Discontinued Operations - Components Comprising Net Income (Loss) from Discontinued Operations, Net (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of tax	$ (401.6)	$ (29.4)	$ (293.3)	$ 23.1
Agricultural Solutions Business \| Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales	422.1	423.7	1,414.6	1,317.2
Cost of sales	(260.0)	(260.8)	(850.7)	(769.4)
Selling, technical, general and administrative	(103.6)	(123.9)	(375.5)	(385.6)
Research and development	(12.0)	(12.2)	(38.9)	(36.3)
Impairment loss	(376.0)	0.0	(376.0)	0.0	$ (376.0)
Operating (loss) profit	(329.5)	26.8	(226.5)	125.9
Other expense items	(30.3)	(17.1)	(14.5)	(55.7)
(Loss) income from discontinued operations, before income taxes	(359.8)	9.7	(241.0)	70.2
Income tax expense	(41.8)	(39.1)	(52.3)	(47.1)
(Loss) income from discontinued operations, net of tax	(401.6)	(29.4)	(293.3)	23.1
Net income from discontinued operations attributable to the non-controlling interests	(1.0)	(2.1)	(0.8)	(2.0)
Net (loss) income from discontinued operations attributable to common stockholders	$ (402.6)	$ (31.5)	$ (294.1)	$ 21.1

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