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Derivative Financial Instruments and Hedging - Schedule of Derivative Instruments Gain (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		$ 15.5	$ (2.8)	$ 9.7
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (a)		11.4	(6.0)	$ 4.1
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		11.7	(2.0)
Cost of Sales and Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (a)	[1]	8.7	(4.6)
Nickel and other raw material contracts [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		6.2	0.0
Nickel and other raw material contracts [Member] | Cost of Sales [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (a)	[1]	5.4	(0.6)
Natural gas contracts [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		5.2	(0.1)
Natural gas contracts [Member] | Cost of Sales [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (a)	[1]	4.0	(2.8)
Foreign Exchange Contract [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		0.2	(0.1)
Foreign Exchange Contract [Member] | Cost of Sales [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (a)	[1]	0.1	(0.1)
Interest Rate Swap [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		0.1	(1.8)
Interest Rate Swap [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (a)	[1]	$ (0.8)	$ (1.1)
[1] The gains (losses) reclassified from accumulated OCI into income related to the derivatives, with the exception of the interest rate swap, are presented in cost of sales in the same period or periods in which the hedged item affects earnings. The gains (losses) reclassified from accumulated OCI into income on the interest rate swap are presented in interest expense in the same period as the interest expense on the Term Loan is recognized in earnings.

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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