Cleveland-Cliffs (CLF) 10-Q 24 Jul 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 20, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	CLEVELAND-CLIFFS INC.
Entity Central Index Key	764,065
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		297,953,281
Trading Symbol	clf
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Statements Of Unaudited Condens

Statements Of Unaudited Condensed Consolidated Financial Position - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
CURRENT ASSETS
Cash and cash equivalents	$ 802.5	$ 978.3
Accounts receivable, net	152.6	106.7
Inventories	256.4	138.4
Supplies and other inventories	88.6	88.8
Derivative assets	174.7	37.9
Current assets of discontinued operations	45.3	118.5
Loans to and accounts receivable from the Canadian Entities	0	51.6
Other current assets	26.8	24.4
TOTAL CURRENT ASSETS	1,546.9	1,544.6
PROPERTY, PLANT AND EQUIPMENT, NET	1,081.3	1,033.8
OTHER ASSETS
Deposits for property, plant and equipment	85.7	17.8
Income tax receivable	219.9	235.3
Non-current assets of discontinued operations	0	20.3
Other non-current assets	117.7	101.6
TOTAL OTHER ASSETS	423.3	375
TOTAL ASSETS	3,051.5	2,953.4
CURRENT LIABILITIES
Accounts payable	119	99.5
Accrued expenses	85.1	79.1
Accrued interest	43.1	31.4
Contingent claims	0	55.6
Partnership distribution payable	44.2	44.2
Current liabilities of discontinued operations	117.3	75
Other current liabilities	66.2	67.4
TOTAL CURRENT LIABILITIES	474.9	452.2
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	245	257.7
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	172.3	167.7
LONG-TERM DEBT	2,297	2,304.2
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3	52.2
OTHER LIABILITIES	158.3	163.5
TOTAL LIABILITIES	3,357.8	3,397.5
COMMITMENTS AND CONTINGENCIES (REFER TO NOTE 20)
CLIFFS SHAREHOLDERS' DEFICIT
Common Shares - par value $0.125 per share, Authorized - 600,000,000 shares (2017 - 600,000,000 shares); Issued - 301,886,794 shares (2017 - 301,886,794 shares); Outstanding - 297,846,632 shares (2017 - 297,400,968 shares)	37.7	37.7
Capital in excess of par value of shares	3,918.2	3,933.9
Retained deficit	(4,092.5)	(4,207.3)
Cost of 4,040,162 common shares in treasury (2017 - 4,485,826 shares)	(147.5)	(169.6)
Accumulated other comprehensive loss	(22.2)	(39)
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	(306.3)	(444.3)
NONCONTROLLING INTEREST	0	0.2
TOTAL DEFICIT	(306.3)	(444.1)
TOTAL LIABILITIES AND DEFICIT	$ 3,051.5	$ 2,953.4

Statements Of Condensed Consoli

Statements Of Condensed Consolidated Financial Position (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
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	297,846,632	297,400,968
Common shares in treasury	4,040,162	4,485,826
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 Conden4

Statements Of Unaudited Condensed Consolidated Operations - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
REVENUES FROM PRODUCT SALES AND SERVICES
Product	$ 672	$ 417	$ 841.2	$ 664.3
Freight and venture partners' cost reimbursements	42.3	54.3	53.1	93.2
TOTAL REVENUES	714.3	471.3	894.3	757.5
COST OF GOODS SOLD AND OPERATING EXPENSES	(429.8)	(326.6)	(548.3)	(563.8)
SALES MARGIN	284.5	144.7	346	193.7
OTHER OPERATING INCOME (EXPENSE)
Selling, general and administrative expenses	(26.2)	(26.6)	(51.3)	(51.7)
Miscellaneous - net	(4.1)	(2.9)	(10.2)	6.6
Other operating expense	(30.3)	(29.5)	(61.5)	(45.1)
OPERATING INCOME	254.2	115.2	284.5	148.6
OTHER INCOME (EXPENSE)
Interest expense, net	(31.2)	(30.1)	(63.6)	(71.5)
Gain (loss) on extinguishment of debt	0.2	(4.9)	0.2	(76.8)
Other non-operating income	4.4	2.5	8.8	5
TOTAL OTHER INCOME (EXPENSE)	(26.6)	(32.5)	(54.6)	(143.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	227.6	82.7	229.9	5.3
INCOME TAX BENEFIT (EXPENSE)	1.8	1.1	(13.9)	0
INCOME FROM CONTINUING OPERATIONS	229.4	83.8	216	5.3
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(64.3)	(53.7)	(135.2)	(5)
NET INCOME	165.1	30.1	80.8	0.3
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST	0	1.7	0	3.4
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ 165.1	$ 31.8	$ 80.8	$ 3.7
INCOME (LOSS) PER COMMON SHARE ATTRIBUTABLE TO CLIFFS SHAREHOLDERS – BASIC
Continuing operations (in dollars per share)	$ 0.77	$ 0.28	$ 0.73	$ 0.03
Discontinued operations (in dollars per share)	(0.22)	(0.18)	(0.46)	(0.01)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share)	0.55	0.10	0.27	0.02
INCOME (LOSS) PER COMMON SHARE ATTRIBUTABLE TO CLIFFS SHAREHOLDERS – DILUTED
Continuing operations (in dollars per share)	0.76	0.28	0.72	0.03
Discontinued operations (in dollars per share)	(0.21)	(0.18)	(0.45)	(0.02)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share)	$ 0.55	$ 0.10	$ 0.27	$ 0.01
AVERAGE NUMBER OF SHARES (IN THOUSANDS)
Basic	297,618	296,100	297,442	280,617
Diluted	301,275	300,700	301,143	285,247

Statements Of Unaudited Conden5

Statements Of Unaudited Condensed Consolidated Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ 165.1	$ 31.8	$ 80.8	$ 3.7
OTHER COMPREHENSIVE INCOME (LOSS)
Changes in pension and other post-retirement benefits, net of tax	6.7	6.7	13.4	11.4
Unrealized net gain (loss) on foreign currency translation	2.2	(1.4)	2.9	(14.1)
Unrealized net gain on derivative financial instruments, net of tax	0.2	0	0.5	0
OTHER COMPREHENSIVE INCOME (LOSS)	9.1	5.3	16.8	(2.7)
OTHER COMPREHENSIVE LOSS (INCOME) ATTRIBUTABLE TO THE NONCONTROLLING INTEREST	0	0.4	0	(4.6)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ 174.2	$ 36.7	$ 97.6	$ 5.6

Statements Of Unaudited Conden6

Statements Of Unaudited Condensed Consolidated Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
NET INCOME	$ 80.8	$ 0.3
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Depreciation, depletion and amortization	49.4	44.8
Loss (gain) on extinguishment of debt	(0.2)	76.8
Loss on deconsolidation	0	48.6
Gain on derivatives	(123.5)	(19.1)
Other	12.6	10.8
Changes in operating assets and liabilities:
Receivables and other assets	61.8	68.3
Inventories	(125.6)	(106.6)
Payables, accrued expenses and other liabilities	(4.6)	(56.1)
Net cash provided (used) by operating activities	(49.3)	67.8
INVESTING ACTIVITIES
Purchase of property, plant and equipment	(42.1)	(44.3)
Deposits for property, plant and equipment	(72.3)	(5.1)
Proceeds on sales of assets	14.6	1.1
Net cash used by investing activities	(99.8)	(48.3)
FINANCING ACTIVITIES
Proceeds from issuance of debt	0	500
Debt issuance costs	(1.5)	(8.5)
Net proceeds from issuance of common shares	0	661.3
Repurchase of debt	(15.3)	(1,154)
Distributions of partnership equity	0	(8.7)
Other financing activities	(8.9)	(13.9)
Net cash used by financing activities	(25.7)	(23.8)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(1)	2.4
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(175.8)	(1.9)
LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	40.5
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(175.8)	(42.4)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	978.3	312.8
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 802.5	$ 270.4

BASIS OF PRESENTATION AND SIGNI

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2018
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 and cash flows for the periods presented. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Management bases its estimates on various assumptions and historical experience, which are believed to be reasonable; however, due to the inherent nature of estimates, actual results may differ significantly due to changed conditions or assumptions. The results of operations for the three and six months ended June 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018 or any other future period. These unaudited condensed consolidated financial statements should be read in conjunction with the financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2017 . As more fully described in NOTE 16 - DISCONTINUED OPERATIONS , on January 25, 2018, we announced that we would accelerate the time frame for the planned closure of our Asia Pacific Iron Ore mining operations in Australia. On April 6, 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 June 2018, we completed a sale of the mobile equipment to a third party and entered into a definitive agreement to sell substantially all of the remaining assets of our Asia Pacific Iron Ore business to Mineral Resources Limited. The sale to Mineral Resources Limited has not been completed as of the date of this report due to the pendency of certain closing conditions. As a result, for the period ended June 30, 2018, 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 205, Presentation of Financial Statements . As such, all current and historical Asia Pacific Iron Ore operating segment results are included in our financial statements and classified within discontinued operations. We now operate in one reportable segment – U.S. Iron Ore. Unless otherwise noted, discussion of our business and results of operations in this Quarterly Report on Form 10-Q refers to our continuing operations. Basis of Consolidation The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, including the following operations as of June 30, 2018 : Name Location Status of Operations Northshore Minnesota Active United Taconite Minnesota Active Tilden Michigan Active Empire Michigan Indefinitely Idled Koolyanobbing 1 Western Australia Not Active 1 During June 2018, we completed the final planned shipment from Asia Pacific Iron Ore and commenced selling its assets. Refer to NOTE 16 - DISCONTINUED OPERATIONS. 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 June 30, 2018 and December 31, 2017 , our investment in Hibbing was $8.0 million and $11.0 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. The functional currency of our Australian subsidiaries is the Australian dollar. Refer to NOTE 16 - DISCONTINUED OPERATIONS for further information regarding our Australian subsidiaries. The functional currency of all other international subsidiaries is the U.S. dollar. To the extent that monetary assets and liabilities, including short-term intercompany loans, are recorded in a currency other than the functional currency, these amounts are remeasured each reporting period, with the resulting gain or loss being recorded in the Statements of Unaudited Condensed Consolidated Operations . Transaction gains and losses resulting from remeasurement of short-term intercompany loans are included in Miscellaneous – net in the Statements of Unaudited Condensed Consolidated Operations . The following represents the transaction gains and losses resulting from remeasurement: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Short-term intercompany loans $ (0.1 ) $ 1.5 $ (0.3 ) $ 16.6 Other — (1.0 ) (0.2 ) (1.3 ) Net impact of transaction gains (losses) resulting from remeasurement $ (0.1 ) $ 0.5 $ (0.5 ) $ 15.3 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, 2017 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 other than those related to the adoption of Topic 606. Refer to NOTE 2 - NEW ACCOUNTING STANDARDS for further information.

NEW ACCOUNTING STANDARDS

NEW ACCOUNTING STANDARDS	6 Months Ended
	Jun. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
NEW ACCOUNTING STANDARDS	NOTE 2 - NEW ACCOUNTING STANDARDS Adoption of New Accounting Standards ASC Topic 606, Revenue from Contracts with Customers (Topic 606). On January 1, 2018, we adopted Topic 606 and applied it to all contracts that were not completed using the modified retrospective method. We recognized the cumulative effect of initially applying Topic 606 as an adjustment of $34.0 million to the opening balance of Retained deficit . The comparative period information has not been restated and continues to be reported under the accounting standards in effect for those periods. We do not expect that the adoption of Topic 606 will have a material impact to our annual net income on an ongoing basis. Under Topic 606, revenue will generally be recognized upon delivery to our customers, which is earlier than under the previous guidance. As an example, for certain iron ore shipments where revenue was previously recognized upon title transfer when payment was received, we will now recognize revenue when control transfers, which is generally upon delivery. While we continue to retain title until we receive payment, we determined upon review of our customer contracts that the preponderance of control indicators pass to our customers' favor when we deliver our products; thus, we generally concluded that control transfers at that point. As a result of the adoption of Topic 606 and vessel deliveries not occurring during the winter months because of the closure of the Soo Locks and the Welland Canal, our revenues and net income will be relatively lower than historical levels during the first quarter of each year and relatively higher than historical levels during the remaining three quarters in future years. However, the total amount of revenue recognized during the year should remain substantially the same as under previous accounting standards, assuming revenue rates and volumes are consistent between years. The cumulative effect of the changes made to our consolidated January 1, 2018 balance sheet for the adoption of Topic 606 were as follows: ($ in Millions) Balance at December 31, 2017 Adjustments due to Topic 606 Balance at January 1, 2018 ASSETS CURRENT ASSETS Cash and cash equivalents $ 978.3 $ — $ 978.3 Accounts receivable, net 106.7 76.6 183.3 Inventories 138.4 (51.4 ) 87.0 Supplies and other inventories 88.8 — 88.8 Derivative assets 37.9 11.6 49.5 Current assets of discontinued operations 118.5 — 118.5 Loans to and accounts receivable from the Canadian Entities 51.6 — 51.6 Other current assets 24.4 — 24.4 TOTAL CURRENT ASSETS 1,544.6 36.8 1,581.4 PROPERTY, PLANT AND EQUIPMENT, NET 1,033.8 — 1,033.8 OTHER ASSETS Deposits for property, plant and equipment 17.8 — 17.8 Income tax receivable 235.3 — 235.3 Long-term assets of discontinued operations 20.3 — 20.3 Other non-current assets 101.6 — 101.6 TOTAL OTHER ASSETS 375.0 — 375.0 TOTAL ASSETS $ 2,953.4 $ 36.8 $ 2,990.2 LIABILITIES CURRENT LIABILITIES Accounts payable $ 99.5 $ 1.4 $ 100.9 Accrued expenses 79.1 — 79.1 Accrued interest 31.4 — 31.4 Contingent claims 55.6 — 55.6 Partnership distribution payable 44.2 — 44.2 Current liabilities of discontinued operations 75.0 — 75.0 Other current liabilities 67.4 1.4 68.8 TOTAL CURRENT LIABILITIES 452.2 2.8 455.0 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 257.7 — 257.7 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS 167.7 — 167.7 LONG-TERM DEBT 2,304.2 — 2,304.2 NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS 52.2 — 52.2 OTHER LIABILITIES 163.5 — 163.5 TOTAL LIABILITIES 3,397.5 2.8 3,400.3 EQUITY CLIFFS SHAREHOLDERS' DEFICIT (444.3 ) 34.0 (410.3 ) NONCONTROLLING INTEREST 0.2 — 0.2 TOTAL DEFICIT (444.1 ) 34.0 (410.1 ) TOTAL LIABILITIES AND DEFICIT $ 2,953.4 $ 36.8 $ 2,990.2 The impact of adoption on our Statements of Unaudited Condensed Consolidated Operations and Statements of Unaudited Condensed Consolidated Financial Position is as follows: ($ in Millions) Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 As Reported Balances without Adoption of Topic 606 Effect of Change As Reported Balances without Adoption of Topic 606 Effect of Change REVENUES FROM PRODUCT SALES AND SERVICES Product $ 672.0 $ 568.0 $ 104.0 $ 841.2 $ 795.6 $ 45.6 Freight and venture partners' cost reimbursements 42.3 36.3 6.0 53.1 51.2 1.9 714.3 604.3 110.0 894.3 846.8 47.5 COST OF GOODS SOLD AND OPERATING EXPENSES (429.8 ) (368.6 ) (61.2 ) (548.3 ) (530.7 ) (17.6 ) SALES MARGIN 284.5 235.7 48.8 346.0 316.1 29.9 OTHER OPERATING EXPENSE Selling, general and administrative expenses (26.2 ) (26.2 ) — (51.3 ) (51.3 ) — Miscellaneous – net (4.1 ) (4.1 ) — (10.2 ) (10.2 ) — (30.3 ) (30.3 ) — (61.5 ) (61.5 ) — OPERATING INCOME 254.2 205.4 48.8 284.5 254.6 29.9 OTHER INCOME (EXPENSE) Interest expense, net (31.2 ) (31.2 ) — (63.6 ) (63.6 ) — Gain on extinguishment of debt 0.2 0.2 — 0.2 0.2 — Other non-operating income 4.4 4.4 — 8.8 8.8 — (26.6 ) (26.6 ) — (54.6 ) (54.6 ) — INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES 227.6 178.8 48.8 229.9 200.0 29.9 INCOME TAX BENEFIT (EXPENSE) 1.8 1.8 — (13.9 ) (13.9 ) — INCOME FROM CONTINUING OPERATIONS 229.4 180.6 48.8 216.0 186.1 29.9 LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX (64.3 ) (64.3 ) — (135.2 ) (135.2 ) — NET INCOME 165.1 116.3 48.8 80.8 50.9 29.9 LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST — — — — — — NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 165.1 $ 116.3 $ 48.8 $ 80.8 $ 50.9 $ 29.9 INCOME (LOSS) PER COMMON SHARE ATTRIBUTABLE TO CLIFFS SHAREHOLDERS – BASIC Continuing operations $ 0.77 $ 0.61 $ 0.16 $ 0.73 $ 0.62 $ 0.10 Discontinued operations (0.22 ) (0.22 ) — (0.46 ) (0.45 ) — $ 0.55 $ 0.39 $ 0.16 $ 0.27 $ 0.17 $ 0.10 INCOME (LOSS) PER COMMON SHARE ATTRIBUTABLE TO CLIFFS SHAREHOLDERS – DILUTED Continuing operations $ 0.76 $ 0.60 $ 0.16 $ 0.72 $ 0.62 $ 0.10 Discontinued operations (0.21 ) (0.21 ) — (0.45 ) (0.45 ) — $ 0.55 $ 0.39 $ 0.16 $ 0.27 $ 0.17 $ 0.10 AVERAGE NUMBER OF SHARES (IN THOUSANDS) Basic 297,618 297,618 297,442 297,442 Diluted 301,275 301,275 301,143 301,143 ($ in Millions) June 30, 2018 As Reported Balances without Adoption of Topic 606 Effect of Change ASSETS CURRENT ASSETS Cash and cash equivalents $ 802.5 $ 802.5 $ — Accounts receivable, net 152.6 53.0 99.6 Inventories 256.4 323.9 (67.5 ) Supplies and other inventories 88.6 88.6 — Derivative assets 174.7 146.2 28.5 Current assets of discontinued operations 45.3 45.3 — Loans to and accounts receivable from the Canadian Entities — — — Other current assets 26.8 26.8 — TOTAL CURRENT ASSETS 1,546.9 1,486.3 60.6 PROPERTY, PLANT AND EQUIPMENT, NET 1,081.3 1,081.3 — OTHER ASSETS Deposits for property, plant and equipment 85.7 85.7 — Income tax receivable 219.9 219.9 — Non-current assets of discontinued operations — — — Other non-current assets 117.7 117.7 — TOTAL OTHER ASSETS 423.3 423.3 — TOTAL ASSETS $ 3,051.5 $ 2,990.9 $ 60.6 LIABILITIES CURRENT LIABILITIES Accounts payable $ 119.0 $ 117.8 $ 1.2 Accrued expenses 85.1 85.1 — Accrued interest 43.1 43.1 — Contingent claims — — — Partnership distribution payable 44.2 44.2 — Current liabilities of discontinued operations 117.3 117.3 — Other current liabilities 66.2 72.1 (5.9 ) TOTAL CURRENT LIABILITIES 474.9 479.6 (4.7 ) PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 245.0 245.0 — ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS 172.3 172.3 — LONG-TERM DEBT 2,297.0 2,297.0 — NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS 10.3 10.3 — OTHER LIABILITIES 158.3 158.3 — TOTAL LIABILITIES 3,357.8 3,362.5 (4.7 ) EQUITY CLIFFS SHAREHOLDERS' DEFICIT (306.3 ) (371.6 ) 65.3 NONCONTROLLING INTEREST — — — TOTAL DEFICIT (306.3 ) (371.6 ) 65.3 TOTAL LIABILITIES AND DEFICIT $ 3,051.5 $ 2,990.9 $ 60.6 The adoption of Topic 606 did not have an impact on net cash flows in our Statements of Unaudited Condensed Consolidated Cash Flows . ASU 2017-07, Retirement Benefits - Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . On January 1, 2018, we adopted the amendments to ASC 715 regarding the presentation of net periodic pension and postretirement benefit costs. We retrospectively adopted the presentation of service cost separate from the other components of net periodic costs. The interest cost, expected return on assets, amortization of prior service costs, net remeasurement, and other costs have been reclassified from Cost of goods sold and operating expenses , Selling, general and administrative expenses and Miscellaneous – net to Other non-operating income . We elected to apply the practical expedient, which allows us to reclassify amounts disclosed previously in our pension and other postretirement benefits footnote as the basis for applying retrospective presentation for comparative periods. On a prospective basis, only service costs will be included in amounts capitalized in inventory or property, plant, and equipment. The effect of the retrospective presentation change related to the net periodic cost of our defined benefit pension and other postretirement employee benefits plans on our Statements of Unaudited Condensed Consolidated Operations was as follows: ($ in Millions) Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 As Revised Without Adoption of ASU 2017-07 Effect of Change As Revised Without Adoption of ASU 2017-07 Effect of Change Cost of goods sold and operating expenses $ (326.6 ) $ (327.1 ) $ 0.5 $ (563.8 ) $ (564.9 ) $ 1.1 Selling, general and administrative expenses $ (26.6 ) $ (24.7 ) $ (1.9 ) $ (51.7 ) $ (47.8 ) $ (3.9 ) Miscellaneous – net $ (2.9 ) $ (2.6 ) $ (0.3 ) $ 6.6 $ 7.3 $ (0.7 ) Operating income $ 115.2 $ 116.9 $ (1.7 ) $ 148.6 $ 152.1 $ (3.5 ) Other non-operating income $ 2.5 $ 0.8 $ 1.7 $ 5.0 $ 1.5 $ 3.5 Net Income $ 30.1 $ 30.1 $ — $ 0.3 $ 0.3 $ — Recent Accounting Pronouncements Issued and Not Effective In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) . The new standard requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases except for short-term leases. For lessees, leases will continue to be classified as either operating or finance leases in the Statements of Unaudited Condensed Consolidated Operations . We plan to adopt the standard on its effective date of January 1, 2019. The new standard may be adopted using either the modified retrospective approach, which requires application of the new guidance at the beginning of the earliest comparative period presented or the optional alternative approach, which requires application of the new guidance at the beginning of the standard's effective date. We have finalized our implementation plan and have compiled an inventory of our existing leases. Based on our analysis to date, the updated standard is not expected to have a material effect on our consolidated financial statements. For example, based on the future minimum payments under non-cancellable operating leases as of June 30, 2018, we would expect to record approximately $16 million , discounted to fair value, in the Statements of Unaudited Condensed Consolidated Financial Position .

SEGMENT REPORTING SEGMENT REPOR

SEGMENT REPORTING SEGMENT REPORTING	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	NOTE 3 - SEGMENT REPORTING We operate in one reportable segment – U.S. Iron Ore. U.S. Iron Ore 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. We evaluate segment performance based on sales margin, defined as revenues less cost of goods sold and operating expenses identifiable to each segment. Additionally, we evaluate performance on a segment basis, as well as a consolidated basis, based on EBITDA and Adjusted EBITDA. These measures allow management and investors to focus on our ability to service our debt as well as illustrate how the business and each operating segment are performing. Additionally, EBITDA and Adjusted EBITDA assist management and investors in their analysis and forecasting as these measures approximate the cash flows associated with operational earnings. The following tables present a summary of our reportable segment including a reconciliation of segment sales margin to Income from Continuing Operations Before Income Taxes and a reconciliation of Net Income to EBITDA and Adjusted EBITDA: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Revenues from product sales and services: U.S. Iron Ore $ 714.3 100 % $ 471.3 100 % $ 894.3 100 % $ 757.5 100 % Sales margin $ 284.5 $ 144.7 $ 346.0 $ 193.7 Other operating expense (30.3 ) (29.5 ) (61.5 ) (45.1 ) Other expense (26.6 ) (32.5 ) (54.6 ) (143.3 ) Income from continuing operations before income taxes $ 227.6 $ 82.7 $ 229.9 $ 5.3 (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Net Income $ 165.1 $ 30.1 $ 80.8 $ 0.3 Less: Interest expense, net (32.3 ) (31.4 ) (65.8 ) (74.2 ) Income tax benefit (expense) 1.8 (2.6 ) (13.9 ) (0.8 ) Depreciation, depletion and amortization (25.5 ) (21.6 ) (49.4 ) (44.8 ) EBITDA $ 221.1 $ 85.7 $ 209.9 $ 120.1 Less: Impact of discontinued operations $ (54.7 ) $ (45.4 ) $ (117.8 ) $ 6.5 Foreign exchange remeasurement (0.1 ) 0.5 (0.5 ) 15.3 Gain (loss) on extinguishment of debt 0.2 (4.9 ) 0.2 (76.8 ) Adjusted EBITDA $ 275.7 $ 135.5 $ 328.0 $ 175.1 EBITDA U.S. Iron Ore $ 296.0 $ 155.0 $ 368.5 $ 212.9 Corporate and Other 1 (74.9 ) (69.3 ) (158.6 ) (92.8 ) Total EBITDA $ 221.1 $ 85.7 $ 209.9 $ 120.1 Adjusted EBITDA: U.S. Iron Ore $ 301.3 $ 161.5 $ 378.4 $ 225.6 Corporate and Other 1 (25.6 ) (26.0 ) (50.4 ) (50.5 ) Total Adjusted EBITDA $ 275.7 $ 135.5 $ 328.0 $ 175.1 1 Corporate and Other includes immaterial costs related to the HBI project. The following table summarizes our depreciation, depletion and amortization expense and capital additions: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Depreciation, depletion and amortization: U.S. Iron Ore $ 15.6 $ 16.7 $ 31.4 $ 33.1 Corporate and Other 1.4 1.6 2.8 3.7 Total depreciation, depletion and amortization $ 17.0 $ 18.3 $ 34.2 $ 36.8 Capital additions 1 : U.S. Iron Ore $ 26.7 $ 24.6 $ 45.4 $ 51.7 Corporate and Other 2 43.7 — 103.9 — Total capital additions $ 70.4 $ 24.6 $ 149.3 $ 51.7 1 Includes cash paid for capital additions of $114.4 million, including deposits of $72.3 million, and an increase in non-cash accruals of $34.9 million for the six months ended June 30, 2018 compared to cash paid for capital additions of $48.5 million, including deposits of $5.1 million, and an increase in non-cash accruals of $3.2 million for the six months ended June 30, 2017. 2 Includes capital additions related to our HBI project. A summary of assets by segment is as follows: (In Millions) June 30, December 31, Assets: U.S. Iron Ore $ 1,822.8 $ 1,500.6 Corporate and Other 1 1,183.4 1,314.0 Assets of Discontinued Operations 45.3 138.8 Total assets $ 3,051.5 $ 2,953.4 1 Corporate and Other includes assets related to the HBI project.

REVENUE

REVENUE	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	NOTE 4 - REVENUE We sell 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 benefits of 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. Certain 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: Platts 62% Price, pellet premiums, Platts international indexed freight rates and changes in specified Producer Price Indices, including industrial commodities, energy and steel. Changes in the expected revenue rate from the date control transfers through final settlement of contract terms is recorded in accordance with ASC Topic 815. Refer to NOTE 15 - DERIVATIVE INSTRUMENTS for further information on how our estimated and final revenue rates are determined. A supply agreement with a customer provides for supplemental revenue or refunds based on the average annual daily market price for hot-rolled coil steel at the time the iron ore is consumed in the customer’s blast furnaces. As control transfers prior to consumption, the supplemental revenue is recorded in accordance with ASC Topic 815. Refer to NOTE 15 - DERIVATIVE INSTRUMENTS for further information on supplemental revenue or refunds. Included within Revenues from product sales and services is derivative revenue related to ASC Topic 815 of $154.7 million and $198.5 million , for three and six months ended June 30, 2018 , respectively. Practical expedients and exemptions We have elected to treat all shipping and handling costs as fulfillment costs because a significant portion of these costs are incurred prior to control transfer. We have various long-term sales contracts with minimum purchase and supply requirement provisions that extend beyond the current reporting period. The portion of our transaction price for these contracts that is allocated entirely to wholly unsatisfied performance obligations is based on market prices that have not yet been determined and therefore is variable in nature. As such, we have not disclosed the value of unsatisfied performance obligations pursuant to the practical expedient. Deferred Revenue The table below summarizes our deferred revenue balances: Deferred Revenue (Current) 1 Deferred Revenue (Long-Term) Opening balance as of January 1, 2018 $ 23.8 $ 51.4 Closing balance as of June 30, 2018 20.0 47.1 Decrease $ (3.8 ) $ (4.3 ) 1 The opening balance includes a $1.4 million adjustment from the December 31, 2017 balance due to the adoption of Topic 606. The terms of one of our pellet supply agreements required supplemental payments to be paid by the customer during the period 2009 through 2012, with the option to defer a portion of the 2009 monthly amount in exchange for interest payments until the deferred amount was repaid in 2013. 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 June 30, 2018 and December 31, 2017 , installment amounts received in excess of sales totaled $59.9 million and $64.2 million , respectively, related to this agreement. As of June 30, 2018 and December 31, 2017 , deferred revenue of $12.8 million was recorded in Other current liabilities and $47.1 million and $51.4 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 $7.2 million and $9.6 million was deferred and included in Other current liabilities in the Statements of Unaudited Condensed Consolidated Financial Position as of June 30, 2018 and December 31, 2017 , respectively.

INVENTORIES

INVENTORIES	6 Months Ended
	Jun. 30, 2018
Inventory Disclosure [Abstract]
Inventories	NOTE 5 - INVENTORIES The following table presents the detail of our Inventories in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) June 30, 2018 December 31, 2017 Finished Goods $ 232.5 $ 127.1 Work-in-Process 23.9 11.3 Total Inventories $ 256.4 $ 138.4

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	NOTE 6 - PROPERTY, PLANT AND EQUIPMENT The following table indicates the value of each of the major classes of our consolidated depreciable assets: (In Millions) June 30, December 31, Land rights and mineral rights $ 549.6 $ 549.6 Office and information technology 65.1 65.8 Buildings 84.0 85.2 Mining equipment 531.2 533.9 Processing equipment 616.0 610.9 Electric power facilities 56.9 56.9 Land improvements 24.2 23.7 Asset retirement obligation 16.9 16.9 Other 25.2 25.2 Construction in-progress 102.2 32.6 2,071.3 2,000.7 Allowance for depreciation and depletion (990.0 ) (966.9 ) $ 1,081.3 $ 1,033.8

DEBT AND CREDIT FACILITIES

DEBT AND CREDIT FACILITIES	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
DEBT AND CREDIT FACILITIES	NOTE 7 - DEBT AND CREDIT FACILITIES The following represents a summary of our long-term debt: (In Millions) June 30, 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 $ (6.3 ) $ (2.4 ) $ 391.3 Unsecured Notes $400 Million 5.90% 2020 Senior Notes 5.98% 88.4 (0.2 ) (0.1 ) 88.1 $500 Million 4.80% 2020 Senior Notes 4.83% 122.3 (0.2 ) (0.1 ) 122.0 $700 Million 4.875% 2021 Senior Notes 4.89% 125.2 (0.3 ) — 124.9 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (6.0 ) (80.6 ) 229.7 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,073.3 (10.6 ) (15.6 ) 1,047.1 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.3 ) (3.4 ) 292.7 ABL Facility N/A 450.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 1.2 Long-term debt $ 2,297.0 (In Millions) December 31, 2017 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 $ (7.1 ) $ (2.6 ) $ 390.3 Unsecured Notes $400 Million 5.90% 2020 Senior Notes 5.98% 88.9 (0.2 ) (0.1 ) 88.6 $500 Million 4.80% 2020 Senior Notes 4.83% 122.4 (0.3 ) (0.1 ) 122.0 $700 Million 4.875% 2021 Senior Notes 4.89% 138.4 (0.3 ) (0.1 ) 138.0 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (6.6 ) (85.6 ) 224.1 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,075.0 (11.3 ) (16.5 ) 1,047.2 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.4 ) (3.4 ) 292.6 ABL Facility N/A 550.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 1.4 Long-term debt $ 2,304.2 $1.075 Billion 5.75% 2025 Senior Notes On February 27, 2017, 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 $500 million aggregate principal amount of 5.75% 2025 Senior Notes. On August 7, 2017, we issued an additional $575 million aggregate principal amount of our 5.75% 2025 Senior Notes. The second tranche was issued at 97.0% of face value. The 5.75% 2025 Senior Notes were originally issued in private transactions exempt from the registration requirements of the Securities Act. Pursuant to the registration rights agreement executed as part of these issuances, we filed on February 14, 2018 a registration statement with the SEC with respect to a registered offer to exchange the 5.75% 2025 Senior Notes for publicly registered notes, with all significant terms and conditions remaining the same. The exchange offer expired on April 26, 2018, and substantially all of the outstanding 5.75% 2025 Senior Notes were tendered for exchange. Debt Extinguishment The following is a summary of the debt extinguished with cash during the three and six months ended June 30, 2018 that resulted in a gain on extinguishment of $0.2 million : (In Millions) Debt Instrument Debt Extinguished $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 13.2 $1.075 Billion 5.75% 2025 Senior Notes 1.7 $ 15.5 Debt Maturities The following represents a summary of our maturities of debt instruments based on the principal amounts outstanding at June 30, 2018 : (In Millions) Maturities of Debt 2018 $ — 2019 — 2020 210.7 2021 125.2 2022 — 2023 — 2024 and thereafter 2,088.0 Total maturities of debt $ 2,423.9 ABL Facility On February 28, 2018, we entered into an amended and restated senior secured asset-based revolving credit facility with various financial institutions. The ABL Facility amends and restates our prior $550.0 million Syndicated Facility Agreement, dated as of March 30, 2015. The ABL Facility will mature upon the earlier of February 28, 2023 or 60 days prior to the maturity of certain other material debt, and provides for up to $450.0 million in borrowings, comprised of (i) a $400.0 million U.S. tranche, including a $248.8 million sublimit for the issuance of letters of credit and a $100.0 million sublimit for U.S. swingline loans, and (ii) at the time of closing, a $50.0 million Australian tranche, including a $24.4 million sublimit for the issuance of letters of credit and a $20.0 million sublimit for Australian swingline loans. On June 19, 2018, the Australian tranche was terminated and reallocated to the U.S. tranche, resulting in a $450.0 million allocation to the U.S. tranche, including a $273.2 million sublimit for the issuance of letters of credit and $120.0 million sublimit for swingline loans. Availability under the U.S. tranche of the ABL Facility is limited to an eligible U.S. borrowing base, as applicable, determined by applying customary advance rates to eligible accounts receivable, inventory and certain mobile equipment. The ABL Facility and certain bank products and hedge obligations are guaranteed by us and certain of our existing wholly-owned U.S. subsidiaries and are required to be guaranteed by certain of our future U.S. subsidiaries. Amounts outstanding under the ABL Facility are secured by (i) a first-priority security interest in the accounts receivable and other rights to payment, inventory, as-extracted collateral, certain investment property, deposit accounts, securities accounts, certain general intangibles and commercial tort claims, certain mobile equipment, commodities accounts, deposit accounts, securities accounts and other related assets of ours, the other borrowers and the guarantors, and proceeds and products of each of the foregoing (collectively, the “ABL Collateral”) and (ii) a second-priority security interest in substantially all of our assets and the assets of the other borrowers and the guarantors other than the ABL Collateral (collectively, the “Notes Collateral” and, together with the ABL Collateral, the “Collateral”). Borrowings under the ABL Facility bear interest, at our option, at a base rate or, if certain conditions are met, a LIBOR rate, in each case plus an applicable margin. The base rate is equal to the greater of the federal funds rate plus ½ of 1%, the LIBOR rate based on a one-month interest period plus 1% and the floating rate announced by Bank of America Merrill Lynch as its “prime rate" and 1%. The LIBOR rate is a per annum fixed rate equal to LIBOR with respect to the applicable interest period and amount of LIBOR rate loan requested. The ABL Facility contains customary representations and warranties and affirmative and negative covenants including, among others, covenants regarding the maintenance of certain financial ratios if certain conditions are triggered, covenants relating to financial reporting, covenants relating to the payment of dividends on, or purchase or redemption of, our capital stock, covenants relating to the incurrence or prepayment of certain debt, covenants relating to the incurrence of liens or encumbrances, covenants relating to compliance with laws, covenants relating to transactions with affiliates, covenants relating to mergers and sales of all or substantially all of our assets and limitations on changes in the nature of our business. The ABL Facility provides for customary events of default, including, among other things, the event of nonpayment of principal, interest, fees, or other amounts, a representation or warranty proving to have been materially incorrect when made, failure to perform or observe certain covenants within a specified period of time, a cross-default to certain material indebtedness, the bankruptcy or insolvency of the Company and certain of its subsidiaries, monetary judgment defaults of a specified amount, invalidity of any loan documentation, a change of control of the Company, and ERISA defaults resulting in liability of a specified amount. If an event of a default exists (beyond any applicable grace or cure period, if any), the administrative agent may and, at the direction of the requisite number of lenders, shall declare all amounts owing under the ABL Facility immediately due and payable, terminate such lenders’ commitments to make loans under the ABL Facility and/or exercise any and all remedies and other rights under the ABL Facility. For certain events of default related to insolvency and receivership, the commitments of the lenders will be automatically terminated and all outstanding loans and other amounts will become immediately due and payable. As of June 30, 2018 and December 31, 2017 , we were in compliance with the ABL Facility liquidity requirements and, therefore, the springing financial covenant requiring a minimum fixed charge coverage ratio of 1.0 to 1.0 was not applicable. As of June 30, 2018 and December 31, 2017 , no loans were drawn under the ABL Facility and we had total availability of $400.3 million and $273.2 million , respectively, as a result of borrowing base limitations. As of June 30, 2018 and December 31, 2017 , the principal amount of letter of credit obligations totaled $39.5 million and $46.5 million , respectively, to support business obligations primarily related to workers compensation and environmental obligations, thereby further reducing available borrowing capacity on our ABL Facility to $360.8 million and $226.7 million , respectively.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	NOTE 8 - FAIR VALUE MEASUREMENTS The following represents the assets and liabilities measured at fair value: (In Millions) June 30, 2018 Description 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 $ 10.5 $ 546.5 $ — $ 557.0 Derivative assets — 0.1 174.6 174.7 Total $ 10.5 $ 546.6 $ 174.6 $ 731.7 Liabilities: Derivative liabilities $ — $ 0.1 $ 3.0 $ 3.1 Total $ — $ 0.1 $ 3.0 $ 3.1 (In Millions) December 31, 2017 Description 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 $ 66.3 $ 550.6 $ — $ 616.9 Derivative assets — — 37.9 37.9 Total $ 66.3 $ 550.6 $ 37.9 $ 654.8 Liabilities: Derivative liabilities $ — $ 0.3 $ 1.7 $ 2.0 Total $ — $ 0.3 $ 1.7 $ 2.0 Financial assets classified in Level 1 include money market funds and treasury bonds. The valuation of these instruments is based upon unadjusted quoted prices for identical assets in active markets. The valuation of financial assets and liabilities classified in Level 2 is determined using a market approach based upon quoted prices for similar assets and liabilities in active markets or other inputs that are observable. Level 2 assets include commercial paper, certificates of deposit and commodity hedge contracts. Level 2 liabilities include commodity hedge contracts. The Level 3 assets and liabilities include derivative assets that consist of freestanding derivative instruments related to a customer supply agreement and certain provisional pricing arrangements with our customers. The supply agreement included in our Level 3 assets includes provisions for supplemental revenue or refunds based on the average annual daily market price for hot-rolled coil steel at the time the iron ore product is consumed in the customer’s blast furnaces. We account for these provisions as derivative instruments at the time of sale and adjust the corresponding asset or liability to fair value as an adjustment to Product revenues each reporting period until the product is consumed and the amounts are settled. The fair value of the instruments are determined using a market approach based on the estimate of the average annual daily market price for hot-rolled coil steel. This estimate takes into consideration current market conditions and nonperformance risk. We had assets of $169.4 million and $37.9 million at June 30, 2018 and December 31, 2017 , respectively, related to this supply agreement. The provisional pricing arrangements included in our Level 3 assets/liabilities specify provisional price calculations, where the pricing mechanisms generally are based on market pricing, with the final revenue rate to be based on market inputs at a specified point in time in the future, per the terms of the supply agreements. The difference between the estimated final revenue rate at the date of sale and the estimated final revenue rate at the measurement date is characterized as a derivative and is required to be accounted for separately once the revenue has been recognized. The derivative instruments are adjusted to fair value through Product revenues each reporting period based upon current market data and forward-looking estimates provided by management until the final revenue rates are determined. We had assets of $5.2 million and liabilities of $3.0 million related to provisional pricing arrangements at June 30, 2018 compared to liabilities of $1.7 million related to provisional pricing arrangements at December 31, 2017 . The following table illustrates information about quantitative inputs and assumptions for the assets and liabilities categorized in Level 3 of the fair value hierarchy: Qualitative/Quantitative Information About Level 3 Fair Value Measurements (In Millions) Fair Value at June 30, 2018 Balance Sheet Location Valuation Technique Unobservable Input Range or Point Estimate (Weighted Average) Customer supply agreement $ 169.4 Derivative assets Market Approach Management's Estimate of Market Hot-Rolled Coil Steel per net ton $833 Provisional pricing arrangements $ 5.2 Derivative assets Market Approach Management's Estimate of Platts 62% Price per dry metric ton $68 - $69 Provisional pricing arrangements $ 3.0 Other Current Liabilities Market Approach Management's Estimate of Platts 62% Price per dry metric ton $68 - $69 The significant unobservable input used in the fair value measurement of our customer supply agreement is an estimate determined by management including a forward-looking estimate for the average annual daily market price for hot-rolled coil steel. The significant unobservable input used in the fair value measurement of our provisional pricing arrangements is management’s estimate of Platts 62% Price based upon current market data and index pricing, which include forward-looking estimates determined by management. We recognize any transfers between levels as of the beginning of the reporting period, including both transfers into and out of levels. There were no transfers between Level 1 and Level 2 and no transfers into or out of Level 3 of the fair value hierarchy during the three and six months ended June 30, 2018 and 2017 . The following tables represent a reconciliation of the changes in fair value of financial instruments measured at fair value on a recurring basis using significant unobservable inputs (Level 3): (In Millions) Level 3 Assets Three Months Ended Six Months Ended 2018 2017 2018 2017 Beginning balance 1 $ 93.5 $ 59.2 $ 49.5 $ 30.1 Total gains Included in earnings 158.6 51.0 202.8 84.6 Settlements (77.5 ) (40.0 ) (77.7 ) (44.5 ) Ending balance - June 30 $ 174.6 $ 70.2 $ 174.6 $ 70.2 Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ 80.6 $ 17.8 $ 125.1 $ 51.0 1 Beginning balance as of January 1, 2018 includes an $11.6 million adjustment for adoption of Topic 606. (In Millions) Level 3 Liabilities Three Months Ended Six Months Ended 2018 2017 2018 2017 Beginning balance $ — $ — $ (1.7 ) $ — Total losses Included in earnings (3.7 ) (20.2 ) (4.3 ) (20.2 ) Settlements 0.7 — 3.0 — Ending balance - June 30 $ (3.0 ) $ (20.2 ) $ (3.0 ) $ (20.2 ) Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (3.0 ) $ (20.2 ) $ (3.0 ) $ (20.2 ) The carrying amount of certain financial instruments (e.g., Accounts receivable, net , Accounts payable and Accrued expenses ) approximates fair value and, therefore, has been excluded from the table below. A summary of the carrying amount and fair value of other financial instruments were as follows: (In Millions) June 30, 2018 December 31, 2017 Classification Carrying Value Fair Value Carrying Value Fair Value Long-term debt: Secured Notes $400 Million 4.875% 2024 Senior Notes Level 1 $ 391.3 $ 388.5 $ 390.3 $ 398.0 Unsecured Notes $400 Million 5.90% 2020 Senior Notes Level 1 88.1 88.4 88.6 88.0 $500 Million 4.80% 2020 Senior Notes Level 1 122.0 120.5 122.0 118.8 $700 Million 4.875% 2021 Senior Notes Level 1 124.9 124.6 138.0 130.8 $316.25 Million 1.50% 2025 Convertible Senior Notes Level 1 229.7 384.5 224.1 352.9 $1.075 Billion 5.75% 2025 Senior Notes Level 1 1,047.1 1,028.6 1,047.2 1,029.3 $800 Million 6.25% 2040 Senior Notes Level 1 292.7 241.7 292.6 227.1 ABL Facility Level 2 — — — — Fair value adjustment to interest rate hedge Level 2 1.2 1.2 1.4 1.4 Total long-term debt $ 2,297.0 $ 2,378.0 $ 2,304.2 $ 2,346.3 The fair value of long-term debt was determined using quoted market prices based upon current borrowing rates.

PENSIONS AND OTHER POSTRETIREME

PENSIONS AND OTHER POSTRETIREMENT BENEFITS	6 Months Ended
	Jun. 30, 2018
Postemployment Benefits [Abstract]
PENSIONS AND OTHER POSTRETIREMENT BENEFITS	NOTE 9 - PENSIONS AND OTHER POSTRETIREMENT BENEFITS We offer defined benefit pension plans, defined contribution pension plans and OPEB plans, primarily consisting of retiree healthcare benefits, to most employees in the U.S. as part of a total compensation and benefits program. The defined benefit pension plans largely 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 January 1, 2018, we adopted the amendments to ASC 715 regarding the presentation of net periodic pension and postretirement benefit costs. We retrospectively adopted the presentation of service cost separate from the other components of net periodic costs. Service costs are classified within Cost of goods sold and operating expenses , Selling, general and administrative expenses and Miscellaneous – net while the interest cost, expected return on assets, amortization of prior service costs/credits, net actuarial gain/loss, and other costs are classified within Other non-operating income in our Statements of Unaudited Condensed Consolidated Operations . The following are the components of defined benefit pension and OPEB costs and credits: Defined Benefit Pension Costs (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Service cost $ 4.6 $ 4.7 $ 9.3 $ 9.5 Interest cost 7.5 7.5 15.1 15.0 Expected return on plan assets (15.0 ) (13.6 ) (30.0 ) (27.1 ) Amortization: Prior service costs 0.6 0.7 1.1 1.3 Net actuarial loss 5.3 5.3 10.6 10.6 Net periodic benefit cost $ 3.0 $ 4.6 $ 6.1 $ 9.3 Other Postretirement Benefits Credits (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Service cost $ 0.5 $ 0.5 $ 1.0 $ 1.0 Interest cost 2.0 2.2 4.1 4.3 Expected return on plan assets (4.6 ) (4.5 ) (9.2 ) (8.9 ) Amortization: Prior service credits (0.7 ) (0.8 ) (1.5 ) (1.5 ) Net actuarial loss 1.3 1.3 2.5 2.5 Net periodic benefit credit $ (1.5 ) $ (1.3 ) $ (3.1 ) $ (2.6 ) Based on funding requirements, we made pension contributions of $3.3 million and $5.6 million for the three and six months ended June 30, 2018 , respectively, compared to $2.3 million of pension contributions for the three and six months ended June 30, 2017 . 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 six months ended June 30, 2018 and 2017 .

STOCK COMPENSATION PLANS

STOCK COMPENSATION PLANS	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Compensation Plans	NOTE 10 - STOCK COMPENSATION PLANS Employees’ Plans On February 21, 2018, the Compensation Committee approved grants under the A&R 2015 Equity Plan to certain officers and employees for the 2018 to 2020 performance period. Shares granted under the awards consisted of 0.7 million restricted stock units and 0.7 million performance shares. Restricted stock units granted during 2018 are subject to continued employment, are retention based and are payable in common shares. The outstanding restricted stock units that were granted in 2018 cliff vest on December 31, 2020. 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, 2018 to December 31, 2020 and measured against the constituents of the S&P Metals and Mining ETF Index at the beginning of the relevant performance period. The final payouts for the outstanding performance period grants will vary from zero to 200% of the original grant depending on whether and to what extent the Company achieves certain objectives and performance goals as established by the Compensation Committee. Determination of Fair Value The fair value of each performance share grant is estimated on the date of grant using a Monte Carlo simulation to forecast relative TSR performance. A correlation matrix of historic and projected stock prices was developed for both the Company and our predetermined peer group of mining and metals companies. The fair value assumes that the objective will be achieved. The expected term of the grant represents the time from the grant date to the end of the service period. We estimate the volatility of our common shares and that of the peer group of mining and metals companies using daily price intervals for all companies. The risk-free interest rate is the rate at the grant date on zero-coupon government bonds with a term commensurate with the remaining life of the performance period. The following assumptions were utilized to estimate the fair value for the 2018 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 21, 2018 $ 7.53 2.86 86.8% 2.42% —% $ 11.93 158.43%

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 11 - INCOME TAXES Our 2018 estimated annual effective tax rate before discrete items is approximately 0.1% . The annual effective tax rate differs from the U.S. statutory rate of 21.0% primarily due to the deductions for percentage depletion in excess of cost depletion related to U.S. operations and the reversal of valuation allowance from operations in the current year. The 2017 estimated annual effective tax rate before discrete items at June 30, 2017 was negative 3.6% . For the three and six months ended June 30, 2018 , we recorded discrete items that resulted in an income tax benefit of $2.0 million and an expense of $13.7 million , respectively. The $2.0 million benefit relates to the reversal of a reserve for uncertain tax positions due to a lapse in the statute of limitations. The $13.7 million expense relates primarily to a $14.5 million reduction of the refundable AMT credit recorded in Income tax receivable in our Statements of Unaudited Condensed Consolidated Financial Position based on the sequestration guidance issued by the Internal Revenue Service during the first quarter of 2018. The $14.5 million current year expense is a reduction of an asset and will not result in a cash tax outlay. For the three and six months ended June 30, 2017 , we recorded discrete items that resulted in an expense of $0.3 million and $0.2 million , respectively.

LEASE OBLIGATIONS

LEASE OBLIGATIONS	6 Months Ended
	Jun. 30, 2018
Leases [Abstract]
LEASE OBLIGATIONS	NOTE 12 - LEASE OBLIGATIONS We lease certain building space, mining, production and other equipment under operating and capital leases. The capital leases are for varying lengths, generally at market interest rates and contain purchase and/or renewal options at the end of the terms. Our operating lease expense was $0.9 million and $1.8 million for the three and six months ended June 30, 2018 , respectively, compared with $1.2 million and $2.3 million for the comparable period in 2017 . Future minimum payments under capital leases and non-cancellable operating leases as of June 30, 2018 are as follows: (In Millions) Capital Leases Operating Leases 2018 (July 1 - December 31) $ 1.4 $ 1.3 2019 2.8 1.9 2020 2.4 1.8 2021 1.8 1.8 2022 1.4 1.8 2023 and thereafter — 7.5 Total minimum lease payments $ 9.8 $ 16.1 Amounts representing interest 1.0 Present value of net minimum lease payments 1 $ 8.8 1 The total is comprised of $2.4 million and $6.4 million classified as Other current liabilities and Other liabilities , respectively, in the Statements of Unaudited Condensed Consolidated Financial Position as of June 30, 2018.

ENVIRONMENTAL AND MINE CLOSURE

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	6 Months Ended
	Jun. 30, 2018
Environmental Remediation Obligations [Abstract]
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	NOTE 13 - ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS We had environmental and mine closure liabilities of $176.0 million and $171.3 million at June 30, 2018 and December 31, 2017 , respectively. The following is a summary of the obligations: (In Millions) June 30, December 31, Environmental $ 3.2 $ 2.9 Mine closure 1 172.8 168.4 Total environmental and mine closure obligations 176.0 171.3 Less current portion 3.7 3.6 Long-term environmental and mine closure obligations $ 172.3 $ 167.7 1 Includes our active operating mines, our indefinitely idled Empire mine and a closed mine formerly operating as LTVSMC. Mine Closure The accrued mine closure obligation for our active mining operations provides for contractual and legal obligations associated with the eventual closure of the mining operations. The accretion of the liability and amortization of the related asset is recognized over the estimated mine lives for each location. The following represents a roll forward of our mine closure obligation liability for the six months ended June 30, 2018 and for the year ended December 31, 2017 : (In Millions) June 30, December 31, Mine closure obligation at beginning of period $ 168.4 $ 187.8 Accretion expense 4.7 13.9 Remediation payments (0.3 ) (5.6 ) Revision in estimated cash flows — (27.7 ) Mine closure obligation at end of period $ 172.8 $ 168.4 For the year ended December 31, 2017 , the revision in estimated cash flows relates primarily to updates to our estimates resulting from our three-year in-depth review of our mine closure obligations for each of our U.S. mines. The primary driver of the decrease in estimated cash flows was the Empire mine, as the mine closure obligation was reduced by $26.2 million as a result of the refinement of the cash flows required for reclamation, remediation and structural removal. Prior estimates were based on RS Means (a common costing methodology used in the construction and demolition industry) average costing data while the current estimate was compiled using a more detailed cost build-up approach.

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES	6 Months Ended
	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES	NOTE 14 - GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill The carrying amount of goodwill as of June 30, 2018 and December 31, 2017 was $2.0 million and related to our U.S. Iron Ore operating segment. Other Intangible Assets The following table is a summary of definite-lived intangible assets: (In Millions) June 30, 2018 December 31, 2017 Classification Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Permits Other non-current assets $ 72.2 $ (22.9 ) $ 49.3 $ 72.2 $ (22.5 ) $ 49.7 Amortization expense relating to other intangible assets was $0.2 million and $0.4 million for the three and six months ended June 30, 2018 , respectively, and is recognized in Cost of goods sold and operating expenses in the Statements of Unaudited Condensed Consolidated Operations . Amortization expense relating to other intangible assets was $0.2 million and $0.4 million for the comparable periods in 2017 . Amortization expense of other intangible assets is expected to continue to be immaterial going forward.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	NOTE 15 - 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 June 30, 2018 December 31, 2017 June 30, 2018 December 31, 2017 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 $ — Other current liabilities $ 0.1 Other current liabilities $ 0.3 Derivatives not designated as hedging instruments under ASC 815: Customer supply agreement Derivative assets $ 169.4 Derivative assets $ 37.9 $ — $ — Provisional pricing arrangements Derivative assets 5.2 — Other current liabilities 3.0 Other current liabilities 1.7 Total derivatives not designated as hedging instruments under ASC 815 $ 174.6 $ 37.9 $ 3.0 $ 1.7 Total derivatives $ 174.7 $ 37.9 $ 3.1 $ 2.0 Cash Flow Hedges Commodity Contracts As of June 30, 2018 , we had outstanding natural gas hedge contracts for a notional amount of 3.4 million MMBtu in the form of forward contracts with varying maturity dates ranging from July 2018 to May 2019. As of December 31, 2017 , we had outstanding natural gas hedge contracts for a notional amount of 3.5 million MMBtu in the form of forward contracts with varying maturity dates ranging from January 2018 to November 2018. Changes in fair value of highly effective hedges are recorded as a component of Accumulated other comprehensive loss in the Statements of Unaudited Condensed Consolidated Financial Position . During the three and six months ended June 30, 2018 , we recorded unrealized gains of $0.2 million and $0.6 million , respectively, in Other comprehensive income (loss) for changes in the fair value of these instruments. For the six months ended June 30, 2018 , a gain of $0.1 million has been reclassified from Accumulated other comprehensive loss into earnings. We had no commodity contracts designated as hedge instruments for the three and six months ended June 30, 2017 . Derivatives Not Designated as Hedging Instruments Most of our long-term supply agreements are comprised of a base price with annual price adjustment factors. The base price is the primary component of the purchase price for each contract. The indexed price adjustment factors are integral to the iron ore supply contracts and vary based on the agreement, but typically include adjustments based upon changes in the Platts 62% Price, along with pellet premiums, published Platts international indexed freight rates and changes in specified Producer Price Indices, including those for industrial commodities, fuel and steel. The pricing adjustments generally operate in the same manner, with each factor typically comprising a portion of the price adjustment, although the weighting of each factor varies based upon the specific terms of each agreement. In most cases, these adjustment factors have not been finalized at the time our product is sold. In these cases, we estimate the adjustment factors at each reporting period based upon the best third-party information available. The estimates are then adjusted to actual when the information has been finalized. The price adjustment factors have been evaluated to determine if they qualify as embedded derivatives. The price adjustment factors share the same economic characteristics and risks as the host contract and are integral to the host contract as inflation adjustments; accordingly, they have not been separately valued as derivative instruments. Customer Supply Agreement A supply agreement with one customer provides for supplemental revenue or refunds to the customer based on the average annual daily steel market price for hot-rolled coil steel at the time the iron ore product is consumed in the customer’s blast furnace. The supplemental pricing is characterized as a freestanding derivative and is required to be accounted for separately once control transfers to the customer. The derivative instrument, which is finalized based on a future price, is adjusted to fair value as a revenue adjustment each reporting period until the pellets are consumed and the amounts are settled. We recognized net derivative revenue of $155.5 million and $197.4 million in Product revenues in the Statements of Unaudited Condensed Consolidated Operations for the three and six months ended June 30, 2018 , respectively, related to the supplemental payments. This compares with net derivative revenue of $51.9 million and $69.6 million in Product revenues in the Statements of Unaudited Condensed Consolidated Operations for the comparable periods in 2017 , related to supplemental payments. Derivative assets , representing the fair value of the supplemental revenue, were $169.4 million and $37.9 million as of June 30, 2018 and December 31, 2017 in the Statements of Unaudited Condensed Consolidated Financial Position , respectively. Provisional Pricing Arrangements Certain of our customer 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, along with pellet premiums, published Platts international indexed freight rates and changes in specified Producer Price Indices, including those for industrial commodities, fuel and steel. The pricing adjustments generally operate in the same manner, with each factor typically comprising a portion of the price adjustment, although the weighting of each factor varies based upon the specific terms of each agreement. 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. Changes in the expected revenue rate from the date that control transfers through final settlement of contract terms is recorded in accordance with ASC Topic 815 and is characterized as a derivative and accounted for separately. Subsequently, the derivative instruments are adjusted to fair value through Product revenues each reporting period based upon current market data and forward-looking estimates provided by management until the final revenue rate is determined. At June 30, 2018 , we recorded $5.2 million as Derivative assets and $3.0 million as derivative liabilities classified as Other current liabilities related to our estimate of the final revenue rate with our customers in the Statements of Unaudited Condensed Consolidated Financial Position . At December 31, 2017 , we recorded $1.7 million as derivative liabilities classified as Other current liabilities related to our estimate of the final revenue rate with our customers in the Statements of Unaudited Condensed Consolidated Financial Position . These amounts represent the difference between the amount we expected to receive when revenue was initially measured at the point control transfers and our subsequent estimate of the final revenue rate based on the price calculations established in the supply agreements. We recognized a net decrease of $0.8 million and increase of $1.1 million in Product revenues in the Statements of Unaudited Condensed Consolidated Operations for the three and six months ended June 30, 2018 , respectively, related to these arrangements as compared to a net decrease of $21.1 million and $5.3 million in Product revenues for the comparable periods in 2017 . 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 Income (Loss) Recognized on Derivatives Amount of Income (Loss) Recognized on Derivatives Three Months Ended Six Months Ended 2018 2017 2018 2017 Customer Supply Agreements Product revenues $ 155.5 $ 51.9 $ 197.4 $ 69.6 Provisional Pricing Arrangements Product revenues (0.8 ) (21.1 ) 1.1 (5.3 ) Commodity Contracts Cost of goods sold and operating expenses — — — (1.3 ) Total $ 154.7 $ 30.8 $ 198.5 $ 63.0 Refer to NOTE 8 - FAIR VALUE MEASUREMENTS for additional information.

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	6 Months Ended
	Jun. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
DISCONTINUED OPERATIONS	NOTE 16 - DISCONTINUED OPERATIONS The information below sets forth selected financial information related to operating results of our businesses classified as discontinued operations. While the reclassification of revenues and expenses related to discontinued operations from prior periods have no impact upon previously reported net income, the Statements of Unaudited Condensed Consolidated Operations present the revenues and expenses that were reclassified from the specified line items to discontinued operations and the Statements of Unaudited Condensed Consolidated Financial Position present the assets and liabilities that were reclassified from the specified line items to assets and liabilities of discontinued operations. The 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. The charts below provide an asset group breakout for each financial statement line impacted by discontinued operations. (In Millions) Three Months Ended June 30, Six Months Ended 2018 2017 2018 2017 Loss from Discontinued Operations, net of tax Asia Pacific Iron Ore $ (53.3 ) $ (7.3 ) $ (124.7 ) $ 41.0 North American Coal (0.3 ) 2.6 0.1 2.6 Canadian Operations (10.7 ) (49.0 ) (10.6 ) (48.6 ) $ (64.3 ) $ (53.7 ) $ (135.2 ) $ (5.0 ) (In Millions) June 30, December 31, Asia Pacific Iron Ore North American Coal Total Asia Pacific Iron Ore North American Coal Total Current assets of discontinued operations $ 45.3 $ — $ 45.3 $ 118.5 $ — $ 118.5 Non-current assets of discontinued operations $ — $ — $ — $ 20.3 $ — $ 20.3 Current liabilities of discontinued operations $ 114.4 $ 2.9 $ 117.3 $ 71.8 $ 3.2 $ 75.0 Non-current liabilities of discontinued operations $ 10.3 $ — $ 10.3 $ 52.2 $ — $ 52.2 (In Millions) Six Months Ended 2018 2017 Net cash provided (used) by operating activities Asia Pacific Iron Ore $ (31.7 ) $ 92.2 Canadian Operations (14.6 ) — $ (46.3 ) $ 92.2 Net cash provided (used) by investing activities Asia Pacific Iron Ore $ 14.1 $ (0.8 ) $ 14.1 $ (0.8 ) For the six months ended June 30, 2018, we had $28.6 million of non-cash financing activities related to the settlement of capital lease obligations at Asia Pacific Iron Ore. 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 June 2018, we completed a sale of the mobile equipment to a third party and entered into a definitive agreement to sell substantially all of the remaining assets of our Asia Pacific Iron Ore business to Mineral Resources Limited. The sale to Mineral Resources Limited has not been completed as of the date of this report due to the pendency of certain closing conditions. As a result, for the period ended June 30, 2018, 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 205, Presentation of Financial Statements . As such, all current and historical Asia Pacific Iron Ore operating segment results are included in our financial statements and classified within discontinued operations. Loss on Discontinued Operations For the reasons discussed above, our previously reported Asia Pacific Iron Ore operating segment results for all periods prior to June 30, 2018, as well as exit costs, are classified as discontinued operations. (In Millions) Three Months Ended June 30, Six Months Ended Loss from Discontinued Operations 2018 2017 2018 2017 Revenues from product sales and services $ 70.1 $ 98.0 $ 129.1 $ 273.4 Cost of goods sold and operating expenses (106.1 ) (97.1 ) (230.2 ) (225.2 ) Sales margin (36.0 ) 0.9 (101.1 ) 48.2 Other operating expense (16.2 ) (3.2 ) (18.8 ) (3.7 ) Other expense (1.1 ) (1.3 ) (2.2 ) (2.7 ) Loss from discontinued operations before income taxes (53.3 ) (3.6 ) (122.1 ) 41.8 Impairment of long-lived assets — — (2.6 ) — Income tax expense — (3.7 ) — (0.8 ) Loss from discontinued operations, net of tax $ (53.3 ) $ (7.3 ) $ (124.7 ) $ 41.0 Recorded Assets and Liabilities (In Millions) Assets and Liabilities of Discontinued Operations June 30, December 31, Cash and cash equivalents $ 29.4 $ 29.4 Accounts receivable, net 12.5 33.9 Inventories — 45.0 Supplies and other inventories — 5.1 Other current assets 3.4 5.1 Total current assets of discontinued operations 45.3 118.5 Property, plant and equipment, net — 17.2 Other non-current assets — 3.1 Total assets of discontinued operations $ 45.3 $ 138.8 Accounts payable $ 74.3 $ 28.2 Accrued liabilities 21.1 28.0 Other current liabilities 19.0 15.6 Total current liabilities of discontinued operations 114.4 71.8 Environmental and mine closure obligations 10.3 28.8 Other liabilities — 23.4 Total liabilities of discontinued operations $ 124.7 $ 124.0 Foreign Currency The functional currency of our Australian subsidiaries is the Australian dollar. The financial statements of our Australian subsidiaries are translated into U.S. dollars using the exchange rate at each balance sheet date for assets and liabilities and a weighted average exchange rate for each period for revenues, expenses, gains and losses. Translation adjustments are recorded as Accumulated other comprehensive loss . Income taxes generally are not provided for foreign currency translation adjustments. Upon the liquidation of substantially all of the Asia Pacific Iron Ore assets, which is expected to occur during the third quarter 2018, the historical cumulative translation adjustments recorded in Accumulated other comprehensive loss in the Statements of Unaudited Condensed Consolidated Financial Position related to that asset group will be recognized as a gain in the Statements of Unaudited Condensed Consolidated Operations . As of June 30, 2018, the balance of currency translation adjustments related to the Asia Pacific Iron Ore asset group in Accumulated other comprehensive loss was a gain of $228.3 million . Income Taxes We have not recognized a tax benefit or expense during the three and six months ended June 30, 2018 , related to our Asia Pacific Iron Ore operations. For the three and six months ended June 30, 2017, we recognized a tax expense of $3.7 million and $0.8 million , respectively. Eastern Canada Iron Ore Operations Effective January 27, 2015, following the commencement of CCAA proceedings for the Bloom Lake Group, we deconsolidated the Bloom Lake Group and certain other wholly-owned subsidiaries comprising substantially all of our Canadian operations. Additionally, on May 20, 2015, the Wabush Group commenced CCAA proceedings which resulted in the deconsolidation of the remaining Wabush Group entities that were not previously deconsolidated. As a result of this action, the CCAA protection granted to the Bloom Lake Group was extended to include the Wabush Group to facilitate the reorganization of each of their businesses and operations. Prior to the deconsolidations, certain of our wholly-owned subsidiaries made loans to the Canadian Entities for the purpose of funding their operations and had accounts receivable generated in the ordinary course of business. The loans, corresponding interest and the accounts receivable were considered intercompany transactions and eliminated in our consolidated financial statements. Since the deconsolidations, the loans, associated interest and accounts receivable are considered related party transactions and have been recognized in our consolidated financial statements at their estimated fair value. As of June 30, 2018, we had no amounts outstanding classified as Loans to and accounts receivable from the Canadian Entities in the Statements of Unaudited Condensed Consolidated Financial Position in accordance with the Amended Plan, as defined and described below. As of December 31, 2017, we had $51.6 million classified as Loans to and accounts receivable from the Canadian Entities in the Statements of Unaudited Condensed Consolidated Financial Position. The net proceeds from the sale of the assets of the Bloom Lake Group and the Wabush Group are currently being held by the Monitor. Certain of these proceeds will be utilized to fund the accrued and remaining costs of the CCAA proceedings, and the remaining amounts will be available for distribution to the creditors of the Bloom Lake Group and the Wabush Group in accordance with the Amended Plan (as defined below). During 2017, we became aware that it was probable the Monitor will assert a preference claim against us and/or certain of our affiliates. We estimated a liability, which included the value of our related-party claims against the Bloom Lake Group and the Wabush Group, classified as Contingent claims in the Statements of Unaudited Condensed Consolidated Financial Position. As described below, as of June 30, 2018, the estimated liability has been settled pursuant to the Amended Plan. During March 2018, we entered into a restructuring term sheet with the Bloom Lake Group and the Wabush Group, which documents the proposed terms of a plan of compromise or arrangement in the CCAA proceedings to be sponsored by us as negotiated between us and the Monitor. By order of the Québec Superior Court of Justice (Commercial Division) (the “Court”) dated April 20, 2018, the Bloom Lake Group and the Wabush Group were authorized to file a joint plan of compromise and arrangement dated April 16, 2018 (the “Original Plan”). Following discussions with various stakeholder groups, the Original Plan was amended by order of the Court dated May 18, 2018. The Bloom Lake Group and the Wabush Group were authorized to file the amended and restated joint plan of compromise and arrangement dated May 16, 2018 (as same may be further amended from time to time, the “Amended Plan”). The Amended Plan was approved by the required majorities of each unsecured creditor class and was sanctioned by the Court by order dated June 29, 2018 (the “Sanction Order”). In addition, the Bloom Lake Group and the Wabush Group will bring a motion before the Court on July 30, 2018 seeking to make further amendments to the Amended Plan to address the manner in which certain distributions under the Amended Plan will be effected. There are certain conditions precedent to the implementation of the Amended Plan that must be satisfied on or before July 31, 2018, subject to any extension of such date as agreed between the Monitor, the Bloom Lake Group, the Wabush Group and us. Subject to the proposed amendments to the Amended Plan described above and the finalization of certain required arrangements with applicable taxing authorities, the conditions precedent under the Amended Plan are expected to be satisfied by July 31, 2018. Under the terms of the Amended Plan, we and certain of our wholly-owned subsidiaries have made a C$19.0 million cash contribution to the Wabush Group pension plans and will contribute into the CCAA estate any 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 resolves 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. The net financial impact of the Amended Plan has been recorded in our financial statements.

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
SHAREHOLDERS' EQUITY	NOTE 17 - SHAREHOLDERS' DEFICIT The following table reflects the changes in shareholders' deficit attributable to both us and the noncontrolling interests, primarily related to Tilden and Empire. We own 100% of both mines as of June 30, 2018 and 85% and 79% of each mine, respectively, as of June 30, 2017 : (In Millions) Cliffs Noncontrolling Total Equity December 31, 2017 $ (444.3 ) $ 0.2 $ (444.1 ) Adoption of accounting standard (REFER TO NOTE 2) 34.0 — 34.0 Comprehensive income Net income 80.8 — 80.8 Other comprehensive income 16.8 — 16.8 Total comprehensive income 97.6 — 97.6 Stock and other incentive plans 6.4 — 6.4 Distributions to noncontrolling interest — (0.2 ) (0.2 ) June 30, 2018 $ (306.3 ) $ — $ (306.3 ) (In Millions) Cliffs Noncontrolling Total Equity December 31, 2016 $ (1,464.3 ) $ 133.8 $ (1,330.5 ) Comprehensive loss Net income (loss) 3.7 (3.4 ) 0.3 Other comprehensive income (loss) 1.9 (4.6 ) (2.7 ) Total comprehensive income (loss) 5.6 (8.0 ) (2.4 ) Issuance of common shares 661.3 — 661.3 Stock and other incentive plans 8.3 — 8.3 Distributions to noncontrolling interest — (3.4 ) (3.4 ) June 30, 2017 $ (789.1 ) $ 122.4 $ (666.7 ) The following table reflects the changes in Accumulated other comprehensive loss related to Cliffs shareholders’ deficit: (In Millions) Changes in Pension and OPEB, Unrealized Net Gain on Foreign Currency Translation Net Unrealized Gain (Loss) on 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 ) (In Millions) Changes in Pension and OPEB, net of tax Unrealized Net Gain (Loss) on Foreign Currency Translation Accumulated Other Comprehensive Loss December 31, 2016 $ (260.6 ) $ 239.3 $ (21.3 ) Other comprehensive income (loss) before reclassifications 3.3 (12.7 ) (9.4 ) Net loss reclassified from accumulated other comprehensive loss 6.4 — 6.4 March 31, 2017 $ (250.9 ) $ 226.6 $ (24.3 ) Other comprehensive loss before reclassifications (0.1 ) (1.5 ) (1.6 ) Net loss reclassified from accumulated other comprehensive loss 6.5 — 6.5 June 30, 2017 $ (244.5 ) $ 225.1 $ (19.4 ) The following table reflects the details about Accumulated other comprehensive loss components related to Cliffs shareholders’ deficit: (In Millions) Details about Accumulated Other Comprehensive Loss Components Amount of (Gain)/Loss Reclassified into Income Affected Line Item in the Statement of Unaudited Condensed Consolidated Operations Three Months Ended Six Months Ended 2018 2017 2018 2017 Amortization of pension and OPEB liability: Prior service credits $ (0.1 ) $ (0.1 ) $ (0.4 ) $ (0.2 ) Other non-operating income Net actuarial loss 6.6 6.6 13.1 13.1 Other non-operating income $ 6.5 $ 6.5 $ 12.7 $ 12.9 Net of taxes Unrealized loss on derivative financial instruments: Commodity contracts $ — $ — $ (0.1 ) $ — Cost of goods sold and operating expenses $ — $ — $ (0.1 ) $ — Net of taxes Total reclassifications for the period, net of tax $ 6.5 $ 6.5 $ 12.6 $ 12.9

RELATED PARTIES

RELATED PARTIES	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
RELATED PARTIES	NOTE 18 - RELATED PARTIES One of our four operating mines is a co-owned joint venture with companies that are integrated steel producers or their subsidiaries. We are the manager of such co-owned mine and rely on our joint venture partners to make their required capital contributions and to pay for their share of the iron ore pellets that we produce. Our joint venture partners are often our customers. The following is a summary of the mine ownership of the co-owned iron ore mine at June 30, 2018 : 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 Six Months Ended 2018 2017 2018 2017 Product revenues from related parties $ 409.4 $ 227.5 $ 471.4 $ 336.9 Total product revenues $ 672.0 $ 417.0 $ 841.2 $ 664.3 Related party product revenue as a percent of total product revenue 60.9 % 54.6 % 56.0 % 50.7 % The following table presents the classification of related party assets and liabilities in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) Balance Sheet Location June 30, 2018 December 31, 2017 Amounts due from related parties Accounts receivable, net $ 83.2 $ 68.1 Customer supply agreement and provisional pricing agreements Derivative assets 169.4 37.9 Amounts due to related parties Partnership distribution payable (44.2 ) (44.2 ) Amounts due to related parties Other current liabilities (3.6 ) (12.3 ) Amounts due to related parties Other liabilities (42.7 ) (41.4 ) Net amounts due from related parties $ 162.1 $ 8.1 During 2017, our ownership interest in Empire increased to 100% as we reached an agreement to distribute the noncontrolling interest net assets of $132.7 million to ArcelorMittal, in exchange for its interest in Empire. The net assets were agreed to be distributed in three installments of $44.2 million each, the first of which was paid upon the execution of the agreement and the remaining two of which are due in August 2018 and August 2019. The remaining two outstanding installments are reflected in Partnership distribution payable and Other liabilities in the Statements of Unaudited Condensed Consolidated Financial Position as of June 30, 2018 . A supply agreement with a customer provides for supplemental revenue or refunds to the customer based on the average annual daily market price for hot-rolled coil steel at the time the product is consumed in the customer’s blast furnace. The supplemental pricing is characterized as a freestanding derivative. Refer to NOTE 15 - DERIVATIVE INSTRUMENTS for further information.

EARNINGS PER SHARE

EARNINGS PER SHARE	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
EPS AND OTHER NON-GAAP FINANCIAL MEASURES	NOTE 19 - EARNINGS PER SHARE The following table summarizes the computation of basic and diluted earnings (loss) per share: (In Millions, Except Per Share Amounts) Three Months Ended Six Months Ended 2018 2017 2018 2017 Income from Continuing Operations $ 229.4 $ 83.8 $ 216.0 $ 5.3 Loss from Continuing Operations Attributable to Noncontrolling Interest — 1.7 — 3.4 Net Income from Continuing Operations Attributable to Cliffs Shareholders $ 229.4 $ 85.5 $ 216.0 $ 8.7 Loss from Discontinued Operations, net of tax (64.3 ) (53.7 ) (135.2 ) (5.0 ) Net Income Attributable to Cliffs Shareholders $ 165.1 $ 31.8 $ 80.8 $ 3.7 Weighted Average Number of Shares: Basic 297.6 296.1 297.4 280.6 Employee Stock Plans 3.7 4.6 3.7 4.6 Diluted 301.3 300.7 301.1 285.2 Income (Loss) per Common Share Attributable to Continuing operations $ 0.77 $ 0.28 $ 0.73 $ 0.03 Discontinued operations (0.22 ) (0.18 ) (0.46 ) (0.01 ) $ 0.55 $ 0.10 $ 0.27 $ 0.02 Income (Loss) per Common Share Attributable to Continuing operations $ 0.76 $ 0.28 $ 0.72 $ 0.03 Discontinued operations (0.21 ) (0.18 ) (0.45 ) (0.02 ) $ 0.55 $ 0.10 $ 0.27 $ 0.01

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	NOTE 20 - COMMITMENTS AND CONTINGENCIES Contingencies We are currently the subject of, or party to, various claims and legal proceedings incidental to our operations. If management believes that a loss arising from these matters is probable and can reasonably be estimated, we record the amount of the loss or the minimum estimated liability when the loss is estimated using a range, and no point within the range is more probable than another. As additional information becomes available, any potential liability related to these matters is assessed and the estimates are revised, if necessary. Based on currently available information, management believes that the ultimate outcome of these matters, individually and in the aggregate, will not have a material effect on our financial position, results of operations or cash flows. However, these claims and legal proceedings are subject to inherent uncertainties and unfavorable rulings could occur. An unfavorable ruling could include monetary damages, additional funding requirements or an injunction. If an unfavorable ruling were to occur, there exists the possibility of a material impact on the financial position and results of operations for the period in which the ruling occurs or future periods. However, we do not believe that any pending claims or legal proceedings will result in a material liability in relation to our consolidated financial statements. Currently, we have recorded a liability in the Statements of Unaudited Condensed Consolidated Financial Position related to the following legal matter: Michigan Electricity Matters. On February 19, 2015, in connection with various proceedings before FERC with respect to certain cost allocations for continued operation of the Presque Isle Power Plant in Marquette, Michigan, FERC issued an order directing MISO to submit a revised methodology for allocating SSR costs that identified the load serving entities that require the operation of SSR units at the power plant for reliability purposes. On September 17, 2015, FERC issued an order conditionally approving MISO’s revised allocation methodology. On September 22, 2016, FERC denied requests for rehearing of the February 19 order, rejecting arguments that FERC did not have the authority to order refunds in a cost allocation case and to impose retroactive surcharges to effectuate such refunds. FERC, however, suspended any refunds and surcharges pending its review of a July 25, 2016 ALJ initial decision on the appropriate amount of SSR compensation. This suspension was ultimately lifted after FERC’s Order on Initial Decision of October 19, 2017, affirming in part and reversing in part certain aspects of the ALJ’s decision, and FERC’s order on February 28, 2018, directing that refunds and surcharges be effectuated over a ten-month period beginning on the date of the order. Our current estimate of the potential liability to the Empire and Tilden mines is $13.0 million in the aggregate, based on a schedule of anticipated surcharges (including interest) for the Escanaba, White Pine and Presque Isle SSRs from Empire and Tilden's electricity supplier. During the six months ended June 30, 2018, Tilden and Empire made payments on invoiced surcharges totaling $2.2 million . Separate from these SSR compensation issues, Tilden and Empire, along with various Michigan-aligned parties, had filed petitions for review regarding allocation and non-cost SSR issues with the U.S. Court of Appeals for the D.C. Circuit. Oral arguments on those issues were completed on April 6, 2018. We will continue to vigorously challenge the imposition of any retroactive SSR costs before the U.S. Court of Appeals for the D.C. Circuit. As of June 30, 2018 , $10.8 million is included in our Statements of Unaudited Condensed Consolidated Financial Position as part of Accrued expenses for the remaining portion of this estimated liability. Additionally, we previously recorded a liability in the Statements of Unaudited Condensed Consolidated Financial Position related to the following matter, in which a settlement was reached during the period ended June 30, 2018: CCAA Proceedings Effective January 27, 2015, following the commencement of CCAA proceedings for the Bloom Lake Group, we deconsolidated the Bloom Lake Group and certain other wholly-owned subsidiaries comprising substantially all of our Canadian operations. Additionally, on May 20, 2015, the Wabush Group commenced CCAA proceedings which resulted in the deconsolidation of the remaining Wabush Group entities that were not previously deconsolidated. As a result of this action, the CCAA protection granted to the Bloom Lake Group was extended to include the Wabush Group to facilitate the reorganization of each of their businesses and operations. Prior to the deconsolidations, certain of our wholly-owned subsidiaries made loans to the Canadian Entities for the purpose of funding their operations and had accounts receivable generated in the ordinary course of business. The loans, corresponding interest and the accounts receivable were considered intercompany transactions and eliminated in our consolidated financial statements. Since the deconsolidations, the loans, associated interest and accounts receivable are considered related party transactions and have been recognized in our consolidated financial statements at their estimated fair value. As of June 30, 2018, we had no amounts outstanding classified as Loans to and accounts receivable from the Canadian Entities in the Statements of Unaudited Condensed Consolidated Financial Position in accordance with the Amended Plan, as defined and described below. As of December 31, 2017, we had $51.6 million classified as Loans to and accounts receivable from the Canadian Entities in the Statements of Unaudited Condensed Consolidated Financial Position. The net proceeds from the sale of the assets of the Bloom Lake Group and the Wabush Group are currently being held by the Monitor. Certain of these proceeds will be utilized to fund the accrued and remaining costs of the CCAA proceedings, and the remaining amounts will be available for distribution to the creditors of the Bloom Lake Group and the Wabush Group in accordance with the Amended Plan (as defined below). During 2017, we became aware that it was probable the Monitor will assert a preference claim against us and/or certain of our affiliates. We estimated a liability, which included the value of our related-party claims against the Bloom Lake Group and the Wabush Group, classified as Contingent claims in the Statements of Unaudited Condensed Consolidated Financial Position. As described below, as of June 30, 2018, the estimated liability has been settled pursuant to the Amended Plan. During March 2018, we entered into a restructuring term sheet with the Bloom Lake Group and the Wabush Group, which documents the proposed terms of a plan of compromise or arrangement in the CCAA proceedings to be sponsored by us as negotiated between us and the Monitor. By order of the Québec Superior Court of Justice (Commercial Division) (the “Court”) dated April 20, 2018, the Bloom Lake Group and the Wabush Group were authorized to file a joint plan of compromise and arrangement dated April 16, 2018 (the “Original Plan”). Following discussions with various stakeholder groups, the Original Plan was amended by order of the Court dated May 18, 2018. The Bloom Lake Group and the Wabush Group were authorized to file the amended and restated joint plan of compromise and arrangement dated May 16, 2018 (as same may be further amended from time to time, the “Amended Plan”). The Amended Plan was approved by the required majorities of each unsecured creditor class and was sanctioned by the Court by order dated June 29, 2018 (the “Sanction Order”). In addition, the Bloom Lake Group and the Wabush Group will bring a motion before the Court on July 30, 2018 seeking to make further amendments to the Amended Plan to address the manner in which certain distributions under the Amended Plan will be effected. There are certain conditions precedent to the implementation of the Amended Plan that must be satisfied on or before July 31, 2018, subject to any extension of such date as agreed between the Monitor, the Bloom Lake Group, the Wabush Group and us. Subject to the proposed amendments to the Amended Plan described above and the finalization of certain required arrangements with applicable taxing authorities, the conditions precedent under the Amended Plan are expected to be satisfied by July 31, 2018. Under the terms of the Amended Plan, we and certain of our wholly-owned subsidiaries have made a C$19.0 million cash contribution to the Wabush Group pension plans and will contribute into the CCAA estate any 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 resolves 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. The net financial impact of the Amended Plan has been recorded in our financial statements.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	NOTE 21 - SUBSEQUENT EVENTS We have evaluated subsequent events through the date of financial issuance.

SUPPLEMENTARY GUARANTOR INFORMA

SUPPLEMENTARY GUARANTOR INFORMATION	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Guarantor Information [Text Block]	NOTE 22 - SUPPLEMENTARY GUARANTOR INFORMATION The accompanying unaudited condensed consolidating financial information has been prepared and presented pursuant to SEC Regulation S-X, Rule 3-10, “Financial Statements of Guarantors and Issuers of Guaranteed Securities Registered or Being Registered.” Certain of our subsidiaries (the "Guarantors") have guaranteed the obligations under the $1.075 billion 5.75% 2025 Senior Notes issued by Cleveland-Cliffs Inc. See NOTE 7 - DEBT AND CREDIT FACILITIES for further information. The following presents the unaudited condensed consolidating financial information for: (i) the Parent Company and the Issuer of the guaranteed obligations (Cleveland-Cliffs Inc.); (ii) the Guarantor subsidiaries, on a combined basis; (iii) the non-guarantor subsidiaries, on a combined basis; (iv) consolidating eliminations; and (v) Cleveland-Cliffs Inc. and subsidiaries on a consolidated basis. Each Guarantor subsidiary is 100% owned by the Parent Company as of June 30, 2018 and December 31, 2017 . The unaudited condensed consolidating financial information is presented as if the Guarantor structure at June 30, 2018 existed for all periods presented. As a result, the Guarantor subsidiaries within the unaudited condensed consolidating financial information as of June 30, 2018 and December 31, 2017 and for the three and six months ended June 30, 2018 and 2017 include results of subsidiaries that were previously less than wholly-owned and were historically non-guarantors until 100% ownership was obtained. Each of the Guarantor subsidiaries fully and unconditionally guarantee, on a joint and several basis, the obligations of Cleveland-Cliffs Inc. under the $1.075 billion 5.75% 2025 Senior Notes. The guarantee of a Guarantor subsidiary will be automatically and unconditionally released and discharged, and such Guarantor subsidiary’s obligations under the guarantee and the related indenture governing the $1.075 billion 5.75% 2025 Senior Notes (the “Indenture”) will be automatically and unconditionally released and discharged, upon: (a) any sale, exchange, transfer or disposition of such Guarantor subsidiary (by merger, consolidation, or the sale of) or the capital stock of such Guarantor subsidiary after which the applicable Guarantor subsidiary is no longer a subsidiary of the Company or the sale of all or substantially all of such Guarantor subsidiary’s assets (other than by lease); (b) upon designation of any Guarantor subsidiary as an “excluded subsidiary” (as defined in the Indenture); or (c) upon defeasance or satisfaction and discharge of the Indenture. Each entity in the unaudited consolidating financial information follows the same accounting policies as described in the consolidated financial statements. The accompanying unaudited condensed consolidating financial information has been presented on the equity method of accounting for all periods presented. Under this method, investments in subsidiaries are recorded at cost and adjusted for the subsidiaries’ cumulative results of operations, capital contributions and distributions, and other changes in equity. Elimination entries include consolidating and eliminating entries for investments in subsidiaries, and intra-entity activity and balances. Unaudited Condensed Consolidating Statement of Financial Position As of June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 798.4 $ 1.6 $ 2.5 $ — $ 802.5 Accounts receivable, net 8.0 148.2 0.1 (3.7 ) 152.6 Inventories — 256.4 — — 256.4 Supplies and other inventories — 88.6 — — 88.6 Derivative assets 0.1 174.6 — — 174.7 Current assets of discontinued operations — — 45.3 — 45.3 Other current assets 15.9 7.7 3.2 — 26.8 TOTAL CURRENT ASSETS 822.4 677.1 51.1 (3.7 ) 1,546.9 PROPERTY, PLANT AND EQUIPMENT, NET 15.5 966.2 99.6 — 1,081.3 OTHER ASSETS Deposits for property, plant and equipment — 3.8 81.9 — 85.7 Income tax receivable 219.9 — — — 219.9 Investment in subsidiaries 1,299.9 32.8 — (1,332.7 ) — Long-term intercompany notes — — 227.4 (227.4 ) — Other non-current assets 8.7 107.3 1.7 — 117.7 TOTAL OTHER ASSETS 1,528.5 143.9 311.0 (1,560.1 ) 423.3 TOTAL ASSETS $ 2,366.4 $ 1,787.2 $ 461.7 $ (1,563.8 ) $ 3,051.5 LIABILITIES CURRENT LIABILITIES Accounts payable $ 5.2 $ 88.8 $ 28.7 $ (3.7 ) $ 119.0 Accrued expenses 13.6 71.0 0.5 — 85.1 Accrued interest 43.1 — — — 43.1 Partnership distribution payable — 44.2 — — 44.2 Current liabilities of discontinued operations — — 117.3 — 117.3 Other current liabilities 1.8 62.7 1.7 — 66.2 TOTAL CURRENT LIABILITIES 63.7 266.7 148.2 (3.7 ) 474.9 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 65.9 428.4 (249.3 ) — 245.0 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 145.3 27.0 — 172.3 LONG-TERM DEBT 2,297.0 — — — 2,297.0 NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS — — 10.3 — 10.3 LONG-TERM INTERCOMPANY NOTES 227.4 — — (227.4 ) — OTHER LIABILITIES 18.7 139.0 0.6 — 158.3 TOTAL LIABILITIES 2,672.7 979.4 (63.2 ) (231.1 ) 3,357.8 EQUITY TOTAL CLIFFS SHAREHOLDERS' DEFICIT (306.3 ) 807.8 524.9 (1,332.7 ) (306.3 ) TOTAL DEFICIT (306.3 ) 807.8 524.9 (1,332.7 ) (306.3 ) TOTAL LIABILITIES AND DEFICIT $ 2,366.4 $ 1,787.2 $ 461.7 $ (1,563.8 ) $ 3,051.5 Unaudited Condensed Consolidating Statement of Financial Position As of December 31, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 948.9 $ 2.1 $ 27.3 $ — $ 978.3 Accounts receivable, net 4.5 102.9 — (0.7 ) 106.7 Inventories — 138.4 — — 138.4 Supplies and other inventories — 88.8 — — 88.8 Derivative assets — 37.9 — — 37.9 Current assets of discontinued operations — — 118.5 — 118.5 Loans to and accounts receivable from the Canadian Entities 44.7 6.9 — — 51.6 Other current assets 16.4 7.5 0.5 — 24.4 TOTAL CURRENT ASSETS 1,014.5 384.5 146.3 (0.7 ) 1,544.6 PROPERTY, PLANT AND EQUIPMENT, NET 17.5 959.0 57.3 — 1,033.8 OTHER ASSETS Deposits for property, plant and equipment — 1.3 16.5 — 17.8 Income tax receivable 235.3 — — — 235.3 Non-current assets of discontinued operations — — 20.3 — 20.3 Investment in subsidiaries 1,024.3 29.9 — (1,054.2 ) — Long-term intercompany notes — — 242.0 (242.0 ) — Other non-current assets 7.8 91.7 2.1 — 101.6 TOTAL OTHER ASSETS 1,267.4 122.9 280.9 (1,296.2 ) 375.0 TOTAL ASSETS $ 2,299.4 $ 1,466.4 $ 484.5 $ (1,296.9 ) $ 2,953.4 LIABILITIES CURRENT LIABILITIES Accounts payable $ 7.1 $ 89.7 $ 3.4 $ (0.7 ) $ 99.5 Accrued expenses 19.0 59.9 0.2 — 79.1 Accrued interest 31.4 — — — 31.4 Contingent claims 55.6 — — — 55.6 Partnership distribution payable — 44.2 — — 44.2 Current liabilities of discontinued operations — — 75.0 — 75.0 Other current liabilities 2.1 63.5 1.8 — 67.4 TOTAL CURRENT LIABILITIES 115.2 257.3 80.4 (0.7 ) 452.2 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 66.4 430.6 (239.3 ) — 257.7 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 140.6 27.1 — 167.7 LONG-TERM DEBT 2,304.2 — — — 2,304.2 NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS — — 52.2 — 52.2 LONG-TERM INTERCOMPANY NOTES 242.0 — — (242.0 ) — OTHER LIABILITIES 15.7 147.2 0.6 — 163.5 TOTAL LIABILITIES 2,743.5 975.7 (79.0 ) (242.7 ) 3,397.5 EQUITY TOTAL CLIFFS SHAREHOLDERS' DEFICIT (444.1 ) 490.7 563.3 (1,054.2 ) (444.3 ) NONCONTROLLING INTEREST — — 0.2 — 0.2 TOTAL DEFICIT (444.1 ) 490.7 563.5 (1,054.2 ) (444.1 ) TOTAL LIABILITIES AND DEFICIT $ 2,299.4 $ 1,466.4 $ 484.5 $ (1,296.9 ) $ 2,953.4 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income For the Three Months Ended June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 672.0 $ — $ — $ 672.0 Freight and venture partners' cost reimbursements — 42.3 — — 42.3 — 714.3 — — 714.3 COST OF GOODS SOLD AND OPERATING EXPENSES — (429.8 ) — — (429.8 ) SALES MARGIN — 284.5 — — 284.5 OTHER OPERATING EXPENSE Selling, general and administrative expenses (19.7 ) (5.4 ) (1.1 ) — (26.2 ) Miscellaneous – net (0.2 ) (3.6 ) (0.3 ) — (4.1 ) (19.9 ) (9.0 ) (1.4 ) — (30.3 ) OPERATING INCOME (LOSS) (19.9 ) 275.5 (1.4 ) — 254.2 OTHER INCOME (EXPENSE) Interest expense, net (30.8 ) (0.6 ) 0.2 — (31.2 ) Gain on extinguishment of debt 0.2 — — — 0.2 Other non-operating income (expense) (0.8 ) 0.2 5.0 — 4.4 (31.4 ) (0.4 ) 5.2 — (26.6 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (51.3 ) 275.1 3.8 — 227.6 INCOME TAX BENEFIT (EXPENSE) 2.1 (0.1 ) (0.2 ) — 1.8 EQUITY IN INCOME (LOSS) OF SUBSIDIARIES 210.4 4.6 — (215.0 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 161.2 279.6 3.6 (215.0 ) 229.4 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX 3.9 (0.3 ) (67.9 ) — (64.3 ) NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 165.1 $ 279.3 $ (64.3 ) $ (215.0 ) $ 165.1 OTHER COMPREHENSIVE INCOME 9.1 6.0 2.2 (8.2 ) 9.1 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 174.2 $ 285.3 $ (62.1 ) $ (223.2 ) $ 174.2 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended June 30, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 417.0 $ — $ — $ 417.0 Freight and venture partners' cost reimbursements — 54.3 — — 54.3 — 471.3 — — 471.3 COST OF GOODS SOLD AND OPERATING EXPENSES — (326.6 ) — — (326.6 ) SALES MARGIN — 144.7 — — 144.7 OTHER OPERATING EXPENSE Selling, general and administrative expenses (19.7 ) (5.7 ) (1.2 ) — (26.6 ) Miscellaneous – net (0.8 ) (3.7 ) 1.6 — (2.9 ) (20.5 ) (9.4 ) 0.4 — (29.5 ) OPERATING INCOME (LOSS) (20.5 ) 135.3 0.4 — 115.2 OTHER INCOME (EXPENSE) Interest expense, net (30.4 ) — 0.3 — (30.1 ) Loss on extinguishment of debt (4.9 ) — — — (4.9 ) Other non-operating income (expense) (1.0 ) (0.8 ) 4.3 — 2.5 (36.3 ) (0.8 ) 4.6 — (32.5 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (56.8 ) 134.5 5.0 — 82.7 INCOME TAX BENEFIT (EXPENSE) 8.0 0.8 (7.7 ) — 1.1 EQUITY IN INCOME (LOSS) OF SUBSIDIARIES 129.6 3.4 — (133.0 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 80.8 138.7 (2.7 ) (133.0 ) 83.8 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX (49.0 ) 0.7 (5.4 ) — (53.7 ) NET INCOME (LOSS) 31.8 139.4 (8.1 ) (133.0 ) 30.1 LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST — 1.7 — — 1.7 NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 31.8 $ 141.1 $ (8.1 ) $ (133.0 ) $ 31.8 OTHER COMPREHENSIVE INCOME (LOSS) 5.0 5.7 (1.5 ) (4.3 ) 4.9 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 36.8 $ 146.8 $ (9.6 ) $ (137.3 ) $ 36.7 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income For the Six Months Ended June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 841.2 $ — $ — $ 841.2 Freight and venture partners' cost reimbursements — 53.1 — — 53.1 — 894.3 — — 894.3 COST OF GOODS SOLD AND OPERATING EXPENSES — (548.3 ) — — (548.3 ) SALES MARGIN — 346.0 — — 346.0 OTHER OPERATING EXPENSE Selling, general and administrative expenses (39.8 ) (9.7 ) (1.8 ) — (51.3 ) Miscellaneous – net (0.4 ) (8.9 ) (0.9 ) — (10.2 ) (40.2 ) (18.6 ) (2.7 ) — (61.5 ) OPERATING INCOME (40.2 ) 327.4 (2.7 ) — 284.5 OTHER INCOME (EXPENSE) Interest expense, net (62.7 ) (1.4 ) 0.5 — (63.6 ) Gain on extinguishment of debt 0.2 — — — 0.2 Other non-operating income (expense) (1.7 ) 0.7 9.8 — 8.8 (64.2 ) (0.7 ) 10.3 — (54.6 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (104.4 ) 326.7 7.6 — 229.9 INCOME TAX EXPENSE (13.5 ) (0.2 ) (0.2 ) — (13.9 ) EQUITY IN INCOME (LOSS) OF SUBSIDIARIES 194.7 9.1 — (203.8 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 76.8 335.6 7.4 (203.8 ) 216.0 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX 4.0 (0.1 ) (139.1 ) — (135.2 ) NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 80.8 $ 335.5 $ (131.7 ) $ (203.8 ) $ 80.8 OTHER COMPREHENSIVE INCOME 16.8 11.9 3.0 (14.9 ) 16.8 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 97.6 $ 347.4 $ (128.7 ) $ (218.7 ) $ 97.6 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Six Months Ended June 30, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 664.3 $ — $ — $ 664.3 Freight and venture partners' cost reimbursements — 93.2 — — 93.2 — 757.5 — — 757.5 COST OF GOODS SOLD AND OPERATING EXPENSES — (563.8 ) — — (563.8 ) SALES MARGIN — 193.7 — — 193.7 OTHER OPERATING INCOME (EXPENSE) Selling, general and administrative expenses (39.2 ) (10.1 ) (2.4 ) — (51.7 ) Miscellaneous – net (0.9 ) (9.2 ) 16.7 — 6.6 (40.1 ) (19.3 ) 14.3 — (45.1 ) OPERATING INCOME (40.1 ) 174.4 14.3 — 148.6 OTHER INCOME (EXPENSE) Interest expense, net (72.0 ) — 0.5 — (71.5 ) Loss on extinguishment of debt (76.8 ) — — — (76.8 ) Other non-operating income (expense) (2.0 ) (1.6 ) 8.6 — 5.0 (150.8 ) (1.6 ) 9.1 — (143.3 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (190.9 ) 172.8 23.4 — 5.3 INCOME TAX BENEFIT (EXPENSE) 0.2 — (0.2 ) — — EQUITY IN INCOME OF SUBSIDIARIES 243.0 6.6 — (249.6 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 52.3 179.4 23.2 (249.6 ) 5.3 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, net of tax (48.6 ) 0.9 42.7 — (5.0 ) NET INCOME (LOSS) 3.7 180.3 65.9 (249.6 ) 0.3 LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST — 3.4 — — 3.4 NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 3.7 $ 183.7 $ 65.9 $ (249.6 ) $ 3.7 OTHER COMPREHENSIVE INCOME (LOSS) 2.0 16.5 (19.3 ) 2.7 1.9 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 5.7 $ 200.2 $ 46.6 $ (246.9 ) $ 5.6 Unaudited Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (82.1 ) $ 86.8 $ (54.0 ) $ — $ (49.3 ) INVESTING ACTIVITIES Purchase of property, plant and equipment (0.3 ) (24.9 ) (16.9 ) — (42.1 ) Deposits for property, plant and equipment — (3.6 ) (68.7 ) — (72.3 ) Intercompany investing (35.2 ) (5.5 ) 14.6 26.1 — Proceeds on sale of assets — 0.4 14.2 — 14.6 Net cash used by investing activities (35.5 ) (33.6 ) (56.8 ) 26.1 (99.8 ) FINANCING ACTIVITIES Debt issuance costs (1.5 ) — — — (1.5 ) Repurchase of debt (15.3 ) — — — (15.3 ) Intercompany financing (14.6 ) (52.7 ) 93.4 (26.1 ) — Other financing activities (1.5 ) (1.0 ) (6.4 ) — (8.9 ) Net cash used by financing activities (32.9 ) (53.7 ) 87.0 (26.1 ) (25.7 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — (1.0 ) — (1.0 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS (150.5 ) (0.5 ) (24.8 ) — (175.8 ) LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS — — — — — NET DECREASE IN CASH AND CASH EQUIVALENTS (150.5 ) (0.5 ) (24.8 ) — (175.8 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 948.9 2.1 27.3 — 978.3 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 798.4 $ 1.6 $ 2.5 $ — $ 802.5 Unaudited Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (128.8 ) $ 106.3 $ 90.3 $ — $ 67.8 INVESTING ACTIVITIES Purchase of property, plant and equipment (0.8 ) (42.7 ) (0.8 ) — (44.3 ) Deposits for property, plant and equipment — (5.1 ) — — (5.1 ) Intercompany investing 43.5 (1.1 ) (45.0 ) 2.6 — Proceeds on sales of assets — 1.1 — — 1.1 Net cash provided (used) by investing activities 42.7 (47.8 ) (45.8 ) 2.6 (48.3 ) FINANCING ACTIVITIES Net proceeds from issuance of common shares 661.3 — — — 661.3 Proceeds from issuance of debt 500.0 — — — 500.0 Debt issuance costs (8.5 ) — — — (8.5 ) Repurchase of debt (1,154.0 ) — — — (1,154.0 ) Distributions of partnership equity — (8.7 ) — — (8.7 ) Intercompany financing 45.0 (44.3 ) 1.9 (2.6 ) — Other financing activities (0.6 ) (5.0 ) (8.3 ) — (13.9 ) Net cash used by financing activities 43.2 (58.0 ) (6.4 ) (2.6 ) (23.8 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — 2.4 — 2.4 INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS (42.9 ) 0.5 40.5 — (1.9 ) LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS — — 40.5 — 40.5 NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS (42.9 ) 0.5 — — (42.4 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 283.4 2.5 26.9 — 312.8 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 240.5 $ 3.0 $ 26.9 $ — $ 270.4

BASIS OF PRESENTATION AND SIG29

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule Of Subsidiaries	Basis of Consolidation The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, including the following operations as of June 30, 2018 : Name Location Status of Operations Northshore Minnesota Active United Taconite Minnesota Active Tilden Michigan Active Empire Michigan Indefinitely Idled Koolyanobbing 1 Western Australia Not Active 1 During June 2018, we completed the final planned shipment from Asia Pacific Iron Ore and commenced selling its assets. Refer to NOTE 16 - DISCONTINUED OPERATIONS. 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 June 30, 2018 and December 31, 2017 , our investment in Hibbing was $8.0 million and $11.0 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. The functional currency of our Australian subsidiaries is the Australian dollar. Refer to NOTE 16 - DISCONTINUED OPERATIONS for further information regarding our Australian subsidiaries. The functional currency of all other international subsidiaries is the U.S. dollar. To the extent that monetary assets and liabilities, including short-term intercompany loans, are recorded in a currency other than the functional currency, these amounts are remeasured each reporting period, with the resulting gain or loss being recorded in the Statements of Unaudited Condensed Consolidated Operations . Transaction gains and losses resulting from remeasurement of short-term intercompany loans are included in Miscellaneous – net in the Statements of Unaudited Condensed Consolidated Operations . The following represents the transaction gains and losses resulting from remeasurement: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Short-term intercompany loans $ (0.1 ) $ 1.5 $ (0.3 ) $ 16.6 Other — (1.0 ) (0.2 ) (1.3 ) Net impact of transaction gains (losses) resulting from remeasurement $ (0.1 ) $ 0.5 $ (0.5 ) $ 15.3
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, 2017 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 other than those related to the adoption of Topic 606. Refer to NOTE 2 - NEW ACCOUNTING STANDARDS for further information.

BASIS OF PRESENTATION AND SIG30

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Tables)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule Of Subsidiaries	Basis of Consolidation The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, including the following operations as of June 30, 2018 : Name Location Status of Operations Northshore Minnesota Active United Taconite Minnesota Active Tilden Michigan Active Empire Michigan Indefinitely Idled Koolyanobbing 1 Western Australia Not Active 1 During June 2018, we completed the final planned shipment from Asia Pacific Iron Ore and commenced selling its assets. Refer to NOTE 16 - DISCONTINUED OPERATIONS. Intercompany transactions and balances are eliminated upon consolidation.
Foreign Currency	The following represents the transaction gains and losses resulting from remeasurement: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Short-term intercompany loans $ (0.1 ) $ 1.5 $ (0.3 ) $ 16.6 Other — (1.0 ) (0.2 ) (1.3 ) Net impact of transaction gains (losses) resulting from remeasurement $ (0.1 ) $ 0.5 $ (0.5 ) $ 15.3

NEW ACCOUNTING STANDARDS (Table

NEW ACCOUNTING STANDARDS (Tables)	6 Months Ended
	Jun. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The effect of the retrospective presentation change related to the net periodic cost of our defined benefit pension and other postretirement employee benefits plans on our Statements of Unaudited Condensed Consolidated Operations was as follows: ($ in Millions) Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 As Revised Without Adoption of ASU 2017-07 Effect of Change As Revised Without Adoption of ASU 2017-07 Effect of Change Cost of goods sold and operating expenses $ (326.6 ) $ (327.1 ) $ 0.5 $ (563.8 ) $ (564.9 ) $ 1.1 Selling, general and administrative expenses $ (26.6 ) $ (24.7 ) $ (1.9 ) $ (51.7 ) $ (47.8 ) $ (3.9 ) Miscellaneous – net $ (2.9 ) $ (2.6 ) $ (0.3 ) $ 6.6 $ 7.3 $ (0.7 ) Operating income $ 115.2 $ 116.9 $ (1.7 ) $ 148.6 $ 152.1 $ (3.5 ) Other non-operating income $ 2.5 $ 0.8 $ 1.7 $ 5.0 $ 1.5 $ 3.5 Net Income $ 30.1 $ 30.1 $ — $ 0.3 $ 0.3 $ — The cumulative effect of the changes made to our consolidated January 1, 2018 balance sheet for the adoption of Topic 606 were as follows: ($ in Millions) Balance at December 31, 2017 Adjustments due to Topic 606 Balance at January 1, 2018 ASSETS CURRENT ASSETS Cash and cash equivalents $ 978.3 $ — $ 978.3 Accounts receivable, net 106.7 76.6 183.3 Inventories 138.4 (51.4 ) 87.0 Supplies and other inventories 88.8 — 88.8 Derivative assets 37.9 11.6 49.5 Current assets of discontinued operations 118.5 — 118.5 Loans to and accounts receivable from the Canadian Entities 51.6 — 51.6 Other current assets 24.4 — 24.4 TOTAL CURRENT ASSETS 1,544.6 36.8 1,581.4 PROPERTY, PLANT AND EQUIPMENT, NET 1,033.8 — 1,033.8 OTHER ASSETS Deposits for property, plant and equipment 17.8 — 17.8 Income tax receivable 235.3 — 235.3 Long-term assets of discontinued operations 20.3 — 20.3 Other non-current assets 101.6 — 101.6 TOTAL OTHER ASSETS 375.0 — 375.0 TOTAL ASSETS $ 2,953.4 $ 36.8 $ 2,990.2 LIABILITIES CURRENT LIABILITIES Accounts payable $ 99.5 $ 1.4 $ 100.9 Accrued expenses 79.1 — 79.1 Accrued interest 31.4 — 31.4 Contingent claims 55.6 — 55.6 Partnership distribution payable 44.2 — 44.2 Current liabilities of discontinued operations 75.0 — 75.0 Other current liabilities 67.4 1.4 68.8 TOTAL CURRENT LIABILITIES 452.2 2.8 455.0 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 257.7 — 257.7 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS 167.7 — 167.7 LONG-TERM DEBT 2,304.2 — 2,304.2 NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS 52.2 — 52.2 OTHER LIABILITIES 163.5 — 163.5 TOTAL LIABILITIES 3,397.5 2.8 3,400.3 EQUITY CLIFFS SHAREHOLDERS' DEFICIT (444.3 ) 34.0 (410.3 ) NONCONTROLLING INTEREST 0.2 — 0.2 TOTAL DEFICIT (444.1 ) 34.0 (410.1 ) TOTAL LIABILITIES AND DEFICIT $ 2,953.4 $ 36.8 $ 2,990.2 The impact of adoption on our Statements of Unaudited Condensed Consolidated Operations and Statements of Unaudited Condensed Consolidated Financial Position is as follows: ($ in Millions) Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 As Reported Balances without Adoption of Topic 606 Effect of Change As Reported Balances without Adoption of Topic 606 Effect of Change REVENUES FROM PRODUCT SALES AND SERVICES Product $ 672.0 $ 568.0 $ 104.0 $ 841.2 $ 795.6 $ 45.6 Freight and venture partners' cost reimbursements 42.3 36.3 6.0 53.1 51.2 1.9 714.3 604.3 110.0 894.3 846.8 47.5 COST OF GOODS SOLD AND OPERATING EXPENSES (429.8 ) (368.6 ) (61.2 ) (548.3 ) (530.7 ) (17.6 ) SALES MARGIN 284.5 235.7 48.8 346.0 316.1 29.9 OTHER OPERATING EXPENSE Selling, general and administrative expenses (26.2 ) (26.2 ) — (51.3 ) (51.3 ) — Miscellaneous – net (4.1 ) (4.1 ) — (10.2 ) (10.2 ) — (30.3 ) (30.3 ) — (61.5 ) (61.5 ) — OPERATING INCOME 254.2 205.4 48.8 284.5 254.6 29.9 OTHER INCOME (EXPENSE) Interest expense, net (31.2 ) (31.2 ) — (63.6 ) (63.6 ) — Gain on extinguishment of debt 0.2 0.2 — 0.2 0.2 — Other non-operating income 4.4 4.4 — 8.8 8.8 — (26.6 ) (26.6 ) — (54.6 ) (54.6 ) — INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES 227.6 178.8 48.8 229.9 200.0 29.9 INCOME TAX BENEFIT (EXPENSE) 1.8 1.8 — (13.9 ) (13.9 ) — INCOME FROM CONTINUING OPERATIONS 229.4 180.6 48.8 216.0 186.1 29.9 LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX (64.3 ) (64.3 ) — (135.2 ) (135.2 ) — NET INCOME 165.1 116.3 48.8 80.8 50.9 29.9 LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST — — — — — — NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 165.1 $ 116.3 $ 48.8 $ 80.8 $ 50.9 $ 29.9 INCOME (LOSS) PER COMMON SHARE ATTRIBUTABLE TO CLIFFS SHAREHOLDERS – BASIC Continuing operations $ 0.77 $ 0.61 $ 0.16 $ 0.73 $ 0.62 $ 0.10 Discontinued operations (0.22 ) (0.22 ) — (0.46 ) (0.45 ) — $ 0.55 $ 0.39 $ 0.16 $ 0.27 $ 0.17 $ 0.10 INCOME (LOSS) PER COMMON SHARE ATTRIBUTABLE TO CLIFFS SHAREHOLDERS – DILUTED Continuing operations $ 0.76 $ 0.60 $ 0.16 $ 0.72 $ 0.62 $ 0.10 Discontinued operations (0.21 ) (0.21 ) — (0.45 ) (0.45 ) — $ 0.55 $ 0.39 $ 0.16 $ 0.27 $ 0.17 $ 0.10 AVERAGE NUMBER OF SHARES (IN THOUSANDS) Basic 297,618 297,618 297,442 297,442 Diluted 301,275 301,275 301,143 301,143 ($ in Millions) June 30, 2018 As Reported Balances without Adoption of Topic 606 Effect of Change ASSETS CURRENT ASSETS Cash and cash equivalents $ 802.5 $ 802.5 $ — Accounts receivable, net 152.6 53.0 99.6 Inventories 256.4 323.9 (67.5 ) Supplies and other inventories 88.6 88.6 — Derivative assets 174.7 146.2 28.5 Current assets of discontinued operations 45.3 45.3 — Loans to and accounts receivable from the Canadian Entities — — — Other current assets 26.8 26.8 — TOTAL CURRENT ASSETS 1,546.9 1,486.3 60.6 PROPERTY, PLANT AND EQUIPMENT, NET 1,081.3 1,081.3 — OTHER ASSETS Deposits for property, plant and equipment 85.7 85.7 — Income tax receivable 219.9 219.9 — Non-current assets of discontinued operations — — — Other non-current assets 117.7 117.7 — TOTAL OTHER ASSETS 423.3 423.3 — TOTAL ASSETS $ 3,051.5 $ 2,990.9 $ 60.6 LIABILITIES CURRENT LIABILITIES Accounts payable $ 119.0 $ 117.8 $ 1.2 Accrued expenses 85.1 85.1 — Accrued interest 43.1 43.1 — Contingent claims — — — Partnership distribution payable 44.2 44.2 — Current liabilities of discontinued operations 117.3 117.3 — Other current liabilities 66.2 72.1 (5.9 ) TOTAL CURRENT LIABILITIES 474.9 479.6 (4.7 ) PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 245.0 245.0 — ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS 172.3 172.3 — LONG-TERM DEBT 2,297.0 2,297.0 — NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS 10.3 10.3 — OTHER LIABILITIES 158.3 158.3 — TOTAL LIABILITIES 3,357.8 3,362.5 (4.7 ) EQUITY CLIFFS SHAREHOLDERS' DEFICIT (306.3 ) (371.6 ) 65.3 NONCONTROLLING INTEREST — — — TOTAL DEFICIT (306.3 ) (371.6 ) 65.3 TOTAL LIABILITIES AND DEFICIT $ 3,051.5 $ 2,990.9 $ 60.6

SEGMENT REPORTING SEGMENT REP32

SEGMENT REPORTING SEGMENT REPORTING (Tables)	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Schedule Of Segment Reporting Information, By Segment	The following tables present a summary of our reportable segment including a reconciliation of segment sales margin to Income from Continuing Operations Before Income Taxes and a reconciliation of Net Income to EBITDA and Adjusted EBITDA: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Revenues from product sales and services: U.S. Iron Ore $ 714.3 100 % $ 471.3 100 % $ 894.3 100 % $ 757.5 100 % Sales margin $ 284.5 $ 144.7 $ 346.0 $ 193.7 Other operating expense (30.3 ) (29.5 ) (61.5 ) (45.1 ) Other expense (26.6 ) (32.5 ) (54.6 ) (143.3 ) Income from continuing operations before income taxes $ 227.6 $ 82.7 $ 229.9 $ 5.3 (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Net Income $ 165.1 $ 30.1 $ 80.8 $ 0.3 Less: Interest expense, net (32.3 ) (31.4 ) (65.8 ) (74.2 ) Income tax benefit (expense) 1.8 (2.6 ) (13.9 ) (0.8 ) Depreciation, depletion and amortization (25.5 ) (21.6 ) (49.4 ) (44.8 ) EBITDA $ 221.1 $ 85.7 $ 209.9 $ 120.1 Less: Impact of discontinued operations $ (54.7 ) $ (45.4 ) $ (117.8 ) $ 6.5 Foreign exchange remeasurement (0.1 ) 0.5 (0.5 ) 15.3 Gain (loss) on extinguishment of debt 0.2 (4.9 ) 0.2 (76.8 ) Adjusted EBITDA $ 275.7 $ 135.5 $ 328.0 $ 175.1 EBITDA U.S. Iron Ore $ 296.0 $ 155.0 $ 368.5 $ 212.9 Corporate and Other 1 (74.9 ) (69.3 ) (158.6 ) (92.8 ) Total EBITDA $ 221.1 $ 85.7 $ 209.9 $ 120.1 Adjusted EBITDA: U.S. Iron Ore $ 301.3 $ 161.5 $ 378.4 $ 225.6 Corporate and Other 1 (25.6 ) (26.0 ) (50.4 ) (50.5 ) Total Adjusted EBITDA $ 275.7 $ 135.5 $ 328.0 $ 175.1 1 Corporate and Other includes immaterial costs related to the HBI project. The following table summarizes our depreciation, depletion and amortization expense and capital additions: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Depreciation, depletion and amortization: U.S. Iron Ore $ 15.6 $ 16.7 $ 31.4 $ 33.1 Corporate and Other 1.4 1.6 2.8 3.7 Total depreciation, depletion and amortization $ 17.0 $ 18.3 $ 34.2 $ 36.8 Capital additions 1 : U.S. Iron Ore $ 26.7 $ 24.6 $ 45.4 $ 51.7 Corporate and Other 2 43.7 — 103.9 — Total capital additions $ 70.4 $ 24.6 $ 149.3 $ 51.7 1 Includes cash paid for capital additions of $114.4 million, including deposits of $72.3 million, and an increase in non-cash accruals of $34.9 million for the six months ended June 30, 2018 compared to cash paid for capital additions of $48.5 million, including deposits of $5.1 million, and an increase in non-cash accruals of $3.2 million for the six months ended June 30, 2017. 2 Includes capital additions related to our HBI project. (In Millions) June 30, December 31, Land rights and mineral rights $ 549.6 $ 549.6 Office and information technology 65.1 65.8 Buildings 84.0 85.2 Mining equipment 531.2 533.9 Processing equipment 616.0 610.9 Electric power facilities 56.9 56.9 Land improvements 24.2 23.7 Asset retirement obligation 16.9 16.9 Other 25.2 25.2 Construction in-progress 102.2 32.6 2,071.3 2,000.7 Allowance for depreciation and depletion (990.0 ) (966.9 ) $ 1,081.3 $ 1,033.8
Reconciliation of Assets from Segment to Consolidated [Table Text Block]	A summary of assets by segment is as follows: (In Millions) June 30, December 31, Assets: U.S. Iron Ore $ 1,822.8 $ 1,500.6 Corporate and Other 1 1,183.4 1,314.0 Assets of Discontinued Operations 45.3 138.8 Total assets $ 3,051.5 $ 2,953.4 1 Corporate and Other includes assets related to the HBI project.

REVENUE (Tables)

REVENUE (Tables)	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Deferred Revenue Disclosure	The table below summarizes our deferred revenue balances: Deferred Revenue (Current) 1 Deferred Revenue (Long-Term) Opening balance as of January 1, 2018 $ 23.8 $ 51.4 Closing balance as of June 30, 2018 20.0 47.1 Decrease $ (3.8 ) $ (4.3 ) 1 The opening balance includes a $1.4 million adjustment from the December 31, 2017 balance due to the adoption of Topic 606.

INVENTORIES (Tables)

INVENTORIES (Tables)	6 Months Ended
	Jun. 30, 2018
Inventory Disclosure [Abstract]
Schedule Of Inventories	The following table presents the detail of our Inventories in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) June 30, 2018 December 31, 2017 Finished Goods $ 232.5 $ 127.1 Work-in-Process 23.9 11.3 Total Inventories $ 256.4 $ 138.4

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Value Of Each Of The Major Classes Of Consolidated Depreciable Assets	The following table indicates the value of each of the major classes of our consolidated depreciable assets: (In Millions) June 30, December 31, Land rights and mineral rights $ 549.6 $ 549.6 Office and information technology 65.1 65.8 Buildings 84.0 85.2 Mining equipment 531.2 533.9 Processing equipment 616.0 610.9 Electric power facilities 56.9 56.9 Land improvements 24.2 23.7 Asset retirement obligation 16.9 16.9 Other 25.2 25.2 Construction in-progress 102.2 32.6 2,071.3 2,000.7 Allowance for depreciation and depletion (990.0 ) (966.9 ) $ 1,081.3 $ 1,033.8
Schedule Of Segment Reporting Information, By Segment	The following tables present a summary of our reportable segment including a reconciliation of segment sales margin to Income from Continuing Operations Before Income Taxes and a reconciliation of Net Income to EBITDA and Adjusted EBITDA: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Revenues from product sales and services: U.S. Iron Ore $ 714.3 100 % $ 471.3 100 % $ 894.3 100 % $ 757.5 100 % Sales margin $ 284.5 $ 144.7 $ 346.0 $ 193.7 Other operating expense (30.3 ) (29.5 ) (61.5 ) (45.1 ) Other expense (26.6 ) (32.5 ) (54.6 ) (143.3 ) Income from continuing operations before income taxes $ 227.6 $ 82.7 $ 229.9 $ 5.3 (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Net Income $ 165.1 $ 30.1 $ 80.8 $ 0.3 Less: Interest expense, net (32.3 ) (31.4 ) (65.8 ) (74.2 ) Income tax benefit (expense) 1.8 (2.6 ) (13.9 ) (0.8 ) Depreciation, depletion and amortization (25.5 ) (21.6 ) (49.4 ) (44.8 ) EBITDA $ 221.1 $ 85.7 $ 209.9 $ 120.1 Less: Impact of discontinued operations $ (54.7 ) $ (45.4 ) $ (117.8 ) $ 6.5 Foreign exchange remeasurement (0.1 ) 0.5 (0.5 ) 15.3 Gain (loss) on extinguishment of debt 0.2 (4.9 ) 0.2 (76.8 ) Adjusted EBITDA $ 275.7 $ 135.5 $ 328.0 $ 175.1 EBITDA U.S. Iron Ore $ 296.0 $ 155.0 $ 368.5 $ 212.9 Corporate and Other 1 (74.9 ) (69.3 ) (158.6 ) (92.8 ) Total EBITDA $ 221.1 $ 85.7 $ 209.9 $ 120.1 Adjusted EBITDA: U.S. Iron Ore $ 301.3 $ 161.5 $ 378.4 $ 225.6 Corporate and Other 1 (25.6 ) (26.0 ) (50.4 ) (50.5 ) Total Adjusted EBITDA $ 275.7 $ 135.5 $ 328.0 $ 175.1 1 Corporate and Other includes immaterial costs related to the HBI project. The following table summarizes our depreciation, depletion and amortization expense and capital additions: (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Depreciation, depletion and amortization: U.S. Iron Ore $ 15.6 $ 16.7 $ 31.4 $ 33.1 Corporate and Other 1.4 1.6 2.8 3.7 Total depreciation, depletion and amortization $ 17.0 $ 18.3 $ 34.2 $ 36.8 Capital additions 1 : U.S. Iron Ore $ 26.7 $ 24.6 $ 45.4 $ 51.7 Corporate and Other 2 43.7 — 103.9 — Total capital additions $ 70.4 $ 24.6 $ 149.3 $ 51.7 1 Includes cash paid for capital additions of $114.4 million, including deposits of $72.3 million, and an increase in non-cash accruals of $34.9 million for the six months ended June 30, 2018 compared to cash paid for capital additions of $48.5 million, including deposits of $5.1 million, and an increase in non-cash accruals of $3.2 million for the six months ended June 30, 2017. 2 Includes capital additions related to our HBI project. (In Millions) June 30, December 31, Land rights and mineral rights $ 549.6 $ 549.6 Office and information technology 65.1 65.8 Buildings 84.0 85.2 Mining equipment 531.2 533.9 Processing equipment 616.0 610.9 Electric power facilities 56.9 56.9 Land improvements 24.2 23.7 Asset retirement obligation 16.9 16.9 Other 25.2 25.2 Construction in-progress 102.2 32.6 2,071.3 2,000.7 Allowance for depreciation and depletion (990.0 ) (966.9 ) $ 1,081.3 $ 1,033.8

DEBT AND CREDIT FACILITIES (Tab

DEBT AND CREDIT FACILITIES (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	The following represents a summary of our long-term debt: (In Millions) June 30, 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 $ (6.3 ) $ (2.4 ) $ 391.3 Unsecured Notes $400 Million 5.90% 2020 Senior Notes 5.98% 88.4 (0.2 ) (0.1 ) 88.1 $500 Million 4.80% 2020 Senior Notes 4.83% 122.3 (0.2 ) (0.1 ) 122.0 $700 Million 4.875% 2021 Senior Notes 4.89% 125.2 (0.3 ) — 124.9 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (6.0 ) (80.6 ) 229.7 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,073.3 (10.6 ) (15.6 ) 1,047.1 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.3 ) (3.4 ) 292.7 ABL Facility N/A 450.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 1.2 Long-term debt $ 2,297.0 (In Millions) December 31, 2017 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 $ (7.1 ) $ (2.6 ) $ 390.3 Unsecured Notes $400 Million 5.90% 2020 Senior Notes 5.98% 88.9 (0.2 ) (0.1 ) 88.6 $500 Million 4.80% 2020 Senior Notes 4.83% 122.4 (0.3 ) (0.1 ) 122.0 $700 Million 4.875% 2021 Senior Notes 4.89% 138.4 (0.3 ) (0.1 ) 138.0 $316.25 Million 1.50% 2025 Convertible Senior Notes 6.26% 316.3 (6.6 ) (85.6 ) 224.1 $1.075 Billion 5.75% 2025 Senior Notes 6.01% 1,075.0 (11.3 ) (16.5 ) 1,047.2 $800 Million 6.25% 2040 Senior Notes 6.34% 298.4 (2.4 ) (3.4 ) 292.6 ABL Facility N/A 550.0 N/A N/A — Fair Value Adjustment to Interest Rate Hedge 1.4 Long-term debt $ 2,304.2
Extinguishment of Debt, Amount	The following is a summary of the debt extinguished with cash during the three and six months ended June 30, 2018 that resulted in a gain on extinguishment of $0.2 million : (In Millions) Debt Instrument Debt Extinguished $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 13.2 $1.075 Billion 5.75% 2025 Senior Notes 1.7 $ 15.5
Schedule of Maturities of Long-term Debt	Debt Maturities The following represents a summary of our maturities of debt instruments based on the principal amounts outstanding at June 30, 2018 : (In Millions) Maturities of Debt 2018 $ — 2019 — 2020 210.7 2021 125.2 2022 — 2023 — 2024 and thereafter 2,088.0 Total maturities of debt $ 2,423.9

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	The following represents the assets and liabilities measured at fair value: (In Millions) June 30, 2018 Description 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 $ 10.5 $ 546.5 $ — $ 557.0 Derivative assets — 0.1 174.6 174.7 Total $ 10.5 $ 546.6 $ 174.6 $ 731.7 Liabilities: Derivative liabilities $ — $ 0.1 $ 3.0 $ 3.1 Total $ — $ 0.1 $ 3.0 $ 3.1 (In Millions) December 31, 2017 Description 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 $ 66.3 $ 550.6 $ — $ 616.9 Derivative assets — — 37.9 37.9 Total $ 66.3 $ 550.6 $ 37.9 $ 654.8 Liabilities: Derivative liabilities $ — $ 0.3 $ 1.7 $ 2.0 Total $ — $ 0.3 $ 1.7 $ 2.0
Fair Value, Recurring and Nonrecurring, Valuation Techniques	The following table illustrates information about quantitative inputs and assumptions for the assets and liabilities categorized in Level 3 of the fair value hierarchy: Qualitative/Quantitative Information About Level 3 Fair Value Measurements (In Millions) Fair Value at June 30, 2018 Balance Sheet Location Valuation Technique Unobservable Input Range or Point Estimate (Weighted Average) Customer supply agreement $ 169.4 Derivative assets Market Approach Management's Estimate of Market Hot-Rolled Coil Steel per net ton $833 Provisional pricing arrangements $ 5.2 Derivative assets Market Approach Management's Estimate of Platts 62% Price per dry metric ton $68 - $69 Provisional pricing arrangements $ 3.0 Other Current Liabilities Market Approach Management's Estimate of Platts 62% Price per dry metric ton $68 - $69
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation	The following tables represent a reconciliation of the changes in fair value of financial instruments measured at fair value on a recurring basis using significant unobservable inputs (Level 3): (In Millions) Level 3 Assets Three Months Ended Six Months Ended 2018 2017 2018 2017 Beginning balance 1 $ 93.5 $ 59.2 $ 49.5 $ 30.1 Total gains Included in earnings 158.6 51.0 202.8 84.6 Settlements (77.5 ) (40.0 ) (77.7 ) (44.5 ) Ending balance - June 30 $ 174.6 $ 70.2 $ 174.6 $ 70.2 Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date $ 80.6 $ 17.8 $ 125.1 $ 51.0 1 Beginning balance as of January 1, 2018 includes an $11.6 million adjustment for adoption of Topic 606.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	(In Millions) Level 3 Liabilities Three Months Ended Six Months Ended 2018 2017 2018 2017 Beginning balance $ — $ — $ (1.7 ) $ — Total losses Included in earnings (3.7 ) (20.2 ) (4.3 ) (20.2 ) Settlements 0.7 — 3.0 — Ending balance - June 30 $ (3.0 ) $ (20.2 ) $ (3.0 ) $ (20.2 ) Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date $ (3.0 ) $ (20.2 ) $ (3.0 ) $ (20.2 )
Schedule Of Carrying Value And Fair Value Of Financial Instruments	A summary of the carrying amount and fair value of other financial instruments were as follows: (In Millions) June 30, 2018 December 31, 2017 Classification Carrying Value Fair Value Carrying Value Fair Value Long-term debt: Secured Notes $400 Million 4.875% 2024 Senior Notes Level 1 $ 391.3 $ 388.5 $ 390.3 $ 398.0 Unsecured Notes $400 Million 5.90% 2020 Senior Notes Level 1 88.1 88.4 88.6 88.0 $500 Million 4.80% 2020 Senior Notes Level 1 122.0 120.5 122.0 118.8 $700 Million 4.875% 2021 Senior Notes Level 1 124.9 124.6 138.0 130.8 $316.25 Million 1.50% 2025 Convertible Senior Notes Level 1 229.7 384.5 224.1 352.9 $1.075 Billion 5.75% 2025 Senior Notes Level 1 1,047.1 1,028.6 1,047.2 1,029.3 $800 Million 6.25% 2040 Senior Notes Level 1 292.7 241.7 292.6 227.1 ABL Facility Level 2 — — — — Fair value adjustment to interest rate hedge Level 2 1.2 1.2 1.4 1.4 Total long-term debt $ 2,297.0 $ 2,378.0 $ 2,304.2 $ 2,346.3

PENSIONS AND OTHER POSTRETIRE38

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Tables)	6 Months Ended
	Jun. 30, 2018
Postemployment Benefits [Abstract]
Schedule of Net Benefit Costs	The following are the components of defined benefit pension and OPEB costs and credits: Defined Benefit Pension Costs (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Service cost $ 4.6 $ 4.7 $ 9.3 $ 9.5 Interest cost 7.5 7.5 15.1 15.0 Expected return on plan assets (15.0 ) (13.6 ) (30.0 ) (27.1 ) Amortization: Prior service costs 0.6 0.7 1.1 1.3 Net actuarial loss 5.3 5.3 10.6 10.6 Net periodic benefit cost $ 3.0 $ 4.6 $ 6.1 $ 9.3 Other Postretirement Benefits Credits (In Millions) Three Months Ended Six Months Ended 2018 2017 2018 2017 Service cost $ 0.5 $ 0.5 $ 1.0 $ 1.0 Interest cost 2.0 2.2 4.1 4.3 Expected return on plan assets (4.6 ) (4.5 ) (9.2 ) (8.9 ) Amortization: Prior service credits (0.7 ) (0.8 ) (1.5 ) (1.5 ) Net actuarial loss 1.3 1.3 2.5 2.5 Net periodic benefit credit $ (1.5 ) $ (1.3 ) $ (3.1 ) $ (2.6 )

STOCK COMPENSATION PLANS (Table

STOCK COMPENSATION PLANS (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]	The following assumptions were utilized to estimate the fair value for the 2018 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 21, 2018 $ 7.53 2.86 86.8% 2.42% —% $ 11.93 158.43%

LEASE OBLIGATIONS (Tables)

LEASE OBLIGATIONS (Tables)	6 Months Ended
	Jun. 30, 2018
Leases [Abstract]
Schedule Of Future Minimum Lease Payments For Capital Leases And Operating Leases	Future minimum payments under capital leases and non-cancellable operating leases as of June 30, 2018 are as follows: (In Millions) Capital Leases Operating Leases 2018 (July 1 - December 31) $ 1.4 $ 1.3 2019 2.8 1.9 2020 2.4 1.8 2021 1.8 1.8 2022 1.4 1.8 2023 and thereafter — 7.5 Total minimum lease payments $ 9.8 $ 16.1 Amounts representing interest 1.0 Present value of net minimum lease payments 1 $ 8.8 1 The total is comprised of $2.4 million and $6.4 million classified as Other current liabilities and Other liabilities , respectively, in the Statements of Unaudited Condensed Consolidated Financial Position as of June 30, 2018.

ENVIRONMENTAL AND MINE CLOSUR41

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Tables)	6 Months Ended
	Jun. 30, 2018
Environmental Remediation Obligations [Abstract]
Summary Of Mine Closure Obligations	The following is a summary of the obligations: (In Millions) June 30, December 31, Environmental $ 3.2 $ 2.9 Mine closure 1 172.8 168.4 Total environmental and mine closure obligations 176.0 171.3 Less current portion 3.7 3.6 Long-term environmental and mine closure obligations $ 172.3 $ 167.7 1 Includes our active operating mines, our indefinitely idled Empire mine and a closed mine formerly operating as LTVSMC.
Asset Retirement Obligation Disclosure	The following represents a roll forward of our mine closure obligation liability for the six months ended June 30, 2018 and for the year ended December 31, 2017 : (In Millions) June 30, December 31, Mine closure obligation at beginning of period $ 168.4 $ 187.8 Accretion expense 4.7 13.9 Remediation payments (0.3 ) (5.6 ) Revision in estimated cash flows — (27.7 ) Mine closure obligation at end of period $ 172.8 $ 168.4

GOODWILL AND OTHER INTANGIBLE42

GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES (Tables)	6 Months Ended
	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule Of Finite-Lived Intangible Assets By Major Class	The following table is a summary of definite-lived intangible assets: (In Millions) June 30, 2018 December 31, 2017 Classification Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Permits Other non-current assets $ 72.2 $ (22.9 ) $ 49.3 $ 72.2 $ (22.5 ) $ 49.7

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
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 June 30, 2018 December 31, 2017 June 30, 2018 December 31, 2017 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 $ — Other current liabilities $ 0.1 Other current liabilities $ 0.3 Derivatives not designated as hedging instruments under ASC 815: Customer supply agreement Derivative assets $ 169.4 Derivative assets $ 37.9 $ — $ — Provisional pricing arrangements Derivative assets 5.2 — Other current liabilities 3.0 Other current liabilities 1.7 Total derivatives not designated as hedging instruments under ASC 815 $ 174.6 $ 37.9 $ 3.0 $ 1.7 Total derivatives $ 174.7 $ 37.9 $ 3.1 $ 2.0
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 Income (Loss) Recognized on Derivatives Amount of Income (Loss) Recognized on Derivatives Three Months Ended Six Months Ended 2018 2017 2018 2017 Customer Supply Agreements Product revenues $ 155.5 $ 51.9 $ 197.4 $ 69.6 Provisional Pricing Arrangements Product revenues (0.8 ) (21.1 ) 1.1 (5.3 ) Commodity Contracts Cost of goods sold and operating expenses — — — (1.3 ) Total $ 154.7 $ 30.8 $ 198.5 $ 63.0

DISCONTINUED OPERATIONS (Tables

DISCONTINUED OPERATIONS (Tables)	6 Months Ended
	Jun. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
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 June 30, Six Months Ended 2018 2017 2018 2017 Loss from Discontinued Operations, net of tax Asia Pacific Iron Ore $ (53.3 ) $ (7.3 ) $ (124.7 ) $ 41.0 North American Coal (0.3 ) 2.6 0.1 2.6 Canadian Operations (10.7 ) (49.0 ) (10.6 ) (48.6 ) $ (64.3 ) $ (53.7 ) $ (135.2 ) $ (5.0 ) (In Millions) June 30, December 31, Asia Pacific Iron Ore North American Coal Total Asia Pacific Iron Ore North American Coal Total Current assets of discontinued operations $ 45.3 $ — $ 45.3 $ 118.5 $ — $ 118.5 Non-current assets of discontinued operations $ — $ — $ — $ 20.3 $ — $ 20.3 Current liabilities of discontinued operations $ 114.4 $ 2.9 $ 117.3 $ 71.8 $ 3.2 $ 75.0 Non-current liabilities of discontinued operations $ 10.3 $ — $ 10.3 $ 52.2 $ — $ 52.2 (In Millions) Six Months Ended 2018 2017 Net cash provided (used) by operating activities Asia Pacific Iron Ore $ (31.7 ) $ 92.2 Canadian Operations (14.6 ) — $ (46.3 ) $ 92.2 Net cash provided (used) by investing activities Asia Pacific Iron Ore $ 14.1 $ (0.8 ) $ 14.1 $ (0.8 )
Schedule of Disposal Groups, including Discontinued Operations, Income Statement	For the reasons discussed above, our previously reported Asia Pacific Iron Ore operating segment results for all periods prior to June 30, 2018, as well as exit costs, are classified as discontinued operations. (In Millions) Three Months Ended June 30, Six Months Ended Loss from Discontinued Operations 2018 2017 2018 2017 Revenues from product sales and services $ 70.1 $ 98.0 $ 129.1 $ 273.4 Cost of goods sold and operating expenses (106.1 ) (97.1 ) (230.2 ) (225.2 ) Sales margin (36.0 ) 0.9 (101.1 ) 48.2 Other operating expense (16.2 ) (3.2 ) (18.8 ) (3.7 ) Other expense (1.1 ) (1.3 ) (2.2 ) (2.7 ) Loss from discontinued operations before income taxes (53.3 ) (3.6 ) (122.1 ) 41.8 Impairment of long-lived assets — — (2.6 ) — Income tax expense — (3.7 ) — (0.8 ) Loss from discontinued operations, net of tax $ (53.3 ) $ (7.3 ) $ (124.7 ) $ 41.0
Schedule of Disposal Groups, Including Discontinued Operations, Assets and Liabilities	Recorded Assets and Liabilities (In Millions) Assets and Liabilities of Discontinued Operations June 30, December 31, Cash and cash equivalents $ 29.4 $ 29.4 Accounts receivable, net 12.5 33.9 Inventories — 45.0 Supplies and other inventories — 5.1 Other current assets 3.4 5.1 Total current assets of discontinued operations 45.3 118.5 Property, plant and equipment, net — 17.2 Other non-current assets — 3.1 Total assets of discontinued operations $ 45.3 $ 138.8 Accounts payable $ 74.3 $ 28.2 Accrued liabilities 21.1 28.0 Other current liabilities 19.0 15.6 Total current liabilities of discontinued operations 114.4 71.8 Environmental and mine closure obligations 10.3 28.8 Other liabilities — 23.4 Total liabilities of discontinued operations $ 124.7 $ 124.0

SHAREHOLDERS' EQUITY (Tables)

SHAREHOLDERS' EQUITY (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Schedule of Stockholders Equity	The following table reflects the changes in shareholders' deficit attributable to both us and the noncontrolling interests, primarily related to Tilden and Empire. We own 100% of both mines as of June 30, 2018 and 85% and 79% of each mine, respectively, as of June 30, 2017 : (In Millions) Cliffs Noncontrolling Total Equity December 31, 2017 $ (444.3 ) $ 0.2 $ (444.1 ) Adoption of accounting standard (REFER TO NOTE 2) 34.0 — 34.0 Comprehensive income Net income 80.8 — 80.8 Other comprehensive income 16.8 — 16.8 Total comprehensive income 97.6 — 97.6 Stock and other incentive plans 6.4 — 6.4 Distributions to noncontrolling interest — (0.2 ) (0.2 ) June 30, 2018 $ (306.3 ) $ — $ (306.3 ) (In Millions) Cliffs Noncontrolling Total Equity December 31, 2016 $ (1,464.3 ) $ 133.8 $ (1,330.5 ) Comprehensive loss Net income (loss) 3.7 (3.4 ) 0.3 Other comprehensive income (loss) 1.9 (4.6 ) (2.7 ) Total comprehensive income (loss) 5.6 (8.0 ) (2.4 ) Issuance of common shares 661.3 — 661.3 Stock and other incentive plans 8.3 — 8.3 Distributions to noncontrolling interest — (3.4 ) (3.4 ) June 30, 2017 $ (789.1 ) $ 122.4 $ (666.7 )
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table reflects the changes in Accumulated other comprehensive loss related to Cliffs shareholders’ deficit: (In Millions) Changes in Pension and OPEB, Unrealized Net Gain on Foreign Currency Translation Net Unrealized Gain (Loss) on 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 ) (In Millions) Changes in Pension and OPEB, net of tax Unrealized Net Gain (Loss) on Foreign Currency Translation Accumulated Other Comprehensive Loss December 31, 2016 $ (260.6 ) $ 239.3 $ (21.3 ) Other comprehensive income (loss) before reclassifications 3.3 (12.7 ) (9.4 ) Net loss reclassified from accumulated other comprehensive loss 6.4 — 6.4 March 31, 2017 $ (250.9 ) $ 226.6 $ (24.3 ) Other comprehensive loss before reclassifications (0.1 ) (1.5 ) (1.6 ) Net loss reclassified from accumulated other comprehensive loss 6.5 — 6.5 June 30, 2017 $ (244.5 ) $ 225.1 $ (19.4 )
Details of Accumulated Other Comprehensive Income (Loss) Components	The following table reflects the details about Accumulated other comprehensive loss components related to Cliffs shareholders’ deficit: (In Millions) Details about Accumulated Other Comprehensive Loss Components Amount of (Gain)/Loss Reclassified into Income Affected Line Item in the Statement of Unaudited Condensed Consolidated Operations Three Months Ended Six Months Ended 2018 2017 2018 2017 Amortization of pension and OPEB liability: Prior service credits $ (0.1 ) $ (0.1 ) $ (0.4 ) $ (0.2 ) Other non-operating income Net actuarial loss 6.6 6.6 13.1 13.1 Other non-operating income $ 6.5 $ 6.5 $ 12.7 $ 12.9 Net of taxes Unrealized loss on derivative financial instruments: Commodity contracts $ — $ — $ (0.1 ) $ — Cost of goods sold and operating expenses $ — $ — $ (0.1 ) $ — Net of taxes Total reclassifications for the period, net of tax $ 6.5 $ 6.5 $ 12.6 $ 12.9

RELATED PARTIES (Tables)

RELATED PARTIES (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 : 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 Six Months Ended 2018 2017 2018 2017 Product revenues from related parties $ 409.4 $ 227.5 $ 471.4 $ 336.9 Total product revenues $ 672.0 $ 417.0 $ 841.2 $ 664.3 Related party product revenue as a percent of total product revenue 60.9 % 54.6 % 56.0 % 50.7 %
Summary of Balance Sheet Presentation	The following table presents the classification of related party assets and liabilities in the Statements of Unaudited Condensed Consolidated Financial Position : (In Millions) Balance Sheet Location June 30, 2018 December 31, 2017 Amounts due from related parties Accounts receivable, net $ 83.2 $ 68.1 Customer supply agreement and provisional pricing agreements Derivative assets 169.4 37.9 Amounts due to related parties Partnership distribution payable (44.2 ) (44.2 ) Amounts due to related parties Other current liabilities (3.6 ) (12.3 ) Amounts due to related parties Other liabilities (42.7 ) (41.4 ) Net amounts due from related parties $ 162.1 $ 8.1

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share Computation	The following table summarizes the computation of basic and diluted earnings (loss) per share: (In Millions, Except Per Share Amounts) Three Months Ended Six Months Ended 2018 2017 2018 2017 Income from Continuing Operations $ 229.4 $ 83.8 $ 216.0 $ 5.3 Loss from Continuing Operations Attributable to Noncontrolling Interest — 1.7 — 3.4 Net Income from Continuing Operations Attributable to Cliffs Shareholders $ 229.4 $ 85.5 $ 216.0 $ 8.7 Loss from Discontinued Operations, net of tax (64.3 ) (53.7 ) (135.2 ) (5.0 ) Net Income Attributable to Cliffs Shareholders $ 165.1 $ 31.8 $ 80.8 $ 3.7 Weighted Average Number of Shares: Basic 297.6 296.1 297.4 280.6 Employee Stock Plans 3.7 4.6 3.7 4.6 Diluted 301.3 300.7 301.1 285.2 Income (Loss) per Common Share Attributable to Continuing operations $ 0.77 $ 0.28 $ 0.73 $ 0.03 Discontinued operations (0.22 ) (0.18 ) (0.46 ) (0.01 ) $ 0.55 $ 0.10 $ 0.27 $ 0.02 Income (Loss) per Common Share Attributable to Continuing operations $ 0.76 $ 0.28 $ 0.72 $ 0.03 Discontinued operations (0.21 ) (0.18 ) (0.45 ) (0.02 ) $ 0.55 $ 0.10 $ 0.27 $ 0.01
EBITDA and Adjusted EBITDA Reconciliation	(In Millions, Except Per Share Amounts) Three Months Ended Six Months Ended 2018 2017 2018 2017 Income from Continuing Operations $ 229.4 $ 83.8 $ 216.0 $ 5.3 Loss from Continuing Operations Attributable to Noncontrolling Interest — 1.7 — 3.4 Net Income from Continuing Operations Attributable to Cliffs Shareholders $ 229.4 $ 85.5 $ 216.0 $ 8.7 Loss from Discontinued Operations, net of tax (64.3 ) (53.7 ) (135.2 ) (5.0 ) Net Income Attributable to Cliffs Shareholders $ 165.1 $ 31.8 $ 80.8 $ 3.7 Weighted Average Number of Shares: Basic 297.6 296.1 297.4 280.6 Employee Stock Plans 3.7 4.6 3.7 4.6 Diluted 301.3 300.7 301.1 285.2 Income (Loss) per Common Share Attributable to Continuing operations $ 0.77 $ 0.28 $ 0.73 $ 0.03 Discontinued operations (0.22 ) (0.18 ) (0.46 ) (0.01 ) $ 0.55 $ 0.10 $ 0.27 $ 0.02 Income (Loss) per Common Share Attributable to Continuing operations $ 0.76 $ 0.28 $ 0.72 $ 0.03 Discontinued operations (0.21 ) (0.18 ) (0.45 ) (0.02 ) $ 0.55 $ 0.10 $ 0.27 $ 0.01

SUPPLEMENTARY GUARANTOR INFOR48

SUPPLEMENTARY GUARANTOR INFORMATION (Tables)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Supplemental Condensed Consolidating Financial Position	Unaudited Condensed Consolidating Statement of Financial Position As of June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 798.4 $ 1.6 $ 2.5 $ — $ 802.5 Accounts receivable, net 8.0 148.2 0.1 (3.7 ) 152.6 Inventories — 256.4 — — 256.4 Supplies and other inventories — 88.6 — — 88.6 Derivative assets 0.1 174.6 — — 174.7 Current assets of discontinued operations — — 45.3 — 45.3 Other current assets 15.9 7.7 3.2 — 26.8 TOTAL CURRENT ASSETS 822.4 677.1 51.1 (3.7 ) 1,546.9 PROPERTY, PLANT AND EQUIPMENT, NET 15.5 966.2 99.6 — 1,081.3 OTHER ASSETS Deposits for property, plant and equipment — 3.8 81.9 — 85.7 Income tax receivable 219.9 — — — 219.9 Investment in subsidiaries 1,299.9 32.8 — (1,332.7 ) — Long-term intercompany notes — — 227.4 (227.4 ) — Other non-current assets 8.7 107.3 1.7 — 117.7 TOTAL OTHER ASSETS 1,528.5 143.9 311.0 (1,560.1 ) 423.3 TOTAL ASSETS $ 2,366.4 $ 1,787.2 $ 461.7 $ (1,563.8 ) $ 3,051.5 LIABILITIES CURRENT LIABILITIES Accounts payable $ 5.2 $ 88.8 $ 28.7 $ (3.7 ) $ 119.0 Accrued expenses 13.6 71.0 0.5 — 85.1 Accrued interest 43.1 — — — 43.1 Partnership distribution payable — 44.2 — — 44.2 Current liabilities of discontinued operations — — 117.3 — 117.3 Other current liabilities 1.8 62.7 1.7 — 66.2 TOTAL CURRENT LIABILITIES 63.7 266.7 148.2 (3.7 ) 474.9 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 65.9 428.4 (249.3 ) — 245.0 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 145.3 27.0 — 172.3 LONG-TERM DEBT 2,297.0 — — — 2,297.0 NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS — — 10.3 — 10.3 LONG-TERM INTERCOMPANY NOTES 227.4 — — (227.4 ) — OTHER LIABILITIES 18.7 139.0 0.6 — 158.3 TOTAL LIABILITIES 2,672.7 979.4 (63.2 ) (231.1 ) 3,357.8 EQUITY TOTAL CLIFFS SHAREHOLDERS' DEFICIT (306.3 ) 807.8 524.9 (1,332.7 ) (306.3 ) TOTAL DEFICIT (306.3 ) 807.8 524.9 (1,332.7 ) (306.3 ) TOTAL LIABILITIES AND DEFICIT $ 2,366.4 $ 1,787.2 $ 461.7 $ (1,563.8 ) $ 3,051.5 Unaudited Condensed Consolidating Statement of Financial Position As of December 31, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS CURRENT ASSETS Cash and cash equivalents $ 948.9 $ 2.1 $ 27.3 $ — $ 978.3 Accounts receivable, net 4.5 102.9 — (0.7 ) 106.7 Inventories — 138.4 — — 138.4 Supplies and other inventories — 88.8 — — 88.8 Derivative assets — 37.9 — — 37.9 Current assets of discontinued operations — — 118.5 — 118.5 Loans to and accounts receivable from the Canadian Entities 44.7 6.9 — — 51.6 Other current assets 16.4 7.5 0.5 — 24.4 TOTAL CURRENT ASSETS 1,014.5 384.5 146.3 (0.7 ) 1,544.6 PROPERTY, PLANT AND EQUIPMENT, NET 17.5 959.0 57.3 — 1,033.8 OTHER ASSETS Deposits for property, plant and equipment — 1.3 16.5 — 17.8 Income tax receivable 235.3 — — — 235.3 Non-current assets of discontinued operations — — 20.3 — 20.3 Investment in subsidiaries 1,024.3 29.9 — (1,054.2 ) — Long-term intercompany notes — — 242.0 (242.0 ) — Other non-current assets 7.8 91.7 2.1 — 101.6 TOTAL OTHER ASSETS 1,267.4 122.9 280.9 (1,296.2 ) 375.0 TOTAL ASSETS $ 2,299.4 $ 1,466.4 $ 484.5 $ (1,296.9 ) $ 2,953.4 LIABILITIES CURRENT LIABILITIES Accounts payable $ 7.1 $ 89.7 $ 3.4 $ (0.7 ) $ 99.5 Accrued expenses 19.0 59.9 0.2 — 79.1 Accrued interest 31.4 — — — 31.4 Contingent claims 55.6 — — — 55.6 Partnership distribution payable — 44.2 — — 44.2 Current liabilities of discontinued operations — — 75.0 — 75.0 Other current liabilities 2.1 63.5 1.8 — 67.4 TOTAL CURRENT LIABILITIES 115.2 257.3 80.4 (0.7 ) 452.2 PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES 66.4 430.6 (239.3 ) — 257.7 ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS — 140.6 27.1 — 167.7 LONG-TERM DEBT 2,304.2 — — — 2,304.2 NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS — — 52.2 — 52.2 LONG-TERM INTERCOMPANY NOTES 242.0 — — (242.0 ) — OTHER LIABILITIES 15.7 147.2 0.6 — 163.5 TOTAL LIABILITIES 2,743.5 975.7 (79.0 ) (242.7 ) 3,397.5 EQUITY TOTAL CLIFFS SHAREHOLDERS' DEFICIT (444.1 ) 490.7 563.3 (1,054.2 ) (444.3 ) NONCONTROLLING INTEREST — — 0.2 — 0.2 TOTAL DEFICIT (444.1 ) 490.7 563.5 (1,054.2 ) (444.1 ) TOTAL LIABILITIES AND DEFICIT $ 2,299.4 $ 1,466.4 $ 484.5 $ (1,296.9 ) $ 2,953.4
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 June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 672.0 $ — $ — $ 672.0 Freight and venture partners' cost reimbursements — 42.3 — — 42.3 — 714.3 — — 714.3 COST OF GOODS SOLD AND OPERATING EXPENSES — (429.8 ) — — (429.8 ) SALES MARGIN — 284.5 — — 284.5 OTHER OPERATING EXPENSE Selling, general and administrative expenses (19.7 ) (5.4 ) (1.1 ) — (26.2 ) Miscellaneous – net (0.2 ) (3.6 ) (0.3 ) — (4.1 ) (19.9 ) (9.0 ) (1.4 ) — (30.3 ) OPERATING INCOME (LOSS) (19.9 ) 275.5 (1.4 ) — 254.2 OTHER INCOME (EXPENSE) Interest expense, net (30.8 ) (0.6 ) 0.2 — (31.2 ) Gain on extinguishment of debt 0.2 — — — 0.2 Other non-operating income (expense) (0.8 ) 0.2 5.0 — 4.4 (31.4 ) (0.4 ) 5.2 — (26.6 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (51.3 ) 275.1 3.8 — 227.6 INCOME TAX BENEFIT (EXPENSE) 2.1 (0.1 ) (0.2 ) — 1.8 EQUITY IN INCOME (LOSS) OF SUBSIDIARIES 210.4 4.6 — (215.0 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 161.2 279.6 3.6 (215.0 ) 229.4 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX 3.9 (0.3 ) (67.9 ) — (64.3 ) NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 165.1 $ 279.3 $ (64.3 ) $ (215.0 ) $ 165.1 OTHER COMPREHENSIVE INCOME 9.1 6.0 2.2 (8.2 ) 9.1 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 174.2 $ 285.3 $ (62.1 ) $ (223.2 ) $ 174.2 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Three Months Ended June 30, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 417.0 $ — $ — $ 417.0 Freight and venture partners' cost reimbursements — 54.3 — — 54.3 — 471.3 — — 471.3 COST OF GOODS SOLD AND OPERATING EXPENSES — (326.6 ) — — (326.6 ) SALES MARGIN — 144.7 — — 144.7 OTHER OPERATING EXPENSE Selling, general and administrative expenses (19.7 ) (5.7 ) (1.2 ) — (26.6 ) Miscellaneous – net (0.8 ) (3.7 ) 1.6 — (2.9 ) (20.5 ) (9.4 ) 0.4 — (29.5 ) OPERATING INCOME (LOSS) (20.5 ) 135.3 0.4 — 115.2 OTHER INCOME (EXPENSE) Interest expense, net (30.4 ) — 0.3 — (30.1 ) Loss on extinguishment of debt (4.9 ) — — — (4.9 ) Other non-operating income (expense) (1.0 ) (0.8 ) 4.3 — 2.5 (36.3 ) (0.8 ) 4.6 — (32.5 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (56.8 ) 134.5 5.0 — 82.7 INCOME TAX BENEFIT (EXPENSE) 8.0 0.8 (7.7 ) — 1.1 EQUITY IN INCOME (LOSS) OF SUBSIDIARIES 129.6 3.4 — (133.0 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 80.8 138.7 (2.7 ) (133.0 ) 83.8 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX (49.0 ) 0.7 (5.4 ) — (53.7 ) NET INCOME (LOSS) 31.8 139.4 (8.1 ) (133.0 ) 30.1 LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST — 1.7 — — 1.7 NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 31.8 $ 141.1 $ (8.1 ) $ (133.0 ) $ 31.8 OTHER COMPREHENSIVE INCOME (LOSS) 5.0 5.7 (1.5 ) (4.3 ) 4.9 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 36.8 $ 146.8 $ (9.6 ) $ (137.3 ) $ 36.7 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income For the Six Months Ended June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 841.2 $ — $ — $ 841.2 Freight and venture partners' cost reimbursements — 53.1 — — 53.1 — 894.3 — — 894.3 COST OF GOODS SOLD AND OPERATING EXPENSES — (548.3 ) — — (548.3 ) SALES MARGIN — 346.0 — — 346.0 OTHER OPERATING EXPENSE Selling, general and administrative expenses (39.8 ) (9.7 ) (1.8 ) — (51.3 ) Miscellaneous – net (0.4 ) (8.9 ) (0.9 ) — (10.2 ) (40.2 ) (18.6 ) (2.7 ) — (61.5 ) OPERATING INCOME (40.2 ) 327.4 (2.7 ) — 284.5 OTHER INCOME (EXPENSE) Interest expense, net (62.7 ) (1.4 ) 0.5 — (63.6 ) Gain on extinguishment of debt 0.2 — — — 0.2 Other non-operating income (expense) (1.7 ) 0.7 9.8 — 8.8 (64.2 ) (0.7 ) 10.3 — (54.6 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (104.4 ) 326.7 7.6 — 229.9 INCOME TAX EXPENSE (13.5 ) (0.2 ) (0.2 ) — (13.9 ) EQUITY IN INCOME (LOSS) OF SUBSIDIARIES 194.7 9.1 — (203.8 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 76.8 335.6 7.4 (203.8 ) 216.0 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, NET OF TAX 4.0 (0.1 ) (139.1 ) — (135.2 ) NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 80.8 $ 335.5 $ (131.7 ) $ (203.8 ) $ 80.8 OTHER COMPREHENSIVE INCOME 16.8 11.9 3.0 (14.9 ) 16.8 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 97.6 $ 347.4 $ (128.7 ) $ (218.7 ) $ 97.6 Unaudited Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) For the Six Months Ended June 30, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated REVENUES FROM PRODUCT SALES AND SERVICES Product $ — $ 664.3 $ — $ — $ 664.3 Freight and venture partners' cost reimbursements — 93.2 — — 93.2 — 757.5 — — 757.5 COST OF GOODS SOLD AND OPERATING EXPENSES — (563.8 ) — — (563.8 ) SALES MARGIN — 193.7 — — 193.7 OTHER OPERATING INCOME (EXPENSE) Selling, general and administrative expenses (39.2 ) (10.1 ) (2.4 ) — (51.7 ) Miscellaneous – net (0.9 ) (9.2 ) 16.7 — 6.6 (40.1 ) (19.3 ) 14.3 — (45.1 ) OPERATING INCOME (40.1 ) 174.4 14.3 — 148.6 OTHER INCOME (EXPENSE) Interest expense, net (72.0 ) — 0.5 — (71.5 ) Loss on extinguishment of debt (76.8 ) — — — (76.8 ) Other non-operating income (expense) (2.0 ) (1.6 ) 8.6 — 5.0 (150.8 ) (1.6 ) 9.1 — (143.3 ) INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (190.9 ) 172.8 23.4 — 5.3 INCOME TAX BENEFIT (EXPENSE) 0.2 — (0.2 ) — — EQUITY IN INCOME OF SUBSIDIARIES 243.0 6.6 — (249.6 ) — INCOME (LOSS) FROM CONTINUING OPERATIONS 52.3 179.4 23.2 (249.6 ) 5.3 INCOME (LOSS) FROM DISCONTINUED OPERATIONS, net of tax (48.6 ) 0.9 42.7 — (5.0 ) NET INCOME (LOSS) 3.7 180.3 65.9 (249.6 ) 0.3 LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST — 3.4 — — 3.4 NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 3.7 $ 183.7 $ 65.9 $ (249.6 ) $ 3.7 OTHER COMPREHENSIVE INCOME (LOSS) 2.0 16.5 (19.3 ) 2.7 1.9 TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS $ 5.7 $ 200.2 $ 46.6 $ (246.9 ) $ 5.6
Schedule of Supplemental Statements of Condensed Consolidating Cash Flows	Unaudited Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2018 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (82.1 ) $ 86.8 $ (54.0 ) $ — $ (49.3 ) INVESTING ACTIVITIES Purchase of property, plant and equipment (0.3 ) (24.9 ) (16.9 ) — (42.1 ) Deposits for property, plant and equipment — (3.6 ) (68.7 ) — (72.3 ) Intercompany investing (35.2 ) (5.5 ) 14.6 26.1 — Proceeds on sale of assets — 0.4 14.2 — 14.6 Net cash used by investing activities (35.5 ) (33.6 ) (56.8 ) 26.1 (99.8 ) FINANCING ACTIVITIES Debt issuance costs (1.5 ) — — — (1.5 ) Repurchase of debt (15.3 ) — — — (15.3 ) Intercompany financing (14.6 ) (52.7 ) 93.4 (26.1 ) — Other financing activities (1.5 ) (1.0 ) (6.4 ) — (8.9 ) Net cash used by financing activities (32.9 ) (53.7 ) 87.0 (26.1 ) (25.7 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — (1.0 ) — (1.0 ) DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS (150.5 ) (0.5 ) (24.8 ) — (175.8 ) LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS — — — — — NET DECREASE IN CASH AND CASH EQUIVALENTS (150.5 ) (0.5 ) (24.8 ) — (175.8 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 948.9 2.1 27.3 — 978.3 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 798.4 $ 1.6 $ 2.5 $ — $ 802.5 Unaudited Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2017 (In Millions) Cleveland-Cliffs Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided (used) by operating activities $ (128.8 ) $ 106.3 $ 90.3 $ — $ 67.8 INVESTING ACTIVITIES Purchase of property, plant and equipment (0.8 ) (42.7 ) (0.8 ) — (44.3 ) Deposits for property, plant and equipment — (5.1 ) — — (5.1 ) Intercompany investing 43.5 (1.1 ) (45.0 ) 2.6 — Proceeds on sales of assets — 1.1 — — 1.1 Net cash provided (used) by investing activities 42.7 (47.8 ) (45.8 ) 2.6 (48.3 ) FINANCING ACTIVITIES Net proceeds from issuance of common shares 661.3 — — — 661.3 Proceeds from issuance of debt 500.0 — — — 500.0 Debt issuance costs (8.5 ) — — — (8.5 ) Repurchase of debt (1,154.0 ) — — — (1,154.0 ) Distributions of partnership equity — (8.7 ) — — (8.7 ) Intercompany financing 45.0 (44.3 ) 1.9 (2.6 ) — Other financing activities (0.6 ) (5.0 ) (8.3 ) — (13.9 ) Net cash used by financing activities 43.2 (58.0 ) (6.4 ) (2.6 ) (23.8 ) EFFECT OF EXCHANGE RATE CHANGES ON CASH — — 2.4 — 2.4 INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS (42.9 ) 0.5 40.5 — (1.9 ) LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS — — 40.5 — 40.5 NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS (42.9 ) 0.5 — — (42.4 ) CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD 283.4 2.5 26.9 — 312.8 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 240.5 $ 3.0 $ 26.9 $ — $ 270.4

BASIS OF PRESENTATION AND SIG49

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Schedule Of Subsidiaries) (Details)	6 Months Ended
	Jun. 30, 2018
Northshore
Related Party Transaction [Line Items]
Entity Address, State or Province	Minnesota
United Taconite
Related Party Transaction [Line Items]
Entity Address, State or Province	Minnesota
Tilden
Related Party Transaction [Line Items]
Entity Address, State or Province	Michigan
Empire
Related Party Transaction [Line Items]
Entity Address, State or Province	Michigan
Koolyanobbing
Related Party Transaction [Line Items]
Entity Address, State or Province	Western Australia

BASIS OF PRESENTATION AND SIG50

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Foreign Currency Translation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Foreign currency transaction gain (loss), before tax	$ (0.1)	$ 0.5	$ (0.5)	$ 15.3
Short-term intercompany loan [Member]
Foreign currency transaction gain (loss), before tax	(0.1)	1.5	(0.3)	16.6
Other Remeasurement
Foreign currency transaction gain (loss), before tax	$ 0	$ (1)	$ (0.2)	$ (1.3)

BASIS OF PRESENTATION AND SIG51

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) - Hibbing [Member] - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Other Noncurrent Assets [Member]
Related Party Transaction [Line Items]
Ownership interest, equity method investment	23.00%	23.00%
Other Noncurrent Liabilities [Member]
Related Party Transaction [Line Items]
Equity Method Investments	$ 8	$ 11

NEW ACCOUNTING STANDARDS (Sched

NEW ACCOUNTING STANDARDS (Schedule of New Accounting Pronouncements and Changes in Accounting Principles) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents	$ 802.5	$ 270.4	$ 802.5	$ 270.4	$ 978.3	$ 978.3
Accounts receivable, net	152.6		152.6		183.3	106.7
Inventories	(256.4)		(256.4)		(87)	(138.4)
Supplies and other inventories	88.6		88.6		88.8	88.8
Derivative assets	174.7		174.7		49.5	37.9
Current assets of discontinued operations	45.3		45.3		118.5	118.5
Loans to and accounts receivable from the Canadian Entities	0		0		51.6	51.6
Other current assets	26.8		26.8		24.4	24.4
TOTAL CURRENT ASSETS	1,546.9		1,546.9		1,581.4	1,544.6
PROPERTY, PLANT AND EQUIPMENT, NET	1,081.3		1,081.3		1,033.8	1,033.8
Deposits for property, plant and equipment	85.7		85.7		17.8	17.8
Income tax receivable	219.9		219.9		235.3	235.3
Non-current assets of discontinued operations	0		0		20.3	20.3
Other non-current assets	117.7		117.7		101.6	101.6
TOTAL OTHER ASSETS	423.3		423.3		375	375
Assets	3,051.5		3,051.5		2,990.2	2,953.4
Accounts payable	119		119		100.9	99.5
Accrued expenses	85.1		85.1		79.1	79.1
Accrued interest	43.1		43.1		31.4	31.4
Contingent claims	0		0		55.6	55.6
Partnership distribution payable	44.2		44.2		44.2	44.2
Current liabilities of discontinued operations	117.3		117.3		75	75
Other current liabilities	(66.2)		(66.2)		(68.8)	(67.4)
Liabilities, Current	(474.9)		(474.9)		(455)	(452.2)
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	245		245		257.7	257.7
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	172.3		172.3		167.7	167.7
LONG-TERM DEBT	2,297		2,297		2,304.2	2,304.2
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3		10.3		52.2	52.2
OTHER LIABILITIES	158.3		158.3		163.5	163.5
Liabilities	(3,357.8)		(3,357.8)		(3,400.3)	(3,397.5)
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	(306.3)		(306.3)		(410.3)	(444.3)
NONCONTROLLING INTEREST	0		0		0.2	0.2
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(306.3)	(666.7)	(306.3)	(666.7)	(410.1)	(444.1)	$ (1,330.5)
TOTAL LIABILITIES AND DEFICIT	3,051.5		3,051.5		2,990.2	$ 2,953.4
Product	672	417	841.2	664.3
Freight and venture partners' cost reimbursements	42.3	54.3	53.1	93.2
Revenues	714.3	471.3	894.3	757.5
COST OF GOODS SOLD AND OPERATING EXPENSES	(429.8)	(326.6)	(548.3)	(563.8)
SALES MARGIN	284.5	144.7	346	193.7
Selling, general and administrative expenses	(26.2)	(26.6)	(51.3)	(51.7)
Miscellaneous - net	(4.1)	(2.9)	(10.2)	6.6
Other operating expense	(30.3)	(29.5)	(61.5)	(45.1)
OPERATING INCOME	254.2	115.2	284.5	148.6
Interest expense, net	(31.2)	(30.1)	(63.6)	(71.5)
Gain (loss) on extinguishment of debt	0.2	(4.9)	0.2	(76.8)
Other non-operating income	4.4	2.5	8.8	5
TOTAL OTHER INCOME (EXPENSE)	(26.6)	(32.5)	(54.6)	(143.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	227.6	82.7	229.9	5.3
INCOME TAX BENEFIT (EXPENSE)	1.8	1.1	(13.9)	0
INCOME FROM CONTINUING OPERATIONS	229.4	83.8	216	5.3
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(64.3)	(53.7)	(135.2)	(5)
NET INCOME	165.1	30.1	80.8	0.3
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST	0	1.7	0	3.4
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ 165.1	$ 31.8	$ 80.8	$ 3.7
Continuing operations (in dollars per share)	$ 0.77	$ 0.28	$ 0.73	$ 0.03
Discontinued operations (in dollars per share)	(0.22)	(0.18)	(0.46)	(0.01)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share)	0.55	0.10	0.27	0.02
Continuing operations (in dollars per share)	0.76	0.28	0.72	0.03
Discontinued operations (in dollars per share)	(0.21)	(0.18)	(0.45)	(0.02)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share)	$ 0.55	$ 0.10	$ 0.27	$ 0.01
Basic	297,618	296,100	297,442	280,617
Diluted	301,275	300,700	301,143	285,247
Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
COST OF GOODS SOLD AND OPERATING EXPENSES		$ (327.1)		$ (564.9)
Selling, general and administrative expenses		(24.7)		(47.8)
Miscellaneous - net		(2.6)		7.3
OPERATING INCOME		116.9		152.1
Other non-operating income		0.8		1.5
NET INCOME		30.1		0.3
Accounting Standards Update 2017-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
COST OF GOODS SOLD AND OPERATING EXPENSES		(0.5)		(1.1)
Selling, general and administrative expenses		1.9		3.9
Miscellaneous - net		(0.3)		(0.7)
OPERATING INCOME		(1.7)		(3.5)
Other non-operating income		1.7		3.5
NET INCOME		$ 0		$ 0
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents	$ 802.5		$ 802.5
Accounts receivable, net	53		53
Inventories	(323.9)		(323.9)
Supplies and other inventories	88.6		88.6
Derivative assets	146.2		146.2
Current assets of discontinued operations	45.3		45.3
Loans to and accounts receivable from the Canadian Entities	0		0
Other current assets	26.8		26.8
TOTAL CURRENT ASSETS	1,486.3		1,486.3
PROPERTY, PLANT AND EQUIPMENT, NET	1,081.3		1,081.3
Deposits for property, plant and equipment	85.7		85.7
Income tax receivable	219.9		219.9
Non-current assets of discontinued operations	0		0
Other non-current assets	117.7		117.7
TOTAL OTHER ASSETS	423.3		423.3
Assets	2,990.9		2,990.9
Accounts payable	117.8		117.8
Accrued expenses	85.1		85.1
Accrued interest	43.1		43.1
Contingent claims	0		0
Partnership distribution payable	44.2		44.2
Current liabilities of discontinued operations	117.3		117.3
Other current liabilities	(72.1)		(72.1)
Liabilities, Current	(479.6)		(479.6)
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	245		245
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	172.3		172.3
LONG-TERM DEBT	2,297		2,297
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3		10.3
OTHER LIABILITIES	158.3		158.3
Liabilities	(3,362.5)		(3,362.5)
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	(371.6)		(371.6)
NONCONTROLLING INTEREST	0		0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(371.6)		(371.6)
TOTAL LIABILITIES AND DEFICIT	2,990.9		2,990.9
Product	568		795.6
Freight and venture partners' cost reimbursements	36.3		51.2
Revenues	604.3		846.8
COST OF GOODS SOLD AND OPERATING EXPENSES	(368.6)		(530.7)
SALES MARGIN	235.7		316.1
Selling, general and administrative expenses	(26.2)		(51.3)
Miscellaneous - net			(10.2)
Other operating expense	(30.3)		(61.5)
OPERATING INCOME	205.4		254.6
Interest expense, net	(31.2)		(63.6)
Gain (loss) on extinguishment of debt	0.2		0.2
Other non-operating income	4.4		8.8
TOTAL OTHER INCOME (EXPENSE)	(26.6)		(54.6)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	178.8		200
INCOME TAX BENEFIT (EXPENSE)	1.8		(13.9)
INCOME FROM CONTINUING OPERATIONS	180.6		186.1
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(64.3)		(135.2)
NET INCOME	116.3		50.9
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST	0		0
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ 116.3		$ 50.9
Continuing operations (in dollars per share)	$ 0.61		$ 0.62
Discontinued operations (in dollars per share)	(0.22)		(0.45)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share)	0.39		0.17
Continuing operations (in dollars per share)	0.60		0.62
Discontinued operations (in dollars per share)	(0.21)		(0.45)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share)	$ 0.39		$ 0.17
Basic	297,618		297,442
Diluted	301,275		301,143
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents	$ 0		$ 0		0
Accounts receivable, net	99.6		99.6		76.6
Inventories	(67.5)		(67.5)		(51.4)
Supplies and other inventories	0		0		0
Derivative assets	28.5		28.5		11.6
Current assets of discontinued operations	0		0		0
Loans to and accounts receivable from the Canadian Entities	0		0		0
Other current assets	0		0		0
TOTAL CURRENT ASSETS	60.6		60.6		36.8
PROPERTY, PLANT AND EQUIPMENT, NET	0		0		0
Deposits for property, plant and equipment	0		0		0
Income tax receivable	0		0		0
Non-current assets of discontinued operations	0		0		0
Other non-current assets	0		0		0
TOTAL OTHER ASSETS	0		0		0
Assets	60.6		60.6		36.8
Accounts payable	1.2		1.2		1.4
Accrued expenses	0		0		0
Accrued interest	0		0		0
Contingent claims	0		0		0
Partnership distribution payable	0		0		0
Current liabilities of discontinued operations	0		0		0
Other current liabilities	(5.9)		(5.9)		(1.4)
Liabilities, Current	(4.7)		(4.7)		(2.8)
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	0		0		0
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	0		0		0
LONG-TERM DEBT	0		0		0
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	0		0		0
OTHER LIABILITIES	0		0		0
Liabilities	(4.7)		(4.7)		(2.8)
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	65.3		65.3		34
NONCONTROLLING INTEREST	0		0		0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	65.3		65.3		34
TOTAL LIABILITIES AND DEFICIT	60.6		60.6		$ 36.8
Product	104		45.6
Freight and venture partners' cost reimbursements	6		1.9
Revenues	110		47.5
COST OF GOODS SOLD AND OPERATING EXPENSES	(61.2)		(17.6)
SALES MARGIN	48.8		29.9
Selling, general and administrative expenses	0		0
Miscellaneous - net	0		0
Other operating expense	0		0
OPERATING INCOME	48.8		29.9
Interest expense, net	0		0
Gain (loss) on extinguishment of debt	0		0
Other non-operating income	0		0
TOTAL OTHER INCOME (EXPENSE)	0		0
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	48.8		29.9
INCOME TAX BENEFIT (EXPENSE)	0		0
INCOME FROM CONTINUING OPERATIONS	48.8		29.9
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	0		0
NET INCOME	48.8		29.9
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST	0		0
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ 48.8		$ 29.9
Continuing operations (in dollars per share)	$ 0.16		$ 0.10
Discontinued operations (in dollars per share)	0		0
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share)	0.16		0.10
Continuing operations (in dollars per share)	0.16		0.10
Discontinued operations (in dollars per share)	0		0
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share)	$ 0.16		$ 0.10

NEW ACCOUNTING STANDARDS (Narra

NEW ACCOUNTING STANDARDS (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
TOTAL DEFICIT	$ (306.3)	$ (410.1)	$ (444.1)	$ (666.7)	$ (1,330.5)
Retained deficit	(306.3)	(410.3)	$ (444.3)
Total minimum lease payments	16.1
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
TOTAL DEFICIT	65.3	34
Retained deficit	$ 65.3	$ 34

SEGMENT REPORTING SEGMENT REP54

SEGMENT REPORTING SEGMENT REPORTING (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Amortization of Intangible Assets	$ 0.2	$ 0.2	$ 0.4	$ 0.4
Payments To Acquire Property Plant And Equipment Net			(114.4)	(48.5)
Payments to Acquire Property, Plant, and Equipment			72.3	5.1
Capital Expenditures Incurred but Not yet Paid			$ 34.9	$ 3.2

SEGMENT REPORTING SEGMENT REP55

SEGMENT REPORTING SEGMENT REPORTING (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Amortization of Intangible Assets	$ 0.2	$ 0.2	$ 0.4	$ 0.4
NET INCOME	165.1	30.1	80.8	0.3
Revenues	714.3	471.3	894.3	757.5
Gross Profit	284.5	144.7	346	193.7
Other operating expense	(30.3)	(29.5)	(61.5)	(45.1)
Nonoperating Income (Expense)	(26.6)	(32.5)	(54.6)	(143.3)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	227.6	82.7	229.9	5.3
Interest expense, net	(31.2)	(30.1)	(63.6)	(71.5)
Income Tax Expense (Benefit)	(1.8)	(1.1)	13.9	0
Depreciation, depletion and amortization			(49.4)	(44.8)
EBITDA	221.1	85.7	209.9	120.1
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(64.3)	(53.7)	(135.2)	(5)
Foreign currency transaction gain (loss), before tax	(0.1)	0.5	(0.5)	15.3
Gain (loss) on extinguishment of debt	0.2	(4.9)	0.2	(76.8)
Adjusted EBITDA	275.7	135.5	328	175.1
Property, Plant and Equipment, Additions	70.4	24.6	149.3	51.7
Payments To Acquire Property Plant And Equipment Net			(114.4)	(48.5)
Payments to Acquire Property, Plant, and Equipment			72.3	5.1
Capital Expenditures Incurred but Not yet Paid			34.9	3.2
U.S. Iron Ore [Member]
Segment Reporting Information [Line Items]
Revenues	$ 714.3	$ 471.3	$ 894.3	$ 757.5
Percentage Of Segment Revenue	100.00%	100.00%	100.00%	100.00%
Gross Profit	$ 284.5	$ 144.7	$ 346	$ 193.7
Depreciation, depletion and amortization	(15.6)	(16.7)	(31.4)	(33.1)
EBITDA	296	155	368.5	212.9
Adjusted EBITDA	301.3	161.5	378.4	225.6
Property, Plant and Equipment, Additions	26.7	24.6	45.4	51.7
All Segments
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	(17)	(18.3)	(34.2)	(36.8)
EBITDA	(74.9)	(69.3)	(158.6)	(92.8)
Adjusted EBITDA	(25.6)	(26)	(50.4)	(50.5)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	(1.4)	(1.6)	(2.8)	(3.7)
Property, Plant and Equipment, Additions	43.7	0	103.9	0
EBITDA Calculation [Member]
Segment Reporting Information [Line Items]
Interest expense, net	(32.3)	(31.4)	(65.8)	(74.2)
Income Tax Expense (Benefit)	1.8	(2.6)	(13.9)	(0.8)
Depreciation, depletion and amortization	(25.5)	(21.6)	(49.4)	(44.8)
Adjusted EBITDA Calculation [Member]
Segment Reporting Information [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ (54.7)	$ (45.4)	$ (117.8)	$ 6.5

SEGMENT REPORTING SEGMENT REP56

SEGMENT REPORTING SEGMENT REPORTING (Summary of Assets by Segment) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 3,051.5	$ 2,990.2	$ 2,953.4
U.S. Iron Ore [Member]
Segment Reporting Information [Line Items]
Assets	1,822.8		1,500.6
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Assets	1,183.4		1,314
Discontinued Operations, Held-for-sale [Member]
Segment Reporting Information [Line Items]
Assets	$ 45.3		$ 138.8

REVENUE (Deferred Revenue) (Det

REVENUE (Deferred Revenue) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]
Deferred revenue, current	$ 20	$ 23.8
Deferred revenue, noncurrent	47.1	$ 51.4
Other Current Liabilities [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue, Period Increase (Decrease)	(3.8)
Other Noncurrent Liabilities [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue, Period Increase (Decrease)	$ (4.3)

REVENUE (Narrative) (Details)

REVENUE (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Revenues	$ 714.3	$ 471.3	$ 894.3	$ 757.5
Deferred revenue, current	20		20			$ 23.8
Deferred revenue, noncurrent	47.1		47.1			51.4
Other current liabilities	66.2		66.2		$ 68.8	67.4
Customer Supplemental Payments [Member]
Deferred revenue	59.9		59.9			64.2
Deferred revenue, current	12.8		12.8			12.8
Take or Pay Contracts [Member]
Deferred revenue	7.2		7.2			$ 9.6
U.S. Iron Ore [Member]
Revenues	714.3	471.3	894.3	757.5
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenues	110		47.5
Other current liabilities	5.9		5.9		$ 1.4
Not Designated as Hedging Instrument [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 154.7	$ 30.8	$ 198.5	$ 63

INVENTORIES (Schedule Of Invent

INVENTORIES (Schedule Of Inventories) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Inventory, Net [Abstract]
Total Inventory	$ 256.4	$ 87	$ 138.4
U.S. Iron Ore [Member]
Inventory, Net [Abstract]
Finished Goods	232.5		127.1
Work-in Process	$ 23.9		$ 11.3

PROPERTY, PLANT AND EQUIPMENT60

PROPERTY, PLANT AND EQUIPMENT (Value Of Each Of The Major Classes Of Consolidated Depreciable Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,071.3		$ 2,000.7
Allowance for depreciation and depletion	(990)		(966.9)
Property, plant and equipment, net	1,081.3	$ 1,033.8	1,033.8
Land rights and mineral rights
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	549.6		549.6
Office and information technology
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	65.1		65.8
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	84		85.2
Mining equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	531.2		533.9
Processing equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	616		610.9
Electric power facilities
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	56.9		56.9
Land improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	24.2		23.7
Asset retirement obligation
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	16.9		16.9
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	25.2		25.2
Construction in-progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 102.2		$ 32.6

DEBT AND CREDIT FACILITIES (Sch

DEBT AND CREDIT FACILITIES (Schedule Of Long-Term Debt) (Details) - USD ($)	Jun. 30, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
LONG-TERM DEBT	$ 2,297,000,000		$ 2,304,200,000	$ 2,304,200,000
$400 Million 4.875% 2024 Senior Notes [Domain]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.00%			5.00%
Debt Instrument, Par Value	$ 400,000,000			$ 400,000,000
Unamortized Debt Issuance Expense	(6,300,000)			(7,100,000)
Debt Instrument, Unamortized Discount	(2,400,000)			(2,600,000)
Long-term Debt	$ 391,300,000			$ 390,300,000
$400 Million 5.90% 2020 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.98%			5.98%
Debt Instrument, Par Value	$ 88,400,000			$ 88,900,000
Unamortized Debt Issuance Expense	(200,000)			(200,000)
Debt Instrument, Unamortized Discount	(100,000)			(100,000)
Long-term Debt	$ 88,100,000			$ 88,600,000
$500 million 4.80% 2020 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	4.83%			4.83%
Debt Instrument, Par Value	$ 122,300,000			$ 122,400,000
Unamortized Debt Issuance Expense	(200,000)			(300,000)
Debt Instrument, Unamortized Discount	(100,000)			(100,000)
Long-term Debt	$ 122,000,000			$ 122,000,000
$700 Million 4.875% 2021 Senior Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	4.89%			4.89%
Debt Instrument, Par Value	$ 125,200,000			$ 138,400,000
Unamortized Debt Issuance Expense	(300,000)			(300,000)
Debt Instrument, Unamortized Discount	0			(100,000)
Long-term Debt	$ 124,900,000			$ 138,000,000
$316 Million 1.5% 2025 Senior Notes [Domain]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.26%			6.26%
Debt Instrument, Par Value	$ 316,300,000			$ 316,300,000
Unamortized Debt Issuance Expense	(6,000,000)			(6,600,000)
Debt Instrument, Unamortized Discount	(80,600,000)			(85,600,000)
Long-term Debt	$ 229,700,000			$ 224,100,000
$1,075 Million 5.75% 2025 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.01%			6.01%
Debt Instrument, Par Value	$ 1,073,300,000			$ 1,075,000,000
Unamortized Debt Issuance Expense	(10,600,000)			(11,300,000)
Debt Instrument, Unamortized Discount	(15,600,000)			(16,500,000)
Long-term Debt	$ 1,047,100,000			$ 1,047,200,000
$800 Million 6.25% 2040 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	6.34%			6.34%
Debt Instrument, Par Value	$ 298,400,000			$ 298,400,000
Unamortized Debt Issuance Expense	(2,300,000)			(2,400,000)
Debt Instrument, Unamortized Discount	(3,400,000)			(3,400,000)
Long-term Debt	292,700,000			292,600,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	450,000,000	$ 450,000,000		550,000,000
Credit facility, amount outstanding	0			0
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Fair Value Adjustment to Interest Rate Hedge	$ 1,200,000			$ 1,400,000

DEBT AND CREDIT FACILITIES DEBT

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES (Schedule of Extinguishment of Debt) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
$400 Million 5.90% 2020 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	$ 88.4	$ 88.9
$1,075 Million 5.75% 2025 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	1,073.3	1,075
$500 million 4.80% 2020 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	122.3	122.4
$700 Million 4.875% 2021 Senior Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	125.2	$ 138.4
Debt Repurchase [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	15.5
Debt Repurchase [Member] | $400 Million 5.90% 2020 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	0.5
Debt Repurchase [Member] | $1,075 Million 5.75% 2025 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	1.7
Debt Repurchase [Member] | $500 million 4.80% 2020 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	0.1
Debt Repurchase [Member] | $700 Million 4.875% 2021 Senior Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Par Value	$ 13.2

DEBT AND CREDIT FACILITIES (S63

DEBT AND CREDIT FACILITIES (Schedule of Debt Maturities) (Details) $ in Millions	Jun. 30, 2018USD ($)
Debt Disclosure [Abstract]
Debt Maturities 2018	$ 0
Debt Maturities 2019	0
Debt Maturities 2020	210.7
Debt Maturities 2021	125.2
Debt Maturities 2022	0
Debt Maturities 2023	0
2024 and thereafter	2,088
Total maturities of debt	$ 2,423.9

DEBT AND CREDIT FACILITIES (Nar

DEBT AND CREDIT FACILITIES (Narrative) (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Gain (loss) on extinguishment of debt	$ 200,000		$ (4,900,000)		$ 200,000	$ (76,800,000)
$1,075 Million 5.75% 2025 Senior Notes [Member]
Line of Credit Facility [Line Items]
Proceeds from Issuance of Debt		$ 575,000,000		$ 500,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.75%				5.75%
Debt issuance, discount rate	97.00%				97.00%
Debt Instrument, Par Value	$ 1,073,300,000				$ 1,073,300,000			$ 1,075,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Par Value	450,000,000				450,000,000		$ 450,000,000	550,000,000
U.S. Tranche	450,000,000				450,000,000		400,000,000
Sublimit for Issuers of Letters of Credit for U.S. Tranche	273,200,000				273,200,000		248,800,000
Sublimit for U.S. Swingline Loans	120,000,000				120,000,000		100,000,000
Australian Tranche							50,000,000
Sublimit for Issuance of Letters of Credit for Australian Tranche							24,400,000
Sublimit for Australian Swingline Loans							$ 20,000,000
Credit facility, amount outstanding	0				0			0
Line of Credit Facility, Maximum Borrowing Capacity	400,300,000				400,300,000			273,200,000
Letters of credit outstanding	39,500,000				39,500,000			46,500,000
Credit facility remaining capacity	$ 360,800,000				$ 360,800,000			$ 226,700,000

FAIR VALUE MEASUREMENTS (Fair V

FAIR VALUE MEASUREMENTS (Fair Value of Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	$ 557		$ 616.9
Derivative assets	174.7	$ 49.5	37.9
Total Asset	731.7		654.8
Derivative Liability	3.1		2
Total Liability	3.1		2
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	10.5		66.3
Derivative assets	0		0
Total Asset	10.5		66.3
Derivative Liability	0		0
Total Liability	0		0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	546.5		550.6
Derivative assets	0.1		0
Total Asset	546.6		550.6
Derivative Liability	0.1		0.3
Total Liability	0.1		0.3
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0		0
Derivative assets	174.6		37.9
Total Asset	174.6		37.9
Derivative Liability	3		1.7
Total Liability	$ 3		$ 1.7

FAIR VALUE MEASUREMENTS (Schedu

FAIR VALUE MEASUREMENTS (Schedule Of Quantitative Inputs And Assumptions For Level 3 Assets And Liabilities) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 174,700,000	$ 49,500,000	$ 37,900,000
Management Estimate of 62% Fe	62.00%
Derivative Liability	$ 3,100,000		2,000,000
Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	174,600,000		37,900,000
Derivative Liability	3,000,000		1,700,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	174,600,000		37,900,000
Derivative Liability	$ 3,000,000		1,700,000
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Managements Estimate Of 62% Fee [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Management Estimate of 62% Fe	62.00%
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Market Approach Valuation Technique [Member] | Provisional Pricing Arrangements [Member] | Managements Estimate Of 62% Fee [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement with unobservable inputs derivative asset range	$ 68
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Market Approach Valuation Technique [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 derivative asset range	68
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Market Approach Valuation Technique [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 derivative asset range	69
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Market Approach Valuation Technique [Member] | Customer Supply Agreement [Member] | Customer's Hot-Rolled Steel Estimate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value measurement with unobservable inputs derivative asset range	833
Derivative Financial Instruments, Assets [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	5,200,000		0
Derivative Financial Instruments, Assets [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	169,400,000		37,900,000
Other Current Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	3,000,000		1,700,000
Other Current Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	0		$ 0
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 28,500,000	$ 11,600,000

FAIR VALUE MEASUREMENTS (Fair67

FAIR VALUE MEASUREMENTS (Fair Value, Assets and Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fair Value, Assets Measured On Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 93.5	$ 59.2	$ 49.5	$ 30.1
Total gains
Included in earnings	158.6	51	202.8	84.6
Settlements	(77.5)	(40)	(77.7)	(44.5)
Ending balance - June 30	174.6	70.2	174.6	70.2
Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date	80.6	17.8	125.1	51
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	0	0	(1.7)	0
Total losses
Included in earnings	(3.7)	(20.2)	(4.3)	(20.2)
Settlements	0.7	0	3	0
Ending balance - June 30	(3)	(20.2)	(3)	(20.2)
Total losses for the period included in earnings attributable to the change in unrealized losses on liabilities still held at the reporting date	$ (3)	$ (20.2)	$ (3)	$ (20.2)

FAIR VALUE MEASUREMENTS (Carryi

FAIR VALUE MEASUREMENTS (Carrying Value And Fair Value Of Financial Instruments Disclosure) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	$ 2,378	$ 2,346.3
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	1.2	1.4
Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	2,297	2,304.2
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	1.2	1.4
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 4.875% 2024 Senior Notes [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	388.5	398
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 5.90% 2020 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	88.4	88
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $500 million 4.80% 2020 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	120.5	118.8
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Note [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	124.6	130.8
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316 Million 1.5% 2025 Senior Notes [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	384.5	352.9
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $1,075 Million 5.75% 2025 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	1,028.6	1,029.3
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	241.7	227.1
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 4.875% 2024 Senior Notes [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	391.3	390.3
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 5.90% 2020 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	88.1	88.6
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $500 million 4.80% 2020 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	122	122
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Note [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	124.9	138
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316 Million 1.5% 2025 Senior Notes [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	229.7	224.1
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $1,075 Million 5.75% 2025 Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, fair value	1,047.1	1,047.2
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	292.7	292.6
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	6 Months Ended
	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	$ 174.7	$ 49.5	$ 37.9
Derivative Liability	$ 3.1		2
Management Estimate of 62% Fe	62.00%
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	$ 0		0
Derivative Liability	0		0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	0.1		0
Derivative Liability	0.1		0.3
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	174.6		37.9
Derivative Liability	3		1.7
Not Designated as Hedging Instrument [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	174.6		37.9
Derivative Liability	3		1.7
Derivative Financial Instruments, Assets [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	169.4		37.9
Derivative Financial Instruments, Assets [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative assets	5.2		0
Other Current Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative Liability	0		0
Other Current Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member]
Fair Value, Assets And Liabilities Components [Line Items]
Derivative Liability	$ 3		$ 1.7

PENSIONS AND OTHER POSTRETIRE70

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Estimated Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 4.6	$ 4.7	$ 9.3	$ 9.5
Interest cost	7.5	7.5	15.1	15
Expected return on plan assets	(15)	(13.6)	(30)	(27.1)
Prior service credits	0.6	0.7	1.1	1.3
Net actuarial loss	5.3	5.3	10.6	10.6
Net periodic benefit credit	3	4.6	6.1	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	0.5	1	1
Interest cost	2	2.2	4.1	4.3
Expected return on plan assets	(4.6)	(4.5)	(9.2)	(8.9)
Prior service credits	(0.7)	(0.8)	(1.5)	(1.5)
Net actuarial loss	1.3	1.3	2.5	2.5
Net periodic benefit credit	$ (1.5)	$ (1.3)	$ (3.1)	$ (2.6)

PENSIONS AND OTHER POSTRETIRE71

PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Plans, Defined Benefit [Member]
Definted Benefit Plan Disclosure [Line Items]
Payment for Pension Benefits	$ 3.3	$ 2.3	$ 5.6	$ 2.3
Other Postretirement Benefit Plans, Defined Benefit [Member]
Definted 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)	6 Months Ended
	Jun. 30, 2018$ / shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Grant Date Market Price	$ 7.53
Average Expected Term	2 years 10 months 9 days
Expected Volatility	86.80%
Risk-Free Interest Rate	2.42%
Dividend Yield	0.00%
Fair Value	$ 11.93
Fair Value (Percent of Grant Date Market Price)	158.43%

STOCK COMPENSATION PLANS (Narra

STOCK COMPENSATION PLANS (Narrative) (Details) - 2015 Equity Plan [Member] shares in Millions	6 Months Ended
	Jun. 30, 2018shares
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted shares granted	0.7
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted shares granted	0.7
2017 to 2019 Performance Period [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Goods And Nonemployee Services Transaction Valuation Method Payout Rate	0.00%
2017 to 2019 Performance Period [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Goods And Nonemployee Services Transaction Valuation Method Payout Rate	200.00%

INCOME TAXES (Narrative) (Detai

INCOME TAXES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent			0.10%	(3.60%)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ (2)	$ (0.3)	$ (13.7)	$ (0.2)
Change in refundable AMT, amount			$ 14.5

LEASE OBLIGATIONS (Future Minim

LEASE OBLIGATIONS (Future Minimum Lease Payments) (Details) $ in Millions	Jun. 30, 2018USD ($)
Capital Leases
2018 (July 1 - December 31)	$ 1.4
2,019	2.8
2,020	2.4
2,021	1.8
2,022	1.4
2023 and thereafter	0
Total minimum lease payments	9.8
Amounts representing interest	1
Present value of net minimum lease payments	8.8
Operating Leases
2018 (July 1 - December 31)	1.3
2,019	1.9
2,020	1.8
2,021	1.8
2,022	1.8
2023 and thereafter	7.5
Total minimum lease payments	16.1
Other Current Liabilities [Member]
Capital Leases
Present value of net minimum lease payments	2.4
Other Noncurrent Liabilities [Member]
Capital Leases
Present value of net minimum lease payments	$ 6.4

LEASE OBLIGATIONS (Narrative) (

LEASE OBLIGATIONS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Leases [Abstract]
Operating lease expense	$ 0.9	$ 1.2	$ 1.8	$ 2.3

ENVIRONMENTAL AND MINE CLOSUR77

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Summary Of Mine Closure Obligations) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Environmental	$ 3.2	$ 2.9
Environmental Loss Contingency And Mine Reclamation And Closing Liability Current And Noncurrent	176	171.3
Environmental Loss Contingency And Mine Reclamation And Closing Liability Current	3.7	3.6
Environmental Loss Contingency And Mine Reclamation And Closing Liability Noncurrent	172.3	167.7
Owned Or Operating Facilities [Member]
Loss Contingencies [Line Items]
Mine Reclamation and Closing Liability, current and noncurrent	$ 172.8	$ 168.4

ENVIRONMENTAL AND MINE CLOSUR78

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Asset Retirement Obligation Disclosure) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Asset Retirement Obligation [Roll Forward]
Asset retirement obligation at beginning of period	$ 168.4	$ 187.8
Accretion expense	4.7	13.9
Remediation payments	(0.3)	(5.6)
Revision in estimated cash flows	0	(27.7)
Asset retirement obligation at end of period	$ 172.8	$ 168.4

ENVIRONMENTAL AND MINE CLOSUR79

ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Jun. 30, 2018
Environmental Loss Contingency And Mine Reclamation And Closing Liability Current And Noncurrent	$ 171.3	$ 176
U.S. Iron Ore [Member]
Accrual for Environmental Loss Contingencies, Period Increase (Decrease)	$ (26.2)

GOODWILL AND OTHER INTANGIBLE80

GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES (Schedule Of Finite-Lived Intangible Assets By Major Class) (Details) - Permits [Member] - Other Assets [Member] - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Definite lived intangible assets - Gross Carrying Amount	$ 72.2	$ 72.2
Definite lived intangible assets - Accumulated Amortization	(22.9)	(22.5)
Definite lived intangible assets - Net Carrying Amount	$ 49.3	$ 49.7

GOODWILL AND OTHER INTANGIBLE81

GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Goodwill [Line Items]
Amortization of Intangible Assets	$ 0.2	$ 0.2	$ 0.4	$ 0.4
Cost of Sales [Member]
Goodwill [Line Items]
Amortization of Intangible Assets	0.2	$ 0.2	0.4	$ 0.4
U.S. Iron Ore [Member]
Goodwill [Line Items]
Goodwill	$ 2		$ 2		$ 2

DERIVATIVE INSTRUMENTS (Schedul

DERIVATIVE INSTRUMENTS (Schedule Of Derivative Instruments In Statement Of Financial Position, Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative assets	$ 174.7	$ 49.5	$ 37.9
Derivative Liability	3.1		2
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	174.6		37.9
Derivative Liability	3		1.7
Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Derivative Financial Instruments, Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	169.4		37.9
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Derivative Financial Instruments, Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	5.2		0
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	3		1.7
Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	174.6		37.9
Derivative Liability	3		1.7
Fair Value, Inputs, Level 3 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Derivative Financial Instruments, Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0.1		0
Fair Value, Inputs, Level 3 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	0.1		0.3
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	$ 0		$ 0

DERIVATIVE INSTRUMENTS (Sched83

DERIVATIVE INSTRUMENTS (Schedule Of Derivatives Not Designated As Hedging Instruments) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 154.7	$ 30.8	$ 198.5	$ 63
Customer Supply Agreement [Member] | Product Revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in income on derivative	155.5	51.9	197.4	69.6
Provisional Pricing Arrangements [Member] | Product Revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in income on derivative	(0.8)	(21.1)	1.1	(5.3)
Commodity Contract [Member] | Other Nonoperating Income (Expense) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 0	$ 0	$ 0	$ (1.3)

DERIVATIVE INSTRUMENTS (Narrati

DERIVATIVE INSTRUMENTS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Derivative [Line Items]
Natural Gas Hedges	$ 3.4		$ 3.4			$ 3.5
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(0.2)		(0.6)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0.1
Derivative assets	174.7		174.7		$ 49.5	37.9
Derivative Liability	3.1		3.1			2
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative assets	174.6		174.6			37.9
Derivative Liability	3		3			1.7
Customer Supply Agreement [Member] | Not Designated as Hedging Instrument [Member] | Product Revenues [Member]
Derivative [Line Items]
Amount of gain/(loss) recognized in income on derivative	(155.5)	$ (51.9)	(197.4)	$ (69.6)
Customer Supply Agreement [Member] | Not Designated as Hedging Instrument [Member] | Derivative Financial Instruments, Assets [Member]
Derivative [Line Items]
Derivative assets	169.4		169.4			37.9
Provisional Pricing Arrangements [Member] | Not Designated as Hedging Instrument [Member] | Product Revenues [Member]
Derivative [Line Items]
Amount of gain/(loss) recognized in income on derivative	0.8	$ 21.1	(1.1)	$ 5.3
Provisional Pricing Arrangements [Member] | Not Designated as Hedging Instrument [Member] | Derivative Financial Instruments, Assets [Member]
Derivative [Line Items]
Derivative assets	$ 5.2		$ 5.2			$ 0

DISCONTINUED OPERATIONS (Dispos

DISCONTINUED OPERATIONS (Disposal Groups, Including Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ (64.3)	$ (53.7)	$ (135.2)	$ (5)
Current assets of discontinued operations	45.3		45.3		$ 118.5	$ 118.5
Non-current assets of discontinued operations	0		0		20.3	20.3
Current liabilities of discontinued operations	117.3		117.3		75	75
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3		10.3		$ 52.2	52.2
Net cash provided (used) by operating activities			(49.3)	67.8
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(53.3)	(7.3)	(124.7)	41
Current assets of discontinued operations	45.3		45.3			118.5
Non-current assets of discontinued operations	0		0			20.3
Current liabilities of discontinued operations	114.4		114.4			71.8
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3		10.3			52.2
North American Coal [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.3)	2.6	0.1	2.6
Current assets of discontinued operations	0		0			0
Non-current assets of discontinued operations	0		0			0
Current liabilities of discontinued operations	2.9		2.9			3.2
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	0		0			$ 0
Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ (10.7)	$ (49)	(10.6)	(48.6)
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash provided (used) by operating activities			(46.3)	92.2
Discontinued Operations [Member] | Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash provided (used) by operating activities			(31.7)	92.2
Non-cash financing activities			28.6
Discontinued Operations [Member] | Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash provided (used) by operating activities			$ (14.6)	$ 0

DISCONTINUED OPERATIONS (Schedu

DISCONTINUED OPERATIONS (Schedule of Disposal Groups, including Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Cash Provided by (Used in) Investing Activities			$ (99.8)	$ (48.3)
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ (64.3)	$ (53.7)	(135.2)	(5)
Current assets of discontinued operations	45.3		45.3		$ 118.5	$ 118.5
Non-current assets of discontinued operations	0		0		20.3	20.3
Current liabilities of discontinued operations	117.3		117.3		75	75
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3		10.3		$ 52.2	52.2
Depreciation, depletion and amortization			49.4	44.8
Payments to Acquire Property, Plant, and Equipment			72.3	5.1
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues from product sales and services	70.1	98	129.1	273.4
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(53.3)	(7.3)	(124.7)	41
Current assets of discontinued operations	45.3		45.3			118.5
Non-current assets of discontinued operations	0		0			20.3
Current liabilities of discontinued operations	114.4		114.4			71.8
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3		10.3			52.2
Disposal Group, Including Discontinued Operation, Costs of Goods Sold	(106.1)	(97.1)	(230.2)	(225.2)
Sales margin	(36)	0.9	(101.1)	48.2
Disposal Group, Including Discontinued Operation, Operating Expense	(16.2)	(3.2)	(18.8)	(3.7)
Disposal Group, Including Discontinued Operation, Other Expense	(1.1)	(1.3)	(2.2)	(2.7)
Loss from discontinued operations before income taxes	(53.3)	(3.6)	(122.1)	41.8
Impairment of Long-Lived Assets to be Disposed of	0	0	(2.6)	0
Discontinued Operation, Tax Effect of Discontinued Operation	0	(3.7)	0	(0.8)
North American Coal [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.3)	2.6	0.1	2.6
Current assets of discontinued operations	0		0			0
Non-current assets of discontinued operations	0		0			0
Current liabilities of discontinued operations	2.9		2.9			3.2
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	0		0			$ 0
Canadian Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ (10.7)	$ (49)	(10.6)	(48.6)
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Cash Provided by (Used in) Investing Activities			14.1	(0.8)
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 Provided by (Used in) Investing Activities			$ 14.1	$ (0.8)

DISCONTINUED OPERATIONS (Sche87

DISCONTINUED OPERATIONS (Schedule of Disposal Groups, including Discontinued Operations, Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ (64.3)	$ (53.7)	$ (135.2)	$ (5)
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues from product sales and services	70.1	98	129.1	273.4
Cost of goods sold and operating expenses	106.1	97.1	230.2	225.2
Sales margin	(36)	0.9	(101.1)	48.2
Other operating expense	(16.2)	(3.2)	(18.8)	(3.7)
Other expense	(1.1)	(1.3)	(2.2)	(2.7)
Loss from discontinued operations before income taxes	(53.3)	(3.6)	(122.1)	41.8
Impairment of long-lived assets	0	0	(2.6)	0
Income tax expense	0	(3.7)	0	(0.8)
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	$ (53.3)	$ (7.3)	$ (124.7)	$ 41

DISCONTINUED OPERATIONS (Sche88

DISCONTINUED OPERATIONS (Schedule of Disposal Groups, including Discontinued Operations, Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets of discontinued operations	$ 45.3	$ 118.5	$ 118.5
Current liabilities of discontinued operations	117.3	$ 75	75
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	29.4		29.4
Accounts receivable, net	12.5		33.9
Inventories	0		45
Supplies and other inventories	0		5.1
Other current assets	3.4		5.1
Current assets of discontinued operations	45.3		118.5
Property, plant and equipment, net	0		17.2
Other non-current assets	0		3.1
Total assets of discontinued operations	45.3		138.8
Accounts payable	74.3		28.2
Accrued liabilities	21.1		28
Other current liabilities	19		15.6
Current liabilities of discontinued operations	114.4		71.8
Environmental and mine closure obligations	10.3		28.8
Other liabilities	0		23.4
Total liabilities of discontinued operations	$ 124.7		$ 124

DISCONTINUED OPERATIONS (Narrat

DISCONTINUED OPERATIONS (Narrative) (Details) $ in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2018CAD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2018USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated other comprehensive loss	$ (306.3)	$ (666.7)	$ (306.3)		$ (666.7)		$ (410.1)	$ (444.1)		$ (1,330.5)
Loans to and accounts receivable from the Canadian Entities	0		0				$ 51.6	51.6
Cash contribution				$ 19
Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense	0	3.7	0		0.8
Unrealized Net Gain (Loss) on Foreign Currency Translation [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated other comprehensive loss	$ 228.3	$ 225.1	228.3		$ 225.1	$ 226.1		$ 225.4	$ 226.6	$ 239.3
Discontinued Operations [Member] | Asia Pacific Iron Ore [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-cash financing activities			$ 28.6

SHAREHOLDERS' EQUITY (Schedule

SHAREHOLDERS' EQUITY (Schedule of Shareholders' Equity) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ (444.3)
Beginning balance			0.2
Beginning Balance			(444.1)	$ (1,330.5)
Cumulative Effect of New Accounting Principle in Period of Adoption			34
Net Income (Loss) Available to Common Stockholders, Basic			80.8	3.7
Net Income (Loss) Attributable to Noncontrolling Interest	$ 0	$ (1.7)	0	(3.4)
NET INCOME	165.1	30.1	80.8	0.3
Other comprehensive income (loss)	9.1	4.9	16.8	1.9
OTHER COMPREHENSIVE LOSS (INCOME) ATTRIBUTABLE TO THE NONCONTROLLING INTEREST	0	0.4	0	(4.6)
Other Comprehensive Income (Loss), Net of Tax	9.1	5.3	16.8	(2.7)
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	174.2	36.7	97.6	5.6
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest			97.6	(2.4)
Stock and Other Incentive Plans			6.4	8.3
Undistributed Earnings Losses Related to Noncontrolling Interests			0.2	3.4
Ending balance	(306.3)		(306.3)
Ending balance	0		0
Ending Balance	(306.3)	(666.7)	(306.3)	(666.7)
Cliffs Shareholders Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(444.3)	(1,464.3)
Cumulative Effect of New Accounting Principle in Period of Adoption			34
Other comprehensive income (loss)			16.8	1.9
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS			97.6	5.6
Stock and Other Incentive Plans			6.4	8.3
Undistributed Earnings Losses Related to Noncontrolling Interests			0	0
Ending balance	(306.3)	(789.1)	(306.3)	(789.1)
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			0.2	133.8
Cumulative Effect of New Accounting Principle in Period of Adoption			0
Net Income (Loss) Attributable to Noncontrolling Interest			0	(3.4)
OTHER COMPREHENSIVE LOSS (INCOME) ATTRIBUTABLE TO THE NONCONTROLLING INTEREST			0	(4.6)
OTHER COMPREHENSIVE LOSS (INCOME) ATTRIBUTABLE TO THE NONCONTROLLING INTEREST			0	(8)
Stock and Other Incentive Plans			0	0
Undistributed Earnings Losses Related to Noncontrolling Interests			0.2	3.4
Ending balance	$ 0	$ 122.4	$ 0	122.4
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, New Issues				661.3
Common Stock [Member] | Cliffs Shareholders Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, New Issues				661.3
Common Stock [Member] | Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, New Issues				$ 0

SHAREHOLDERS' EQUITY (Accumulat

SHAREHOLDERS' EQUITY (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		$ (444.1)		$ (1,330.5)	$ (444.1)	$ (1,330.5)
Ending Balance	$ (306.3)		$ (666.7)		(306.3)	(666.7)
Changes in Pension and Other Post-Retirement Benefits, net of tax [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(257.2)	(263.9)	(250.9)	(260.6)	(263.9)	(260.6)
Other comprehensive income (loss) before reclassifications	0.2	0.5	(0.1)	3.3
Net loss reclassified from accumulated other comprehensive income (loss)	6.5	6.2	6.5	6.4
Ending Balance	(250.5)	(257.2)	(244.5)	(250.9)	(250.5)	(244.5)
Unrealized Net Gain (Loss) on Foreign Currency Translation [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	226.1	225.4	226.6	239.3	225.4	239.3
Other comprehensive income (loss) before reclassifications	2.2	0.7	(1.5)	(12.7)
Net loss reclassified from accumulated other comprehensive income (loss)	0	0	0	0
Ending Balance	228.3	226.1	225.1	226.6	228.3	225.1
Net Unrealized Gain (Loss) on Derivative Financial Instruments, net of tax [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(0.2)	(0.5)			(0.5)
Other comprehensive income (loss) before reclassifications	0.2	0.4
Net loss reclassified from accumulated other comprehensive income (loss)	0	(0.1)
Ending Balance	0	(0.2)			0
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(31.3)	(39)	(24.3)	(21.3)	(39)	(21.3)
Other comprehensive income (loss) before reclassifications	2.6	1.6	(1.6)	(9.4)
Net loss reclassified from accumulated other comprehensive income (loss)	6.5	6.1	6.5	6.4
Ending Balance	$ (22.2)	$ (31.3)	$ (19.4)	$ (24.3)	$ (22.2)	$ (19.4)

SHAREHOLDERS' EQUITY (Details o

SHAREHOLDERS' EQUITY (Details of Accumulated Other Comprehensive Income (Loss) Components) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net					$ 0.1
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0		$ 0		(0.1)	$ 0
Net loss reclassified from accumulated other comprehensive income (loss)	6.5		6.5		12.6	12.9
Realized Gain Loss On Derivatives [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amount of gain/(loss) recognized in income on derivative	0		0		(0.1)	0
Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net loss reclassified from accumulated other comprehensive income (loss)	6.5	$ 6.2	6.5	$ 6.4
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Prior service credits	(0.1)		(0.1)		(0.4)	(0.2)
Net actuarial loss	6.6		6.6		13.1	13.1
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	$ 6.5		$ 6.5		$ 12.7	$ 12.9

SHAREHOLDERS' EQUITY (Narrative

SHAREHOLDERS' EQUITY (Narrative (Details)	Jun. 30, 2018	Mar. 31, 2017
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
Empire
Noncontrolling Interest, Ownership Percentage by Parent	100.00%	79.00%
Tilden
Noncontrolling Interest, Ownership Percentage by Parent	100.00%	85.00%

RELATED PARTIES (Summary Of Oth

RELATED PARTIES (Summary Of Other Ownership Interests) (Details) - Hibbing [Member]	Jun. 30, 2018	Dec. 31, 2017
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%
Other Noncurrent Assets [Member]
Related Party Transaction [Line Items]
Ownership interest, equity method investment	23.00%	23.00%

RELATED PARTIES (Summary Of Rel

RELATED PARTIES (Summary Of Related Party Transactions Table Disclosure) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Related Party Transactions [Abstract]
Product revenues from related parties	$ 409.4	$ 227.5	$ 471.4	$ 336.9
Product	$ 672	$ 417	$ 841.2	$ 664.3
Related party product revenue as a percent of total product revenue	60.90%	54.60%	56.00%	50.70%

RELATED PARTIES (Summary of Bal

RELATED PARTIES (Summary of Balance Sheet Presentation) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Partnership distribution payable	$ 44.2	$ 44.2	$ 44.2
Related Party Transaction, Due from (to) Related Party	162.1		8.1
Trade Accounts Receivable [Member]
Related Party Transaction [Line Items]
Due from Related Parties, Current	83.2		68.1
Derivative [Member]
Related Party Transaction [Line Items]
Due from Related Parties, Current	169.4		37.9
Due to Related Parties, Current	(42.7)		(41.4)
Other Current Liabilities [Member]
Related Party Transaction [Line Items]
Due to Related Parties, Current	$ (3.6)		$ (12.3)

RELATED PARTIES (Narrative) (De

RELATED PARTIES (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)Facility	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)	Mar. 31, 2017
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
Partnership distribution payable	$ 44.2	$ 44.2	$ 44.2
U.S. Iron Ore [Member]
Segment Reporting Information [Line Items]
Number of mines (in number of facilities) | Facility	4
Joint Venture Partners [Member] | U.S. Iron Ore [Member]
Segment Reporting Information [Line Items]
Number of mines (in number of facilities) | Facility	1
Empire
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	100.00%			79.00%
Purchase of Noncontrolling Interest	$ 132.7
Other Noncurrent Liabilities [Member] | Empire
Segment Reporting Information [Line Items]
Noncontrolling Interest Purchase, Installment Amount	$ 44.2

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Income from Continuing Operations	$ 229.4	$ 83.8	$ 216	$ 5.3
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST	0	1.7	0	3.4
Net Income from Continuing Operations Attributable to Cliffs Shareholders	229.4	85.5	216	8.7
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(64.3)	(53.7)	(135.2)	(5)
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ 165.1	$ 31.8	$ 80.8	$ 3.7
Weighted Average Number of Shares:
Basic	297,618	296,100	297,442	280,617
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	3,700	4,600	3,700	4,600
Diluted	301,275	300,700	301,143	285,247
Income (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic:
Continuing operations (in dollars per share)	$ 0.77	$ 0.28	$ 0.73	$ 0.03
Discontinued operations (in dollars per share)	(0.22)	(0.18)	(0.46)	(0.01)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic (in dollars per share)	0.55	0.10	0.27	0.02
Income (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted:
Continuing operations (in dollars per share)	0.76	0.28	0.72	0.03
Discontinued operations (in dollars per share)	(0.21)	(0.18)	(0.45)	(0.02)
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted (in dollars per share)	$ 0.55	$ 0.10	$ 0.27	$ 0.01

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Narrative) (Details) $ in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2018CAD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Loans to and accounts receivable from the Canadian Entities	$ 0		$ 51.6	$ 51.6
Cash contribution		$ 19
Michigan Electricity Matters [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual	10.8			$ 13
Loss Contingency Accrual, Period Increase (Decrease)	$ 2.2

SUPPLEMENTARY GUARANTOR INFO100

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Financial Position) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 802.5	$ 978.3	$ 978.3	$ 270.4
Accounts receivable, net	152.6	183.3	106.7
Inventories	256.4	87	138.4
Supplies and other inventories	88.6	88.8	88.8
Derivative assets	174.7	49.5	37.9
Current assets of discontinued operations	45.3	118.5	118.5
Loans to and accounts receivable from the Canadian Entities	0	51.6	51.6
Other current assets	26.8	24.4	24.4
TOTAL CURRENT ASSETS	1,546.9	1,581.4	1,544.6
PROPERTY, PLANT AND EQUIPMENT, NET	1,081.3	1,033.8	1,033.8
Deposits for property, plant and equipment	85.7	17.8	17.8
Income tax receivable	219.9		235.3
Non-current assets of discontinued operations	0	20.3	20.3
Investment in subsidiaries	0		0
Long-term intercompany notes	0		0
Other non-current assets	117.7	101.6	101.6
TOTAL OTHER ASSETS	423.3	375	375
Assets	3,051.5	2,990.2	2,953.4
Accounts payable	119	100.9	99.5
Accrued expenses	85.1	79.1	79.1
Accrued interest	43.1	31.4	31.4
Contingent claims	0	55.6	55.6
Partnership distribution payable	44.2	44.2	44.2
Current liabilities of discontinued operations	117.3	75	75
Other current liabilities	66.2	68.8	67.4
TOTAL CURRENT LIABILITIES	474.9	455	452.2
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	245	257.7	257.7
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	172.3	167.7	167.7
LONG-TERM DEBT	2,297	2,304.2	2,304.2
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3	52.2	52.2
LONG-TERM INTERCOMPANY NOTES	0		0
OTHER LIABILITIES	158.3	163.5	163.5
Liabilities	3,357.8	3,400.3	3,397.5
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	(306.3)	(410.3)	(444.3)
NONCONTROLLING INTEREST	0	0.2	0.2
TOTAL DEFICIT	(306.3)	(410.1)	(444.1)	$ (666.7)	$ (1,330.5)
TOTAL LIABILITIES AND DEFICIT	3,051.5	$ 2,990.2	2,953.4
Consolidation, Eliminations [Member]
Cash and cash equivalents	0		0
Accounts receivable, net	(3.7)		(0.7)
Inventories	0		0
Supplies and other inventories	0		0
Derivative assets	0		0
Current assets of discontinued operations	0		0
Loans to and accounts receivable from the Canadian Entities			0
Other current assets	0		0
TOTAL CURRENT ASSETS	(3.7)		(0.7)
PROPERTY, PLANT AND EQUIPMENT, NET	0		0
Deposits for property, plant and equipment	0		0
Income tax receivable	0		0
Non-current assets of discontinued operations			0
Investment in subsidiaries	(1,332.7)		(1,054.2)
Long-term intercompany notes	(227.4)		(242)
Other non-current assets	0		0
TOTAL OTHER ASSETS	(1,560.1)		(1,296.2)
Assets	(1,563.8)		(1,296.9)
Accounts payable	(3.7)		(0.7)
Accrued expenses	0		0
Accrued interest	0		0
Contingent claims			0
Partnership distribution payable	0		0
Current liabilities of discontinued operations	0		0
Other current liabilities	0		0
TOTAL CURRENT LIABILITIES	(3.7)		(0.7)
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	0		0
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	0		0
LONG-TERM DEBT	0		0
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	0		0
LONG-TERM INTERCOMPANY NOTES	(227.4)		(242)
OTHER LIABILITIES	0		0
Liabilities	(231.1)		(242.7)
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	(1,332.7)		(1,054.2)
NONCONTROLLING INTEREST			0
TOTAL DEFICIT	(1,332.7)		(1,054.2)
TOTAL LIABILITIES AND DEFICIT	(1,563.8)		(1,296.9)
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Cash and cash equivalents	2.5		27.3
Accounts receivable, net	0.1		0
Inventories	0		0
Supplies and other inventories	0		0
Derivative assets	0		0
Current assets of discontinued operations	45.3		118.5
Loans to and accounts receivable from the Canadian Entities			0
Other current assets	3.2		0.5
TOTAL CURRENT ASSETS	51.1		146.3
PROPERTY, PLANT AND EQUIPMENT, NET	99.6		57.3
Deposits for property, plant and equipment	81.9		16.5
Income tax receivable	0		0
Non-current assets of discontinued operations			20.3
Investment in subsidiaries	0		0
Long-term intercompany notes	227.4		242
Other non-current assets	1.7		2.1
TOTAL OTHER ASSETS	311		280.9
Assets	461.7		484.5
Accounts payable	28.7		3.4
Accrued expenses	0.5		0.2
Accrued interest	0		0
Contingent claims			0
Partnership distribution payable	0		0
Current liabilities of discontinued operations	117.3		75
Other current liabilities	1.7		1.8
TOTAL CURRENT LIABILITIES	148.2		80.4
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	(249.3)		(239.3)
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	27		27.1
LONG-TERM DEBT	0		0
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	10.3		52.2
LONG-TERM INTERCOMPANY NOTES	0		0
OTHER LIABILITIES	0.6		0.6
Liabilities	(63.2)		(79)
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	524.9		563.3
NONCONTROLLING INTEREST			0.2
TOTAL DEFICIT	524.9		563.5
TOTAL LIABILITIES AND DEFICIT	461.7		484.5
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Cash and cash equivalents	1.6		2.1
Accounts receivable, net	148.2		102.9
Inventories	256.4		138.4
Supplies and other inventories	88.6		88.8
Derivative assets	174.6		37.9
Current assets of discontinued operations	0		0
Loans to and accounts receivable from the Canadian Entities			6.9
Other current assets	7.7		7.5
TOTAL CURRENT ASSETS	677.1		384.5
PROPERTY, PLANT AND EQUIPMENT, NET	966.2		959
Deposits for property, plant and equipment	3.8		1.3
Income tax receivable	0		0
Non-current assets of discontinued operations			0
Investment in subsidiaries	32.8		29.9
Long-term intercompany notes	0		0
Other non-current assets	107.3		91.7
TOTAL OTHER ASSETS	143.9		122.9
Assets	1,787.2		1,466.4
Accounts payable	88.8		89.7
Accrued expenses	71		59.9
Accrued interest	0		0
Contingent claims			0
Partnership distribution payable	44.2		44.2
Current liabilities of discontinued operations	0		0
Other current liabilities	62.7		63.5
TOTAL CURRENT LIABILITIES	266.7		257.3
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	428.4		430.6
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	145.3		140.6
LONG-TERM DEBT	0		0
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	0		0
LONG-TERM INTERCOMPANY NOTES	0		0
OTHER LIABILITIES	139		147.2
Liabilities	979.4		975.7
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	807.8		490.7
NONCONTROLLING INTEREST			0
TOTAL DEFICIT	807.8		490.7
TOTAL LIABILITIES AND DEFICIT	1,787.2		1,466.4
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Cash and cash equivalents	798.4		948.9
Accounts receivable, net	8		4.5
Inventories	0		0
Supplies and other inventories	0		0
Derivative assets	0.1		0
Current assets of discontinued operations	0		0
Loans to and accounts receivable from the Canadian Entities			44.7
Other current assets	15.9		16.4
TOTAL CURRENT ASSETS	822.4		1,014.5
PROPERTY, PLANT AND EQUIPMENT, NET	15.5		17.5
Deposits for property, plant and equipment	0		0
Income tax receivable	219.9		235.3
Non-current assets of discontinued operations			0
Investment in subsidiaries	1,299.9		1,024.3
Long-term intercompany notes	0		0
Other non-current assets	8.7		7.8
TOTAL OTHER ASSETS	1,528.5		1,267.4
Assets	2,366.4		2,299.4
Accounts payable	5.2		7.1
Accrued expenses	13.6		19
Accrued interest	43.1		31.4
Contingent claims			55.6
Partnership distribution payable	0		0
Current liabilities of discontinued operations	0		0
Other current liabilities	1.8		2.1
TOTAL CURRENT LIABILITIES	63.7		115.2
PENSION AND POSTEMPLOYMENT BENEFIT LIABILITIES	65.9		66.4
ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS	0		0
LONG-TERM DEBT	2,297		2,304.2
NON-CURRENT LIABILITIES OF DISCONTINUED OPERATIONS	0		0
LONG-TERM INTERCOMPANY NOTES	227.4		242
OTHER LIABILITIES	18.7		15.7
Liabilities	2,672.7		2,743.5
TOTAL CLIFFS SHAREHOLDERS' DEFICIT	(306.3)		(444.1)
NONCONTROLLING INTEREST			0
TOTAL DEFICIT	(306.3)		(444.1)
TOTAL LIABILITIES AND DEFICIT	$ 2,366.4		$ 2,299.4

SUPPLEMENTARY GUARANTOR INFO101

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Operations and Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Product	$ 672	$ 417	$ 841.2	$ 664.3
Freight and venture partners' cost reimbursements	42.3	54.3	53.1	93.2
Revenues	714.3	471.3	894.3	757.5
COST OF GOODS SOLD AND OPERATING EXPENSES	(429.8)	(326.6)	(548.3)	(563.8)
SALES MARGIN	284.5	144.7	346	193.7
Selling, general and administrative expenses	(26.2)	(26.6)	(51.3)	(51.7)
Miscellaneous - net	(4.1)	(2.9)	(10.2)	6.6
Other operating expense	(30.3)	(29.5)	(61.5)	(45.1)
OPERATING INCOME	254.2	115.2	284.5	148.6
Interest expense, net	(31.2)	(30.1)	(63.6)	(71.5)
Gain (loss) on extinguishment of debt	0.2	(4.9)	0.2	(76.8)
Other non-operating income	4.4	2.5	8.8	5
TOTAL OTHER INCOME (EXPENSE)	(26.6)	(32.5)	(54.6)	(143.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	227.6	82.7	229.9	5.3
Income Tax Expense (Benefit)	1.8	1.1	(13.9)	0
Equity in income (loss) of subsidiaries	0	0	0	0
INCOME FROM CONTINUING OPERATIONS	229.4	83.8	216	5.3
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(64.3)	(53.7)	(135.2)	(5)
NET INCOME	165.1	30.1	80.8	0.3
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST	0	1.7	0	3.4
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	165.1	31.8	80.8	3.7
Other comprehensive income (loss)	9.1	4.9	16.8	1.9
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	174.2	36.7	97.6	5.6
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Product	0	0	0	0
Freight and venture partners' cost reimbursements	0	0	0	0
Revenues	0	0	0	0
COST OF GOODS SOLD AND OPERATING EXPENSES	0	0	0	0
SALES MARGIN	0	0	0	0
Selling, general and administrative expenses	(19.7)	(19.7)	(39.8)	(39.2)
Miscellaneous - net	(0.2)	(0.8)	(0.4)	(0.9)
Other operating expense	(19.9)	(20.5)	(40.2)	(40.1)
OPERATING INCOME	(19.9)	(20.5)	(40.2)	(40.1)
Interest expense, net	(30.8)	(30.4)	(62.7)	(72)
Gain (loss) on extinguishment of debt	0.2	(4.9)	0.2	(76.8)
Other non-operating income	(0.8)	(1)	(1.7)	(2)
TOTAL OTHER INCOME (EXPENSE)	(31.4)	(36.3)	(64.2)	(150.8)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(51.3)	(56.8)	(104.4)	(190.9)
Income Tax Expense (Benefit)	2.1	8	(13.5)	0.2
Equity in income (loss) of subsidiaries	210.4	129.6	194.7	243
INCOME FROM CONTINUING OPERATIONS	161.2	80.8	76.8	52.3
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	3.9	(49)	4	(48.6)
NET INCOME		31.8		3.7
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST		0		0
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	165.1	31.8	80.8	3.7
Other comprehensive income (loss)	9.1	5	16.8	2
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	174.2	36.8	97.6	5.7
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Product	672	417	841.2	664.3
Freight and venture partners' cost reimbursements	42.3	54.3	53.1	93.2
Revenues	714.3	471.3	894.3	757.5
COST OF GOODS SOLD AND OPERATING EXPENSES	(429.8)	(326.6)	(548.3)	(563.8)
SALES MARGIN	284.5	144.7	346	193.7
Selling, general and administrative expenses	(5.4)	(5.7)	(9.7)	(10.1)
Miscellaneous - net	(3.6)	(3.7)	(8.9)	(9.2)
Other operating expense	(9)	(9.4)	(18.6)	(19.3)
OPERATING INCOME	275.5	135.3	327.4	174.4
Interest expense, net	(0.6)	0	(1.4)	0
Gain (loss) on extinguishment of debt	0	0	0	0
Other non-operating income	0.2	(0.8)	0.7	(1.6)
TOTAL OTHER INCOME (EXPENSE)	(0.4)	(0.8)	(0.7)	(1.6)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	275.1	134.5	326.7	172.8
Income Tax Expense (Benefit)	(0.1)	0.8	(0.2)	0
Equity in income (loss) of subsidiaries	4.6	3.4	9.1	6.6
INCOME FROM CONTINUING OPERATIONS	279.6	138.7	335.6	179.4
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(0.3)	0.7	(0.1)	0.9
NET INCOME		139.4		180.3
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST		1.7		3.4
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	279.3	141.1	335.5	183.7
Other comprehensive income (loss)	6	5.7	11.9	16.5
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	285.3	146.8	347.4	200.2
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Product	0	0	0	0
Freight and venture partners' cost reimbursements	0	0	0	0
Revenues	0	0	0	0
COST OF GOODS SOLD AND OPERATING EXPENSES	0	0	0	0
SALES MARGIN	0	0	0	0
Selling, general and administrative expenses	(1.1)	(1.2)	(1.8)	(2.4)
Miscellaneous - net	(0.3)	1.6	(0.9)	16.7
Other operating expense	(1.4)	0.4	(2.7)	14.3
OPERATING INCOME	(1.4)	0.4	(2.7)	14.3
Interest expense, net	0.2	0.3	0.5	0.5
Gain (loss) on extinguishment of debt	0	0	0	0
Other non-operating income	5	4.3	9.8	8.6
TOTAL OTHER INCOME (EXPENSE)	5.2	4.6	10.3	9.1
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	3.8	5	7.6	23.4
Income Tax Expense (Benefit)	(0.2)	(7.7)	(0.2)	(0.2)
Equity in income (loss) of subsidiaries	0	0	0	0
INCOME FROM CONTINUING OPERATIONS	3.6	(2.7)	7.4	23.2
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	(67.9)	(5.4)	(139.1)	42.7
NET INCOME		(8.1)		65.9
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST		0		0
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	(64.3)	(8.1)	(131.7)	65.9
Other comprehensive income (loss)	2.2	(1.5)	3	(19.3)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	(62.1)	(9.6)	(128.7)	46.6
Consolidation, Eliminations [Member]
Product	0	0	0	0
Freight and venture partners' cost reimbursements	0	0	0	0
Revenues	0	0	0	0
COST OF GOODS SOLD AND OPERATING EXPENSES	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	0	0	0	0
Interest expense, net	0	0	0	0
Gain (loss) on extinguishment of debt	0	0	0	0
Other non-operating income	0	0	0	0
TOTAL OTHER INCOME (EXPENSE)	0	0	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	0	0	0	0
Income Tax Expense (Benefit)	0	0	0	0
Equity in income (loss) of subsidiaries	(215)	(133)	(203.8)	(249.6)
INCOME FROM CONTINUING OPERATIONS	(215)	(133)	(203.8)	(249.6)
LOSS FROM DISCONTINUED OPERATIONS, NET OF TAX	0	0	0	0
NET INCOME		(133)		(249.6)
LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST		0		0
NET INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	(215)	(133)	(203.8)	(249.6)
Other comprehensive income (loss)	(8.2)	(4.3)	(14.9)	2.7
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO CLIFFS SHAREHOLDERS	$ (223.2)	$ (137.3)	$ (218.7)	$ (246.9)

SUPPLEMENTARY GUARANTOR INFO102

SUPPLEMENTARY GUARANTOR INFORMATION (Supplementary Statements of Condensed Consolidating Cash Flows) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Net cash provided (used) by operating activities	$ (49.3)	$ 67.8
Purchase of property, plant and equipment	(42.1)	(44.3)
Deposits for property, plant and equipment	(72.3)	(5.1)
Intercompany investing	0	0
Proceeds on sales of assets	14.6	1.1
Net cash used by investing activities	(99.8)	(48.3)
Net proceeds from issuance of common shares	0	661.3
Proceeds from issuance of debt	0	500
Debt issuance costs	(1.5)	(8.5)
For the Six Months Ended June 30, 2018	(15.3)	(1,154)
Distributions of partnership equity	0	(8.7)
Intercompany financing	0	0
Other financing activities	(8.9)	(13.9)
Net cash used by financing activities	(25.7)	(23.8)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(1)	2.4
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(175.8)	(1.9)
LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	40.5
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(175.8)	(42.4)
Cash And Cash Equivalents, At Carrying Value, Including Assets Held For Sale	802.5		$ 978.3	$ 270.4	$ 312.8
Reportable Legal Entities [Member] | Cliffs Shareholders Equity [Member]
Net cash provided (used) by operating activities	(82.1)	(128.8)
Purchase of property, plant and equipment	(0.3)	(0.8)
Deposits for property, plant and equipment	0	0
Intercompany investing	(35.2)	43.5
Proceeds on sales of assets	0	0
Net cash used by investing activities	(35.5)	42.7
Net proceeds from issuance of common shares		661.3
Proceeds from issuance of debt		500
Debt issuance costs	(1.5)	(8.5)
For the Six Months Ended June 30, 2018	(15.3)	(1,154)
Distributions of partnership equity		0
Intercompany financing	(14.6)	45
Other financing activities	(1.5)	(0.6)
Net cash used by financing activities	(32.9)	43.2
EFFECT OF EXCHANGE RATE CHANGES ON CASH	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(150.5)	(42.9)
LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(150.5)	(42.9)
Cash And Cash Equivalents, At Carrying Value, Including Assets Held For Sale	798.4		948.9	240.5	283.4
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Net cash provided (used) by operating activities	86.8	106.3
Purchase of property, plant and equipment	(24.9)	(42.7)
Deposits for property, plant and equipment	(3.6)	(5.1)
Intercompany investing	(5.5)	(1.1)
Proceeds on sales of assets	0.4	1.1
Net cash used by investing activities	(33.6)	(47.8)
Net proceeds from issuance of common shares		0
Proceeds from issuance of debt		0
Debt issuance costs	0	0
For the Six Months Ended June 30, 2018	0	0
Distributions of partnership equity		(8.7)
Intercompany financing	(52.7)	(44.3)
Other financing activities	(1)	(5)
Net cash used by financing activities	(53.7)	(58)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(0.5)	0.5
LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(0.5)	0.5
Cash And Cash Equivalents, At Carrying Value, Including Assets Held For Sale	1.6		2.1	3	2.5
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Net cash provided (used) by operating activities	(54)	90.3
Purchase of property, plant and equipment	(16.9)	(0.8)
Deposits for property, plant and equipment	(68.7)	0
Intercompany investing	14.6	(45)
Proceeds on sales of assets	14.2	0
Net cash used by investing activities	(56.8)	(45.8)
Net proceeds from issuance of common shares		0
Proceeds from issuance of debt		0
Debt issuance costs	0	0
For the Six Months Ended June 30, 2018	0	0
Distributions of partnership equity		0
Intercompany financing	93.4	1.9
Other financing activities	(6.4)	(8.3)
Net cash used by financing activities	87	(6.4)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(1)	2.4
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(24.8)	40.5
LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	(40.5)
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	(24.8)	0
Cash And Cash Equivalents, At Carrying Value, Including Assets Held For Sale	2.5		27.3	26.9	26.9
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	26.1	2.6
Proceeds on sales of assets	0	0
Net cash used by investing activities	26.1	2.6
Net proceeds from issuance of common shares		0
Proceeds from issuance of debt		0
Debt issuance costs	0	0
For the Six Months Ended June 30, 2018	0	0
Distributions of partnership equity		0
Intercompany financing	(26.1)	(2.6)
Other financing activities	0	0
Net cash used by financing activities	(26.1)	(2.6)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	0
LESS: INCREASE IN CASH AND CASH EQUIVALENTS CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	0
DECREASE IN CASH AND CASH EQUIVALENTS, INCLUDING CASH CLASSIFIED WITHIN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	$ 0
Cash And Cash Equivalents, At Carrying Value, Including Assets Held For Sale	$ 0		$ 0	$ 0	$ 0

SUPPLEMENTARY GUARANTOR INFO103

SUPPLEMENTARY GUARANTOR INFORMATION (Narrative) (Details) $ in Millions	Jun. 30, 2018USD ($)
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
$1,075 Million 5.75% 2025 Senior Notes [Member]
Debt Instrument, Par Value	$ 1,075
Debt Instrument, Interest Rate, Stated Percentage	5.75%