Restructuring and Other Charges (Income) - Activity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Severance and Employee Benefits	$ 5.6	$ 2.7
Other Charges (Income)	0.3	1.0
Asset Disposal Charges	0.7	1.5
Total	6.6	5.2
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	14.6
Change in reserves	5.9
Cash payments	(1.9)
Restructuring Reserve, Ending Balance	18.6
Environmental charges, net	6.4	2.6
Other items, net	0.4	0.0
Other charges (income), net	6.8	2.6
DuPont Crop restructuring
Restructuring Cost and Reserve [Line Items]
Severance and Employee Benefits	5.6	2.7
Other Charges (Income)	0.3	1.0
Asset Disposal Charges	1.1	0.2
Total	7.0	3.9
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	14.5
Change in reserves	5.9
Cash payments	(1.9)
Restructuring Reserve, Ending Balance	18.5
Other items
Restructuring Cost and Reserve [Line Items]
Severance and Employee Benefits	0.0	0.0
Other Charges (Income)	0.0	0.0
Asset Disposal Charges	(0.4)	1.3
Total	(0.4)	$ 1.3
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	0.1
Change in reserves	0.0
Cash payments	0.0
Restructuring Reserve, Ending Balance	$ 0.1