Quarterly report pursuant to Section 13 or 15(d)

EARNINGS PER SHARE (Earnings Per Share Computation) (Details)

v2.4.1.9
EARNINGS PER SHARE (Earnings Per Share Computation) (Details) (USD $)
In Millions, except Share data in Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Income (Loss) from Continuing Operations Attributable to Parent $ 168.7us-gaap_IncomeLossFromContinuingOperations $ 70.1us-gaap_IncomeLossFromContinuingOperations
LOSS FROM DISCONTINUED OPERATIONS, net of tax (928.5)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax (140.4)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
Net Loss Attributable to Cliffs Shareholders (759.8)us-gaap_NetIncomeLoss (70.3)us-gaap_NetIncomeLoss
PREFERRED STOCK DIVIDENDS (12.8)us-gaap_DividendsPreferredStock (12.8)us-gaap_DividendsPreferredStock
NET INCOME ATTRIBUTABLE TO CLIFFS COMMON SHAREHOLDERS (772.6)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic (83.1)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Earnings (Loss) Per Common Share Attributable to Cliffs Common Shareholders - Basic    
Continuing operations $ 1.02us-gaap_IncomeLossFromContinuingOperationsPerBasicShare $ 0.37us-gaap_IncomeLossFromContinuingOperationsPerBasicShare
Discontinued operations $ (6.06)us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare $ (0.92)us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Basic: $ (5.04)us-gaap_EarningsPerShareBasic $ (0.55)us-gaap_EarningsPerShareBasic
Earnings (Loss) Per Common Share Attributable to Cliffs Shareholders - Diluted    
Continuing operations $ 0.94us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare $ 0.37us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare
Discontinued operations $ (5.20)us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare $ (0.91)us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare
Earnings (Loss) per Common Share Attributable to Cliffs Common Shareholders - Diluted: $ (4.26)us-gaap_EarningsPerShareDiluted $ (0.54)us-gaap_EarningsPerShareDiluted
Weighted Average Number of Shares:    
Basic 153,185us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 153,040us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Depositary Shares 25,215clf_WeightedAverageNumberOfSharesOustandingDepositary 0clf_WeightedAverageNumberOfSharesOustandingDepositary
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements 296us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements 613us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements
Diluted 178,696us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 153,653us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Preferred Class A [Member]    
PREFERRED STOCK DIVIDENDS $ (12.8)us-gaap_DividendsPreferredStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredClassAMember
$ (12.8)us-gaap_DividendsPreferredStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredClassAMember