SUBSEQUENT EVENTS - (Details) - Subsequent Event - USD ($)			1 Months Ended	3 Months Ended
	Oct. 19, 2015	Oct. 01, 2015	Oct. 31, 2015	Dec. 31, 2015
Mercury (Cayman) Holdings
Business Acquisition [Line Items]
Consideration transferred to acquire business	$ 838,000,000
Sprout Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Consideration transferred to acquire business		$ 1,000,000,000
Payment to acquire business		530,000,000
Payable incurred to acquire business		$ 500,000,000
License Agreement
Business Acquisition [Line Items]
Up-front payment for license agreement			$ 100,000,000
Expected payment for pre-launch milestones related to license agreement, maximum				$ 170,000,000
Expected sale-related milestone payments related to license agreement, maximum				$ 175,000,000