Fair Value Measurements - Financial Instruments at Fair Value (Details) - USD ($) $ in Millions		Sep. 29, 2018		Dec. 31, 2017
Measured at fair value on a non-recurring basis:
Goodwill carrying amount		$ 3,994.2		$ 4,175.4
Indefinite-lived intangible assets carrying value		47.8		90.3
Definite-lived intangible assets carrying value		2,959.3		3,290.5
Measured at fair value on a recurring basis | Level 1
Assets:
Investment securities		7.0		17.0
Foreign currency forward contracts		0.0		0.0
Funds associated with Israeli severance liability		0.0		0.0
Royalty Pharma contingent milestone payments		0.0		0.0
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 non-recurring basis:
Assets, Fair Value Disclosure		7.0		17.0
Measured at fair value on a recurring basis | Level 2
Assets:
Investment securities		0.0		0.0
Foreign currency forward contracts		3.3		6.3
Funds associated with Israeli severance liability		14.2		16.3
Royalty Pharma contingent milestone payments		0.0		0.0
Liabilities:
Foreign currency forward contracts		6.6		3.8
Contingent consideration		0.0		0.0
Total liabilities		6.6		3.8
Measured at fair value on a non-recurring basis:
Assets, Fair Value Disclosure		17.5		22.6
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
Funds associated with Israeli severance liability		0.0		0.0
Royalty Pharma contingent milestone payments		200.4		134.5
Liabilities:
Foreign currency forward contracts		0.0		0.0
Contingent consideration		16.4		22.0
Total liabilities		16.4		22.0
Measured at fair value on a non-recurring basis:
Assets, Fair Value Disclosure		200.4		134.5
Measured at fair value on a non-recurring basis
Measured at fair value on a non-recurring basis:
Indefinite-lived intangible assets carrying value		46.7
Definite-lived intangible assets carrying value		71.3		31.2
Measured at fair value on a non-recurring basis | Level 1
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
Assets, Fair Value Disclosure		0.0		0.0
Measured at fair value on a non-recurring basis | Level 2
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
Assets, Fair Value Disclosure		0.0		0.0
Measured at fair value on a non-recurring basis | Level 3
Measured at fair value on a non-recurring basis:
Goodwill				0.0
Indefinite-lived intangible assets		10.5	[1]	0.0
Definite-lived intangible assets	[2]	22.4		11.5
Assets, Fair Value Disclosure		75.1		11.5
CHCA
Measured at fair value on a non-recurring basis:
Goodwill carrying amount		1,710.2		$ 1,847.4
CHCA | Measured at fair value on a non-recurring basis
Measured at fair value on a non-recurring basis:
Goodwill carrying amount		178.9
CHCA | Measured at fair value on a non-recurring basis | Level 3
Measured at fair value on a non-recurring basis:
Goodwill	[3]	$ 42.2

[1] (2)As of September 29, 2018, indefinite-lived intangible assets with a carrying amount of $46.7 million were written down to a fair value of $10.5 million.

[2] As of September 29, 2018, definite-lived intangible assets with a carrying amount of $71.3 million were written down to a fair value of $22.4 million. As of December 31, 2017, definite-lived intangible assets with a carrying amount of $31.2 million were written down to a fair value of $11.5 million.

[3] (1)As of September 29, 2018, goodwill with a carrying amount of $178.9 million was written down to a fair value of $42.2 million.