INVESTMENTS - Investment Gains (Losses), Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net Investment Income [Line Items]
Investment gains (losses), net	$ (18)	$ (58)	$ (56)	$ (136)
Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	(16)	(22)	(18)	(100)
Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	(2)	(36)	(38)	(36)
Fixed maturities
Net Investment Income [Line Items]
Investment gains (losses), net	(4)	(49)	(30)	(120)
Fixed maturities | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	(3)	(15)	(6)	(86)
Fixed maturities | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	(1)	(34)	(24)	(34)
Mortgage loans on real estate
Net Investment Income [Line Items]
Investment gains (losses), net	(13)	(7)	(29)	(16)
Mortgage loans on real estate | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	(12)	(5)	(15)	(14)
Mortgage loans on real estate | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	(1)	(2)	(14)	(2)
Other equity investments
Net Investment Income [Line Items]
Investment gains (losses), net	0	0	0	0
Other equity investments | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	0	0	0	0
Other equity investments | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	0	0	0	0
Other
Net Investment Income [Line Items]
Investment gains (losses), net	(1)	(2)	3	0
Other | Excluding Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	(1)	(2)	3	0
Other | Funds Withheld and NI Modco
Net Investment Income [Line Items]
Investment gains (losses), net	$ 0	$ 0	$ 0	$ 0