SEGMENT INFORMATION - Narrative (Details) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
Dec. 31, 2022 segment	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) segment	Jun. 30, 2022 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment	2			2
Member co-share amounts and government subsidies		$ 5,000	$ 4,800	$ 9,000	$ 8,800
Depreciation and amortization classified as benefit expense		$ 34	$ 29	$ 67	$ 59

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-18

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration