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	Jun. 30, 2024	Dec. 31, 2023
Term
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	$ 5,677	$ 5,860
Expected future gross premiums (undiscounted)	6,802	6,956
Expected future benefit payments and expenses (discounted)	3,232	3,466
Expected future gross premiums (discounted)	3,613	3,862
Payout - Legacy
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	5,798	5,204
Expected future gross premiums (undiscounted)	0	0
Expected future benefit payments and expenses (discounted)	3,820	3,538
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)	1,404	1,426
Expected future gross premiums (undiscounted)	0	0
Expected future benefit payments and expenses (discounted)	767	812
Expected future gross premiums (discounted)	0	0
Group Pension
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	640	668
Expected future gross premiums (undiscounted)	0	0
Expected future benefit payments and expenses (discounted)	439	471
Expected future gross premiums (discounted)	0	0
Health
Liability for Future Policy Benefit, Activity [Line Items]
Expected future benefit payments and expenses (undiscounted)	2,246	2,318
Expected future gross premiums (undiscounted)	78	85
Expected future benefit payments and expenses (discounted)	1,378	1,468
Expected future gross premiums (discounted)	$ 61	$ 68