Fair Value Measurements - Financial Instruments at Fair Value (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Apr. 01, 2017	Apr. 02, 2016	Dec. 31, 2016	Oct. 03, 2016	Apr. 04, 2016	Dec. 31, 2015
Assets:
Royalty Pharma contingent milestone payments	$ 184.5
Tysabri® royalty stream	0.0		$ 2,350.0
Indefinite-lived intangible assets				$ 674.2	$ 364.5
Liabilities:
Indefinite-lived intangibles carrying amount	101.9		114.5
Finite-lived intangible assets	4,459.4		4,417.2
Definite lived asset impairment		$ 273.4
Recurring | Level 1
Assets:
Investment securities	22.8		38.2
Recurring | Level 2
Assets:
Foreign currency forward contracts	6.5		3.8
Funds associated with Israeli severance liability	17.1		15.9
Total assets	23.6		19.7
Liabilities:
Foreign currency forward contracts	2.5		5.0
Recurring | Level 3
Assets:
Total assets	184.5		2,350.0
Nonrecurring | Level 3
Assets:
Goodwill	0.0		1,148.4
Indefinite-lived intangible assets	13.8		0.3
Definite-lived intangible assets	0.0		758.0
Assets held for sale, net	11.0		18.2
Total assets	24.8		1,924.9
Liabilities:
Goodwill			2,200.0
Indefinite-lived intangibles carrying amount	26.0		0.7
Impairment of intangible assets	12.2
Contingent consideration | Recurring | Level 3
Liabilities:
Contingent consideration	$ 52.0	48.0	69.9			$ 17.9
Contingent consideration | Recurring | Level 3
Assets:
Royalty Pharma contingent milestone payments			0.0
CHCI
Liabilities:
Finite-lived intangible assets			2,300.0
Omega | Brands
Liabilities:
Impairment of intangible assets		$ 273.4
Definite lived asset impairment			$ 1,500.0