FAIR VALUE OF ASSETS AND LIABILITIES - SUCCESSOR COMPANY - Changes in Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Secured receivable | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			$ 1,622
Total realized and unrealized gains (losses)			(59)
Purchases			22
Sales			(75)
Issuances			0
Settlements			0
Other			(1,510)
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period	$ 0	$ 1,622	0
Unrealized gains (losses) for assets still held			0
Deposit asset | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			2,596
Total realized and unrealized gains (losses)			(117)
Purchases			0
Sales			0
Issuances			0
Settlements			0
Other			(1,872)
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period	607	2,596	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		1,881	1,866	$ 409
Total realized and unrealized gains (losses)		201		(153)
Purchases		4		17
Sales		0		0
Issuances		0		245
Settlements		19		0
Other		(239)		1,363
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		1,866		1,881
Unrealized gains (losses) for assets still held		222		(136)
Reinsurance recoverables | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			250
Total realized and unrealized gains (losses)			(15)
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	235	250	235
Unrealized gains (losses) for assets still held			0
Net modified coinsurance receivable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)	(5,640)
Net modified coinsurance receivable | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)	0
Net modified coinsurance receivable | Ceded Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			68
Total realized and unrealized gains (losses)	(5,640)		(50)
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	18	68	18
Unrealized gains (losses) for assets still held			0
Fixed maturity securities | U.S. corporate private securities | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			0
Total realized and unrealized gains (losses)			(6)
Purchases			152
Sales			0
Issuances			0
Settlements			0
Other			0
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period	146	0	146
Unrealized gains (losses) for assets still held			(6)
Fixed maturity securities | Foreign corporate public securities | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			0
Total realized and unrealized gains (losses)			(10)
Purchases			46
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	0	36
Unrealized gains (losses) for assets still held			(10)
Fixed maturity securities | Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		76	47	19
Total realized and unrealized gains (losses)		(4)		1
Purchases		0		261
Sales		(10)		0
Issuances		0		0
Settlements		(2)		(8)
Other		0		(33)
Transfers into Level 3		0		31
Transfers out of Level 3		(13)		(195)
Fair Value, end of period		47		76
Unrealized gains (losses) for assets still held		(4)		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			0
Total realized and unrealized gains (losses)			(5)
Purchases			160
Sales			0
Issuances			0
Settlements			0
Other			0
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period	155	0	155
Unrealized gains (losses) for assets still held			(5)
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		1		4
Total realized and unrealized gains (losses)				0
Purchases				0
Sales				0
Issuances				0
Settlements				0
Other				(3)
Transfers into Level 3				0
Transfers out of Level 3				0
Fair Value, end of period				1
Unrealized gains (losses) for assets still held				$ 1
Equity securities | Residential mortgage loans | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			0
Total realized and unrealized gains (losses)			0
Purchases			168
Sales			0
Issuances			0
Settlements			(7)
Other			0
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period	161	0	161
Unrealized gains (losses) for assets still held			0
Equity securities | Commercial mortgage loans | Retained Business
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period			0
Total realized and unrealized gains (losses)			0
Purchases			35
Sales			0
Issuances			0
Settlements			0
Other			0
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period	$ 35	$ 0	35
Unrealized gains (losses) for assets still held			$ 0