Derivative Financial Instruments and Hedging (Details2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	$ 15.4	$ 6.2
Derivative Fair Value Of Derivative Liability	6.0	11.8
[DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	14.8	5.8
Derivative Fair Value Of Derivative Liability	5.5	10.2
[NondesignatedMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0.6	0.4
Derivative Fair Value Of Derivative Liability	0.5	1.6
[PrepaidExpensesAndOtherCurrentAssetsMember] | [NickelAndOtherRawMaterialContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0.1	0.6
[PrepaidExpensesAndOtherCurrentAssetsMember] | [ForeignExchangeContractMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	7.5	2.9
[PrepaidExpensesAndOtherCurrentAssetsMember] | [ForeignExchangeContractMember] | [NondesignatedMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0.6	0.4
[PrepaidExpensesAndOtherCurrentAssetsMember] | [NaturalGasContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	1.8	0.4
[PrepaidExpensesAndOtherCurrentAssetsMember] | [ElectricityContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0	0
[OtherAssetsMember] | [NickelAndOtherRawMaterialContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0.1	0.3
[OtherAssetsMember] | [ForeignExchangeContractMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	4.6	0.9
[OtherAssetsMember] | [NaturalGasContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0.7	0.7
[OtherAssetsMember] | [ElectricityContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0	0
[AccruedLiabilitiesMember] | [NickelAndOtherRawMaterialContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	2.6	1.1
[AccruedLiabilitiesMember] | [ForeignExchangeContractMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0	1.7
[AccruedLiabilitiesMember] | [ForeignExchangeContractMember] | [NondesignatedMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0.5	1.6
[AccruedLiabilitiesMember] | [NaturalGasContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	1.8	4.4
[AccruedLiabilitiesMember] | [ElectricityContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0	0.3
[OtherLiabilitiesMember] | [NickelAndOtherRawMaterialContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0.4	0.3
[OtherLiabilitiesMember] | [ForeignExchangeContractMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0	1.4
[OtherLiabilitiesMember] | [NaturalGasContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0.4	0.6
[OtherLiabilitiesMember] | [ElectricityContractsMember] | [DesignatedAsHedgingInstrumentMember]
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	$ 0.3	$ 0.4