Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 771.3	$ 761.1	$ 2,284.0	$ 2,267.5
Companion Animal Disease Prevention
Disaggregation of Revenue [Line Items]
Revenue	207.6	188.6	616.9	603.9
Companion Animal Therapeutics
Disaggregation of Revenue [Line Items]
Revenue	87.6	80.5	252.4	211.1
Food Animal Future Protein & Health
Disaggregation of Revenue [Line Items]
Revenue	191.5	162.8	534.5	502.1
Food Animal Ruminants & Swine
Disaggregation of Revenue [Line Items]
Revenue	266.2	301.5	811.8	881.1
Strategic Exits
Disaggregation of Revenue [Line Items]
Revenue	$ 18.4	$ 27.7	$ 68.4	$ 69.3

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration