LIABILITIES FOR FUTURE POLICYHOLDER BENEFITS - Schedule of Liability for Future Policy Benefits, Undiscounted and Discounted Expected Gross Premiums and Expected Future Benefits and Expenses (Details) - Payout-Legacy - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	$ 686	$ 508
Expected future gross premiums (undiscounted)	0	0
Expected future benefit payments and expenses (discounted)	447	340
Expected future gross premiums (discounted)	$ 0	$ 0