COMMITMENTS, GUARANTEES AND CONTINGENCIES (Details) beneficiary in Millions, $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) State	Sep. 30, 2020 USD ($) State	Sep. 30, 2020 USD ($) beneficiary State	Dec. 31, 2021	Dec. 31, 2019	Nov. 02, 2017 USD ($)
Loss Contingencies [Line Items]
Percentage of risk score calculated from claims submitted through EDS			50.00%		25.00%
Number of states comprising TRICARE beneficiaries | State	32	32	32
Number of TRICARE beneficiaries | beneficiary			6
US Risk Corridor Premium Stabilization Program
Loss Contingencies [Line Items]
Litigation recoveries sought						$ 611
Payment received upon judgement	$ 609	$ 609	$ 609
Related legal fees and expenses		$ 31	$ 31
Tricare East Region Contract
Loss Contingencies [Line Items]
Contract term years			5 years
Medicare
Loss Contingencies [Line Items]
Percentage of premiums and services revenue			82.00%
Military services
Loss Contingencies [Line Items]
Percentage of premiums and services revenue			1.00%
Medicaid
Loss Contingencies [Line Items]
Percentage of premiums and services revenue			5.00%
Forecast
Loss Contingencies [Line Items]
Percentage of risk score calculated from claims submitted through EDS				75.00%