MARGIN — 154.9 — — 154.9 OTHER OPERATING EXPENSE Selling, general and administrative expenses (20.7 ) (4.7 ) (0.1 ) — (25.5 ) Miscellaneous – net — (7.7 ) (0.1 ) — (7.8 ) (20.7 ) (12.4 ) (0.2 ) — (33.3 ) OPERATING INCOME (LOSS) (20.7 ) 142.5 (0.2 ) — 121.6 OTHER INCOME (EXPENSE) Interest income (expense), net (24.9 ) (0.6 ) 0.2 — (25.3 ) Other non-operating income (expense) (0.9 ) (3.4 ) 4.6 — 0.3 (25.8 ) (4.0 ) 4.8 — (25.0 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (46.5 ) 138.5 4.6 — 96.6 INCOME TAX EXPENSE (4.8 ) — — — (4.8 ) EQUITY IN INCOME OF SUBSIDIARIES 142.2 4.6 — (146.8 ) — INCOME FROM CONTINUING OPERATIONS 90.9 143.1 4.6 (146.8 ) 91.8 LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX — (0.3 ) (0.6 ) — (0.9 ) NET INCOME $ 90.9 $ 142.8 $ 4.0 $ (146.8 ) $ 90.9 OTHER COMPREHENSIVE INCOME 6.2 6.8 — (6.8 ) 6.2 TOTAL COMPREHENSIVE INCOME $ 97.1 $ 149.6 $ 4.0 $ (153.6 ) $ 97.1 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended September 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 684.7 $ — $ — $ 684.7 Freight — 57.1 — — 57.1 — 741.8 — — 741.8 COST OF GOODS SOLD — (480.2 ) — — (480.2 ) SALES MARGIN — 261.6 — — 261.6 OTHER OPERATING EXPENSE Selling, general and administrative expenses (23.1 ) (5.7 ) (0.3 ) — (29.1 ) Miscellaneous – net — (6.5 ) (0.5 ) — (7.0 ) (23.1 ) (12.2 ) (0.8 ) — (36.1 ) OPERATING INCOME (LOSS) (23.1 ) 249.4 (0.8 ) — 225.5 OTHER INCOME (EXPENSE) Interest income (expense), net (29.2 ) (0.4 ) 0.1 — (29.5 ) Other non-operating income (expense) (0.9 ) 0.1 5.1 — 4.3 (30.1 ) (0.3 ) 5.2 — (25.2 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (53.2 ) 249.1 4.4 — 200.3 INCOME TAX EXPENSE (0.3 ) — (0.2 ) — (0.5 ) EQUITY IN INCOME OF SUBSIDIARIES 471.0 4.7 — (475.7 ) — INCOME FROM CONTINUING OPERATIONS 417.5 253.8 4.2 (475.7 ) 199.8 INCOME FROM DISCONTINUED OPERATIONS, net of tax 20.3 12.9 204.8 — 238.0 NET INCOME $ 437.8 $ 266.7 $ 209.0 $ (475.7 ) $ 437.8 OTHER COMPREHENSIVE INCOME (LOSS) (221.2 ) 6.1 (230.5 ) 224.4 (221.2 ) TOTAL COMPREHENSIVE INCOME (LOSS) $ 216.6 $ 272.8 $ (21.5 ) $ (251.3 ) $ 216.6
Schedule of Supplemental Statements of Condensed Consolidating Cash Flows	Unaudited Condensed Consolidating Statement of Cash Flows For the Nine Months Ended September 30, 2019 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (11.0 ) $ 402.8 $ (3.7 ) $ — $ 388.1 INVESTING ACTIVITIES Purchase of property, plant and equipment (1.2 ) (446.7 ) — — (447.9 ) Deposits for property, plant and equipment — (12.3 ) (0.5 ) — (12.8 ) Intercompany investing (83.6 ) (1.2 ) — 84.8 — Other investing activities — 10.4 0.8 — 11.2 Net cash provided (used) by investing activities (84.8 ) (449.8 ) 0.3 84.8 (449.5 ) FINANCING ACTIVITIES Repurchase of common shares (252.9 ) — — — (252.9 ) Dividends paid (45.1 ) — — — (45.1 ) Proceeds from issuance of debt 720.9 — — — 720.9 Debt issuance costs (6.8 ) — — — (6.8 ) Repurchase of debt (729.3 ) — — — (729.3 ) Distributions of partnership equity — (44.2 ) — — (44.2 ) Intercompany financing — 83.1 1.7 (84.8 ) — Other financing activities (14.6 ) 7.8 (2.7 ) — (9.5 ) Net cash provided (used) by financing activities (327.8 ) 46.7 (1.0 ) (84.8 ) (366.9 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (423.6 ) (0.3 ) (4.4 ) — (428.3 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — (4.4 ) — (4.4 ) NET DECREASE IN CASH AND CASH EQUIVALENTS (423.6 ) (0.3 ) — — (423.9 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 819.8 0.7 2.7 — 823.2 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 396.2 $ 0.4 $ 2.7 $ — $ 399.3 Unaudited Condensed Consolidating Statement of Cash Flows For the Nine Months Ended September 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (100.6 ) $ 425.6 $ (136.3 ) $ — $ 188.7 INVESTING ACTIVITIES Purchase of property, plant and equipment (1.1 ) (110.2 ) (0.1 ) — (111.4 ) Deposits for property, plant and equipment — (78.1 ) (5.2 ) — (83.3 ) Intercompany investing 185.7 (6.3 ) 120.7 (300.1 ) — Other investing activities — 3.1 17.9 — 21.0 Net cash provided (used) by investing activities 184.6 (191.5 ) 133.3 (300.1 ) (173.7 ) FINANCING ACTIVITIES Debt issuance costs (1.5 ) — — — (1.5 ) Repurchase of debt (16.3 ) — — — (16.3 ) Distributions of partnership equity — (44.2 ) — — (44.2 ) Intercompany financing (120.7 ) (188.6 ) 9.2 300.1 — Other financing activities (1.9 ) (1.5 ) (42.3 ) — (45.7 ) Net cash used by financing activities (140.4 ) (234.3 ) (33.1 ) 300.1 (107.7 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — (2.3 ) — (2.3 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS (56.4 ) (0.2 ) (38.4 ) — (95.0 ) LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS — — (13.8 ) — (13.8 ) NET DECREASE IN CASH AND CASH EQUIVALENTS (56.4 ) (0.2 ) (24.6 ) — (81.2 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 948.9 2.1 27.3 — 978.3 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 892.5 $ 1.9 $ 2.7 $ — $ 897.1

BASIS OF PRESENTATION AND SIG_4

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)unit	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Schedule of Equity Method Investments [Line Items]
Number of Reporting Units | unit		2
Gain on foreign currency translation	$ 228.1	$ 0	$ 228.1
Hibbing [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest, equity method investment		23.00%		23.00%
Hibbing [Member] | Other Noncurrent Liabilities [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments		$ 14		$ 15.4

SEGMENT REPORTING (Narrative) (

SEGMENT REPORTING (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)unit	Sep. 30, 2018USD ($)
Segment Reporting Information [Line Items]
Number of Reporting Units | unit			2
Revenues	$ 555.6	$ 741.8	$ 1,455.8	$ 1,636.1
SALES MARGIN	154.9	261.6	448.8	607.6
Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
Revenues	555.6	741.8	1,455.8	1,636.1
SALES MARGIN	$ 154.9	$ 261.6	$ 448.8	$ 607.6

SEGMENT REPORTING (Schedule of

SEGMENT REPORTING (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenues	$ 555.6			$ 741.8			$ 1,455.8	$ 1,636.1
SALES MARGIN	154.9			261.6			448.8	607.6
NET INCOME	90.9	$ 160.8	$ (22.1)	437.8	$ 165.1	$ (84.3)	229.6	518.6
Interest expense, net	(25.3)			(29.5)			(76.5)	(93.1)
Income tax expense	4.8			0.5			23.1	14.4
Depreciation, depletion and amortization							63.1	68.6
Depreciation, Depletion and Amortization excluding Depreciation, Amortization and Depletion expense for Discontinued Operations	22.2			19.2			63.1	53.4
EBITDA	143.3			487.2			392.6	697.1
Impact of discontinued operations	(0.9)			238			(1.5)	102.8
Gain (loss) on extinguishment of debt				0			(18.2)	0.2
Adjusted EBITDA	144.1			250.3			413.7	578.3
Property, Plant and Equipment, Additions	184.7			92.6			505.6	241.9
Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
Revenues	555.6			741.8			1,455.8	1,636.1
SALES MARGIN	154.9			261.6			448.8	607.6
Depreciation, depletion and amortization	20.8			17.8			58.9	49.2
EBITDA	177.5			273.1			494.9	641.6
Adjusted EBITDA	182.7			279.5			510.7	657.9
Property, Plant and Equipment, Additions	22.1			51.8			104.5	97.2
Metallics [Member]
Segment Reporting Information [Line Items]
Revenues	0						0
SALES MARGIN	0						0
EBITDA	(2.1)			(1)			(4)	(2.5)
Adjusted EBITDA	(2.1)			(1)			(4)	(2.5)
Property, Plant and Equipment, Additions	160.5			40.6			398	143.6
Corporate and Other Segments [Member]
Segment Reporting Information [Line Items]
EBITDA	(32.1)			215.1			(98.3)	58
Adjusted EBITDA	(36.5)			(28.2)			(93)	(77.1)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	1.4			1.4			4.2	4.2
Property, Plant and Equipment, Additions	2.1			0.2			3.1	1.1
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	590.6						1,494.8
SALES MARGIN	165.8						461.3
Operating Segments [Member] | Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
Revenues	590.6						1,494.8
SALES MARGIN	165.8						461.3
Operating Segments [Member] | Metallics [Member]
Segment Reporting Information [Line Items]
Revenues	0						0
SALES MARGIN	0						0
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	(35)						(39)
SALES MARGIN	(10.9)						(12.5)
Intersegment Eliminations [Member] | Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
Revenues	(35)						(39)
SALES MARGIN	(10.9)						(12.5)
Intersegment Eliminations [Member] | Metallics [Member]
Segment Reporting Information [Line Items]
Revenues	0						0
SALES MARGIN	0						0
EBITDA Calculation [Member]
Segment Reporting Information [Line Items]
Interest expense, net	(25.4)			(29.7)			(76.8)	(95.5)
Income tax expense	(4.8)			(0.5)			(23.1)	(14.4)
Depreciation, depletion and amortization	22.2			19.2			63.1	68.6
Adjusted EBITDA Calculation [Member]
Segment Reporting Information [Line Items]
Impact of discontinued operations	(0.8)			238.2			(1.2)	120.4
Gain (loss) on extinguishment of debt	0			0			(18.2)	0.2
Severance costs	0			0			(1.7)	0
Foreign exchange remeasurement	0			(0.2)			0	(0.7)
Impairment of long-lived assets	$ 0			$ (1.1)			$ 0	$ (1.1)

SEGMENT REPORTING (Reconciliati

SEGMENT REPORTING (Reconciliation of Assets from Segment to Consolidated) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 3,491.2	$ 3,529.6
Mining and Pelletizing [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	1,793.9	1,694.1
Metallics [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	708.5	265.9
Operating Segments [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	2,502.4	1,960
Corporate and Other [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 988.8	$ 1,569.6

REVENUE (Deferred Revenue) (Det

REVENUE (Deferred Revenue) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Other Current Liabilities [Member]
Deferred Revenue Arrangement [Line Items]
Contract with Customer, Liability, Current	$ 18.3	$ 16.1	$ 21	$ 23.8
Contract With Customer, Liability, Period Increase (Decrease)	(2.7)	(7.7)
Other Noncurrent Liabilities [Member]
Deferred Revenue Arrangement [Line Items]
Contract with Customer, Liability, Noncurrent	30	42.8	$ 38.5	$ 51.4
Contract With Customer, Liability, Period Increase (Decrease)	$ (8.5)	$ (8.6)

REVENUE (Narrative) (Details)

REVENUE (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 555.6	$ 741.8	$ 1,455.8	$ 1,636.1
Contract with Customer, Liability, Revenue Recognized			42.8		$ 51.3
Up-front Payment Arrangement [Member]
Contract with Customer, Liability	5.5		5.5		8.2
Not Designated as Hedging Instrument [Member]
Revenues	(40.9)	135.9	43.4	334.4
Other Current Liabilities [Member]
Contract with Customer, Liability	12.8		12.8		12.8
Other Noncurrent Liabilities [Member]
Contract with Customer, Liability, Noncurrent	$ 30	$ 42.8	$ 30	$ 42.8	$ 38.5	$ 51.4

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT (Value Of Each Of The Major Classes Of Consolidated Depreciable Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,851.7	$ 2,308.4
Allowance for depreciation and depletion	(1,081.8)	(1,022.4)
Property, plant and equipment, net	1,769.9	1,286
Land rights and mineral rights
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	549.7	549.6
Office and information technology
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	72.9	70
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	101.2	87.2
Mining equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	577	548.5
Processing equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	755.5	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	29.2	25.2
Construction-in-progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 668.9	$ 284.8

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Interest Costs Capitalized	$ 7	$ 1.8	$ 16.9	$ 3.9

DEBT AND CREDIT FACILITIES DEBT

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Debt Instrument, Par Value		$ 2,238
Extinguishment of Debt, Amount	$ 1	724	$ 16.5
$750 Million 5.875% 2027 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value		$ 750
Debt issuance, discount rate		96.125%
Debt Instrument, Interest Rate, Stated Percentage		5.875%
Repurchase price if triggering event occurs		101.00%
Debt Issuance Costs, Gross		$ 6.8
$1.075 Billion 5.75% 2025 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value		473.3		$ 1,073.3
Extinguishment of Debt, Amount	$ 0	$ 600	$ 1.7

DEBT AND CREDIT FACILITIES (Sch

DEBT AND CREDIT FACILITIES (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt Instrument, Par Value	$ 2,238
LONG-TERM DEBT	$ 2,109.1	$ 2,092.9
$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	$ 400
Unamortized Debt Issuance Expense	(4.9)	(5.7)
Debt Instrument, Unamortized Discount	(1.9)	(2.2)
Long-term Debt	$ 393.2	$ 392.1
$316.25 Million 1.50% 2025 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.26%	6.26%
Debt Instrument, Par Value	$ 316.3	$ 316.3
Unamortized Debt Issuance Expense	(4.8)	(5.5)
Debt Instrument, Unamortized Discount	(67.7)	(75.6)
Long-term Debt	$ 243.8	$ 235.2
$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	$ 473.3	$ 1,073.3
Unamortized Debt Issuance Expense	(3.8)	(9.9)
Debt Instrument, Unamortized Discount	(5.8)	(14.6)
Long-term Debt	$ 463.7	$ 1,048.8
$750 Million 5.875% 2027 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.49%
Debt Instrument, Par Value	$ 750
Unamortized Debt Issuance Expense	(6.5)
Debt Instrument, Unamortized Discount	(28)
Long-term Debt	$ 715.5
$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	$ 298.4	$ 298.4
Unamortized Debt Issuance Expense	(2.2)	(2.3)
Debt Instrument, Unamortized Discount	(3.3)	(3.3)
Long-term Debt	292.9	292.8
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	450	450
Credit facility, amount outstanding	$ 0	$ 0
$700 Million 4.875% 2021 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		4.89%
Debt Instrument, Par Value		$ 124
Unamortized Debt Issuance Expense		(0.2)
Debt Instrument, Unamortized Discount		0
Long-term Debt		123.8
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Fair Value Adjustment to Interest Rate Hedge		$ 0.2

DEBT AND CREDIT FACILITIES DE_2

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES (Debt Instrument Redemption) (Details) - $750 Million 5.875% 2027 Senior Notes [Member]	9 Months Ended
	Sep. 30, 2019
Debt Instrument, Redemption, Period One, Upon Equity Issuance [Member]
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	105.875%
Debt Instrument, Redemption, Period One, Including Premium [Member]
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	100.00%
Debt Instrument, Redemption, Period Two [Member]
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	102.938%
Debt Instrument, Redemption, Period Three [Member]
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	101.958%
Debt Instrument, Redemption, Period Four [Member]
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	100.979%
Debt Instrument, Redemption, Period Five [Member]
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	100.00%

DEBT AND CREDIT FACILITIES DE_3

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES (Schedule of Extinguishment of Debt) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	$ 1	$ 724	$ 16.5
Gain (loss) on extinguishment of debt	0	(18.2)	0.2
$400 million 5.90% 2020 Senior Notes [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	0		0.5
Gain (loss) on extinguishment of debt	0		0
$500 Million 4.80% 2020 Senior Notes [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	0		0.1
Gain (loss) on extinguishment of debt	0		0
$700 Million 4.875% 2021 Senior Notes [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	1	124	14.2
Gain (loss) on extinguishment of debt	0	(5.3)	0.1
$1.075 Billion 5.75% 2025 Senior Notes [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	0	600	1.7
Gain (loss) on extinguishment of debt	$ 0	$ (12.9)	$ 0.1

DEBT AND CREDIT FACILITIES (S_2

DEBT AND CREDIT FACILITIES (Schedule of Debt Maturities) (Details) $ in Millions	Sep. 30, 2019USD ($)
Debt Disclosure [Abstract]
Debt Maturities 2019	$ 0
Debt Maturities 2020	0
Debt Maturities 2021	0
Debt Maturities 2022	0
Debt Maturities 2023	0
Debt Maturities 2024	400
2025 and thereafter	1,838
Total maturities of debt	$ 2,238

DEBT AND CREDIT FACILITIES DE_4

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES (ABL Facility) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 450
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	400.8	$ 323.7
Long-term Line of Credit	0	0
Line of Credit Facility, Remaining Borrowing Capacity	366.7	268.7
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit	$ (34.1)	$ (55)

FAIR VALUE MEASUREMENTS (Fair V

FAIR VALUE MEASUREMENTS (Fair Value of Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	$ 272.5	$ 543.4
Derivative assets	72.8	91.5
Assets, Fair Value Disclosure	345.3	634.9
Derivative liability	32.6	3.7
Liabilities, Fair Value Disclosure	32.6	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
Assets, Fair Value Disclosure	0	0.8
Derivative liability	0	0
Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	272.5	542.6
Derivative assets	0	0.1
Assets, Fair Value Disclosure	272.5	542.7
Derivative liability	2.4	3.7
Liabilities, Fair Value Disclosure	2.4	3.7
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Derivative assets	72.8	91.4
Assets, Fair Value Disclosure	72.8	91.4
Derivative liability	30.2	0
Liabilities, Fair Value Disclosure	$ 30.2	$ 0

FAIR VALUE MEASUREMENTS (Schedu

FAIR VALUE MEASUREMENTS (Schedule Of Quantitative Inputs And Assumptions For Level 3 Assets And Liabilities) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 72,800,000	$ 91,500,000
Derivative liability	32,600,000	3,700,000
Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	72,800,000	91,400,000
Derivative liability	30,200,000	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	72,800,000	91,400,000
Derivative liability	30,200,000	0
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 assets	71,200,000	89,300,000
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 assets	1,600,000	2,100,000
Derivative liability	30,200,000
Derivative Asset [Member] | 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] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	631
Derivative Asset [Member] | 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] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	633
Derivative Asset [Member] | 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] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	700
Derivative Asset [Member] | 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] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	100
Derivative Liability [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		$ 0
Derivative Liability [Member] | 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] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	87
Derivative Liability [Member] | 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] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	96
Derivative Liability [Member] | 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] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	100
Derivative Liability [Member] | 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 Range	172
Derivative Liability [Member] | 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 Range	214
Derivative Liability [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member] | Atlantic Basin Pellet Premium [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	59
Derivative Liability [Member] | 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] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement With Unobservable Inputs Range	$ 198

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		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 118.1	$ 174.6	$ 91.4	$ 49.5
Included in earnings	(6.5)	139	83.1	341.8
Settlements	(38.8)	(123)	(101.7)	(200.7)
Ending balance - September 30	72.8	190.6	72.8	190.6
Total gains (losses) for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date	(6.5)	15.9	81.8	141
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	0	(3)	0	(1.7)
Included in earnings	(34.4)	(3.1)	(39.7)	(7.4)
Settlements	4.2	0.4	9.5	3.4
Ending balance - September 30	(30.2)	(5.7)	(30.2)	(5.7)
Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date	$ (30.2)	$ (2.7)	$ (30.2)	$ (5.7)

FAIR VALUE MEASUREMENTS (Carryi

FAIR VALUE MEASUREMENTS (Carrying Value And Fair Value Of Financial Instruments Disclosure) (Details) - USD ($) $ in Millions	Sep. 30, 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
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	$ 2,187.5	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	0.2
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	2,109.1	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	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	408.9	370.2
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	0	122.3
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316.25 Million 1.50% 2025 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	345.8	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	466.2	962
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $750 Million 5.875% 2027 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	712.2	0
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	254.4	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	393.2	392.1
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	0	123.8
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316.25 Million 1.50% 2025 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	243.8	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	463.7	1,048.8
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $750 Million 5.875% 2027 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	715.5	0
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	Sep. 30, 2019	Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	$ 72.8	$ 91.5
Derivative liability	32.6	3.7
Fair Value, Inputs, Level 1 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0	0
Derivative liability	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	0	0.1
Derivative liability	2.4	3.7
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	72.8	91.4
Derivative liability	30.2	0
Not Designated as Hedging Instrument [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	72.8	91.4
Derivative liability	30.2	0
Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Customer Supply Agreement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	71.2	89.3
Not Designated as Hedging Instrument [Member] | Valuation, Market Approach [Member] | Provisional Pricing Arrangements [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets	1.6	$ 2.1
Derivative liability	$ 30.2

PENSIONS AND OTHER POSTRETIRE_3

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Estimated Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 4.6	$ 4.7	$ 12.9	$ 14
Interest cost	8.9	7.6	26.2	22.7
Expected return on plan assets	(13.7)	(15)	(41)	(45)
Prior service cost (credits)	0.3	0.6	0.9	1.7
Net actuarial loss	5.9	5.3	17.7	15.9
Net periodic benefit cost (credit)	6	3.2	16.7	9.3
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.5	0.6	1.3	1.6
Interest cost	2.3	2.1	7	6.2
Expected return on plan assets	(4.2)	(4.6)	(12.6)	(13.8)
Prior service cost (credits)	(0.5)	(0.7)	(1.5)	(2.2)
Net actuarial loss	1.3	1.3	3.8	3.8
Net periodic benefit cost (credit)	$ (0.6)	$ (1.3)	$ (2)	$ (4.4)

PENSIONS AND OTHER POSTRETIRE_4

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Pension Contributions	$ 5.6	$ 18.3	$ 12.3	$ 23.9
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
OPEB Contributions	$ 0	$ 0	$ 0	$ 0

STOCK COMPENSATION PLANS (Assum

STOCK COMPENSATION PLANS (Assumptions Utilized to Estimate Fair Value for Performance Share Grants) (Details) - $ / shares	9 Months Ended
	Sep. 30, 2019	Feb. 19, 2019
Share-based Payment Arrangement [Abstract]
Grant Date Market Price		$ 11.24
Average Expected Term	2 years 10 months 13 days
Expected Volatility	67.50%
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	Feb. 19, 2019	Sep. 30, 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 Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	0.00%
2019 to 2021 Performance Period [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	200.00%

INCOME TAXES (Narrative) (Detai

INCOME TAXES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent			9.60%	0.10%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ 0.5	$ 0.2	$ 1.3	$ 13.9
Repeal of AMT, amount				$ 14.5

ENVIRONMENTAL AND MINE CLOSUR_3

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Summary Of Mine Closure Obligations) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Environmental	$ 2.1	$ 2.5
Asset Retirement Obligation	179.5	172.4	$ 168.4
Mine Reclamation and Closing Liability, current and noncurrent	181.6	174.9
Accrued Reclamation Costs, Current	2.5	2.9
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	179.1	172
Mining and Pelletizing [Member]
Loss Contingencies [Line Items]
Asset Retirement Obligation	$ 179.5	$ 172.4

ENVIRONMENTAL AND MINE CLOSUR_4

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Asset Retirement Obligation Disclosure) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Asset Retirement Obligation [Roll Forward]
Asset retirement obligation at beginning of period	$ 172.4	$ 168.4
Accretion expense	7.6	9.5
Remediation payments	(0.5)	(1)
Revision in estimated cash flows	0	(4.5)
Asset retirement obligation at end of period	$ 179.5	$ 172.4

DERIVATIVE INSTRUMENTS (Schedul

DERIVATIVE INSTRUMENTS (Schedule Of Derivative Instruments In Statement Of Financial Position, Fair Value) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets	$ 72.8	$ 91.5
Derivative liability	32.6	3.7
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	72.8	91.4
Derivative liability	30.2	0
Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0	0.1
Derivative liability	2.4	3.7
Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	72.8	91.4
Derivative liability	30.2	0
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 2 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Derivative Asset [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0	0.1
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 2 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Derivative Liability [Member]
Derivatives, Fair Value [Line Items]
Derivative liability	2.4	3.7
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	71.2	89.3
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1.6	2.1
Derivative liability	$ 30.2
Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Derivative Liability [Member]
Derivatives, Fair Value [Line Items]
Derivative liability		$ 0

DERIVATIVE INSTRUMENTS (Sched_2

DERIVATIVE INSTRUMENTS (Schedule Of Derivatives Not Designated As Hedging Instruments) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Revenues	$ 555.6	$ 741.8	$ 1,455.8	$ 1,636.1
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Revenues	(40.9)	135.9	43.4	334.4
Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Revenue from Contract with Customer Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in income on derivative	7.6	139.7	82.2	337.1
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Revenue from Contract with Customer Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in income on derivative	$ (48.5)	$ (3.8)	$ (38.8)	$ (2.7)

DERIVATIVE INSTRUMENTS (Sched_3

DERIVATIVE INSTRUMENTS (Schedule of Notional Amounts of Outstanding Derivatives) (Details) - Designated as Hedging Instrument [Member] gal in Millions, MMcf in Millions	3 Months Ended
	Sep. 30, 2019galMMcf	Dec. 31, 2018galMMcf
Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | MMcf	7	1.8
Diesel [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | gal	2.4	11

DISCONTINUED OPERATIONS (Schedu

DISCONTINUED OPERATIONS (Schedule of Disposal Groups, Including Discontinued Operations) (Details) $ in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2018CAD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of tax	$ (0.9)	$ 238		$ (1.5)	$ 102.8
Net cash used by operating activities				388.1	188.7
Net cash provided by investing activities				(449.5)	$ (173.7)
Noncash Investing and Financing Activities Related Text					For the nine months ended September 30, 2018, we had $27.1 million of non-cash financing activities related to the release of asset retirement obligations at Asia Pacific Iron Ore as part of the sale of substantially all remaining assets.
Gain on foreign currency translation		228.1		0	$ 228.1
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of tax	(0.1)	242.3		(1.1)	117.6
Revenues from product sales and services	0	0		0	129.1
Cost of goods sold	0	(0.5)		0	(230.7)
Sales margin	0	(0.5)		0	(101.6)
Other operating expense	0	14.8		(0.8)	(4)
Other expense	(0.1)	(0.1)		(0.3)	(2.3)
Gain on foreign currency translation	0	228.1		0	228.1
Impairment of long-lived assets	0	0		0	(2.6)
North American Coal [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of tax	(0.8)	(4.3)		(0.4)	(4.2)
Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of tax	$ 0	$ 0		0	(10.6)
Cash Contribution			$ 19
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash used by operating activities				(1.9)	(91.6)
Net cash provided by investing activities				0.1	17.8
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 used by operating activities				(1.9)	(77)
Net cash provided by investing activities				0.1	17.8
Discontinued Operations [Member] | Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash used by operating activities				$ 0	$ (14.6)

SHAREHOLDERS' EQUITY (Details)

SHAREHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2019	Sep. 03, 2019	May 31, 2019	Apr. 24, 2019	Feb. 19, 2019	Nov. 26, 2018	Oct. 18, 2018
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 100		$ 200
Stock Repurchased During Period, Shares			24.4
Common Share Repurchases, Value	$ 128.6	$ 124.3	$ 252.9
Stock Repurchase Program, Remaining Authorized Repurchase Amount			0.2
Common Stock [Member]
Class of Stock [Line Items]
Dividends payable, per share				$ 0.10	$ 0.06		$ 0.05		$ 0.05
Regular Dividend [Member] | Common Stock [Member]
Class of Stock [Line Items]
Dividends payable, per share				0.06
Special Dividend [Member] | Common Stock [Member]
Class of Stock [Line Items]
Dividends payable, per share				$ 0.04
Other Current Liabilities [Member]
Class of Stock [Line Items]
Dividends Payable			$ 28.2

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	$ 285.6	$ 261.7	$ 424.2				$ 424.2
Balance, beginning of period PY				$ (306.3)	$ (484.8)	$ (444.1)		$ (444.1)
Balance, end of period	359.9	285.6	261.7				359.9
Balance, end of period PY				(86.2)	(306.3)	(484.8)		(86.2)
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	(269.6)	(275.4)	(281.1)				(281.1)
Balance, beginning of period PY				(250.5)	(257.2)	(263.9)		(263.9)
Other comprehensive income (loss) before reclassifications	0.3	0.3	0.2	0.3	0.2	0.5
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	5.5	5.5	5.5	6.5	6.5	6.2
Balance, end of period		(269.6)	(275.4)
Balance, end of period PY	(263.8)			(243.7)	(250.5)	(257.2)	(263.8)	(243.7)
Unrealized Net Gain (Loss) on Foreign Currency Translation [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period PY				228.3	226.1	225.4		225.4
Other comprehensive income (loss) before reclassifications				(0.2)	2.2	0.7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				(228.1)	0	0
Balance, end of period PY				0	228.3	226.1		0
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	(2.2)	(0.1)	(2.8)				(2.8)
Balance, beginning of period PY				0	(0.2)	(0.5)		(0.5)
Other comprehensive income (loss) before reclassifications	(0.5)	(2.3)	2.5	0.2	0.2	0.4
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.9	0.2	0.2	0.1	0	(0.1)
Balance, end of period		(2.2)	(0.1)
Balance, end of period PY	(1.8)			0.3	0	(0.2)	(1.8)	0.3
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(271.8)	(275.5)	(283.9)				(283.9)
Balance, beginning of period PY				(22.2)	(31.3)	(39)		(39)
Other comprehensive income (loss) before reclassifications	(0.2)	(2)	2.7	0.3	2.6	1.6
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	6.4	5.7	5.7	(221.5)	6.5	6.1
Balance, end of period	(265.6)	$ (271.8)	$ (275.5)				(265.6)
Balance, end of period PY	$ (265.6)			$ (243.4)	$ (22.2)	$ (31.3)	$ (265.6)	$ (243.4)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details of Accumulated Other Comprehensive Income (Loss) Components) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 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	$ 1.2			$ 0.1			$ 1.7	$ 0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	6.4			(221.5)			17.8	(208.9)
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	$ 5.5	$ 5.5	6.5	$ 6.5	$ 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 cost (credits)	(0.2)			(0.1)			(0.6)	(0.5)
Net actuarial loss	7.2			6.6			21.5	19.7
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	7			6.5			20.9	19.2
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	(1.5)			0			(4.4)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	5.5			6.5			16.5	19.2
Foreign Currency Translation Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	0			(228.1)			0	(228.1)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	0			(228.1)			0	(228.1)
AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), Adjustments, Tax	(0.3)			0			(0.4)	0
Amount of gain/(loss) recognized in income on derivative	$ 0.9			$ 0.1			$ 1.3	$ 0

CASH FLOW INFORMATION (Narrativ

CASH FLOW INFORMATION (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Sep. 30, 2019	Sep. 03, 2019	May 31, 2019	Feb. 19, 2019	Oct. 18, 2018
Dividends Payable [Line Items]
Dividends Payable	$ 27
Common Stock [Member]
Dividends Payable [Line Items]
Dividends payable, per share		$ 0.10	$ 0.06	$ 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		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Supplemental Cash Flow Information [Abstract]
Capital Expenditure, Discontinued Operations				$ 0.1
Capital Additions	$ 184.7	$ 92.6	$ 505.6	241.9
Capital Additions, Including Discontinued Operations				242
Non-cash accruals			26.1	42.2
Right-of-Use Assets - Finance Leases			29.3	7.6
Government grant rebate			(10.5)	(2.5)
Cash paid for capital expenditures including deposits			$ 460.7	$ 194.7

RELATED PARTIES (Summary Of Oth

RELATED PARTIES (Summary Of Other Ownership Interests) (Details) - Hibbing [Member]	Sep. 30, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Ownership interest, equity method investment	23.00%	23.00%
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%

RELATED PARTIES (Summary Of Rel

RELATED PARTIES (Summary Of Related Party Transactions Table Disclosure) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Related Party Transaction [Line Items]
Revenues	$ 555.6	$ 741.8	$ 1,455.8	$ 1,636.1
Related party product revenue as a percent of total product revenue	50.90%	57.30%	52.90%	56.60%
Product [Member]
Related Party Transaction [Line Items]
Product revenues from related parties	$ 262	$ 392.4	$ 718.9	$ 863.8
Revenues	$ 515	$ 684.7	$ 1,357.8	$ 1,525.9

RELATED PARTIES (Summary of Bal

RELATED PARTIES (Summary of Balance Sheet Presentation) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Partnership distribution payable	$ 0	$ (43.5)
Related Party Transaction, Due from (to) Related Party	152.6	220
Trade Accounts Receivable [Member]
Related Party Transaction [Line Items]
Due from Related Parties, Current	108.7	176
Derivative Asset [Member]
Related Party Transaction [Line Items]
Due from Related Parties, Current	71.2	89.3
Derivative Liability [Member]
Related Party Transaction [Line Items]
Due to Related Parties, Current	(26.1)	0
Other Current Assets [Member]
Related Party Transaction [Line Items]
Due from Related Parties, Current	0.2	0
Other Current Liabilities [Member]
Related Party Transaction [Line Items]
Due to Related Parties, Current	$ (1.4)	$ (1.8)

RELATED PARTIES (Narrative) (De

RELATED PARTIES (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2017	Dec. 31, 2018
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
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]
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						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Income from continuing operations	$ 91.8			$ 199.8			$ 231.1	$ 415.8
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.9)			238			(1.5)	102.8
NET INCOME (LOSS)	$ 90.9	$ 160.8	$ (22.1)	$ 437.8	$ 165.1	$ (84.3)	$ 229.6	$ 518.6
Weighted average number of shares:
Basic	269,960			297,878			278,418	297,587
Convertible Senior Notes	3,700			8,000			5,800	1,900
Employee stock plans	2,900			4,300			3,600	4,000
Diluted	276,578			310,203			287,755	303,518
Earnings (loss) per common share - basic:
Continuing operations (in dollars per share)	$ 0.34			$ 0.67			$ 0.83	$ 1.40
Discontinued operations (in dollars per share)	0			0.80			(0.01)	0.35
Earnings (Loss) per Common Share - Basic (in dollars per share)	0.34			1.47			0.82	1.75
Earnings (loss) per common share - diluted:
Continuing operations (in dollars per share)	0.33			0.64			0.80	1.37
Discontinued operations (in dollars per share)	0			0.77			0	0.34
Earnings (Loss) per Common Share - Diluted (in dollars per share)	$ 0.33			$ 1.41			$ 0.80	$ 1.71

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Purchase Commitments) (Details) $ in Millions	Sep. 30, 2019USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
Estimated Project Capital Expenditures	$ 830
Estimated Project Capital Expenditures, Variable Contingency	20.00%
Capital commitments, amount expected in remainder of 2019	$ 180
Capital commitments, amount expected in 2020	245
Capital Addition Purchase Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Capital Additions, Purchase Commitments	$ 390

SUPPLEMENTARY GUARANTOR INFOR_3

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Financial Position) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 399.3			$ 823.2	$ 897.1	$ 978.3
Accounts receivable, net	164.9			226.7
Finished goods inventories	162.2			77.8
Work-in-process inventories	55.2			10.1
Supplies and other inventories	110.8			93.2
Derivative assets	72.8			91.5
Income tax receivable, current	58.7			117.3
Other current assets	40.7			39.8
TOTAL CURRENT ASSETS	1,064.6			1,479.6
PROPERTY, PLANT AND EQUIPMENT, NET	1,769.9			1,286
Deposits for property, plant and equipment	41.6			83
Income tax receivable, non-current	62.7			121.3
Deferred income taxes	437.5			464.8
Investment in subsidiaries	0			0
Long-term intercompany notes	0			0
Other non-current assets	114.9			94.9
TOTAL OTHER ASSETS	656.7			764
TOTAL ASSETS	3,491.2			3,529.6
Accounts payable	212.8			186.8
Accrued employment costs	57.3			74
Accrued interest	34.1			38.4
Derivative liabilities	32.6			3.7
Partnership distribution payable	0			43.5
Other current liabilities	121.7			121.8
TOTAL CURRENT LIABILITIES	458.5			468.2
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	233.2			248.7
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	179.1			172
LONG-TERM DEBT	2,109.1			2,092.9
LONG-TERM INTERCOMPANY NOTES	0			0
OTHER LIABILITIES	151.4			123.6
TOTAL LIABILITIES	3,131.3			3,105.4
TOTAL EQUITY	359.9	$ 285.6	$ 261.7	424.2
TOTAL LIABILITIES AND EQUITY	3,491.2			3,529.6
Consolidation, Eliminations [Member]
Cash and cash equivalents	0			0	0	0
Accounts receivable, net	(4.1)			(4.1)
Finished goods inventories	0			0
Work-in-process 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	(4.1)			(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 taxes	0			0
Investment in subsidiaries	(1,820.2)			(1,313.1)
Long-term intercompany notes	(121.3)			(121.3)
Other non-current assets	0			0
TOTAL OTHER ASSETS	(1,941.5)			(1,434.4)
TOTAL ASSETS	(1,945.6)			(1,438.5)
Accounts payable	(4.1)			(4.1)
Accrued employment costs	0			0
Accrued interest	0			0
Derivative liabilities	0			0
Partnership distribution payable	0			0
Other current liabilities	0			0
TOTAL CURRENT LIABILITIES	(4.1)			(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	(125.4)			(125.4)
TOTAL EQUITY	(1,820.2)			(1,313.1)
TOTAL LIABILITIES AND EQUITY	(1,945.6)			(1,438.5)
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Cash and cash equivalents	2.7			2.7	2.7	27.3
Accounts receivable, net	0.2			0.3
Finished goods inventories	0			0
Work-in-process inventories	0			0
Supplies and other inventories	0			0
Derivative assets	0			0
Income tax receivable, current	0			0
Other current assets	8.5			12.9
TOTAL CURRENT ASSETS	11.4			15.9
PROPERTY, PLANT AND EQUIPMENT, NET	50.8			50.8
Deposits for property, plant and equipment	14.5			14.6
Income tax receivable, non-current	0			0
Deferred income taxes	1.2			1.2
Investment in subsidiaries	0			0
Long-term intercompany notes	121.3			121.3
Other non-current assets	1.3			1.5
TOTAL OTHER ASSETS	138.3			138.6
TOTAL ASSETS	200.5			205.3
Accounts payable	4.4			4.2
Accrued employment costs	0.1			0.1
Accrued interest	0			0
Derivative liabilities	0			0
Partnership distribution payable	0			0
Other current liabilities	7.3			8.2
TOTAL CURRENT LIABILITIES	11.8			12.5
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	(244.3)			(230)
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	19.4			19.9
LONG-TERM DEBT	0			0
LONG-TERM INTERCOMPANY NOTES	0			0
OTHER LIABILITIES	6.1			8.8
TOTAL LIABILITIES	(207)			(188.8)
TOTAL EQUITY	407.5			394.1
TOTAL LIABILITIES AND EQUITY	200.5			205.3
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Cash and cash equivalents	0.4			0.7	1.9	2.1
Accounts receivable, net	161.4			221.3
Finished goods inventories	162.2			77.8
Work-in-process inventories	55.2			10.1
Supplies and other inventories	110.8			93.2
Derivative assets	72.8			91.4
Income tax receivable, current	0			0
Other current assets	22.9			16.9
TOTAL CURRENT ASSETS	585.7			511.4
PROPERTY, PLANT AND EQUIPMENT, NET	1,706.8			1,221.9
Deposits for property, plant and equipment	27.1			68.4
Income tax receivable, non-current	4.1			4.1
Deferred income taxes	0			0
Investment in subsidiaries	39.7			50.8
Long-term intercompany notes	0			0
Other non-current assets	98			85.4
TOTAL OTHER ASSETS	168.9			208.7
TOTAL ASSETS	2,461.4			1,942
Accounts payable	207.8			181.4
Accrued employment costs	40.1			45.4
Accrued interest	0			0
Derivative liabilities	30.2			0
Partnership distribution payable	0			43.5
Other current liabilities	75.9			86.7
TOTAL CURRENT LIABILITIES	354			357
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	414.2			414.4
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	159.7			152.1
LONG-TERM DEBT	0			0
LONG-TERM INTERCOMPANY NOTES	0			0
OTHER LIABILITIES	120.8			99.5
TOTAL LIABILITIES	1,048.7			1,023
TOTAL EQUITY	1,412.7			919
TOTAL LIABILITIES AND EQUITY	2,461.4			1,942
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Cash and cash equivalents	396.2			819.8	$ 892.5	$ 948.9
Accounts receivable, net	7.4			9.2
Finished goods inventories	0			0
Work-in-process inventories	0			0
Supplies and other inventories	0			0
Derivative assets	0			0.1
Income tax receivable, current	58.7			117.3
Other current assets	9.3			10
TOTAL CURRENT ASSETS	471.6			956.4
PROPERTY, PLANT AND EQUIPMENT, NET	12.3			13.3
Deposits for property, plant and equipment	0			0
Income tax receivable, non-current	58.6			117.2
Deferred income taxes	436.3			463.6
Investment in subsidiaries	1,780.5			1,262.3
Long-term intercompany notes	0			0
Other non-current assets	15.6			8
TOTAL OTHER ASSETS	2,291			1,851.1
TOTAL ASSETS	2,774.9			2,820.8
Accounts payable	4.7			5.3
Accrued employment costs	17.1			28.5
Accrued interest	34.1			38.4
Derivative liabilities	2.4			3.7
Partnership distribution payable	0			0
Other current liabilities	38.5			26.9
TOTAL CURRENT LIABILITIES	96.8			102.8
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	63.3			64.3
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	0			0
LONG-TERM DEBT	2,109.1			2,092.9
LONG-TERM INTERCOMPANY NOTES	121.3			121.3
OTHER LIABILITIES	24.5			15.3
TOTAL LIABILITIES	2,415			2,396.6
TOTAL EQUITY	359.9			424.2
TOTAL LIABILITIES AND EQUITY	$ 2,774.9			$ 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						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues	$ 555.6			$ 741.8			$ 1,455.8	$ 1,636.1
COST OF GOODS SOLD	(400.7)			(480.2)			(1,007)	(1,028.5)
SALES MARGIN	154.9			261.6			448.8	607.6
Selling, general and administrative expenses	(25.5)			(29.1)			(82.2)	(78.9)
Miscellaneous - net	(7.8)			(7)			(19)	(18.7)
Other operating expense	(33.3)			(36.1)			(101.2)	(97.6)
OPERATING INCOME (LOSS)	121.6			225.5			347.6	510
Interest expense, net	(25.3)			(29.5)			(76.5)	(93.1)
Gain (loss) on extinguishment of debt				0			(18.2)	0.2
Other non-operating income (expense)	0.3			4.3			1.3	13.1
TOTAL OTHER INCOME (EXPENSE)	(25)			(25.2)			(93.4)	(79.8)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	96.6			200.3			254.2	430.2
Income tax benefit (expense)	(4.8)			(0.5)			(23.1)	(14.4)
EQUITY IN INCOME OF SUBSIDIARIES	0			0			0	0
INCOME FROM CONTINUING OPERATIONS	91.8			199.8			231.1	415.8
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.9)			238			(1.5)	102.8
NET INCOME (LOSS)	90.9	$ 160.8	$ (22.1)	437.8	$ 165.1	$ (84.3)	229.6	518.6
Other Comprehensive Income (Loss), Net of Tax	6.2	3.7	8.4	(221.2)	$ 9.1	$ 7.7	18.3	(204.4)
TOTAL COMPREHENSIVE INCOME (LOSS)	97.1	$ 164.5	$ (13.7)	216.6			247.9	314.2
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Revenues	0			0			0	0
COST OF GOODS SOLD	0			0			0	0
SALES MARGIN	0			0			0	0
Selling, general and administrative expenses	(20.7)			(23.1)			(67.1)	(62.9)
Miscellaneous - net	0			0			0	(0.4)
Other operating expense	(20.7)			(23.1)			(67.1)	(63.3)
OPERATING INCOME (LOSS)	(20.7)			(23.1)			(67.1)	(63.3)
Interest expense, net	(24.9)			(29.2)			(75)	(91.9)
Gain (loss) on extinguishment of debt							(18.2)	0.2
Other non-operating income (expense)	(0.9)			(0.9)			(3)	(2.6)
TOTAL OTHER INCOME (EXPENSE)	(25.8)			(30.1)			(96.2)	(94.3)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(46.5)			(53.2)			(163.3)	(157.6)
Income tax benefit (expense)	(4.8)			(0.3)			(22.7)	(13.8)
EQUITY IN INCOME OF SUBSIDIARIES	142.2			471			415.5	665.7
INCOME FROM CONTINUING OPERATIONS	90.9			417.5			229.5	494.3
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX	0			20.3			0.1	24.3
NET INCOME (LOSS)	90.9			437.8			229.6	518.6
Other Comprehensive Income (Loss), Net of Tax	6.2			(221.2)			18.3	(204.4)
TOTAL COMPREHENSIVE INCOME (LOSS)	97.1			216.6			247.9	314.2
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Revenues	555.6			741.8			1,455.8	1,636.1
COST OF GOODS SOLD	(400.7)			(480.2)			(1,007)	(1,028.5)
SALES MARGIN	154.9			261.6			448.8	607.6
Selling, general and administrative expenses	(4.7)			(5.7)			(14.7)	(15.3)
Miscellaneous - net	(7.7)			(6.5)			(17.9)	(16.9)
Other operating expense	(12.4)			(12.2)			(32.6)	(32.2)
OPERATING INCOME (LOSS)	142.5			249.4			416.2	575.4
Interest expense, net	(0.6)			(0.4)			(1.9)	(1.8)
Gain (loss) on extinguishment of debt							0	0
Other non-operating income (expense)	(3.4)			0.1			(9.8)	0.8
TOTAL OTHER INCOME (EXPENSE)	(4)			(0.3)			(11.7)	(1)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	138.5			249.1			404.5	574.4
Income tax benefit (expense)	0			0			(0.3)	(0.2)
EQUITY IN INCOME OF SUBSIDIARIES	4.6			4.7			13.3	13.8
INCOME FROM CONTINUING OPERATIONS	143.1			253.8			417.5	588
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.3)			12.9			(0.3)	12.8
NET INCOME (LOSS)	142.8			266.7			417.2	600.8
Other Comprehensive Income (Loss), Net of Tax	6.8			6.1			20.1	18
TOTAL COMPREHENSIVE INCOME (LOSS)	149.6			272.8			437.3	618.8
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Revenues	0			0			0	0
COST OF GOODS SOLD	0			0			0	0
SALES MARGIN	0			0			0	0
Selling, general and administrative expenses	(0.1)			(0.3)			(0.4)	(0.7)
Miscellaneous - net	(0.1)			(0.5)			(1.1)	(1.4)
Other operating expense	(0.2)			(0.8)			(1.5)	(2.1)
OPERATING INCOME (LOSS)	(0.2)			(0.8)			(1.5)	(2.1)
Interest expense, net	0.2			0.1			0.4	0.6
Gain (loss) on extinguishment of debt							0	0
Other non-operating income (expense)	4.6			5.1			14.1	14.9
TOTAL OTHER INCOME (EXPENSE)	4.8			5.2			14.5	15.5
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	4.6			4.4			13	13.4
Income tax benefit (expense)	0			(0.2)			(0.1)	(0.4)
EQUITY IN INCOME OF SUBSIDIARIES	0			0			0	0
INCOME FROM CONTINUING OPERATIONS	4.6			4.2			12.9	13
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.6)			204.8			(1.3)	65.7
NET INCOME (LOSS)	4			209			11.6	78.7
Other Comprehensive Income (Loss), Net of Tax	0			(230.5)			0	(227.5)
TOTAL COMPREHENSIVE INCOME (LOSS)	4			(21.5)			11.6	(148.8)
Consolidation, Eliminations [Member]
Revenues	0			0			0	0
COST OF GOODS SOLD	0			0			0	0
SALES MARGIN	0			0			0	0
Selling, general and administrative expenses	0			0			0	0
Miscellaneous - net	0			0			0	0
Other operating expense	0			0			0	0
OPERATING INCOME (LOSS)	0			0			0	0
Interest expense, net	0			0			0	0
Gain (loss) on extinguishment of debt							0	0
Other non-operating income (expense)	0			0			0	0
TOTAL OTHER INCOME (EXPENSE)	0			0			0	0
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	0			0			0	0
Income tax benefit (expense)	0			0			0	0
EQUITY IN INCOME OF SUBSIDIARIES	(146.8)			(475.7)			(428.8)	(679.5)
INCOME FROM CONTINUING OPERATIONS	(146.8)			(475.7)			(428.8)	(679.5)
INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX	0			0			0	0
NET INCOME (LOSS)	(146.8)			(475.7)			(428.8)	(679.5)
Other Comprehensive Income (Loss), Net of Tax	(6.8)			224.4			(20.1)	209.5
TOTAL COMPREHENSIVE INCOME (LOSS)	(153.6)			(251.3)			(448.9)	(470)
Product [Member]
Revenues	515			684.7			1,357.8	1,525.9
Product [Member] | Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Revenues	0			0			0	0
Product [Member] | Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Revenues	515			684.7			1,357.8	1,525.9
Product [Member] | Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Revenues	0			0			0	0
Product [Member] | Consolidation, Eliminations [Member]
Revenues	0			0			0	0
Freight [Member]
Revenues	40.6			57.1			98	110.2
Freight [Member] | Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Revenues	0			0			0	0
Freight [Member] | Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Revenues	40.6			57.1			98	110.2
Freight [Member] | Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Revenues	0			0			0	0
Freight [Member] | Consolidation, Eliminations [Member]
Revenues	$ 0			$ 0			$ 0	$ 0

SUPPLEMENTARY GUARANTOR INFOR_5

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Cash Flows) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Net cash provided (used) by operating activities	$ 388.1	$ 188.7
Purchase of property, plant and equipment	(447.9)	(111.4)
Deposits for property, plant and equipment	(12.8)	(83.3)
Intercompany investing	0	0
Other investing activities	11.2	21
Net cash provided (used) by investing activities	(449.5)	(173.7)
Repurchase of common shares	(252.9)	0
Dividends paid	(45.1)	0
Proceeds from issuance of debt	720.9	0
Debt issuance costs	(6.8)	(1.5)
Repurchase of debt	(729.3)	(16.3)
Distributions of partnership equity	(44.2)	(44.2)
Intercompany financing	0	0
Other financing activities	(9.5)	(45.7)
Net cash provided (used) by financing activities	(366.9)	(107.7)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	0	(2.3)
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS	(428.3)	(95)
LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS	(4.4)	(13.8)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(423.9)	(81.2)
Cash and cash equivalents	399.3	897.1	$ 823.2	$ 978.3
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Net cash provided (used) by operating activities	(11)	(100.6)
Purchase of property, plant and equipment	(1.2)	(1.1)
Deposits for property, plant and equipment	0	0
Intercompany investing	(83.6)	185.7
Other investing activities	0	0
Net cash provided (used) by investing activities	(84.8)	184.6
Repurchase of common shares	(252.9)
Dividends paid	(45.1)
Proceeds from issuance of debt	720.9
Debt issuance costs	(6.8)	(1.5)
Repurchase of debt	(729.3)	(16.3)
Distributions of partnership equity	0	0
Intercompany financing	0	(120.7)
Other financing activities	(14.6)	(1.9)
Net cash provided (used) by financing activities	(327.8)	(140.4)
EFFECT OF EXCHANGE RATE CHANGES ON CASH		0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS	(423.6)	(56.4)
LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS	0	0
NET DECREASE IN CASH AND CASH EQUIVALENTS	(423.6)	(56.4)
Cash and cash equivalents	396.2	892.5	819.8	948.9
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Net cash provided (used) by operating activities	402.8	425.6
Purchase of property, plant and equipment	(446.7)	(110.2)
Deposits for property, plant and equipment	(12.3)	(78.1)
Intercompany investing	(1.2)	(6.3)
Other investing activities	10.4	3.1
Net cash provided (used) by investing activities	(449.8)	(191.5)
Repurchase of common shares	0
Dividends paid	0
Proceeds from issuance of debt	0
Debt issuance costs	0	0
Repurchase of debt	0	0
Distributions of partnership equity	(44.2)	(44.2)
Intercompany financing	83.1	(188.6)
Other financing activities	7.8	(1.5)
Net cash provided (used) by financing activities	46.7	(234.3)
EFFECT OF EXCHANGE RATE CHANGES ON CASH		0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS	(0.3)	(0.2)
LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS	0	0
NET DECREASE IN CASH AND CASH EQUIVALENTS	(0.3)	(0.2)
Cash and cash equivalents	0.4	1.9	0.7	2.1
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Net cash provided (used) by operating activities	(3.7)	(136.3)
Purchase of property, plant and equipment	0	(0.1)
Deposits for property, plant and equipment	(0.5)	(5.2)
Intercompany investing	0	120.7
Other investing activities	0.8	17.9
Net cash provided (used) by investing activities	0.3	133.3
Repurchase of common shares	0
Dividends paid	0
Proceeds from issuance of debt	0
Debt issuance costs	0	0
Repurchase of debt	0	0
Distributions of partnership equity	0	0
Intercompany financing	1.7	9.2
Other financing activities	(2.7)	(42.3)
Net cash provided (used) by financing activities	(1)	(33.1)
EFFECT OF EXCHANGE RATE CHANGES ON CASH		(2.3)
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS	(4.4)	(38.4)
LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS	(4.4)	(13.8)
NET DECREASE IN CASH AND CASH EQUIVALENTS	0	(24.6)
Cash and cash equivalents	2.7	2.7	2.7	27.3
Consolidation, Eliminations [Member]
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	84.8	(300.1)
Other investing activities	0	0
Net cash provided (used) by investing activities	84.8	(300.1)
Repurchase of common shares	0
Dividends paid	0
Proceeds from issuance of debt	0
Debt issuance costs	0	0
Repurchase of debt	0	0
Distributions of partnership equity	0	0
Intercompany financing	(84.8)	300.1
Other financing activities	0	0
Net cash provided (used) by financing activities	(84.8)	300.1
EFFECT OF EXCHANGE RATE CHANGES ON CASH		0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN OTHER CURRENT ASSETS RELATED TO DISCONTINUED OPERATIONS	0	0
LESS: DECREASE IN CASH AND CASH EQUIVALENTS FROM DISCONTINUED OPERATIONS, CLASSIFIED WITHIN OTHER CURRENT ASSETS	0	0
NET DECREASE IN CASH AND CASH EQUIVALENTS	0	0
Cash and cash equivalents	$ 0	$ 0	$ 0	$ 0

SUPPLEMENTARY GUARANTOR INFOR_6

SUPPLEMENTARY GUARANTOR INFORMATION (Narrative) (Details)	Sep. 30, 2019
Noncontrolling Interest, Ownership Percentage by Parent	100.00%