Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Antidilutive shares excluded from diluted EPS (in shares)	100	400
Earnings (loss) attributable to FMC stockholders:
Continuing operations, net of income taxes	$ 213.7	$ 206.1
Discontinued operations, net of income taxes	(7.5)	9.6
Net income (loss) attributable to FMC stockholders	206.2	215.7
Less: Distributed and undistributed earnings allocable to restricted award holders	(0.5)	(0.7)
Net income (loss) allocable to common stockholders	$ 205.7	$ 215.0
Basic earnings (loss) per common share attributable to FMC stockholders:
Continuing operations (in USD per share)	$ 1.65	$ 1.56
Discontinued operations (in USD per share)	(0.06)	0.07
Net income (loss) attributable to FMC stockholders (in USD per share)	1.59	1.63
Diluted earnings (loss) per common share attributable to FMC stockholders:
Continuing operations (in USD per share)	1.64	1.55
Discontinued operations (in USD per share)	(0.06)	0.07
Net income (loss) attributable to FMC stockholders (in USD per share)	$ 1.58	$ 1.62
Shares (in thousands):
Weighted average number of shares of common stock outstanding - Basic (in shares)	129,527	131,887
Weighted average additional shares assuming conversion of potential common shares (in shares)	939	1,327
Shares – diluted basis (in shares)	130,466	133,214