SHARE-BASED COMPENSATION - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Components and classification of share-based compensation expense
Share-based compensation expense	$ 27	$ 24
Research and development expenses
Components and classification of share-based compensation expense
Share-based compensation expense	3	2
Selling, general and administrative expenses
Components and classification of share-based compensation expense
Share-based compensation expense	24	22
Stock options
Components and classification of share-based compensation expense
Share-based compensation expense	4	6
RSUs
Components and classification of share-based compensation expense
Share-based compensation expense	$ 23	$ 18

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Balance Type:	debit
Period Type:	duration