Earnings Per Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings Per Share [Abstract]
Antidilutive shares excluded from diluted EPS																	215,406	0	278,173
Amounts attributable to FMC stockholders:
Continuing operations, net of income taxes	$ 86.5		$ 93.1		$ 116.1		$ 102.0		$ (45.2)		$ 83.2		$ 85.0		$ 83.1		$ 397.7	$ 206.1	$ 246.7
Discontinued operations, net of income taxes	(8.6)		(6.3)		(8.9)		(8.0)		(8.3)		(0.3)		(19.3)		(5.7)		(31.8)	(33.6)	(18.2)
Net income attributable to FMC stockholders	77.9		86.8		107.2		94.0		(53.5)		82.9		65.7		77.4		365.9	172.5	228.5
Less: Distributed and undistributed earnings allocable to restricted award holders																	(1.7)	(1.0)	(1.1)
Net income allocable to common stockholders																	$ 364.2	$ 171.5	$ 227.4
Basic earnings per common share attributable to FMC stockholders:
Continuing operations	$ 1.23		$ 1.31		$ 1.61		$ 1.42		$ (0.63)		$ 1.14		$ 1.17		$ 1.14		$ 5.58	$ 2.84	$ 3.40
Discontinued operations	$ (0.12)		$ (0.09)		$ (0.12)		$ (0.11)		$ (0.11)		$ 0.00		$ (0.27)		$ (0.08)		$ (0.45)	$ (0.46)	$ (0.25)
Net income	$ 1.11	[1]	$ 1.22	[1]	$ 1.49	[1]	$ 1.31	[1]	$ (0.74)	[1]	$ 1.14	[1]	$ 0.90	[1]	$ 1.06	[1]	$ 5.13	$ 2.38	$ 3.15
Diluted earnings per common share attributable to FMC stockholders:
Continuing operations	$ 1.22		$ 1.30		$ 1.61		$ 1.41		$ (0.63)		$ 1.14		$ 1.16		$ 1.14		$ 5.54	$ 2.82	$ 3.37
Discontinued operations	$ (0.12)		$ (0.09)		$ (0.12)		$ (0.11)		$ (0.11)		$ (0.01)		$ (0.26)		$ (0.08)		$ (0.44)	$ (0.46)	$ (0.25)
Net income	$ 1.10	[1]	$ 1.21	[1]	$ 1.49	[1]	$ 1.30	[1]	$ (0.74)	[1]	$ 1.13	[1]	$ 0.90	[1]	$ 1.06	[1]	$ 5.10	$ 2.36	$ 3.12
Shares:
Weighted average number of shares of common stock outstanding - Basic	70,200,000		71,000,000		71,600,000		71,500,000		71,800,000		72,300,000		72,500,000		72,300,000		71,028,000	72,210,000	72,163,000
Weighted average additional shares assuming conversion of potential common shares																	626,000	870,000	1,138,000
Shares – diluted basis	70,700,000		71,500,000		72,200,000		72,100,000		71,800,000		73,100,000		73,400,000		73,300,000		71,654,000	73,080,000	73,301,000

[1] The sum of quarterly earnings per common share may differ from the full-year amount.