Segment and Geographical Data (Schedule of Net Sales from External Costumers by Product) (Details) - USD ($) $ in Millions		1 Months Ended	6 Months Ended		11 Months Ended	12 Months Ended
		Dec. 29, 2023	Dec. 30, 2022	Jun. 16, 2022	Nov. 14, 2023	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net sales		$ 243.0	$ 1,039.7	$ 874.6	$ 1,622.9	$ 2,208.8
Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales		139.8	682.4	587.1	949.2	1,547.0
Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		103.2	357.3	287.5	673.7	661.8
Acthar Gel | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales		57.0	294.1	221.9	368.3	593.6
Inomax | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales		35.3	173.9	165.8	267.9	448.5
Therakos | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales		39.1	130.5	109.6	220.0	266.5
Amitiza | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales	[1]	5.0	77.1	81.5	72.0	196.9
Other Products | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales		1.1	5.6	8.3	7.7	41.5
Opioids | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		31.6	117.9	88.8	230.7	213.2
ADHD | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		13.5	28.4	17.5	101.4	37.4
Addiction Treatment | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		10.5	35.0	30.0	55.6	68.3
Other Generics | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		1.6	6.8	4.9	8.2	12.0
Generics | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		57.2	188.1	141.2	395.9	330.9
Controlled substances | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		11.6	47.0	37.6	75.5	93.4
APAP | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		32.5	111.4	96.5	184.8	215.9
Other API | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		1.9	10.8	12.2	17.5	21.6
API | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales		46.0	169.2	146.3	277.8	330.9
Terlivaz | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales		$ 2.3	$ 1.2	$ 0.0	$ 13.3	$ 0.0

[1] Amitiza net sales consist of both product and royalty net sales.