Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jun. 27, 2015	Jul. 02, 2016		Jun. 27, 2015		Dec. 31, 2015
Segment Reporting Information [Line Items]
Total Assets	$ 18,291.2	$ 19,349.6	$ 18,291.2		$ 19,349.6		$ 19,349.6
Total Revenue	1,340.5	1,415.2	2,687.8	[1]	2,382.4	[1]
Operating Income (Loss)	184.8	192.3	(46.8)	[1]	382.7	[1]
Intangible Asset Amortization	88.9	70.1	174.1	[1]	105.3	[1]
Tysabri® royalty stream - change in fair value	910.8	69.2	1,115.3		(31.5)
CHC
Segment Reporting Information [Line Items]
Total Assets	3,748.3	3,384.8	3,748.3		3,384.8
Total Revenue	686.3	746.4	1,386.6		1,431.3
Operating Income (Loss)	115.0	130.1	214.5		234.4
Intangible Asset Amortization	19.0	16.6	38.8		32.8
BCH
Segment Reporting Information [Line Items]
Total Assets	6,290.7	7,083.5	6,290.7		7,083.5
Total Revenue	343.1	368.3	705.9	[1]	368.3	[1]
Operating Income (Loss)	(1.8)	16.7	(400.0)	[1]	16.8	[1]
Intangible Asset Amortization	39.5	34.2	74.9	[1]	34.2	[1]
Rx
Segment Reporting Information [Line Items]
Total Assets	3,340.1	2,738.0	3,340.1		2,738.0
Total Revenue	293.3	278.3	556.9		529.9
Operating Income (Loss)	96.8	99.5	191.1		199.5
Intangible Asset Amortization	29.9	18.6	59.4		36.9
Specialty Sciences
Segment Reporting Information [Line Items]
Total Assets	4,710.1	5,930.2	4,710.1		5,930.2
Total Revenue	0.0	0.0	0.0		0.0
Operating Income (Loss)	(3.8)	(5.2)	(5.1)		(8.5)
Intangible Asset Amortization	0.0	0.2	0.0		0.5
Other
Segment Reporting Information [Line Items]
Total Assets	202.0	213.1	202.0		213.1
Total Revenue	17.8	22.2	38.4		52.9
Operating Income (Loss)	(1.3)	1.9	4.1		12.4
Intangible Asset Amortization	0.5	0.5	1.0		0.9
Unallocated
Segment Reporting Information [Line Items]
Total Revenue	0.0	0.0	0.0		0.0
Operating Income (Loss)	(20.1)	(50.7)	(51.4)		(71.9)
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 six months ended June 27, 2015 includes only three months of results from operations attributable to Omega.