Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended			12 Months Ended
	Dec. 18, 2013	Jul. 02, 2016	Apr. 02, 2016	Dec. 31, 2015	Jun. 27, 2015	Jul. 02, 2016	Dec. 31, 2015	Jun. 27, 2015	Jun. 27, 2015	May 01, 2014	Nov. 08, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate						7.52%	7.72%
Growth rate		0.40%	1.80%	3.40%
Reduction in cumulative cash flows (percent)		18.00%	3.00%			18.00%
Reduction in fair value		$ 910.8			$ 69.2	$ 1,115.3		$ (31.5)
Decrease in fair value if discount rate increases by 0.5%		190.0		$ 260.0		190.0	$ 260.0
Increase in fair value if discount rate decreases by 0.5%		200.0		270.0		200.0	270.0
Increase in fair value if royalty rate increases by 5.0%		200.0		270.0		200.0	270.0
Decrease in fair value if royalty rate decreases by 5.0%		210.0		280.0		210.0	280.0
Accounts receivable		1,194.1		1,189.0		1,194.1	1,189.0
Debt, carrying value		5,918.6		4,698.3		5,918.6	4,698.3				$ 2,300.0
Public bonds and private placement notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt, carrying value		5,200.0		3,900.0		5,200.0	3,900.0
Public bonds and private placement notes | Level 1
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt, fair value		5,100.0		3,800.0		5,100.0	3,800.0
Retail bonds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt, carrying value		818.6		798.3		818.6	798.3
Debt, unamortized premium		67.5		82.5		67.5	82.5
Retail bonds | Level 2
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt, fair value		885.3		859.8		885.3	859.8
Tysabri
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Percent of royalty revenues generated by specific agreement										12.00%
Tysabri | Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Percent of royalty revenues generated by specific agreement									18.00%
Net sales									$ 2,000.0
Tysabri | Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Percent of royalty revenues generated by specific agreement									25.00%
Net sales									$ 2,000.0
Elan
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition date	Dec. 18, 2013
Royalty rights | Tysabri
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Accounts receivable		$ 89.2		$ 83.4		$ 89.2	$ 83.4