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Financial Instruments and Risk Management (Fair Value for Assets and Liabilities Narrative) (Details) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2023 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Disclosure of detailed information about financial instruments [line items] |  |  |
Probability factor |  | 25.00% | 75.00%
Decrease in fair value of milestone payments | $ 11.0 |  |
Discount rate, milestone payments | 0.1475 | 0.1475 |
Profit (loss) before tax |  | $ 293.7 | $ 102.4
Change in Assumptions, Effect |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Profit (loss) before tax |  | $ 0.8 |

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