INVESTMENTS - Net Investment Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Net Investment Income [Line Items]
Gross investment income (loss)	$ 3,853	$ 3,926	$ 3,370
Investment expenses	(350)	(325)	(293)
Net investment income (loss)	3,503	3,601	3,077
Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	2,436	2,825	3,370
Investment expenses	(222)	(229)	(293)
Net investment income (loss)	2,214	2,596	3,077
Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	1,417	1,101	0
Investment expenses	(128)	(96)	0
Net investment income (loss)	1,289	1,005	0
Fixed maturities
Net Investment Income [Line Items]
Gross investment income (loss)	2,586	2,764	2,478
Fixed maturities | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	1,574	1,936	2,478
Fixed maturities | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	1,012	828	0
Mortgage loans on real estate
Net Investment Income [Line Items]
Gross investment income (loss)	915	803	586
Mortgage loans on real estate | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	581	542	586
Mortgage loans on real estate | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	334	261	0
Policy loans
Net Investment Income [Line Items]
Gross investment income (loss)	205	199	203
Policy loans | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	191	188	203
Policy loans | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	14	11	0
Other equity investments
Net Investment Income [Line Items]
Gross investment income (loss)	192	104	74
Other equity investments | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	169	125	74
Other equity investments | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	23	(21)	0
Trading securities
Net Investment Income [Line Items]
Gross investment income (loss)	50	26	(28)
Trading securities | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	50	26	(28)
Trading securities | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	0	0	0
Other investment income
Net Investment Income [Line Items]
Gross investment income (loss)	(95)	30	57
Other investment income | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	(129)	8	57
Other investment income | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	$ 34	$ 22	$ 0