Pensions and Other Postretirement Benefits (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Components of net annual benefit cost (income):
Recognized loss due to curtailment							$ (5.3)
Pension Plan [Member]
Components of net annual benefit cost (income):
Service cost		$ 2.6		$ 3.5		$ 5.3	7.6
Interest cost		12.7		15.3		25.4	30.7
Expected return on plan assets		(21.9)		(22.3)		(43.7)	(44.5)
Amortization of prior service cost (credit)		0.2		0.2		0.4	0.5
Recognized net actuarial and other (gain) loss		10.3		15.2		20.5	28.2
Recognized loss due to curtailment	[1]	0.0		0.0		0.0	4.8
Net periodic benefit cost		3.9	[2]	11.9	[2]	7.9	27.3
Other Benefits
Components of net annual benefit cost (income):
Service cost		0.0		0.0		0.0	0.0
Interest cost		0.2		0.2		0.4	0.5
Expected return on plan assets		0.0		0.0		0.0	0.0
Amortization of prior service cost (credit)		0.0		0.0		0.0	0.1
Recognized net actuarial and other (gain) loss		(0.3)		(0.2)		(0.5)	(0.5)
Recognized loss due to curtailment	[1]	0.0		0.0		0.0	0.5
Net periodic benefit cost		(0.1)	[2]	$ 0.0	[2]	(0.1)	0.6
U.S. Defined Benefit Pension Plan
Pension and Other Postretirement Benefit Contributions [Abstract]
Voluntary cash contributions made to U.S. defined benefit pension plan						21.0	$ 49.0
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year, Voluntary Cash Contributions		$ 35.0				$ 35.0

[1] Curtailment loss is associated with the disposal of our FMC Alkali Chemicals division and was recorded to discontinued operations within the condensed consolidated statements of income (loss).

[2] Net periodic benefit cost represents both continuing and discontinued operations.