LIABILITIES FOR FUTURE POLICYHOLDER BENEFITS - Policyholder Account Balance (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for additional liability	$ 1,801		$ 1,653	$ 1,450	$ 1,298
Payout-Legacy
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Net liability for additional liability	447		340
Payout-Legacy | Legacy Segment
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]
Balance, beginning of period	340	$ 0
Beginning balance of original discount rate	333	0
Effect of changes in cash flow assumptions			0			$ 0
Effect of actual variances from expected experience			0			0
Adjusted beginning of period balance			$ 333			$ 0
Issuances	119	0
Interest accrual	4	0
Benefit payments	(8)	0
Ending balance at original discount rate	448	0
Effect of changes in discount rate assumptions	(1)	0
Balance, end of period	447	0
Net liability for additional liability	447	0
Less: Reinsurance recoverable	0	0
Net liability for additional liability, after reinsurance recoverable	$ 447	$ 0
Weighted-average duration of additional liability - death benefit (years)	7 years 8 months 12 days