INTANGIBLE ASSETS AND GOODWILL - Narrative (Details) - USD ($)					3 Months Ended								12 Months Ended
	Oct. 01, 2020	Oct. 01, 2019	Oct. 01, 2018	Jan. 01, 2018	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Mar. 01, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Net loss attributable to Bausch Health Companies Inc.					$ (153,000,000)	$ 71,000,000	$ (326,000,000)	$ (152,000,000)	$ (1,516,000,000)	$ (49,000,000)	$ (171,000,000)	$ (52,000,000)	$ (560,000,000)	$ (1,788,000,000)	$ (4,148,000,000)
Decrease to earnings per share, basic and diluted (in dollars per share)					$ 0.43	$ (0.20)	$ 0.92	$ 0.43	$ 4.30	$ 0.14	$ 0.49	$ 0.15	$ 1.58	$ 5.08	$ 11.81
Carrying value of intangible assets, net					$ 8,445,000,000				$ 10,201,000,000				$ 8,445,000,000	$ 10,201,000,000
Goodwill impairments		$ 0
Goodwill reallocated into (out of)					13,044,000,000				13,126,000,000				13,044,000,000	13,126,000,000	$ 13,142,000,000			$ 15,593,000,000
Revenue					2,213,000,000	$ 2,138,000,000	$ 1,664,000,000	$ 2,012,000,000	$ 2,224,000,000	$ 2,209,000,000	$ 2,152,000,000	$ 2,016,000,000	8,027,000,000	8,601,000,000	8,380,000,000
Revenue, year-over-year decrease					$ 11,000,000
Revenue, year-over-year decrease, percentage					1.00%	3.00%	23.00%
Accumulated goodwill impairment charges to date					$ 3,711,000,000								3,711,000,000
Ortho Dermatologics Reporting Unit
Finite-Lived Intangible Assets [Line Items]
Goodwill impairments	$ 0						$ 0	$ 0							2,213,000,000
Percentage of fair value in excess of carrying value	10.00%
Reporting unit, impairment test, long-term growth rates	2.00%
Dentistry Reporting Unit
Finite-Lived Intangible Assets [Line Items]
Goodwill impairments			$ 109,000,000												109,000,000
Reporting Units Excluding Dentistry
Finite-Lived Intangible Assets [Line Items]
Goodwill impairments			$ 0
Reporting Units Excluding Ortho Dermatologics and Dentistry
Finite-Lived Intangible Assets [Line Items]
Percentage of fair value in excess of carrying value			15.00%
Maximum | Ortho Dermatologics Reporting Unit
Finite-Lived Intangible Assets [Line Items]
Reporting unit, impairment test, estimated cash flows, discount rate	9.75%
Minimum | Ortho Dermatologics Reporting Unit
Finite-Lived Intangible Assets [Line Items]
Reporting unit, impairment test, estimated cash flows, discount rate	9.50%
Branded Rx Segment | Scenario, Adjustment
Finite-Lived Intangible Assets [Line Items]
Goodwill reallocated into (out of)																	$ 115,000,000
Branded Rx Segment | Salix Reporting Unit
Finite-Lived Intangible Assets [Line Items]
Goodwill impairments				$ 1,970,000,000
Branded Rx Segment | Ortho Dermatologics Reporting Unit
Finite-Lived Intangible Assets [Line Items]
Goodwill impairments				$ 243,000,000
Bausch Lomb/International And U.S. Diversified Products Segments | Scenario, Adjustment
Finite-Lived Intangible Assets [Line Items]
Goodwill reallocated into (out of)																$ (115,000,000)
Uceris
Finite-Lived Intangible Assets [Line Items]
Impairment of finite-lived intangible assets															263,000,000
Arestin
Finite-Lived Intangible Assets [Line Items]
Impairment of finite-lived intangible assets															132,000,000
Xifaxan
Finite-Lived Intangible Assets [Line Items]
Carrying value of intangible assets, net					$ 3,771,000,000								3,771,000,000
Xifaxan | Intangible Assets, Amortization Period
Finite-Lived Intangible Assets [Line Items]
Net loss attributable to Bausch Health Companies Inc.													$ 476,000,000	$ 473,000,000	$ 143,000,000
Decrease to earnings per share, basic and diluted (in dollars per share)													$ 1.34	$ 1.34	$ 0.41
Acquired IPR&D
Finite-Lived Intangible Assets [Line Items]
Impairment of indefinite-lived intangible assets													$ 1,000,000	$ 4,000,000	$ 28,000,000
Held For Sale
Finite-Lived Intangible Assets [Line Items]
Impairment of long-lived assets															5,000,000
Held For Sale | Certain Products For Disposal, September 2019
Finite-Lived Intangible Assets [Line Items]
Impairment of long-lived assets										$ 8,000,000				8,000,000
Held For Sale | A Certain International Business
Finite-Lived Intangible Assets [Line Items]
Impairment of long-lived assets													96,000,000
Product brands
Finite-Lived Intangible Assets [Line Items]
Impairment of finite-lived intangible assets													16,000,000	58,000,000	85,000,000
Discontinued Product Lines
Finite-Lived Intangible Assets [Line Items]
Impairment of finite-lived intangible assets													$ 1,000,000
Product rights/patents
Finite-Lived Intangible Assets [Line Items]
Impairment of finite-lived intangible assets														$ 5,000,000	$ 55,000,000