EARNINGS (LOSS) PER SHARE - Schedule of Calculation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income (loss) attributable to Bausch Health Companies Inc.	$ 188	$ 71	$ (1,017)	$ (407)
Basic weighted-average common shares outstanding (in shares)	359.6	355.6	358.5	354.7
Diluted effect of stock options and RSUs (in shares)	4.4	2.2	0.0	0.0
Diluted weighted-average common shares outstanding (in shares)	364.0	357.8	358.5	354.7
Earnings (loss) per share attributable to Bausch Health Companies Inc.
Basic (in usd per share)	$ 0.52	$ 0.20	$ (2.84)	$ (1.15)
Diluted (in usd per share)	$ 0.52	$ 0.20	$ (2.84)	$ (1.15)