Derivative Financial Instruments and Hedging - Schedule of Derivative Instruments Gain (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gain (loss) on hedge transactions	$ 53.8	$ 15.5	$ (2.8)
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (a)	42.8	11.4	$ (6.0)
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gain (loss) on hedge transactions	41.0	11.7
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)	32.6	8.7
Nickel and other raw material contracts [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gain (loss) on hedge transactions	27.1	6.2
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)	20.5	5.4
Natural gas contracts [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gain (loss) on hedge transactions	10.9	5.2
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)	11.5	4.0
Foreign Exchange Contract [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gain (loss) on hedge transactions	0.7	0.2
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)	0.7	0.1
Interest Rate Swap [Member] | Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gain (loss) on hedge transactions	2.3	0.1
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)	$ (0.1)	$ (0.8)