Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Purchase of Noncontrolling Interest	6.25%
Acquisition of noncontrolling interests					$ (80.0)	[1]	$ 0	[1]
Payments of Ordinary Dividends, Common Stock					37.1	[1]	22.9	[1]
Common Stock, Dividends, Per Share, Declared					$ 0.135
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity, beginning balance					1,554.8
Net Income	121.2		110.3		256.2		234.9
Stock compensation plans					17.9
Excess tax benefit from share-based compensation					6.3
Shares for benefit plan trust					0.5
Net unrealized pension and other benefit actuarial gains/(losses) and prior service (cost) credits	10.2		9.2		21.6	[2]	16.2
Unrealized hedging gains/(losses) and other	(10.8)		(0.3)		(5.3)	[2]	0.9
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	1.1	[3]	(29.4)	[3]	(13.5)	[2],[3]	(18.2)	[3]
Dividends					(37.0)
Shares repurchased, value					(116.3)
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent					(80.0)	[4]
Distributions to noncontrolling interests					(6.6)		(7.0)
Total equity, ending balance	1,598.6				1,598.6
Dividends, payment date	Jul. 18, 2013
Dividends payable, current	18.5				18.5
Dividends, record date	Jun. 28, 2013
Remaining authorized repurchase amount					500
Stock Repurchase Program, Authorized Amount	500
Previous Unsued Board Authorized Repurchase Amount					134.9
Shares repurchased	1,843,200
Treasury Stock, Value, Acquired, Cost Method	109.9
Noncontrolling Interest, Ownership Percentage by Parent	93.75%				93.75%				87.50%
FMC's Stockholders' Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity, beginning balance					1,480.3
Net Income					248.9
Stock compensation plans					17.9
Excess tax benefit from share-based compensation					6.3
Shares for benefit plan trust					0.5
Net unrealized pension and other benefit actuarial gains/(losses) and prior service (cost) credits					21.6	[2]
Unrealized hedging gains/(losses) and other					(5.3)	[2]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax					(14.1)	[2]
Dividends					(37.0)
Shares repurchased, value					(116.3)
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent					(55.2)	[4]
Distributions to noncontrolling interests					0
Total equity, ending balance	1,547.6				1,547.6
Non-controlling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity, beginning balance					74.5
Net Income					7.3
Stock compensation plans					0
Excess tax benefit from share-based compensation					0
Shares for benefit plan trust					0
Net unrealized pension and other benefit actuarial gains/(losses) and prior service (cost) credits					0	[2]
Unrealized hedging gains/(losses) and other					0	[2]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax					0.6	[2]
Dividends					0
Shares repurchased, value					0
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent					(24.8)	[4]
Distributions to noncontrolling interests					(6.6)
Total equity, ending balance	$ 51.0				$ 51.0

[1] See Note 13 regarding quarterly cash dividend and acquisition of noncontrolling interest.

[2] See Condensed Consolidated Statements of Comprehensive Income.

[3] Income taxes are not provided on the equity in undistributed earnings of our foreign subsidiaries or affiliates since it is our intention that such earnings will remain invested in those affiliates permanently.

[4] See "FMC Wyoming" discussion below.