INVESTMENTS - Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net Investment Income [Line Items]
Gross investment income (loss)	$ 980	$ 867	$ 2,878	$ 2,458
Investment expenses	(87)	(79)	(242)	(220)
Net investment income (loss)	893	788	2,636	2,238
Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	597	867	2,170	2,458
Investment expenses	(49)	(79)	(174)	(220)
Net investment income (loss)	548	788	1,996	2,238
Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	383	0	708	0
Investment expenses	(38)	0	(68)	0
Net investment income (loss)	345	0	640	0
Fixed maturities
Net Investment Income [Line Items]
Gross investment income (loss)	683	663	2,042	1,830
Fixed maturities | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	401	663	1,488	1,830
Fixed maturities | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	282	0	554	0
Mortgage loans on real estate
Net Investment Income [Line Items]
Gross investment income (loss)	224	147	599	423
Mortgage loans on real estate | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	136	147	424	423
Mortgage loans on real estate | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	88	0	175	0
Policy loans
Net Investment Income [Line Items]
Gross investment income (loss)	50	50	147	151
Policy loans | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	43	50	140	151
Policy loans | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	7	0	7	0
Other equity investments
Net Investment Income [Line Items]
Gross investment income (loss)	30	(1)	65	57
Other equity investments | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	30	(1)	100	57
Other equity investments | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	0	0	(35)	0
Trading securities
Net Investment Income [Line Items]
Gross investment income (loss)	(9)	(6)	11	(47)
Trading securities | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	(9)	(6)	11	(47)
Trading securities | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	0	0	0	0
Other investment income
Net Investment Income [Line Items]
Gross investment income (loss)	2	14	14	44
Other investment income | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	(4)	14	7	44
Other investment income | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Gross investment income (loss)	$ 6	$ 0	$ 7	$ 0