XML 55 R56.htm IDEA: XBRL DOCUMENT v2.4.1.9
Investments in Affiliates (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Oct. 04, 2011
Combined Metals of Chicago, LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity method investment, ownership percentage (in hundredths) 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_CombinedMetalsofChicagoLLCMember
     
Delaco Processing, LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity method investment, ownership percentage (in hundredths) 49.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_DelacoProcessingLLCMember
     
Double Eagle Steel Coating Company [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity method investment, ownership percentage (in hundredths) 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_DoubleEagleSteelCoatingCompanyMember
[1]      
Magnetation LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity method investment, ownership percentage (in hundredths) 49.90%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_MagnetationLlcMember
     
Payments to Acquire Equity Method Investments $ 100.0us-gaap_PaymentsToAcquireEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_MagnetationLlcMember
     
Other Commitment       297.5us-gaap_OtherCommitment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_MagnetationLlcMember
Difference between carrying amount and underlying equity 118.0us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_MagnetationLlcMember
     
Rockport Roll Shop LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity method investment, ownership percentage (in hundredths) 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_RockportRollShopLLCMember
     
Spartan Steel Coating, LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity method investment, ownership percentage (in hundredths) 48.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_SpartanSteelCoatingLLCMember
     
Difference between carrying amount and underlying equity 15.0us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= aks_SpartanSteelCoatingLLCMember
     
Other Income (Expense) [Member]        
Schedule of Equity Method Investments [Line Items]        
Share of income (loss) from equity method investments (15.2)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_OtherNonoperatingIncomeExpenseMember
(4.9)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_OtherNonoperatingIncomeExpenseMember
7.7us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_OtherNonoperatingIncomeExpenseMember
 
Cost of Products Sold [Member]        
Schedule of Equity Method Investments [Line Items]        
Share of income (loss) from equity method investments $ 11.7us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
$ 8.1us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
$ 7.4us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
 
[1] Double Eagle Steel Coating Company (“DESCCO”) is a joint venture between United States Steel Corporation (“US Steel”) and AK Steel that was acquired as part of the Dearborn acquisition. See Note 10 for information on a dispute with US Steel regarding DESCCO.