Discontinued Operations - Components Comprising Net Income (Loss) from Discontinued Operations, Net (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of tax	$ 50.4	$ (401.6)	$ 61.4	$ 46.9	$ (126.9)	$ (29.4)	$ 13.9	$ 38.6	$ (242.9)	$ (103.8)	$ 113.8
Agricultural Solutions Business | Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales									1,991.8	1,897.3	1,815.8
Cost of sales									(1,190.3)	(1,122.1)	(1,085.4)
Selling, technical, general and administrative									(466.4)	(531.4)	(524.7)
Research and development									(52.4)	(52.0)	(39.4)
Goodwill impairment									0.0	(160.0)	0.0
Impairment loss	$ (74.0)	$ (376.0)			$ (160.0)				(450.0)	0.0	0.0
Operating (loss) profit									(167.3)	31.8	166.3
Other income (expense) items									11.5	(60.4)	17.4
(Loss) income from discontinued operations, before income taxes									(155.8)	(28.6)	183.7
Income tax expense									(87.1)	(75.2)	(69.9)
(Loss) income from discontinued operations, net of tax									(242.9)	(103.8)	113.8
Net income from discontinued operations attributable to the non-controlling interests									(3.0)	1.7	(2.6)
Net (loss) income from discontinued operations attributable to common stockholders									$ (245.9)	(102.1)	$ 111.2
Agricultural Solutions Business | Held-for-sale | Agro Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment loss										$ (160.0)