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Marketable Securities - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract] |  |  |  |
Marketable securities, realized gain (loss) | $ 0.0 | $ 0.0 | $ 0.0 |
Marketable securities, realized gain |  |  |  | $ 28.5
Marketable securities, realized loss |  |  |  | $ 0.0

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- Definition Marketable Securities, Realized Gain + References No definition available. + Details
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- Definition Marketable Securities, Realized Loss + References No definition available. + Details
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- Definition Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). + References No definition available. + Details
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