Statements Of Condensed Consolidated Comprehensive Income - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Statement of Comprehensive Income [Abstract] | Ìý | Ìý | Ìý |
| NET INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS | $ 367.0 | $ 174.1 | $ (749.3) |
| OTHER COMPREHENSIVE INCOME (LOSS) | Ìý | Ìý | Ìý |
| Pension and OPEB liability, net of tax | 11.5 | (19.8) | 45.2 |
| Unrealized net gain on marketable securities, net of tax | 0.0 | 0.0 | 1.7 |
| Unrealized net gain (loss) on foreign currency translation | (13.9) | 18.6 | 155.6 |
| Unrealized net gain (loss) on derivative financial instruments, net of tax | (0.5) | (2.6) | 20.7 |
| OTHER COMPREHENSIVE INCOME (LOSS) | (2.9) | (3.8) | 223.2 |
| OTHER COMPREHENSIVE LOSS (INCOME) ATTRIBUTABLE TO THE NONCONTROLLING INTEREST | 1.1 | (0.5) | (4.6) |
| TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO CLIFFS SHAREHOLDERS | $ 363.0 | $ 170.8 | $ (521.5) |
| X | ||||||||||
- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount after tax of other comprehensive income (loss) attributable to noncontrolling interests. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|