Restructuring and Other Charges (Income) - Activity (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Severance and Employee Benefits	$ 0.8	$ 0.9	$ 9.6	$ 7.1
Other Charges (Income)	2.1	1.3	3.4	3.3
Asset Disposal Charges (Income)	4.0	0.4	16.7	4.5
Total	6.9	2.6	29.7	14.9
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance			14.6
Change in reserves			13.0
Cash payments			(8.5)
Other			0.3
Restructuring Reserve, Ending Balance	19.4		19.4
Environmental charges, net	4.0	4.1	13.7	12.3
Product portfolio sales	0.0	0.1	0.0	0.1
Other items, net	0.1	0.0	0.5	0.0
Other charges (income), net	4.1	4.2	14.2	12.4
DuPont Crop restructuring
Restructuring Cost and Reserve [Line Items]
Severance and Employee Benefits	0.3	0.9	9.1	5.4
Other Charges (Income)	2.1	1.3	3.4	3.3
Asset Disposal Charges (Income)	4.0	0.4	17.1	4.5
Total	6.4	2.6	29.6	13.2
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance			14.5
Change in reserves			12.5
Cash payments			(8.3)
Other			0.3
Restructuring Reserve, Ending Balance	19.0		19.0
Other items
Restructuring Cost and Reserve [Line Items]
Severance and Employee Benefits	0.5	0.0	0.5	1.7
Other Charges (Income)	0.0	0.0	0.0	0.0
Asset Disposal Charges (Income)	0.0	0.0	(0.4)	0.0
Total	0.5	$ 0.0	0.1	$ 1.7
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance			0.1
Change in reserves			0.5
Cash payments			(0.2)
Other			0.0
Restructuring Reserve, Ending Balance	$ 0.4		$ 0.4

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