INVESTMENTS - Credit Quality (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	$ 18,174	$ 18,154
Total accruing loans	18,105	17,901
Non-accruing Loans	69	253
Non-accruing Loans with No Allowance	0	0
Interest Income on Non-accruing Loans	0	7
Past Due
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	49	84
30-59 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	16	39
60-89 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	6	5
90 Days or More
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	27	40
Current
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	18,056	17,817
Total commercial and agricultural mortgage loans:
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	193	1,364
Fiscal year before current fiscal year	1,360	3,585
Two years before current fiscal year	3,508	2,445
Three years before current fiscal year	2,434	1,798
Four years before current fiscal year	1,777	826
Prior	7,632	7,207
Revolving Loans Amortized Cost Basis	572	500
Revolving Loans Converted to Term Loans Amortized Cost Basis	242	131
Total	17,718	17,856
Total commercial and agricultural mortgage loans: | Greater than 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	8	182
Fiscal year before current fiscal year	182	743
Two years before current fiscal year	735	1,161
Three years before current fiscal year	1,256	1,194
Four years before current fiscal year	1,190	269
Prior	3,709	3,435
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	7,080	6,984
Total commercial and agricultural mortgage loans: | 1.8x to 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	11	18
Fiscal year before current fiscal year	17	16
Two years before current fiscal year	24	238
Three years before current fiscal year	263	200
Four years before current fiscal year	195	194
Prior	629	723
Revolving Loans Amortized Cost Basis	231	383
Revolving Loans Converted to Term Loans Amortized Cost Basis	206	96
Total	1,576	1,868
Total commercial and agricultural mortgage loans: | 1.5x to 1.8x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	47	92
Fiscal year before current fiscal year	153	1,110
Two years before current fiscal year	857	265
Three years before current fiscal year	171	109
Four years before current fiscal year	110	179
Prior	1,198	1,117
Revolving Loans Amortized Cost Basis	113	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	2,649	2,872
Total commercial and agricultural mortgage loans: | 1.2x to 1.5x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	20	515
Fiscal year before current fiscal year	509	798
Two years before current fiscal year	1,273	605
Three years before current fiscal year	569	170
Four years before current fiscal year	218	109
Prior	1,266	1,203
Revolving Loans Amortized Cost Basis	0	41
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	3,855	3,441
Total commercial and agricultural mortgage loans: | 1.0x to 1.2x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	96	517
Fiscal year before current fiscal year	459	725
Two years before current fiscal year	424	106
Three years before current fiscal year	130	57
Four years before current fiscal year	56	69
Prior	740	601
Revolving Loans Amortized Cost Basis	228	76
Revolving Loans Converted to Term Loans Amortized Cost Basis	36	35
Total	2,169	2,186
Total commercial and agricultural mortgage loans: | Less than 1.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	11	40
Fiscal year before current fiscal year	40	193
Two years before current fiscal year	195	70
Three years before current fiscal year	45	68
Four years before current fiscal year	8	6
Prior	90	128
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	389	505
Total commercial and agricultural mortgage loans: | 0% - 50%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	23	293
Fiscal year before current fiscal year	352	326
Two years before current fiscal year	299	320
Three years before current fiscal year	318	270
Four years before current fiscal year	283	132
Prior	2,477	2,342
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	3,752	3,683
Total commercial and agricultural mortgage loans: | 50% - 70%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	170	763
Fiscal year before current fiscal year	766	2,062
Two years before current fiscal year	1,466	823
Three years before current fiscal year	813	951
Four years before current fiscal year	888	357
Prior	2,611	2,607
Revolving Loans Amortized Cost Basis	495	463
Revolving Loans Converted to Term Loans Amortized Cost Basis	206	96
Total	7,415	8,122
Total commercial and agricultural mortgage loans: | 70% - 90%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	308
Fiscal year before current fiscal year	242	1,197
Two years before current fiscal year	1,276	1,236
Three years before current fiscal year	1,145	523
Four years before current fiscal year	515	245
Prior	1,711	1,400
Revolving Loans Amortized Cost Basis	77	37
Revolving Loans Converted to Term Loans Amortized Cost Basis	36	35
Total	5,002	4,981
Total commercial and agricultural mortgage loans: | 90% plus
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	467	66
Three years before current fiscal year	158	54
Four years before current fiscal year	91	92
Prior	833	858
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	1,549	1,070
Commercial:
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	73	1,202
Fiscal year before current fiscal year	1,199	3,277
Two years before current fiscal year	3,209	2,102
Three years before current fiscal year	2,097	1,362
Four years before current fiscal year	1,357	636
Prior	6,407	6,101
Revolving Loans Amortized Cost Basis	572	500
Revolving Loans Converted to Term Loans Amortized Cost Basis	242	131
Total	15,156	15,311
Total accruing loans	15,123	15,077
Non-accruing Loans	33	234
Non-accruing Loans with No Allowance	0	0
Interest Income on Non-accruing Loans	0	7
Commercial: | Past Due
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	32
Commercial: | 30-59 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	32
Commercial: | 60-89 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	0
Commercial: | 90 Days or More
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	0
Commercial: | Current
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	15,123	15,045
Commercial: | Greater than 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	175
Fiscal year before current fiscal year	175	693
Two years before current fiscal year	693	1,125
Three years before current fiscal year	1,222	1,135
Four years before current fiscal year	1,131	249
Prior	3,527	3,256
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	6,748	6,633
Commercial: | 1.8x to 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	182
Three years before current fiscal year	208	167
Four years before current fiscal year	166	171
Prior	549	662
Revolving Loans Amortized Cost Basis	231	383
Revolving Loans Converted to Term Loans Amortized Cost Basis	206	96
Total	1,360	1,661
Commercial: | 1.5x to 1.8x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	80
Fiscal year before current fiscal year	141	1,060
Two years before current fiscal year	808	234
Three years before current fiscal year	143	0
Four years before current fiscal year	0	162
Prior	992	924
Revolving Loans Amortized Cost Basis	113	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	2,197	2,460
Commercial: | 1.2x to 1.5x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	469
Fiscal year before current fiscal year	463	687
Two years before current fiscal year	1,168	457
Three years before current fiscal year	429	0
Four years before current fiscal year	60	11
Prior	838	838
Revolving Loans Amortized Cost Basis	0	41
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	2,958	2,503
Commercial: | 1.0x to 1.2x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	73	470
Fiscal year before current fiscal year	412	668
Two years before current fiscal year	369	38
Three years before current fiscal year	61	0
Four years before current fiscal year	0	43
Prior	443	317
Revolving Loans Amortized Cost Basis	228	76
Revolving Loans Converted to Term Loans Amortized Cost Basis	36	35
Total	1,622	1,647
Commercial: | Less than 1.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	8
Fiscal year before current fiscal year	8	169
Two years before current fiscal year	171	66
Three years before current fiscal year	34	60
Four years before current fiscal year	0	0
Prior	58	104
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	271	407
Commercial: | 0% - 50%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	191
Fiscal year before current fiscal year	251	164
Two years before current fiscal year	140	129
Three years before current fiscal year	130	35
Four years before current fiscal year	35	0
Prior	1,574	1,540
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	2,130	2,059
Commercial: | 50% - 70%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	73	703
Fiscal year before current fiscal year	706	1,916
Two years before current fiscal year	1,326	671
Three years before current fiscal year	664	750
Four years before current fiscal year	716	299
Prior	2,305	2,319
Revolving Loans Amortized Cost Basis	495	463
Revolving Loans Converted to Term Loans Amortized Cost Basis	206	96
Total	6,491	7,217
Commercial: | 70% - 90%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	308
Fiscal year before current fiscal year	242	1,197
Two years before current fiscal year	1,276	1,236
Three years before current fiscal year	1,145	523
Four years before current fiscal year	515	245
Prior	1,695	1,384
Revolving Loans Amortized Cost Basis	77	37
Revolving Loans Converted to Term Loans Amortized Cost Basis	36	35
Total	4,986	4,965
Commercial: | 90% plus
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	467	66
Three years before current fiscal year	158	54
Four years before current fiscal year	91	92
Prior	833	858
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	1,549	1,070
Agricultural:
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	120	162
Fiscal year before current fiscal year	161	308
Two years before current fiscal year	299	343
Three years before current fiscal year	337	436
Four years before current fiscal year	420	190
Prior	1,225	1,106
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	2,562	2,545
Total accruing loans	2,526	2,526
Non-accruing Loans	36	19
Non-accruing Loans with No Allowance	0	0
Interest Income on Non-accruing Loans	0	0
Agricultural: | Past Due
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	49	52
Agricultural: | 30-59 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	16	7
Agricultural: | 60-89 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	6	5
Agricultural: | 90 Days or More
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	27	40
Agricultural: | Current
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	2,477	2,474
Agricultural: | Greater than 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	8	7
Fiscal year before current fiscal year	7	50
Two years before current fiscal year	42	36
Three years before current fiscal year	34	59
Four years before current fiscal year	59	20
Prior	182	179
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	332	351
Agricultural: | 1.8x to 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	11	18
Fiscal year before current fiscal year	17	16
Two years before current fiscal year	24	56
Three years before current fiscal year	55	33
Four years before current fiscal year	29	23
Prior	80	61
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	216	207
Agricultural: | 1.5x to 1.8x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	47	12
Fiscal year before current fiscal year	12	50
Two years before current fiscal year	49	31
Three years before current fiscal year	28	109
Four years before current fiscal year	110	17
Prior	206	193
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	452	412
Agricultural: | 1.2x to 1.5x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	20	46
Fiscal year before current fiscal year	46	111
Two years before current fiscal year	105	148
Three years before current fiscal year	140	170
Four years before current fiscal year	158	98
Prior	428	365
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	897	938
Agricultural: | 1.0x to 1.2x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	23	47
Fiscal year before current fiscal year	47	57
Two years before current fiscal year	55	68
Three years before current fiscal year	69	57
Four years before current fiscal year	56	26
Prior	297	284
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	547	539
Agricultural: | Less than 1.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	11	32
Fiscal year before current fiscal year	32	24
Two years before current fiscal year	24	4
Three years before current fiscal year	11	8
Four years before current fiscal year	8	6
Prior	32	24
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	118	98
Agricultural: | 0% - 50%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	23	102
Fiscal year before current fiscal year	101	162
Two years before current fiscal year	159	191
Three years before current fiscal year	188	235
Four years before current fiscal year	248	132
Prior	903	802
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	1,622	1,624
Agricultural: | 50% - 70%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	97	60
Fiscal year before current fiscal year	60	146
Two years before current fiscal year	140	152
Three years before current fiscal year	149	201
Four years before current fiscal year	172	58
Prior	306	288
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	924	905
Agricultural: | 70% - 90%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	16	16
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	16	16
Agricultural: | 90% plus
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	0	0
Residential mortgages:
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	98
Fiscal year before current fiscal year	263	121
Two years before current fiscal year	117	74
Three years before current fiscal year	72	2
Four years before current fiscal year	2	1
Prior	2	2
Total	456	298
Total accruing loans	456	298
Non-accruing Loans	0	0
Non-accruing Loans with No Allowance	0	0
Interest Income on Non-accruing Loans	0	0
Residential mortgages: | Past Due
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	0
Residential mortgages: | 30-59 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	0
Residential mortgages: | 60-89 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	0
Residential mortgages: | 90 Days or More
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	0	0
Residential mortgages: | Current
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total accruing loans	$ 456	$ 298