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Derivatives - Narrative (Details) € in Millions, $ in Millions, kr in Billions	12 Months Ended
	Dec. 31, 2022 USD ($) MWh t	Dec. 31, 2022 EUR (€)	Dec. 31, 2022 ISK (kr)	Dec. 31, 2021 USD ($)
Supply Commitment [Line Items]
Restricted cash \| $	$ 0.0			$ 8.6
LME Swap
Supply Commitment [Line Items]
Open position to offset fixed prices \| t	111,741
Fixed to Floating Swap
Supply Commitment [Line Items]
Open position to offset fixed prices \| t	946
FX Swap
Supply Commitment [Line Items]
Derivative asset \| €		€ 32.7
Nordpool Power Price Swap
Supply Commitment [Line Items]
Realized gain \| $	$ 16.0
Derivative liability (in MwH) \| MWh	989,880
Indiana Hub Power Price Swaps
Supply Commitment [Line Items]
Derivative liability (in MwH) \| MWh	175,200
USD ISK Forward Swap \| Not Designated as Hedging Instrument \| Short
Supply Commitment [Line Items]
Derivative, forward contracts \| kr			kr 5.5
USD Euro Forward Swap \| Not Designated as Hedging Instrument \| Long
Supply Commitment [Line Items]
Derivative, forward contracts \| €		€ 8.9