DIVESTITURES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses	$ 364	$ 137	$ 947	$ 526
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	(108)	1	(178)	(126)
Business Sale Royalty Income	(217)	(136)	(644)	(420)
Mature brand, Cheplapharm [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses			153
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal			127
Manufacturing Facility in Swords, Ireland [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses			159
Divestiture and other proceeds					$ 165
Diabetes business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses	165	82	408	333
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal				(100)
Business Sale Royalty Income	(170)	(78)	(497)	(252)
Other Income				100
Erbitux [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses	59	54	168	162
Business Sale Royalty Income	(48)	(56)	(145)	(164)
Other [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses	140	1	212	31
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	(108)	1	(178)	(26)
Business Sale Royalty Income	$ 1	$ (2)	$ (2)	(4)
Biogen [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Collaborators				300
Potential Milestone Receipts					410
Roche [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Collaborators				$ 170
Potential Milestone Receipts					$ 205