DERIVATIVES - Derivatives by Category (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Total derivative instruments
Derivatives, Fair Value [Line Items]
Notional Amount	$ 19,092	$ 17,227
Notional Amount - FWH and NI Modco	71,910	66,813
Derivative Assets	11,581	9,189
Derivative Assets - FWH and NI Modco	12,009	10,034
Derivative Liabilities	22,905	18,412
Derivative Liabilities - FWH and NI Modco	2,571	2,204
Net Derivatives	(1,886)	(1,393)
Total embedded derivatives
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	8,372	6,729
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	11,171	9,181
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	(2,799)	(2,452)
SCS, SIO, MSO and IUL indexed features
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	8,664	7,140
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	11,200	9,081
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	(2,536)	(1,941)
Funds withheld payable
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	0	0
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	(29)	100
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	29	(100)
Modco payable
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	(292)	(411)
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	0	0
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	(292)	(411)
Derivatives: not designated for hedge accounting
Derivatives, Fair Value [Line Items]
Notional Amount	15,767	13,917
Notional Amount - FWH and NI Modco	71,910	66,813
Derivative Assets	3,127	2,381
Derivative Assets - FWH and NI Modco	12,009	10,034
Derivative Liabilities	11,315	8,830
Derivative Liabilities - FWH and NI Modco	2,571	2,204
Net Derivatives	1,250	1,381
Derivatives: not designated for hedge accounting | Currency swaps
Derivatives, Fair Value [Line Items]
Notional Amount	840	823
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	4	0
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	1	27
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	3	(27)
Derivatives: not designated for hedge accounting | Interest swaps
Derivatives, Fair Value [Line Items]
Notional Amount	486	495
Notional Amount - FWH and NI Modco	2,356	2,381
Derivative Assets	1	34
Derivative Assets - FWH and NI Modco	24	83
Derivative Liabilities	12	1
Derivative Liabilities - FWH and NI Modco	6	1
Net Derivatives	7	115
Derivatives: not designated for hedge accounting | Futures
Derivatives, Fair Value [Line Items]
Notional Amount	2,428	2,055
Notional Amount - FWH and NI Modco	4,249	3,429
Derivative Assets	0	0
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	0	0
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	0	0
Derivatives: not designated for hedge accounting | Swaps
Derivatives, Fair Value [Line Items]
Notional Amount	2,173	1,996
Notional Amount - FWH and NI Modco	14,096	12,930
Derivative Assets	8	7
Derivative Assets - FWH and NI Modco	51	45
Derivative Liabilities	0	0
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	59	52
Derivatives: not designated for hedge accounting | Options
Derivatives, Fair Value [Line Items]
Notional Amount	8,614	7,445
Notional Amount - FWH and NI Modco	44,414	41,501
Derivative Assets	2,799	2,169
Derivative Assets - FWH and NI Modco	11,665	9,675
Derivative Liabilities	694	524
Derivative Liabilities - FWH and NI Modco	2,565	2,203
Net Derivatives	11,205	9,117
Derivatives: not designated for hedge accounting | Futures
Derivatives, Fair Value [Line Items]
Notional Amount	1,124	1,000
Notional Amount - FWH and NI Modco	6,795	6,572
Derivative Assets	0	0
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	0	0
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	0	0
Derivatives: not designated for hedge accounting | Credit default swaps
Derivatives, Fair Value [Line Items]
Notional Amount	102	103
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	0	0
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	2	2
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	(2)	(2)
Derivatives: not designated for hedge accounting | Margin
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	100	96
Derivative Assets - FWH and NI Modco	269	231
Derivative Liabilities	0	0
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	369	327
Derivatives: not designated for hedge accounting | Collateral
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	215	75
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	10,606	8,276
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	(10,391)	(8,201)
Cash flow hedges: | Derivatives: designated for hedge accounting
Derivatives, Fair Value [Line Items]
Notional Amount	3,325	3,310
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	82	79
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	419	401
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	(337)	(322)
Cash flow hedges: | Derivatives: designated for hedge accounting | Currency swaps
Derivatives, Fair Value [Line Items]
Notional Amount	2,373	2,358
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	82	79
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	96	90
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	(14)	(11)
Cash flow hedges: | Derivatives: designated for hedge accounting | Interest swaps
Derivatives, Fair Value [Line Items]
Notional Amount	952	952
Notional Amount - FWH and NI Modco	0	0
Derivative Assets	0	0
Derivative Assets - FWH and NI Modco	0	0
Derivative Liabilities	323	311
Derivative Liabilities - FWH and NI Modco	0	0
Net Derivatives	$ (323)	$ (311)