Fair Value Measurements - Financial Instruments at Fair Value (Details) - USD ($) $ in Millions		Sep. 28, 2019	Dec. 31, 2018
Measured at fair value on a non-recurring basis:
Goodwill carrying amount		$ 4,222.9	$ 3,979.8
Indefinite-lived intangible assets carrying value		46.8	49.3
Definite-lived intangible assets carrying value		2,899.3	2,858.9
Measured at fair value on a recurring basis | Level 1
Assets:
Investment securities		2.6	9.4
Foreign currency forward contracts		0.0	0.0
Cross-currency swap		0.0	0.0
Funds associated with Israeli severance liability		0.0	0.0
Royalty Pharma contingent milestone payments		0.0	0.0
Total assets		2.6	9.4
Liabilities:
Foreign currency forward contracts		0.0	0.0
Contingent consideration		0.0	0.0
Total liabilities		0.0	0.0
Measured at fair value on a recurring basis | Level 2
Assets:
Investment securities		0.0	0.0
Foreign currency forward contracts		8.4	3.8
Cross-currency swap		30.1	0.0
Funds associated with Israeli severance liability		14.3	13.0
Royalty Pharma contingent milestone payments		0.0	0.0
Total assets		52.8	16.8
Liabilities:
Foreign currency forward contracts		4.9	9.2
Contingent consideration		0.0	0.0
Total liabilities		4.9	9.2
Measured at fair value on a recurring basis | Level 3
Assets:
Investment securities		0.0	0.0
Foreign currency forward contracts		0.0	0.0
Cross-currency swap		0.0	0.0
Funds associated with Israeli severance liability		0.0	0.0
Royalty Pharma contingent milestone payments		91.7	323.2
Total assets		91.7	323.2
Liabilities:
Foreign currency forward contracts		0.0	0.0
Contingent consideration		13.2	15.3
Total liabilities		13.2	15.3
Measured at fair value on a non-recurring basis
Measured at fair value on a non-recurring basis:
Indefinite-lived intangible assets carrying value			46.9
Definite-lived intangible assets carrying value		22.4	72.0
Measured at fair value on a non-recurring basis | Level 1
Assets:
Total assets		0.0	0.0
Measured at fair value on a non-recurring basis:
Goodwill		0.0	0.0
Indefinite-lived intangible assets		0.0	0.0
Definite-lived intangible assets		0.0	0.0
Measured at fair value on a non-recurring basis | Level 2
Assets:
Total assets		0.0	0.0
Measured at fair value on a non-recurring basis:
Goodwill		0.0	0.0
Indefinite-lived intangible assets		0.0	0.0
Definite-lived intangible assets		0.0	0.0
Measured at fair value on a non-recurring basis | Level 3
Assets:
Total assets		11.6	75.1
Measured at fair value on a non-recurring basis:
Goodwill		0.0	42.2	[1]
Indefinite-lived intangible assets		0.0	10.5	[2]
Definite-lived intangible assets	[3]	11.6	22.4
CSCA
Measured at fair value on a non-recurring basis:
Goodwill carrying amount		$ 1,943.7	1,713.7
CSCA | Measured at fair value on a non-recurring basis
Measured at fair value on a non-recurring basis:
Goodwill carrying amount			$ 178.9

[1] (1) As of December 31, 2018, goodwill with a carrying amount of $178.9 million was written down to a fair value of $42.2 million.

[2] (2) As of December 31, 2018, indefinite-lived intangible assets with carrying amounts of $46.9 million were written down to a fair value of $10.5 million.

[3] (3) As of September 28, 2019, a definite-lived intangible asset with a carrying amount of $22.4 million was written down to a fair value of $11.6 million. As of December 31, 2018, definite-lived intangible assets with carrying amounts of $72.0 million were written down to a fair value of $22.4 million.