INTANGIBLE ASSETS AND GOODWILL - Narrative (Details) - USD ($)				3 Months Ended			12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2022	Mar. 31, 2024	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Asset impairments				$ 1,000,000		$ 13,000,000
Finite-lived intangible assets	$ 4,480,000,000	$ 4,753,000,000		4,480,000,000			$ 4,753,000,000
Goodwill impairment							493,000,000
Goodwill	11,160,000,000	11,183,000,000		11,160,000,000			11,183,000,000	$ 11,547,000,000
Accumulated goodwill impairment charges	5,497,000,000			5,497,000,000
Salix
Goodwill [Line Items]
Goodwill impairment							0
Goodwill	3,159,000,000	$ 3,159,000,000		3,159,000,000			$ 3,159,000,000	$ 3,159,000,000
Dermatology Reporting Unit | Bausch + Lomb
Goodwill [Line Items]
Reporting unit, impairment test, long-term growth rate					0.00%
Reporting unit, impairment test, estimated cash flows, discount rate					10.75%
Goodwill impairment					$ 151,000,000
Goodwill	329,000,000			329,000,000	$ 329,000,000
Neurology Reporting Unit | Bausch + Lomb
Goodwill [Line Items]
Reporting unit, impairment test, long-term growth rate					(2.50%)
Reporting unit, impairment test, estimated cash flows, discount rate					10.50%
Goodwill impairment					$ 251,000,000
Goodwill	1,186,000,000			1,186,000,000	$ 1,192,000,000
Generics Reporting Unit
Goodwill [Line Items]
Reporting unit, impairment test, long-term growth rate		1.00%					1.00%
Reporting unit, impairment test, estimated cash flows, discount rate		10.25%					10.25%
Goodwill impairment		$ 91,000,000
Goodwill	227,000,000	$ 227,000,000		227,000,000			$ 227,000,000
Xifaxan Branded Products
Goodwill [Line Items]
Impairment of intangible assets	0		$ 0
Finite-lived intangible assets	$ 2,020,000,000			$ 2,020,000,000
Finite lived intangible assets, useful life	45 months			45 months
Trade Names No Longer Used
Goodwill [Line Items]
Impairment of intangible assets						8,000,000
Discontinued Product Lines
Goodwill [Line Items]
Impairment of intangible assets						$ 5,000,000