Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016		Sep. 26, 2015		Dec. 31, 2015
Segment Reporting Information [Line Items]
Total Assets	$ 15,888.1		$ 15,888.1				$ 19,349.6
Net sales	1,261.6	$ 1,273.1	3,949.3	[1]	$ 3,655.6	[1]
Operating Income (Loss)	(1,468.3)	175.3	(1,515.1)	[1]	558.0	[1]
Intangible Asset Amortization	89.7	75.0	263.9	[1]	180.4	[1]
Tysabri® royalty stream - change in fair value	377.4	(173.8)	1,492.6		(205.4)
CHC
Segment Reporting Information [Line Items]
Total Assets	3,594.8		3,594.8				3,384.8
Net sales	669.1	675.1	2,055.6		2,106.5
Operating Income (Loss)	99.3	117.2	313.8		351.7
Intangible Asset Amortization	19.2	19.3	58.1		52.2
BCH
Segment Reporting Information [Line Items]
Total Assets	4,605.5		4,605.5				7,083.5
Net sales	304.0	315.2	1,009.9	[1]	683.6	[1]
Operating Income (Loss)	(1,619.3)	2.8	(2,019.2)	[1]	19.7	[1]
Intangible Asset Amortization	39.3	36.3	114.3	[1]	70.5	[1]
Rx
Segment Reporting Information [Line Items]
Total Assets	3,303.9		3,303.9				2,738.0
Net sales	267.4	260.3	824.3		790.1
Operating Income (Loss)	77.9	91.0	268.9		290.3
Intangible Asset Amortization	30.7	18.6	90.1		55.5
Specialty Sciences
Segment Reporting Information [Line Items]
Total Assets	4,188.3		4,188.3				5,930.2
Net sales	0.0	0.0	0.0		0.0
Operating Income (Loss)	3.2	(2.7)	(2.0)		(11.1)
Intangible Asset Amortization	0.0	0.3	0.0		0.8
Other
Segment Reporting Information [Line Items]
Total Assets	195.6		195.6				$ 213.1
Net sales	21.1	22.5	59.5		75.4
Operating Income (Loss)	(1.5)	6.2	2.6		18.5
Intangible Asset Amortization	0.5	0.5	1.4		1.4
Unallocated
Segment Reporting Information [Line Items]
Net sales	0.0	0.0	0.0		0.0
Operating Income (Loss)	(27.9)	(39.2)	(79.2)		(111.1)
Intangible Asset Amortization	$ 0.0	$ 0.0	$ 0.0		$ 0.0

[1] The BCH segment was created on March 30, 2015 as a result of the Omega acquisition, thus data for the nine months ended September 26, 2015 includes only six months of results from operations attributable to Omega.