SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Revenues	$ 7,945	$ 6,007	$ 6,273	$ 5,920	$ 5,973	$ 5,691	$ 5,704	$ 5,193	$ 26,145	$ 22,561	$ 20,776
Gross Margin	5,453	4,217	4,301	4,096	4,303	4,063	4,099	3,629	18,067	16,094
Net Earnings	(1,060)	1,366	1,439	1,715	1,158	1,912	382	1,495	3,460	4,947	975
Net Earnings/(Loss) Attributable to Noncontrolling Interest	(4)	13	7	5	(2)	11	9	9	21	27	(32)
Net Earnings/(Loss) Attributable to BMS	$ (1,056)	$ 1,353	$ 1,432	$ 1,710	$ 1,160	$ 1,901	$ 373	$ 1,486	$ 3,439	$ 4,920	$ 1,007
Earnings per Share - Basic	$ (0.55)	$ 0.83	$ 0.88	$ 1.05	$ 0.71	$ 1.16	$ 0.23	$ 0.91	$ 2.02	$ 3.01	$ 0.61
Earnings per Share - Diluted	(0.55)	0.83	0.87	1.04	0.71	1.16	0.23	0.91	2.01	3.01	0.61
Common Stock, Dividends, Per Share, Declared	$ 0.45	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.40	$ 0.40	$ 0.40	$ 1.68	$ 1.61	$ 1.57
Cash and cash equivalents	$ 12,346	$ 30,489	$ 28,404	$ 7,335	$ 6,911	$ 5,408	$ 4,999	$ 5,342	$ 12,346	$ 6,911
Marketable securities	3,814	2,978	1,947	2,662	3,623	3,298	3,057	3,548	3,814	3,623
Total Assets	129,944	57,433	55,163	34,834	34,986	33,734	32,641	33,083	129,944	34,986
Long-term Debt	46,150	24,390	24,433	5,635	6,895	5,687	5,671	5,775	46,150	6,895
Equity	51,698	17,754	16,151	15,317	14,127	13,750	12,418	12,906	51,698	14,127
Specified Items
Cost of products sold	685	22	139	12	18	13	14	13	858	58
Marketing, selling and administrative	35	0	0	1	1	0	0	1	36	2
Research and development	142	20	44	51	22	18	1,094	80	257	1,214
Amortization of Acquired Intangible Assets - Specified Items	1,062	0	0	0					1,062
Other income (net)	962	798	429	73	392	(133)	380	7	2,262	646
Increase/(decrease) to pretax income	2,886	840	612	137	433	(102)	1,488	101	4,475	1,920
Income tax on items above	(264)	(275)	(105)	(43)	(43)	1	(218)	(8)	(687)	(268)
Otezla Divestiture Tax Impact - Specified	808	0	0	0					808
Impact of 2017 Tax Act - Specified					(7)	(20)	3	(32)		(56)
Income taxes	544	(275)	(105)	(43)	(50)	(19)	(215)	(40)	121	(324)
Increase/(decrease) to Net Earnings	3,430	565	507	94	383	(121)	1,273	61	4,596	1,596
Unwind of Inventory Fair Value Adjustments [Member]
Specified Items
Increase/(decrease) to pretax income	660	0	0	0					660
License and asset acquisition charges
Specified Items
Increase/(decrease) to pretax income	0	0	25	0	0	0	1,075	60	25	1,135
IPRD Impairments [Member]
Specified Items
Increase/(decrease) to pretax income	0	0	0	32					32
Interest Expense [Member]
Specified Items
Increase/(decrease) to pretax income	73	166	83	0					322
Pension charges [Member]
Specified Items
Increase/(decrease) to pretax income	(3)	1,545	44	49	26	27	37	31	1,635	121
Royalties and licensing income [Member]
Specified Items
Increase/(decrease) to pretax income	(15)	(9)	0	0	0	0	(25)	(50)	(24)	(75)
Divestiture gains [Member]
Specified Items
Increase/(decrease) to pretax income	3	(1,179)	8	0	(1)	(108)	(25)	(43)	(1,168)	(177)
Acquisition expenses [Member]
Specified Items
Increase/(decrease) to pretax income	182	7	303	165					657
Contingent Value Rights [Member]
Specified Items
Increase/(decrease) to pretax income	523	0	0	0					523
Investment Income [Member]
Specified Items
Increase/(decrease) to pretax income	(44)	(99)	(54)	0					(197)
Integration expenses [Member]
Specified Items
Increase/(decrease) to pretax income	191	96	106	22					415
Provision For Restructuring [Member]
Specified Items
Increase/(decrease) to pretax income	269	10	10	12	29	45	37	20	301	131
Loss/(gain) on equity investments [Member]
Specified Items
Increase/(decrease) to pretax income	(294)	261	(71)	(175)	268	(97)	356	(15)	(279)	512
Litigation Charges Recoveries [Member]
Specified Items
Increase/(decrease) to pretax income	75	0	0	0	70	0	0	0	75	70
Intangible asset impairment [Member]
Specified Items
Increase/(decrease) to pretax income	0	0	0	0	0	0	0	64	0	64
Other Expense [Member]
Specified Items
Increase/(decrease) to pretax income	2	0	0	0					2
Cost of products sold [Member] | Employee compensation charges [Member]
Specified Items
Increase/(decrease) to pretax income	1	0	0	0					1
Cost of products sold [Member] | Accelerated Depreciation and Other Shutdown Costs [Member]
Specified Items
Increase/(decrease) to pretax income	24	22	139	12	18	13	14	13	197	58
Selling, General and Administrative Expenses [Member] | Employee compensation charges [Member]
Specified Items
Increase/(decrease) to pretax income	27	0	0	0					27
Selling, General and Administrative Expenses [Member] | Accelerated Depreciation and Other Shutdown Costs [Member]
Specified Items
Increase/(decrease) to pretax income	8	0	0	1					9
Research and development [Member] | Employee compensation charges [Member]
Specified Items
Increase/(decrease) to pretax income	33	0	0	0					33
Research and development [Member] | Accelerated Depreciation and Other Shutdown Costs [Member]
Specified Items
Increase/(decrease) to pretax income	$ 109	$ 20	$ 19	$ 19	$ 22	$ 18	$ 19	$ 20	$ 167	$ 79