Segment and Geographical Data (Schedule of Net Sales and Long-Lived Assets by Geographic Area) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 25, 2020		Dec. 27, 2019
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales (includes refined estimate of the retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)		$ 2,208.8	$ 2,213.4		$ 3,162.5
Long-Lived Assets	[1]	790.2	846.4
Medicaid lawsuit (Note 19)			641.1
Sales [Member]
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Medicaid lawsuit (Note 19)	[2]	0.0	(536.0)	[3]	0.0
Operating Segments
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales (includes refined estimate of the retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)		2,208.8	2,749.4		3,162.5
United States
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales (includes refined estimate of the retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)	[4]	1,991.8	2,465.5		2,765.6
Long-Lived Assets	[1]	629.3	676.3
EMEA
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales (includes refined estimate of the retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)	[4]	181.8	227.5		281.8
Long-Lived Assets	[1],[5]	156.2	165.5
EMEA | IRELAND
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Long-Lived Assets		154.5	164.0
Other Countries
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales (includes refined estimate of the retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)	[4]	35.2	56.4		$ 115.1
Long-Lived Assets	[1]	$ 4.7	$ 4.6

[1] Long-lived assets are primarily composed of property, plant and equipment, net.

[2] Specialty Brands net sales for fiscal 2020 includes the prospective change to the Medicaid rebate calculation, which served to reduce Acthar Gel net sales by $40.4 million for the period from June 15, 2020 through December 25, 2020. See Note 19 for further detail on the status of the Medicaid lawsuit.

[3] Excludes the $105.1 million that is reflected as a component of operating expenses as it represents a pre-acquisition contingency related to the portion of the liability that arose from sales of Acthar Gel prior to the Company's acquisition of Questcor in August 2014. See Note 19 for further detail on the status of the Medicaid lawsuit.

[4] Net sales are attributed to regions based on the location of the entity that records the transaction, none of which relate to the country of Ireland.

[5] Includes long-lived assets located in Ireland of $154.5 million and $164.0 million as of December 31, 2021 and December 25, 2020, respectively.