Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 30, 2018	Mar. 31, 2017
Segment Reporting Information
Net sales	$ 572.6	$ 560.0
Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	572.6	560.0
Acthar | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	243.8	271.8
Inomax | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	139.8	128.4
Ofirmev | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	82.0	73.4
Therakos immunotherapy | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	57.4	51.2
Amitiza [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	23.0	0.0
BioVectra Inc [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	10.5	9.9
Other | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	$ 16.1	$ 25.3