SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Revenues	$ 5,973	$ 5,691	$ 5,704	$ 5,193	$ 5,449	$ 5,254	$ 5,144	$ 4,929	$ 22,561	$ 20,776	$ 19,427
Gross Margin	4,283	4,043	4,079	3,609	3,768	3,675	3,575	3,664	16,014	14,682
Net Earnings	1,158	1,912	382	1,495	(2,329)	856	922	1,526	4,947	975	4,507
Net Earnings/(Loss) Attributable to Noncontrolling Interest	(2)	11	9	9	(1)	11	6	(48)	27	(32)	50
Net Earnings/(Loss) Attributable to BMS	$ 1,160	$ 1,901	$ 373	$ 1,486	$ (2,328)	$ 845	$ 916	$ 1,574	$ 4,920	$ 1,007	$ 4,457
Earnings per Share - Basic	$ 0.71	$ 1.16	$ 0.23	$ 0.91	$ (1.42)	$ 0.52	$ 0.56	$ 0.95	$ 3.01	$ 0.61	$ 2.67
Earnings per Share - Diluted	0.71	1.16	0.23	0.91	(1.42)	0.51	0.56	0.94	3.01	0.61	2.65
Common Stock, Dividends, Per Share, Declared	$ 0.41	$ 0.40	$ 0.40	$ 0.40	$ 0.40	$ 0.39	$ 0.39	$ 0.39	$ 1.61	$ 1.57	$ 1.53
Cash and cash equivalents	$ 6,911	$ 5,408	$ 4,999	$ 5,342	$ 5,421	$ 4,644	$ 3,470	$ 3,910	$ 6,911	$ 5,421	$ 4,237	$ 2,385
Marketable securities	3,748	3,439	3,193	3,680	3,871	5,004	5,615	4,884	3,748	3,871
Total Assets	34,986	33,734	32,641	33,083	33,551	33,977	33,409	32,937	34,986	33,551
Long-term Debt	6,895	5,687	5,671	5,775	6,975	6,982	6,911	7,237	6,895	6,975
Equity	14,127	13,750	12,418	12,906	11,847	14,914	14,821	14,535	14,127	11,847
Specified Items
Cost of products sold	18	13	14	13	18	1	130	0	58	149
Marketing, selling and administrative	1	0	0	1	1	0	0	0	2	1
Research and development	22	18	1,094	80	528	374	489	197	1,214	1,588
Other income (net)	392	(133)	380	7	131	50	(337)	(384)	646	(540)
Increase/(decrease) to pretax income	433	(102)	1,488	101	678	425	282	(187)	1,920	1,198
Income tax on items above	(43)	1	(218)	(8)	(138)	(41)	20	72	(268)	(87)
Income taxes attributed to U.S. tax reform	(7)	(20)	3	(32)	2,911	0	0	0	(56)	2,911
Income taxes	(50)	(19)	(215)	(40)	2,773	(41)	20	72	(324)	2,824
Increase/(decrease) to Net Earnings	383	(121)	1,273	61	3,451	384	302	(115)	1,596	4,022
Noncontrolling interest - specified items					0	0	0	(59)		(59)
Increase/(decrease) to net earnings used for Dilutd Non-GAAP EPS					3,451	384	302	(174)		3,963
License and asset acquisition charges
Specified Items
Increase/(decrease) to pretax income	0	0	1,075	60	377	310	393	50	1,135	1,130
IPRD impairments [Member]
Specified Items
Increase/(decrease) to pretax income					0	0	0	75		75
Site exit costs and other [Member]
Specified Items
Increase/(decrease) to pretax income	22	18	19	20	151	64	96	72	79	383
Loss/(gain) on equity investments [Member]
Specified Items
Increase/(decrease) to pretax income	268	(97)	356	(15)					512
Provision for restructuring [Member]
Specified Items
Increase/(decrease) to pretax income	29	45	37	20	86	28	15	164	131	293
Litigation and other settlements [Member]
Specified Items
Increase/(decrease) to pretax income	70	0	0	0	0	0	0	(481)	70	(481)
Divestiture gains [Member]
Specified Items
Increase/(decrease) to pretax income	(1)	(108)	(25)	(43)	(26)	0	0	(100)	(177)	(126)
Royalties and licensing income [Member]
Specified Items
Increase/(decrease) to pretax income	0	0	(25)	(50)	0	0	(497)	0	(75)	(497)
Pension charges [Member]
Specified Items
Increase/(decrease) to pretax income	26	27	37	31	71	22	36	33	121	162
Intangible asset impairment [Member]
Specified Items
Increase/(decrease) to pretax income	$ 0	$ 0	$ 0	$ 64					$ 64
Loss on debt redemption [Member]
Specified Items
Increase/(decrease) to pretax income					$ 0	$ 0	$ 109	$ 0		$ 109