BUSINESS SEGMENT INFORMATION (Net Sales of Key Products) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net product sales									$ 19,258	$ 17,702	$ 14,045
Alliance revenues									1,518	1,725	2,515
Other revenues									224	96	107
Total Revenues	$ 5,449	$ 5,254	$ 5,144	$ 4,929	$ 5,243	$ 4,922	$ 4,871	$ 4,391	20,776	19,427	16,560
Opdivo [Member]
Segment Reporting Information [Line Items]
Total Revenues									4,948	3,774	942
Eliquis [Member]
Segment Reporting Information [Line Items]
Total Revenues									4,872	3,343	1,860
Orencia [Member]
Segment Reporting Information [Line Items]
Total Revenues									2,479	2,265	1,885
Sprycel [Member]
Segment Reporting Information [Line Items]
Total Revenues									2,005	1,824	1,620
Yervoy [Member]
Segment Reporting Information [Line Items]
Total Revenues									1,244	1,053	1,126
Empliciti [Member]
Segment Reporting Information [Line Items]
Total Revenues									231	150	3
Baraclude [Member]
Segment Reporting Information [Line Items]
Total Revenues									1,052	1,192	1,312
Sustiva Franchise [Member]
Segment Reporting Information [Line Items]
Total Revenues									729	1,065	1,252
Reyataz [Member]
Segment Reporting Information [Line Items]
Total Revenues									698	912	1,139
Hepatitis C Franchise [Member]
Segment Reporting Information [Line Items]
Total Revenues									406	1,578	1,603
Other Brands [Member]
Segment Reporting Information [Line Items]
Total Revenues									2,112	2,271	3,818
Alliance Partners [Member]
Segment Reporting Information [Line Items]
Net product sales									6,949	5,568	4,308
Alliance revenues									1,294	1,629	2,408
Total Revenues									$ 8,243	$ 7,197	$ 6,716