LICENSING ARRANGEMENTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017
Halozyme [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payments for licensing and alliance arrangements		$ 105
Collaborative Arrangement Contingent Payments Maximum Exposure	$ 160
CytomX [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payments for licensing and alliance arrangements		75
Collaborative Arrangement Contingent Payments Maximum Exposure	448
Payment for Additional Targets Made To Collaborative Partner		200
Biogen [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from out-licensed arrangements		300
Potential Milestone Receipts	$ 360
Roche [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from out-licensed arrangements		170
F-Star [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)		$ 75