Goodwill and Intangible Assets - Intangible categories (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 28, 2019	Jun. 29, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018	Dec. 31, 2018	Oct. 01, 2018
Finite And Indefinite Lived Assets By Major Class [Line Items]
Goodwill	$ 4,222,900,000			$ 4,222,900,000		$ 3,979,800,000
Indefinite-lived intangibles:	46,800,000			46,800,000		49,300,000
Gross	4,587,100,000			4,587,100,000		4,379,300,000
Accumulated Amortization	1,687,800,000			1,687,800,000		1,520,400,000
Total other intangible assets	4,633,900,000			4,633,900,000		4,428,600,000
Intangible assets amortization expense	78,700,000		$ 84,300,000	227,700,000	$ 256,800,000
Impairment charges	10,900,000		221,800,000	42,900,000	223,500,000
Trademarks, trade names, and brands
Finite And Indefinite Lived Assets By Major Class [Line Items]
Indefinite-lived intangibles:	17,500,000			17,500,000		18,100,000
In-process research and development
Finite And Indefinite Lived Assets By Major Class [Line Items]
Indefinite-lived intangibles:	29,300,000			29,300,000		31,200,000
Impairment of indefinite lived intangible assets				4,300,000	8,500,000
Distribution and license agreements and supply agreements
Finite And Indefinite Lived Assets By Major Class [Line Items]
Gross	183,600,000			183,600,000		178,600,000
Accumulated Amortization	107,100,000			107,100,000		99,000,000.0
Developed product technology, formulations, and product rights
Finite And Indefinite Lived Assets By Major Class [Line Items]
Gross	1,373,400,000			1,373,400,000		1,318,800,000
Accumulated Amortization	717,900,000			717,900,000		654,600,000
Customer relationships and distribution networks
Finite And Indefinite Lived Assets By Major Class [Line Items]
Gross	1,762,900,000			1,762,900,000		1,586,600,000
Accumulated Amortization	628,600,000			628,600,000		566,500,000
Trademarks, trade names, and brands
Finite And Indefinite Lived Assets By Major Class [Line Items]
Gross	1,260,800,000			1,260,800,000		1,282,400,000
Accumulated Amortization	228,400,000			228,400,000		188,500,000
Non-compete agreements
Finite And Indefinite Lived Assets By Major Class [Line Items]
Gross	6,400,000			6,400,000		12,900,000
Accumulated Amortization	5,800,000			5,800,000		11,800,000
RX
Finite And Indefinite Lived Assets By Major Class [Line Items]
Goodwill	1,122,200,000	$ 1,100,000,000		1,122,200,000		1,114,800,000
Fair value in excess of book value (percent)		10.00%					25.00%
Intangible assets amortization expense	22,800,000		20,800,000	65,400,000	62,400,000
Goodwill impairment		$ 0
RX | Evamist branded product
Finite And Indefinite Lived Assets By Major Class [Line Items]
Impairment of definite-lived intangible assets	10,800,000
RX | Generic Product Acquisition
Finite And Indefinite Lived Assets By Major Class [Line Items]
Impairment charges		$ 27,800,000
CSCA
Finite And Indefinite Lived Assets By Major Class [Line Items]
Goodwill	1,943,700,000			1,943,700,000		$ 1,713,700,000
Intangible assets amortization expense	12,600,000		$ 15,300,000	$ 31,900,000	$ 45,800,000
Impairment charges	213,300,000
Goodwill impairment	136,700,000
Intangible assets reclassified to definite-lived intangible assets	5,400,000
CSCA | Brand
Finite And Indefinite Lived Assets By Major Class [Line Items]
Impairment of indefinite lived intangible assets	27,700,000
CSCA | Developed product technology and distribution agreements
Finite And Indefinite Lived Assets By Major Class [Line Items]
Impairment of definite-lived intangible assets	41,600,000
CSCA | Supply agreement
Finite And Indefinite Lived Assets By Major Class [Line Items]
Impairment of definite-lived intangible assets	2,800,000
CSCA | Trade name and trademark
Finite And Indefinite Lived Assets By Major Class [Line Items]
Impairment of definite-lived intangible assets	$ 4,500,000