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Derivative Financial Instruments and Hedging (Details2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024	Dec. 29, 2024
Cash Flow Hedging
Derivatives Fair Value [Line Items]
Amount of gain (loss) reclassified from accumulated OCI into Income	$ (1.2)	$ (2.0)	$ (2.0)	$ (3.3)
Cash Flow Hedging \| Other Comprehensive Income (Loss) [Member]
Derivatives Fair Value [Line Items]
Net derivative gain (loss) on hedge transactions	(3.4)	(0.4)	1.5	(1.8)
Nickel and other raw material contracts \| Cash Flow Hedging
Derivatives Fair Value [Line Items]
Amount of gain (loss) reclassified from accumulated OCI into Income	(1.2)	(1.1)	(2.2)	(1.1)
Nickel and other raw material contracts \| Cash Flow Hedging \| Other Comprehensive Income (Loss) [Member]
Derivatives Fair Value [Line Items]
Net derivative gain (loss) on hedge transactions	(1.4)	(0.9)	(0.7)	(1.1)
Interest Rate Swap \| Cash Flow Hedging
Derivatives Fair Value [Line Items]
Amount of gain (loss) reclassified from accumulated OCI into Income	0.0	0.9	0.0	1.2
Interest Rate Swap \| Cash Flow Hedging \| Other Comprehensive Income (Loss) [Member]
Derivatives Fair Value [Line Items]
Net derivative gain (loss) on hedge transactions	0.0	0.0	0.0	0.0
Natural gas contracts \| Cash Flow Hedging
Derivatives Fair Value [Line Items]
Amount of gain (loss) reclassified from accumulated OCI into Income	0.0	(1.8)	0.1	(3.6)
Natural gas contracts \| Cash Flow Hedging \| Other Comprehensive Income (Loss) [Member]
Derivatives Fair Value [Line Items]
Net derivative gain (loss) on hedge transactions	(1.9)	0.4	2.4	(1.0)
Foreign exchange contracts \| Cash Flow Hedging
Derivatives Fair Value [Line Items]
Amount of gain (loss) reclassified from accumulated OCI into Income	0.0	0.0	0.1	0.2
Foreign exchange contracts \| Cash Flow Hedging \| Other Comprehensive Income (Loss) [Member]
Derivatives Fair Value [Line Items]
Net derivative gain (loss) on hedge transactions	(0.1)	$ 0.1	(0.2)	$ 0.3
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	3.1		3.1		$ 1.9
Derivative Fair Value Of Derivative Liability	2.6		2.6		6.0
Designated as Hedging Instrument \| Nickel and other raw material contracts \| Accrued liabilities
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	2.2		2.2		4.2
Designated as Hedging Instrument \| Nickel and other raw material contracts \| Other long-term liabilities
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0.1		0.1		0.0
Designated as Hedging Instrument \| Natural gas contracts \| Prepaid expenses and other current assets
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	2.3		2.3		0.8
Designated as Hedging Instrument \| Natural gas contracts \| Other assets
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0.8		0.8		0.9
Designated as Hedging Instrument \| Natural gas contracts \| Accrued liabilities
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0.2		0.2		1.7
Designated as Hedging Instrument \| Natural gas contracts \| Other long-term liabilities
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	0.0		0.0		0.1
Designated as Hedging Instrument \| Foreign exchange contracts \| Prepaid expenses and other current assets
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Asset	0.0		0.0		0.2
Designated as Hedging Instrument \| Foreign exchange contracts \| Accrued liabilities
Derivatives Fair Value [Line Items]
Derivative Fair Value Of Derivative Liability	$ 0.1		$ 0.1		$ 0.0