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) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Term
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	$ 5,899	$ 6,002
Expected future gross premiums (undiscounted)	7,015	7,245
Expected future benefit payments and expenses (discounted)	3,242	3,449
Expected future gross premiums (discounted)	3,593	3,883
Payout - Legacy
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	4,872	3,947
Expected future gross premiums (undiscounted)	0	0
Expected future benefit payments and expenses (discounted)	3,105	2,607
Expected future gross premiums (discounted)	0	0
Payout - Non-Legacy
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	759	801
Expected future gross premiums (undiscounted)	0	0
Expected future benefit payments and expenses (discounted)	1,437	1,460
Expected future gross premiums (discounted)	0	0
Group Pension
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	683	730
Expected future gross premiums (undiscounted)	0	0
Expected future benefit payments and expenses (discounted)	456	563
Expected future gross premiums (discounted)	0	0
Health
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	2,375	2,510
Expected future gross premiums (undiscounted)	90	99
Expected future benefit payments and expenses (discounted)	1,403	1,533
Expected future gross premiums (discounted)	$ 69	$ 78