Discontinued Operations - Components of Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, net of income taxes	$ (33.5)	$ (21.3)	$ (18.1)	$ 9.6	$ (122.1)	$ 23.9	$ 32.7	$ 39.4	$ (63.3)	$ (26.1)	$ 671.5
Adjustment for workers' compensation, product liability, and other postretirement benefits and other, tax									(23.9)	(5.2)	(0.1)
Provision for environmental liabilities, net of recoveries, tax									6.3	32.5	24.9
Provision for legal reserves and expenses, net of recoveries, tax									6.3	6.9	7.2
Adjustment for workers’ compensation, product liability, and other postretirement benefits and other, net of income tax benefit (expense)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, net of income taxes									4.3	(1.7)	3.0
Provision for environmental liabilities, net of recoveries, net of income tax benefit (expense)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, net of income taxes									(23.5)	(121.4)	(51.2)
Provision for legal reserves and expenses, net of recoveries, net of income tax benefit (expense)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, net of income taxes									(23.3)	(26.3)	(13.4)
FMC Health and Nutrition
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, net of income taxes									0.5	6.0	683.3
Discontinued operations, tax									(0.2)	(7.1)	(180.1)
FMC Lithium
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, net of income taxes									(21.3)	117.3	49.8
Discontinued operations, tax									$ (12.3)	$ (18.0)	$ (35.2)