Transition period financial data (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																				6 Months Ended		12 Months Ended
	Dec. 31, 2016	[1]	Oct. 01, 2016	[2]	Jul. 02, 2016	[3]	Apr. 02, 2016	[4]	Dec. 31, 2015		Sep. 26, 2015	[6]	Jun. 27, 2015	[7]	Mar. 28, 2015	[8]	Dec. 27, 2014		Sep. 27, 2014		Dec. 31, 2015	Dec. 27, 2014	Dec. 31, 2016	Jun. 27, 2015	Jun. 28, 2014
Net sales	$ 1,331.2		$ 1,261.6		$ 1,340.5		$ 1,347.3		$ 1,359.1	[5]	$ 1,273.1		$ 1,415.2		$ 967.2		$ 985.1	[9]	$ 859.6		$ 2,632.2	$ 1,844.7	$ 5,280.6	$ 4,227.1	$ 3,914.1
Cost of sales																					1,553.3	1,170.9	3,228.8	2,582.9	2,462.0
Gross profit	487.7		484.5		546.5		533.1		543.7	[5]	535.2		601.0		369.4		369.7	[9]	304.1		1,078.9	673.8	2,051.8	1,644.2	1,452.1
Distribution																					47.9	29.2	88.3	67.7	55.3
Research and development																					88.2	89.8	184.0	187.8	152.5
Selling																					325.9	95.3	665.0	319.0	208.6
Administration																					306.8	165.6	452.2	385.3	411.3
Impairment charges																					215.6	0.0	2,631.0	6.8	6.0
Restructuring									24.7												26.9	4.2	31.0	5.1	47.0
Total operating expenses																					1,011.3	384.1	4,051.5	971.7	880.7
Operating income (loss)																					67.6	289.7	(1,999.7)	672.5	571.4
Tysabri® royalty stream - change in fair value	(1,115.6)		377.4		910.8		204.4		(116.6)	[5]	(173.8)		69.2		(100.8)		105.8	[9]	(58.9)		(57.3)	(46.9)	2,608.2	(78.5)	(26.6)
Interest expense, net																					89.9	56.7	216.6	146.0	103.5
Other expense, net																					25.2	60.3	22.7	334.2	25.1
Loss on extinguishment of debt																	9.6				0.9	9.6	1.1	10.5	165.8
Income (loss) before income taxes																					8.9	210.0	(4,848.3)	260.3	303.6
Income tax expense (benefit)																					(33.6)	29.4	(835.5)	124.2	70.8
Net income (loss)	$ (1,359.1)		$ (1,590.2)		$ (534.3)		$ (529.2)		$ (218.4)	[5]	$ 260.9		$ (22.2)		$ (22.2)		$ 151.1	[9]	$ 29.4		$ 42.5	$ 180.6	$ (4,012.8)	$ 136.1	$ 232.8
Basic (in dollars per share)	$ (9.48)	[10]	$ (11.10)	[10]	$ (3.73)	[10]	$ (3.70)	[10]	$ (1.51)	[5],[10]	$ 1.78	[10]	$ (0.15)	[10]	$ (0.16)	[10]	$ 1.11	[9],[10]	$ 0.22	[10]	$ 0.29	$ 1.34	$ (28.01)	$ 0.97	$ 2.02
Diluted (in dollars per share)	$ (9.48)	[10]	$ (11.10)	[10]	$ (3.73)	[10]	$ (3.70)	[10]	$ (1.51)	[5],[10]	$ 1.78	[10]	$ (0.15)	[10]	$ (0.16)	[10]	$ 1.10	[9],[10]	$ 0.22	[10]	$ 0.29	$ 1.34	$ (28.01)	$ 0.97	$ 2.01
Basic (in shares)	143.4		143.3		143.2		143.2		144.9	[5]	146.3		146.3		140.8		136.3	[9]	133.9		145.6	135.1	143.3	139.3	115.1
Diluted (in shares)	143.4		143.3		143.2		143.2		144.9	[5]	146.9		146.3		140.8		136.8	[9]	134.4		146.1	135.6	143.3	139.8	115.6
Dividends declared per share																					$ 0.25	$ 0.21	$ 0.580	$ 0.4600	$ 0.3900

[1] ncludes intangible asset impairment charges of $378.6 million, goodwill impairment charges of $224.1 million, and a reduction in held-for-sale impairment charges of $4.5 million. September 26, 2015 (2) December 31, 2015 (3)Six Months Ended December 31, 2015Restated RestatedNet sales$1,273.1 $1,359.1Gross profit$535.2 $543.7Tysabri® royalty stream - change in fair value$(173.8) $116.6Net income (loss)$260.9 $(218.4)Income (loss) per share(1): Basic$1.78 $(1.51)Diluted$1.78 $(1.51)Weighted-average shares outstanding Basic146.3 144.9Diluted146.9 144.9

[2] Includes intangible asset impairment charges of $866.6 million, goodwill impairment charges of $737.9 million, and held-for-sale impairment charges of $10.2 million.

[3] Includes held-for-sale impairment charges of $10.5 million and change in fair market value on royalty rights of $910.8 million.

[4] Includes an intangible asset impairment charges of $273.3 million, and a goodwill impairment charge of $130.5 million.

[5] Includes an intangible asset impairment charge of $185.1 million, Mylan defense-related fees of $71.3 million, an impairment charge on our India API held for sale assets of $29.0 million, restructuring charges of $24.7 million, and an investment impairment charge of $10.7 million.

[6] Includes Mylan defense-related fees of $15.6 million.

[7] (4) Includes acquisition costs of $18.5 million, an initial payment made in connection with an R&D agreement of $18.0 million, an inventory step up related to the Omega acquisition totaling $15.6 million, and $13.4 million of Mylan defense-related fees.

[8] Includes losses on derivatives associated with the Omega acquisition of $258.2 million and Omega financing fees of $18.6 million.

[9] Includes losses on derivatives associated with the Omega acquisition of $64.7 million, Omega transaction expenses of $17.8 million, an R&D payment made in connection with a collaborative agreement of $10.0 million, a $9.6 million loss on extinguishment of debt, partially offset by income from transfer of rights agreement of $12.5 million.

[10] The sum of individual per share amounts may not equal due to rounding.