FAIR VALUE OF ASSETS AND LIABILITIES - Changes in Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Future policy benefits
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		$ 4,060	$ 4,060
Total realized and unrealized gains (losses)		715
Purchases		0
Sales		0
Issuances		(48)
Settlements		0
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period		3,393
Unrealized gains (losses) for liabilities still held		686
Policyholders' account balances
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		2,041	2,041
Total realized and unrealized gains (losses)		124
Purchases		0
Sales		0
Issuances		0
Settlements		(17)
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period		1,934
Unrealized gains (losses) for liabilities still held		89
Insurance Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)	$ 205		(8,065)
Insurance Liabilities | Retained Business
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	2,941
Total realized and unrealized gains (losses)	115		(421)
Reduction in estimates of ultimate losses	(348)
Increase in estimates of ultimate losses	132
Change in fair value (discount rate)	235
Paid losses	100
Other	(4)
Fair Value, end of period	3,056		2,941
Insurance Liabilities | Ceded Business
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	2,605
Total realized and unrealized gains (losses)	90		(7,644)
Reduction in estimates of ultimate losses	(66)
Increase in estimates of ultimate losses	67
Change in fair value (discount rate)	76
Paid losses	13
Other	0
Fair Value, end of period	2,695		2,605
Residential mortgage loans | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	161
Total realized and unrealized gains (losses)	0
Purchases	13
Sales	0
Issuances	0
Settlements	(16)
Other	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, end of period	158		161
Unrealized gains (losses) for assets still held	0
Commercial mortgage-backed securities | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	35
Total realized and unrealized gains (losses)	0
Purchases	13
Sales	0
Issuances	0
Settlements	0
Other	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, end of period	48		35
Unrealized gains (losses) for assets still held	0
Short term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		13	13
Total realized and unrealized gains (losses)		0
Purchases		0
Sales		0
Issuances		0
Settlements		(13)
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period		0
Unrealized gains (losses) for assets still held		0
Cash equivalents
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		8	8
Total realized and unrealized gains (losses)		0
Purchases		0
Sales		0
Issuances		0
Settlements		(8)
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period		0
Unrealized gains (losses) for assets still held		0
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		400	400
Total realized and unrealized gains (losses)		(21)
Purchases		13
Sales		0
Issuances		0
Settlements		(16)
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period		376
Unrealized gains (losses) for assets still held		(6)
Deposit asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	607
Total realized and unrealized gains (losses)	1
Purchases	0
Sales	0
Issuances	0
Settlements	0
Other	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, end of period	608		607
Unrealized gains (losses) for assets still held	0
Reinsurance recoverables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	235	1,881	1,881
Total realized and unrealized gains (losses)	12	201
Purchases	0	4
Sales	0	0
Issuances	0	0
Settlements	0	19
Other	0	(239)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, end of period	247	1,866	235
Unrealized gains (losses) for assets still held	0	222
Net Modified Coinsurance Receivable (Payable)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	18
Total realized and unrealized gains (losses)	(63)
Purchases	0
Sales	0
Issuances	0
Settlements	0
Other	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, end of period	(45)		18
Unrealized gains (losses) for assets still held	0
Fixed maturity securities | U.S Treasury securities and obligations of U.S. government authorities and agencies
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		0	0
Total realized and unrealized gains (losses)		0
Purchases		0
Sales		0
Issuances		0
Settlements		0
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period		0
Unrealized gains (losses) for assets still held		0
Fixed maturity securities | Corporate Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	146	190	190
Total realized and unrealized gains (losses)	0	(9)
Purchases	19	5
Sales	0	(4)
Issuances	0	0
Settlements	(1)	(2)
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	18	0
Fair Value, end of period	182	180	146
Unrealized gains (losses) for assets still held	0	(9)
Fixed maturity securities | Structured securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		76	76
Total realized and unrealized gains (losses)		(4)
Purchases		0
Sales		(10)
Issuances		0
Settlements		(2)
Other		0
Transfers into Level 3		0
Transfers out of Level 3		(13)
Fair Value, end of period		47
Unrealized gains (losses) for assets still held		(4)
Fixed maturity securities | Foreign corporate private securities | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	36
Total realized and unrealized gains (losses)	0
Purchases	0
Sales	0
Issuances	0
Settlements	0
Other	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, end of period	36		36
Unrealized gains (losses) for assets still held	1
Fixed maturity securities | Asset-backed securities | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	155
Total realized and unrealized gains (losses)	(2)
Purchases	38
Sales	0
Issuances	0
Settlements	0
Other	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, end of period	191		155
Unrealized gains (losses) for assets still held	$ (2)
Equity securities | Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		1	$ 1
Total realized and unrealized gains (losses)		0
Purchases		0
Sales		0
Issuances		0
Settlements		0
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period		1
Unrealized gains (losses) for assets still held		$ 0