Segment and Other Revenue Information - Revenue by Major Product Category (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Revenue from External Customer [Line Items]
Revenue	$ 1,175	$ 1,158	$ 2,277	$ 2,255
Anti-infectives [Member]
Revenue from External Customer [Line Items]
Revenue	278	287	590	609
Vaccines [Member]
Revenue from External Customer [Line Items]
Revenue	286	304	557	578
Parasiticides [Member]
Revenue from External Customer [Line Items]
Revenue	193	199	346	350
Medicated feed additives [Member]
Revenue from External Customer [Line Items]
Revenue	119	109	240	213
Other pharmaceuticals [Member]
Revenue from External Customer [Line Items]
Revenue	237	207	424	398
Other Non Pharmaceuticals [Member]
Revenue from External Customer [Line Items]
Revenue	48	36	96	80
Contract Manufacturing [Member]
Revenue from External Customer [Line Items]
Revenue	$ 14	$ 16	$ 24	$ 27