ACQUISITIONS (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Asset acquisition [Line Items]
Asset acquisition upfront payment	$ 185	$ 1,014
Upfront payment allocated to research and development expenses	174	967
Deferred tax assets related to asset acquisition	11	47
Contingent and regulatory milestone payments	938	2,325
Cormorant [Member]
Asset acquisition [Line Items]
Asset acquisition upfront payment	35
Upfront payment allocated to research and development expenses	35
Contingent and regulatory milestone payments	485
Padlock Therapeutics, Inc. [Member]
Asset acquisition [Line Items]
Asset acquisition upfront payment	150
Upfront payment allocated to research and development expenses	139
Deferred tax assets related to asset acquisition	11
Contingent and regulatory milestone payments	453
Cardioxyl Pharmaceuticals, Inc. [Member]
Asset acquisition [Line Items]
Asset acquisition upfront payment		200
Upfront payment allocated to research and development expenses		167
Deferred tax assets related to asset acquisition		33
Contingent and regulatory milestone payments		1,875
Flexus Biosciences, Inc. [Member]
Asset acquisition [Line Items]
Asset acquisition upfront payment		814
Upfront payment allocated to research and development expenses		800
Deferred tax assets related to asset acquisition		14
Contingent and regulatory milestone payments		450
Acquisition costs		$ 14
Milestone achieved and paid	$ 100
iPierian, Inc. [Member]
Asset acquisition [Line Items]
Asset acquisition upfront payment			$ 175
Upfront payment allocated to research and development expenses			148
Deferred tax assets related to asset acquisition			27
Contingent and regulatory milestone payments			$ 554