SEGMENT REPORTING (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
|
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| NET INCOME | $ 437.8 | $ 165.1 | $ (84.3) | $ 52.9 | $ 30.1 | $ (29.8) | $ 518.6 | $ 53.2 |
| Revenues | 741.8 | Ìý | Ìý | 596.7 | Ìý | Ìý | 1,636.1 | 1,354.2 |
| SALES MARGIN | 261.6 | Ìý | Ìý | 157.8 | Ìý | Ìý | 607.6 | 351.5 |
| Other operating expense | (36.1) | Ìý | Ìý | (29.1) | Ìý | Ìý | (97.6) | (74.2) |
| TOTAL OTHER INCOME (EXPENSE) | (25.2) | Ìý | Ìý | (113.6) | Ìý | Ìý | (79.8) | (256.9) |
| INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES | 200.3 | Ìý | Ìý | 15.1 | Ìý | Ìý | 430.2 | 20.4 |
| Interest expense, net | (29.5) | Ìý | Ìý | (27.6) | Ìý | Ìý | (93.1) | (99.1) |
| Income Tax Expense (Benefit) | 0.5 | Ìý | Ìý | (7.2) | Ìý | Ìý | 14.4 | (7.2) |
| Depreciation, depletion and amortization | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | (68.6) | (66.3) |
| EBITDA | 487.2 | Ìý | Ìý | 95.7 | Ìý | Ìý | 697.1 | 215.8 |
| INCOME FROM DISCONTINUED OPERATIONS, NET OF TAX | 238.0 | Ìý | Ìý | 30.6 | Ìý | Ìý | 102.8 | 25.6 |
| Foreign currency transaction gain (loss), before tax | (0.2) | Ìý | Ìý | (1.3) | Ìý | Ìý | (0.7) | 14.0 |
| Gain (loss) on extinguishment of debt | 0.0 | Ìý | Ìý | (88.6) | Ìý | Ìý | 0.2 | (165.4) |
| Impairment Charges | (1.1) | Ìý | Ìý | 0.0 | Ìý | Ìý | (1.1) | 0.0 |
| Adjusted EBITDA | 250.3 | Ìý | Ìý | 150.8 | Ìý | Ìý | 578.3 | 325.9 |
| Property, Plant and Equipment, Additions | 92.6 | Ìý | Ìý | 26.3 | Ìý | Ìý | 241.9 | 78.0 |
| Payments To Acquire Property Plant And Equipment Net | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | (194.7) | (77.4) |
| Payments to Acquire Property, Plant, and Equipment | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 83.3 | 16.2 |
| Capital Expenditures Incurred but Not yet Paid | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 42.2 | 0.6 |
| Government grant rebate | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 2.5 | 0.0 |
| Capital Lease Obligations Incurred | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 7.6 | 0.0 |
| U.S. Iron Ore [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Revenues | $ 741.8 | Ìý | Ìý | $ 596.7 | Ìý | Ìý | $ 1,636.1 | $ 1,354.2 |
| Percentage Of Segment Revenue | 100.00% | Ìý | Ìý | 100.00% | Ìý | Ìý | 100.00% | 100.00% |
| SALES MARGIN | $ 261.6 | Ìý | Ìý | $ 157.8 | Ìý | Ìý | $ 607.6 | $ 351.5 |
| Depreciation, depletion and amortization | (17.8) | Ìý | Ìý | (16.5) | Ìý | Ìý | (49.2) | (49.6) |
| EBITDA | 273.1 | Ìý | Ìý | 168.9 | Ìý | Ìý | 641.6 | 381.8 |
| Adjusted EBITDA | 279.5 | Ìý | Ìý | 174.2 | Ìý | Ìý | 657.9 | 399.8 |
| Property, Plant and Equipment, Additions | 51.8 | Ìý | Ìý | 19.2 | Ìý | Ìý | 97.2 | 70.9 |
| All Segments | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Depreciation, depletion and amortization | (19.2) | Ìý | Ìý | (18.2) | Ìý | Ìý | (53.4) | (55.0) |
| EBITDA | 214.1 | Ìý | Ìý | (73.2) | Ìý | Ìý | 55.5 | (166.0) |
| Adjusted EBITDA | (29.2) | Ìý | Ìý | (23.4) | Ìý | Ìý | (79.6) | (73.9) |
| Corporate and Other [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Depreciation, depletion and amortization | (1.4) | Ìý | Ìý | (1.7) | Ìý | Ìý | (4.2) | (5.4) |
| Property, Plant and Equipment, Additions | 40.8 | Ìý | Ìý | 7.1 | Ìý | Ìý | 144.7 | 7.1 |
| EBITDA Calculation [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Interest expense, net | (29.7) | Ìý | Ìý | (28.9) | Ìý | Ìý | (95.5) | (103.1) |
| Income Tax Expense (Benefit) | (0.5) | Ìý | Ìý | 7.6 | Ìý | Ìý | (14.4) | 6.8 |
| Depreciation, depletion and amortization | (19.2) | Ìý | Ìý | (21.5) | Ìý | Ìý | (68.6) | (66.3) |
| Adjusted EBITDA Calculation [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| INCOME FROM DISCONTINUED OPERATIONS, NET OF TAX | $ 238.2 | Ìý | Ìý | $ 34.8 | Ìý | Ìý | $ 120.4 | $ 41.3 |
| X | ||||||||||
- Definition Adjusted Earnings Before Interest, Taxes and Depreciation, Depletion and Amortization No definition available.
|
| X | ||||||||||
- Definition Earnings before Interest, Taxes, and Depreciation, Depletion and Amortization No definition available.
|
| X | ||||||||||
- Definition Government grant rebate No definition available.
|
| X | ||||||||||
- Definition Impairment charges including, but not limited to, impairment charges related to intangible and tangible assets, investment, and goodwill. No definition available.
|
| X | ||||||||||
- Definition Payments To Acquire Property Plant And Equipment, Net No definition available.
|
| X | ||||||||||
- Definition Percentage of Segment Revenue No definition available.
|
| X | ||||||||||
- Definition Future cash outflow to pay for purchases of fixed assets that have occurred. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The increase during the period in capital lease obligations due to entering into new capital leases. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition The net amount of operating interest income (expense). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. No definition available.
|
| X | ||||||||||
- Definition The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. No definition available.
|
| X | ||||||||||
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|