FAIR VALUE OF ASSETS AND LIABILITIES - Quantitative Information Regarding Internally-Prices Level 3 Assets and Liabilities (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Assets
Debt securities, available-for-sale	$ 5,377	$ 5,210
Deposit asset	426	438
Liabilities:
Insurance liabilities, at fair value	4,545	5,003
Net modified coinsurance payable	72	78
Retained Business
Liabilities:
Insurance liabilities, at fair value	2,342	2,835
Net modified coinsurance payable	0	0
Ceded Business
Liabilities:
Insurance liabilities, at fair value	2,203	2,168
Net modified coinsurance payable	$ 72	$ 78
Level 3 | Minimum
Liabilities:
Policyholder age	45 years
Level 3 | Minimum | Mortality rate
Liabilities:
Insurance liability, measurement input	0
Level 3 | Maximum
Liabilities:
Policyholder age	90 years
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Equality volatility curve | Retained Business
Liabilities:
Insurance liability, measurement input	0.15	0.15
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Equality volatility curve | Ceded Business
Liabilities:
Insurance liability, measurement input	0.15	0.15
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Lapse rate | Retained Business
Liabilities:
Insurance liability, measurement input	0.0065	0.0065
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Lapse rate | Ceded Business
Liabilities:
Insurance liability, measurement input	0.0065	0.0065
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Spread over risk free | Retained Business
Liabilities:
Insurance liability, measurement input	0.0000	0.0000
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Spread over risk free | Ceded Business
Liabilities:
Insurance liability, measurement input	0.0000	0.0000
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Utilization rate | Retained Business
Liabilities:
Insurance liability, measurement input	0.875	0.875
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Utilization rate | Ceded Business
Liabilities:
Insurance liability, measurement input	0.875	0.875
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Mortality rate | Retained Business
Liabilities:
Insurance liability, measurement input	0	0
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Mortality rate | Ceded Business
Liabilities:
Insurance liability, measurement input	0	0
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | U.S. corporate private securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0495	0.0519
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Foreign corporate private securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0451	0.0465
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Asset-Backed Securities, Excluding Level 3 Externally Priced Securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0637	0.0637
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Commercial mortgage-backed securities | Discount rate | Retained Business
Assets
Loans receivable, measurement input		0.0587
Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Commercial mortgage-backed securities | Market yield | Retained Business
Assets
Loans receivable, measurement input	0.0630
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Equality volatility curve | Retained Business
Liabilities:
Insurance liability, measurement input	0.25	0.25
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Equality volatility curve | Ceded Business
Liabilities:
Insurance liability, measurement input	0.25	0.25
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Lapse rate | Retained Business
Liabilities:
Insurance liability, measurement input	0.13	0.13
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Lapse rate | Ceded Business
Liabilities:
Insurance liability, measurement input	0.13	0.13
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Spread over risk free | Retained Business
Liabilities:
Insurance liability, measurement input	0.0184	0.0194
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Spread over risk free | Ceded Business
Liabilities:
Insurance liability, measurement input	0.0170	0.0173
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Utilization rate | Retained Business
Liabilities:
Insurance liability, measurement input	1	1
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Utilization rate | Ceded Business
Liabilities:
Insurance liability, measurement input	1	1
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Mortality rate | Retained Business
Liabilities:
Insurance liability, measurement input	0.16	0.16
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Mortality rate | Ceded Business
Liabilities:
Insurance liability, measurement input	0.16	0.16
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | U.S. corporate private securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0894	0.0936
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Foreign corporate private securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0655	0.0678
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Asset-Backed Securities, Excluding Level 3 Externally Priced Securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.1217	0.1217
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Commercial mortgage-backed securities | Discount rate | Retained Business
Assets
Loans receivable, measurement input		0.0715
Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Commercial mortgage-backed securities | Market yield | Retained Business
Assets
Loans receivable, measurement input	0.0758
Level 3 | Valuation Technique, Discounted Cash Flow | Weighted Average | U.S. corporate private securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0681	0.0693
Level 3 | Valuation Technique, Discounted Cash Flow | Weighted Average | Foreign corporate private securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0553	0.0572
Level 3 | Valuation Technique, Discounted Cash Flow | Weighted Average | Asset-Backed Securities, Excluding Level 3 Externally Priced Securities | Discount rate | Retained Business
Assets
Debt securities, measurement input	0.0794	0.0796
Level 3 | Valuation Technique, Discounted Cash Flow | Weighted Average | Commercial mortgage-backed securities | Discount rate | Retained Business
Assets
Loans receivable, measurement input		0.0672
Level 3 | Valuation Technique, Discounted Cash Flow | Weighted Average | Commercial mortgage-backed securities | Market yield | Retained Business
Assets
Loans receivable, measurement input	0.0714
Level 3 | Valuation Technique, Level Yield | Minimum | Residential mortgage loans | Market yield | Retained Business
Assets
Loans receivable, measurement input	0.0539	0.0643
Level 3 | Valuation Technique, Level Yield | Maximum  | Residential mortgage loans | Market yield | Retained Business
Assets
Loans receivable, measurement input	0.1055	0.1161
Level 3 | Valuation Technique, Level Yield | Weighted Average | Residential mortgage loans | Market yield | Retained Business
Assets
Loans receivable, measurement input	0.0750	0.0794
Recurring
Assets
Debt securities, available-for-sale	$ 5,369	$ 5,202
Mortgage and other loans	425	437
Deposit asset	426	438
Liabilities:
Insurance liabilities, at fair value	4,545	5,003
Net modified coinsurance payable	72	78
Recurring | Retained Business
Assets
Debt securities, available-for-sale	4,115	4,150
Mortgage and other loans	425	437
Liabilities:
Insurance liabilities, at fair value	2,342	2,835
Recurring | Ceded Business
Assets
Debt securities, available-for-sale	1,254	1,052
Deposit asset	426	438
Liabilities:
Insurance liabilities, at fair value	2,203	2,168
Net modified coinsurance payable		78
Recurring | Foreign corporate private securities
Assets
Debt securities, available-for-sale	88	88
Recurring | Foreign corporate private securities | Retained Business
Assets
Debt securities, available-for-sale	57	56
Recurring | Foreign corporate private securities | Ceded Business
Assets
Debt securities, available-for-sale	31	32
Recurring | Commercial mortgage-backed securities
Assets
Debt securities, available-for-sale	12	12
Recurring | Commercial mortgage-backed securities | Retained Business
Assets
Debt securities, available-for-sale	12	12
Recurring | Level 3
Assets
Debt securities, available-for-sale	620	553
Mortgage and other loans	425	437
Deposit asset	426	438
Liabilities:
Insurance liabilities, at fair value	4,545	5,003
Net modified coinsurance payable	72	78
Recurring | Level 3 | Retained Business
Assets
Debt securities, available-for-sale	591	551
Mortgage and other loans	425	437
Liabilities:
Insurance liabilities, at fair value	2,342	2,835
Recurring | Level 3 | Ceded Business
Assets
Debt securities, available-for-sale	29	2
Deposit asset	426	438
Liabilities:
Insurance liabilities, at fair value	2,203	2,168
Net modified coinsurance payable		78
Recurring | Level 3 | Foreign corporate private securities
Assets
Debt securities, available-for-sale	57	57
Recurring | Level 3 | Foreign corporate private securities | Retained Business
Assets
Debt securities, available-for-sale	57	56
Recurring | Level 3 | Foreign corporate private securities | Ceded Business
Assets
Debt securities, available-for-sale	0	1
Recurring | Level 3 | Asset-Backed Securities, Excluding Level 3 Externally Priced Securities | Retained Business
Assets
Debt securities, available-for-sale	232	220
Recurring | Level 3 | Commercial mortgage-backed securities
Assets
Debt securities, available-for-sale	0	0
Recurring | Level 3 | Commercial mortgage-backed securities | Retained Business
Assets
Debt securities, available-for-sale	0	0
Recurring | Level 3 | Reinsurance recoverables | Ceded Business
Assets
Reinsurance recoverables	155	206
Recurring | Level 3 | Net modified coinsurance payable
Liabilities:
Net modified coinsurance payable	72	78
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | Retained Business
Liabilities:
Insurance liabilities, at fair value	2,342	2,835
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | Ceded Business
Liabilities:
Insurance liabilities, at fair value	2,203	2,168
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | U.S. corporate private securities | Retained Business
Assets
Debt securities, available-for-sale	227	203
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | Foreign corporate private securities | Retained Business
Assets
Debt securities, available-for-sale	37	36
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | Asset-Backed Securities, Excluding Level 3 Externally Priced Securities | Retained Business
Assets
Debt securities, available-for-sale	104	107
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | Commercial mortgage-backed securities | Retained Business
Assets
Mortgage and other loans	$ 78	$ 76
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | Minimum | Measurement Input, Withdrawal Rate
Liabilities:
Insurance liability, measurement input	0.88	0.88
Recurring | Level 3 | Valuation Technique, Discounted Cash Flow | Maximum  | Measurement Input, Withdrawal Rate
Liabilities:
Insurance liability, measurement input	1	1
Recurring | Level 3 | Valuation, Trade price | Asset-Backed Securities, Excluding Level 3 Externally Priced Securities | Retained Business
Assets
Debt securities, available-for-sale	$ 128	$ 113
Recurring | Level 3 | Valuation Technique, Level Yield | Residential mortgage loans | Retained Business
Assets
Mortgage and other loans	$ 347	$ 361