Revenue (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2019

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Summary of Activity in Sales Rebates and Discounts Liability

The following table summarizes the activity in the sales rebates and discounts liability in the U.S.:

	Three Months Ended March 31,
	2019			2018
Beginning balance	$	118.5		$	114.8
Reduction of revenue	65.7			44.5
Payments	(64.2		)	(68.2		)
Ending balance	$	120.0		$	91.1

The following table summarizes the activity in the sales rebates and discounts liability in the U.S.:

	Year Ended December 31,
	2018			2017
Beginning balance	$	114.8		$	116.1
Reduction of revenue	221.0			236.1
Payments	(217.3		)	(237.4		)
Ending balance	$	118.5		$	114.8

Disaggregation of Revenue

The following table summarizes our revenue disaggregated by product category:

	Three Months Ended March 31,
	2019		2018
Companion Animal Disease Prevention	$	185.9	$	201.3
Companion Animal Therapeutics	81.4		62.3
Food Animal Future Protein & Health	167.2		166.7
Food Animal Ruminants & Swine	274.1		282.5
Strategic Exits(1)	22.5		23.4
Revenue	$	731.1	$	736.2

^{(1) Represents revenue from business activities we have either exited or made a strategic decision to exit.}

The following table summarizes our revenue disaggregated by product category for the years ended December 31:

	2018		2017		2016
Companion Animal Disease Prevention	$	804.6	$	660.2	$	628.4
Companion Animal Therapeutics	283.1		260.8		255.6
Food Animal Future Protein & Health	711.2		649.2		630.8
Food Animal Ruminants Swine	1,174.0		1,175.0		1,309.2
Other	93.9		143.8		89.5
Total Revenue	$	3,066.8	$	2,889.0	$	2,913.5