Financial Information and Accounting Policies - Adjusted Balance Sheet to Apply Adopted Guidance (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories	$ 1,731.5			$ 1,521.9
Total current assets	5,110.6			5,053.8
Deferred income taxes	184.1			194.1
TOTAL ASSETS	10,764.7			10,673.1
Income taxes	99.3			65.4
Deferred income taxes	351.7			342.4
Retained earnings	5,354.8			5,092.9
Accumulated other comprehensive income (loss)	(542.0)			(325.5)
Total FMC stockholders’ equity	3,188.2			3,124.3
Adoption of accounting standards	3,203.6	$ 3,219.1	$ 3,174.0	3,143.7	$ 3,154.0	$ 3,232.1	$ 3,130.3	$ 2,984.2
TOTAL LIABILITIES AND EQUITY	10,764.7			10,673.1
As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories	1,615.3			1,405.7
Total current assets	4,994.4			4,937.6
Deferred income taxes	208.5			218.5
TOTAL ASSETS	10,672.9			10,581.3
Retained earnings	5,248.8			4,991.3
Accumulated other comprehensive income (loss)	(527.8)			(315.7)
Total FMC stockholders’ equity	3,096.4			3,032.5
Adoption of accounting standards	3,111.8	3,127.3	3,082.2	3,051.9	3,057.0	3,134.1	3,031.3	2,984.2
TOTAL LIABILITIES AND EQUITY	10,672.9			10,581.3
Effect of Change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories	116.2
Total current assets	116.2
Deferred income taxes	(24.4)
TOTAL ASSETS	91.8
Retained earnings	106.0
Accumulated other comprehensive income (loss)	(14.2)
Total FMC stockholders’ equity	91.8
Adoption of accounting standards	91.8
TOTAL LIABILITIES AND EQUITY	91.8
Effect of Change | Combined Effect of Changes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories				116.2
Total current assets				116.2
Deferred income taxes				(24.4)
TOTAL ASSETS				91.8
Retained earnings				101.6
Accumulated other comprehensive income (loss)				(9.8)
Total FMC stockholders’ equity				91.8
Adoption of accounting standards		91.8	91.8	91.8	97.0	98.0	99.0	100.0
TOTAL LIABILITIES AND EQUITY				91.8
Effect of Change | Effect of FIFO Change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories				116.2
Total current assets				116.2
Deferred income taxes				(24.4)
TOTAL ASSETS				91.8
Retained earnings				91.8
Accumulated other comprehensive income (loss)				0.0
Total FMC stockholders’ equity				91.8
Adoption of accounting standards		91.8	91.8	91.8	97.0	98.0	99.0	100.0
TOTAL LIABILITIES AND EQUITY				91.8
Effect of Change | Effect of Pension Change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories				0.0
Total current assets				0.0
Deferred income taxes				0.0
TOTAL ASSETS				0.0
Retained earnings				9.8
Accumulated other comprehensive income (loss)				(9.8)
Total FMC stockholders’ equity				0.0
Adoption of accounting standards	$ 91.8	$ 0.0	$ 0.0	0.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0
TOTAL LIABILITIES AND EQUITY				$ 0.0