INVESTMENTS - Accrued Investment Income (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Net Investment Income [Line Items]
Total accrued investment income	$ 60	$ 60
Retained Business
Net Investment Income [Line Items]
Total accrued investment income	52	51
Ceded Business
Net Investment Income [Line Items]
Total accrued investment income	8	9
Fixed maturity securities
Net Investment Income [Line Items]
Total accrued investment income	57	56
Fixed maturity securities | Retained Business
Net Investment Income [Line Items]
Total accrued investment income	50	48
Fixed maturity securities | Ceded Business
Net Investment Income [Line Items]
Total accrued investment income	7	8
Mortgage loans
Net Investment Income [Line Items]
Total accrued investment income	0	3
Mortgage loans | Retained Business
Net Investment Income [Line Items]
Total accrued investment income	0	3
Mortgage loans | Ceded Business
Net Investment Income [Line Items]
Total accrued investment income	0	0
Short-term investments and cash equivalents
Net Investment Income [Line Items]
Total accrued investment income	3	1
Short-term investments and cash equivalents | Retained Business
Net Investment Income [Line Items]
Total accrued investment income	2	0
Short-term investments and cash equivalents | Ceded Business
Net Investment Income [Line Items]
Total accrued investment income	$ 1	$ 1