FAIR VALUE OF ASSETS AND LIABILITIES - Changes in Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2022	Sep. 30, 2023	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]
Fair Value, beginning of period		$ (11,257)		$ (13,611)
Total realized and unrealized gains (losses)					$ (972)	(8,065)
Reduction in estimates of ultimate losses		(4,615)		(6,269)
Increase in estimates of ultimate losses		393		1,599
Change in fair value (discount rate)		(808)		(2,328)
Paid losses		111		209
Other		(34)		(518)
Fair Value, end of period		(6,304)		(6,304)
Insurance Liabilities | Retained Business
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ (2,711)				(2,941)
Total realized and unrealized gains (losses)					(399)	(421)
Reduction in estimates of ultimate losses	(122)				(824)
Increase in estimates of ultimate losses	425				660
Change in fair value (discount rate)	(570)				(524)
Paid losses	98				294
Other	0				(5)
Fair Value, end of period	(2,542)				(2,542)	(2,941)
Insurance Liabilities | Ceded Business
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(2,273)				(2,605)
Total realized and unrealized gains (losses)					(573)	(7,644)
Reduction in estimates of ultimate losses	(317)				(942)
Increase in estimates of ultimate losses	144				354
Change in fair value (discount rate)	(84)				(28)
Paid losses	16				43
Other	0				0
Fair Value, end of period	(2,032)				(2,032)	(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	151				161
Total realized and unrealized gains (losses)	0				0
Purchases	246				290
Sales	0				0
Issuances	0				0
Settlements	(53)				(107)
Other	0				0
Transfers into Level 3	0				0
Transfers out of Level 3	0				0
Fair Value, end of period	344				344	161
Unrealized gains (losses) for assets still held	0				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	78				35
Total realized and unrealized gains (losses)	0				0
Purchases	0				43
Sales	0				0
Issuances	0				0
Settlements	0				0
Other	0				0
Transfers into Level 3	0				0
Transfers out of Level 3	0				0
Fair Value, end of period	78				78	35
Unrealized gains (losses) for assets still held	0				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 | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	476				607
Total realized and unrealized gains (losses)	(13)				(21)
Purchases	0				0
Sales	0				0
Issuances	0				0
Settlements	0				0
Other	(33)				(156)
Transfers into Level 3	0				0
Transfers out of Level 3	0				0
Fair Value, end of period	430				430	607
Unrealized gains (losses) for assets still held	0				0
Reinsurance recoverables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			1,881			1,881
Total realized and unrealized gains (losses)			201
Purchases			4
Sales			0
Issuances			0
Settlements			19
Other			(239)
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period			1,866
Unrealized gains (losses) for assets still held			222
Reinsurance recoverables | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	200				235
Total realized and unrealized gains (losses)	(21)				(56)
Purchases	0				0
Sales	0				0
Issuances	0				0
Settlements	0				0
Other	0				0
Transfers into Level 3	0				0
Transfers out of Level 3	0				0
Fair Value, end of period	179				179	235
Unrealized gains (losses) for assets still held	0				0
Net modified coinsurance receivable (payable) | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(81)				18
Total realized and unrealized gains (losses)	13				(86)
Purchases	0				0
Sales	0				0
Issuances	0				0
Settlements	0				0
Other	0				0
Transfers into Level 3	0				0
Transfers out of Level 3	0				0
Fair Value, end of period	(68)				(68)	18
Unrealized gains (losses) for assets still held	0				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		314	190	190		190
Total realized and unrealized gains (losses)		(22)	(9)	(38)
Purchases		232	5	439
Sales		0	(4)	0
Issuances		0	0	0
Settlements		(44)	(2)	(55)
Other		(114)	0	(117)
Transfers into Level 3		0	0	0
Transfers out of Level 3		0	0	(53)
Fair Value, end of period		366	180	366
Unrealized gains (losses) for assets still held		0	(9)	0
Fixed maturity securities | Corporate Securities | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	210				146
Total realized and unrealized gains (losses)	(5)				(4)
Purchases	0				46
Sales	0				0
Issuances	0				0
Settlements	0				(1)
Other	0				0
Transfers into Level 3	0				18
Transfers out of Level 3	0				0
Fair Value, end of period	205				205	146
Unrealized gains (losses) for assets still held	(4)				(3)
Fixed maturity securities | Structured securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		25	76	33		76
Total realized and unrealized gains (losses)		(2)	(4)	(2)
Purchases		150	0	175
Sales		0	(10)	(10)
Issuances		0	0	0
Settlements		(18)	(2)	(18)
Other		0	0	(10)
Transfers into Level 3		0	0	0
Transfers out of Level 3		0	(13)	(13)
Fair Value, end of period		155	47	155
Unrealized gains (losses) for assets still held		0	(4)	0
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	34				36
Total realized and unrealized gains (losses)	0				(2)
Purchases	0				0
Sales	0				0
Issuances	0				0
Settlements	0				0
Other	0				0
Transfers into Level 3	9				9
Transfers out of Level 3	0				0
Fair Value, end of period	43				43	36
Unrealized gains (losses) for assets still held	0				(2)
Fixed maturity securities | Foreign corporate private securities | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	3				0
Total realized and unrealized gains (losses)	0				0
Purchases	5				10
Sales	0				0
Issuances	0				0
Settlements	(3)				(5)
Other	0				0
Transfers into Level 3	0				0
Transfers out of Level 3	0				0
Fair Value, end of period	5				5	0
Unrealized gains (losses) for assets still held	0				0
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	208				155
Total realized and unrealized gains (losses)	0				(2)
Purchases	6				62
Sales	0				0
Issuances	0				0
Settlements	(1)				(2)
Other	0				0
Transfers into Level 3	0				0
Transfers out of Level 3	0				0
Fair Value, end of period	213				213	155
Unrealized gains (losses) for assets still held	$ (1)				$ (2)
Fixed maturity securities | Other assets
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		0
Purchases		71		71
Sales		0		0
Issuances		0		0
Settlements		0		0
Other		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		71		71
Unrealized gains (losses) for assets still held		0		0
Fixed maturity securities | Secured receivable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		1,555		1,622
Total realized and unrealized gains (losses)		(9)		(59)
Purchases		22		22
Sales		(60)		(75)
Issuances		0		0
Settlements		0		0
Other		(1,508)		(1,510)
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		0		0
Unrealized gains (losses) for assets still held		0		0
Fixed maturity securities | Deposit asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		2,158		2,615
Total realized and unrealized gains (losses)		(3)		(144)
Purchases		0		0
Sales		0		0
Issuances		0		0
Settlements		0		0
Other		(1,296)		(1,612)
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		859		859
Unrealized gains (losses) for assets still held		0		0
Fixed maturity securities | Reinsurance recoverables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		378		344
Total realized and unrealized gains (losses)		(158)		(124)
Purchases		0		0
Sales		0		0
Issuances		0		0
Settlements		0		0
Other		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		220		220
Unrealized gains (losses) for assets still held		0		0
Fixed maturity securities | Net modified coinsurance receivable (payable)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		215		5
Total realized and unrealized gains (losses)		(145)		65
Purchases		0		0
Sales		0		0
Issuances		0		0
Settlements		0		0
Other		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		70		70
Unrealized gains (losses) for assets still held		$ 0		$ 0
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