Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Intangible assets subject to amortization (finite life)
Gross	$ 1,254.1	$ 1,220.2
Accumulated Amortization	(300.5)	(229.3)
Net	953.6	990.9
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	1,671.6	1,638.1
Finite and Indefinite lived intangible assets, gross	2,925.7	2,858.3
Total Accumulated Amortization	(300.5)	(229.3)
Total intangible assets	2,625.2	2,629.0
Crop Protection Brands
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	1,259.1	1,259.1
Brands
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 412.5	379.0
Customer relationships
Intangible assets subject to amortization (finite life)
Weighted avg. useful life remaining at December 31, 2020	16 years
Gross	$ 1,169.4	1,139.7
Accumulated Amortization	(249.7)	(184.7)
Net	919.7	955.0
Indefinite-lived Intangible Assets [Line Items]
Total Accumulated Amortization	$ (249.7)	(184.7)
Patents
Intangible assets subject to amortization (finite life)
Weighted avg. useful life remaining at December 31, 2020	5 years
Gross	$ 1.9	1.7
Accumulated Amortization	(1.2)	(0.9)
Net	0.7	0.8
Indefinite-lived Intangible Assets [Line Items]
Total Accumulated Amortization	$ (1.2)	(0.9)
Brands
Intangible assets subject to amortization (finite life)
Weighted avg. useful life remaining at December 31, 2020	8 years
Gross	$ 18.3	16.7
Accumulated Amortization	(8.9)	(6.7)
Net	9.4	10.0
Indefinite-lived Intangible Assets [Line Items]
Total Accumulated Amortization	$ (8.9)	(6.7)
Purchased and licensed technologies
Intangible assets subject to amortization (finite life)
Weighted avg. useful life remaining at December 31, 2020	9 years
Gross	$ 61.1	60.2
Accumulated Amortization	(38.1)	(35.2)
Net	23.0	25.0
Indefinite-lived Intangible Assets [Line Items]
Total Accumulated Amortization	$ (38.1)	(35.2)
In-process research and development
Intangible assets subject to amortization (finite life)
Weighted avg. useful life remaining at December 31, 2020	1 year
Gross	$ 3.4	1.9
Accumulated Amortization	(2.6)	(1.8)
Net	0.8	0.1
Indefinite-lived Intangible Assets [Line Items]
Total Accumulated Amortization	$ (2.6)	$ (1.8)

Finite and Indefinite lived intangible assets, gross

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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