AOCI (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	$ 0.7	$ 2.5
Derivative Instruments Gain Loss Reclassified From Accumulated OCI Into Income Effective Portion Net	(0.4)
OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeTax	(0.3)
OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsAndTaxAbstract
OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostRecognizedInNetPeriodicBenefitCostBeforeTax	3.8	2.9
Other Comprehensive Income Reclassification Of Defined Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Before Tax	33.5	29.9
Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax	11.5	10.3
Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax	18.2	16.7
[NickelAndOtherRawMaterialContractsMember]
OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	0.1
[ForeignExchangeContractMember]
OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	1.2
[NaturalGasContractsMember]
OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	(1.7)
[ElectricityContractsMember]
OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	$ (0.3)