Acquisitions of Businesses - Purchase Price Allocation, Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Increase (decrease) in goodwill		$ 29.7	$ 80.2
Addition from acquisitions		66.9	$ 2,955.4
OMG
Business Acquisition [Line Items]
Increase (decrease) in noncurrent deferred tax liabilities		2.9
Increase (decrease) in other long-term liabilities		(2.6)
Increase in accrued expenses		2.5
Increase in environmental reserves		1.5
Increase (decrease) in goodwill		(4.4)
Alent
Business Acquisition [Line Items]
Increase (decrease) in noncurrent deferred tax liabilities		6.5
Increase (decrease) in other long-term liabilities		2.8
Increase (decrease) in goodwill		12.7
Increase in environmental and asset retirement obligation reserves		12.9
Increase in short-term assets held for sale		4.0
Increase in investment assets		2.7
Increase in noncurrent deferred tax asset		3.2
OMG Malaysia
Business Acquisition [Line Items]
Increase (decrease) in noncurrent deferred tax liabilities		(3.8)
Decrease in inventory		0.8
Increase (decrease) in intangible assets		(15.1)
Arysta
Business Acquisition [Line Items]
Increase (decrease) in noncurrent deferred tax liabilities	$ 25.7
Increase (decrease) in intangible assets	134.0
Increase in noncontrolling interest	101.0
Increase in property, plant and equipment	$ 13.6
OMG Malaysia, Alent, OMG and Arysta
Business Acquisition [Line Items]
Addition from acquisitions		3,150.0
OMG Malaysia and OMG
Business Acquisition [Line Items]
Goodwill expected to be tax deductible		$ 101.0