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Financial Instruments and Risk Management (Fair Value And Presentation in the Balance Sheet) (Details) - Derivatives - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021
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Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value | $ (4.3) | $ 3.0
Currency Hedging Derivative Instruments |  |
Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value |  | 2.6
Financial liabilities, at fair value | (4.3) |
Fuel Options |  |
Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value | 0.0 | 0.4
Gold Options |  |
Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value |  | $ 0.5
Financial liabilities, at fair value | $ 0.1 |

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