Discontinued Operations (Details) - USD ($) $ in Millions			3 Months Ended								12 Months Ended
		Apr. 01, 2015	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operations, tax effect of workers' compensation, product liability and other postretirement benefits											$ (1.0)	$ (0.6)	$ (0.2)
Discontinued Operation, Transitional Services Agreement, Period		12 months
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total discontinued operations of FMC ACD, net of income taxes			$ (22.4)	$ (5.0)	$ 688.2	$ 15.6	$ 19.4	$ 6.4	$ 15.3	$ (26.6)	676.4	14.5	(63.6)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Current assets of discontinued operations held for sale (primarily trade receivables and inventories)			0.0				203.3				0.0	203.3
Total Assets	[1],[2]		0.0				604.8				0.0	604.8
Current liabilities of discontinued operations held for sale			0.0				88.4				0.0	88.4
Noncurrent liabilities of discontinued operations held for sale			0.0				4.7				0.0	4.7
Workers’ compensation and product liability reserve			11.2				13.8				11.2	13.8
Reserve for discontinued operations	[3]		46.1				53.3				46.1	53.3
Net pretax actuarial gain and prior service credit			7.6				6.5				7.6	6.5
After-tax actuarial gain and prior service credit			4.1				3.5				4.1	3.5
Estimated pre-tax actuarial gain to be recognized in the next fiscal year											1.4
Estimated prior service credit to be recognized in the next fiscal year											0.3
Payments of other discontinued reserves											24.8	34.2	18.7
Discontinued Operation, tax effect of provision for environmental											(16.7)	(16.4)	(14.2)
Discontinued Operations, tax effect of provision for legal expenses											(6.3)	(8.4)	(5.5)
Discontinued Operation, Tax Effect of Discontinued Operation											(379.0)	(17.3)	(17.0)
Discontinued Operations, tax effect of Peroxygens Segment Operations											0.0	(23.7)	25.1
Workers' Compensation and Product Liability Reserve [Member]
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Workers’ compensation and product liability reserve			6.1				6.8				6.1	6.8
Payments of other discontinued reserves											0.8	0.8	0.9
Other Postretirement Medical and Life Insurance Benefits Reserves [Member]
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Postretirement medical and life insurance benefits reserve, net			9.3				10.0				9.3	10.0
Payments of other discontinued reserves											1.1	1.1	0.9
Legal Proceeding Reserve [Member]
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Reserves for legal proceedings			30.7				$ 36.5				30.7	36.5
Payments of other discontinued reserves											22.9	23.0	8.8
FMC Alkali Chemicals division [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds on sale		$ 1,649.8
Disposal Group, Discontinued Operations, Consideration, after tax		$ 1,198.5
Loss from disposal of FMC Peroxygens											1,080.2
Loss from disposal of FMC Peroxygens, after tax											702.1
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenue											194.0	779.0	744.1
Costs of sales and services											149.2	614.9	604.6
Income (loss) from discontinued operations before income taxes (1)	[4]										1,096.1	121.2	112.7
Provision (Benefit) for income taxes											379.0	17.3	17.0
Total discontinued operations of FMC ACD, net of income taxes											717.1	103.9	95.7
Less: discontinued operations of FMC ACD attributable to noncontrolling interests											0.0	5.2	7.6
Discontinued operations of FMC ACD, net of income taxes, attributable to FMC Stockholders											717.1	98.7	88.1
Profit before tax attributable to noncontrolling interest holders											0.0	5.9	8.7
Interest Allocated to Discontinued Operations											2.2	8.3	5.9
Divestiture related costs											15.0	9.0	0.0
Pension curtailment charge											5.3
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Current assets of discontinued operations held for sale (primarily trade receivables and inventories)			203.3								203.3
Property, plant & equipment	[5]		378.6								378.6
Other non-current assets	[5]		22.9								22.9
Total Assets			604.8								604.8
Current liabilities of discontinued operations held for sale			88.4								88.4
Noncurrent liabilities of discontinued operations held for sale	[5]		4.7								4.7
Total Liabilities			93.1								93.1
Net Assets			$ 511.7								511.7
Discontinued workers' compensation, product liability and other postretirement benefits [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total discontinued operations of FMC ACD, net of income taxes											(1.1)	(4.0)	(16.1)
Discontinued Environmental Liabilities [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total discontinued operations of FMC ACD, net of income taxes	[6]										(28.8)	(36.7)	(23.1)
Discontinued Legal Expenses [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total discontinued operations of FMC ACD, net of income taxes	[7]										(10.8)	(14.3)	(9.0)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Insurance recovery	[7]										0.0	0.0	13.9
FMC Peroxygens [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total discontinued operations of FMC ACD, net of income taxes											$ 0.0	$ (34.4)	$ (111.1)

[1] Segment assets are assets recorded and reported by the segments and are equal to segment operating capital employed plus segment liabilities. See Note 1.

[2] We view operating capital employed, which consists of assets, net of liabilities, reported by our operations and excluding corporate items such as cash equivalents, debt, pension liabilities, income taxes and LIFO reserves, as our primary measure of segment capital.

[3] Included in “Other long-term liabilities” on the consolidated balance sheets. Also refer to Note 7 for discontinued restructuring reserves and Note 10 for discontinued environmental reserves.

[4] For the years ended December 31, 2015, 2014 and 2013, respectively, amounts include approximately zero, $5.9 million and $8.7 million attributable to noncontrolling interests, $2.2 million, $8.3 million and $5.9 million of allocated interest expense, $15.0 million, $9.0 million and zero of divestiture related charges, respectively as well as a $5.3 million pension curtailment charge in 2015. Interest was allocated in accordance with relevant discontinued operations accounting guidance.

[5] Presented as "Noncurrent assets\liabilities of discontinued operations held for sale" on the consolidated balance sheet as of December 31, 2014

[6] See a roll forward of our environmental reserves as well as discussion on significant environmental issues that occurred during the year in Note 10.

[7] Includes a gain of $13.9 million in 2013 associated with an insurance recovery related to previously discontinued operations legal matters. No such gain existed in 2015 or 2014.