EARNINGS/(LOSS) PER SHARE (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Earnings Per Share [Abstract]
Net earnings/(loss) attributable to BMS	$ 2,201	$ 1,211	$ 5,967	$ (9,020)
Weighted-average common shares outstanding – basic (in shares)	2,036,000,000	2,028,000,000	2,034,000,000	2,026,000,000
Incremental shares attributable to share-based compensation plans (in shares)	3,000,000	3,000,000	5,000,000	0
Weighted-average common shares outstanding – diluted (in shares)	2,039,000,000	2,031,000,000	2,039,000,000	2,026,000,000
Earnings/(Loss) per common share
Basic (usd per share)	$ 1.08	$ 0.60	$ 2.93	$ (4.45)
Diluted (usd per share)	$ 1.08	$ 0.60	$ 2.93	$ (4.45)
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	21,000,000	25,000,000	18,000,000	41,000,000