Equity - Summary of Capital Stock Activity (Details) - shares	9 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Capital Stock Activity [Roll Forward]
Beginning balance (in shares)	146,085,696
Ending balance (in shares)	146,410,139
Treasury Stock [Roll Forward]
Beginning balance (in shares)	(104,012)
Purchases of Treasury Stock - deferred compensation plan (in shares)	(3,610)
Ending balance (in shares)	(107,622)
Common stock outstanding
Outstanding (in shares)	146,302,517	145,981,684
FMC Plan \| Restricted Stock Units (RSUs)
Capital Stock Activity [Roll Forward]
Stock issued during period (in shares)	131,648
Livent Plan
Capital Stock Activity [Roll Forward]
Stock issued during period (in shares)	69,284
Livent Plan \| Restricted Stock Units (RSUs)
Capital Stock Activity [Roll Forward]
Stock issued during period (in shares)	123,511

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Treasury Stock [Roll Forward]

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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