Pension and Other Post-Retirement Benefit Plans Pension and Other Post-Retirement Benefit Plans (Defined Contribution Plans Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Contribution Plan Disclosure [Line Items]
Nonelective contribution vesting period	3 years
Deferred compensation investments	$ 28.4	$ 35.8
FMC Technologies stock held in trust	7.0	8.0
Non Qualified Deferred Compensation Plan
Defined Contribution Plan Disclosure [Line Items]
Deferred compensation liability	29.0	38.5
Deferred compensation investments	24.4	30.7
Matching Contribution
Defined Contribution Plan Disclosure [Line Items]
Expenses recognized	27.6	28.4	$ 23.5
Nonelective Contributions
Defined Contribution Plan Disclosure [Line Items]
Expenses recognized	$ 17.7	$ 18.9	$ 16.2
Maximum
Defined Contribution Plan Disclosure [Line Items]
Requisite service period for current nonunion employee	5 years