INVESTMENTS - Credit Quality (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	$ 14,505	$ 14,095
Total	14,489	14,079
Non-accruing Loans	16	16
Non-accruing Loans with No Allowance	0	0
Interest Income on Non-accruing Loans	0	0
Past Due
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	46	27
30-59 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	9	1
60-89 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	7	1
90 Days Or Greater
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	30	25
Current
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	14,443	14,052
Commercial mortgage loans
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	590	2,157
Fiscal year before current fiscal year	2,158	1,570
Two years before current fiscal year	1,597	819
Three years before current fiscal year	830	1,253
Four years before current fiscal year	1,252	1,065
Prior	5,470	4,587
Total	11,897	11,451
Total	11,897	11,451
Non-accruing Loans	0	0
Non-accruing Loans with No Allowance	0	0
Interest Income on Non-accruing Loans	0	0
Commercial mortgage loans | Past Due
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	0	0
Commercial mortgage loans | 30-59 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	0	0
Commercial mortgage loans | 60-89 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	0	0
Commercial mortgage loans | 90 Days Or Greater
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	0	0
Commercial mortgage loans | Current
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	11,897	11,451
Commercial mortgage loans | Greater than 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	197	1,143
Fiscal year before current fiscal year	1,143	1,243
Two years before current fiscal year	1,259	210
Three years before current fiscal year	210	772
Four years before current fiscal year	772	485
Prior	2,263	2,235
Total	5,844	6,088
Commercial mortgage loans | 1.8x to 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	94	185
Fiscal year before current fiscal year	186	135
Two years before current fiscal year	135	250
Three years before current fiscal year	322	46
Four years before current fiscal year	46	161
Prior	743	372
Total	1,526	1,149
Commercial mortgage loans | 1.5x to 1.8x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	261	275
Fiscal year before current fiscal year	274	97
Two years before current fiscal year	109	284
Three years before current fiscal year	223	211
Four years before current fiscal year	215	166
Prior	1,244	919
Total	2,326	1,952
Commercial mortgage loans | 1.2x to 1.5x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	0	264
Fiscal year before current fiscal year	264	95
Two years before current fiscal year	0	75
Three years before current fiscal year	75	101
Four years before current fiscal year	47	253
Prior	778	701
Total	1,164	1,489
Commercial mortgage loans | 1.0x to 1.2x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	38	290
Fiscal year before current fiscal year	291	0
Two years before current fiscal year	94	0
Three years before current fiscal year	0	88
Four years before current fiscal year	88	0
Prior	370	287
Total	881	665
Commercial mortgage loans | Less than 1.0x
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	0
Three years before current fiscal year	0	35
Four years before current fiscal year	84	0
Prior	72	73
Total	156	108
Commercial mortgage loans | 0% - 50%
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	184
Four years before current fiscal year	184	293
Prior	1,204	1,009
Total	1,388	1,486
Commercial mortgage loans | 50% - 70%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	450	1,967
Fiscal year before current fiscal year	1,915	1,334
Two years before current fiscal year	1,361	407
Three years before current fiscal year	418	619
Four years before current fiscal year	619	491
Prior	3,166	2,533
Total	7,929	7,351
Commercial mortgage loans | 70% - 90%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	140	190
Fiscal year before current fiscal year	243	236
Two years before current fiscal year	236	412
Three years before current fiscal year	412	415
Four years before current fiscal year	414	276
Prior	1,100	972
Total	2,545	2,501
Commercial 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	0	0
Three years before current fiscal year	0	35
Four years before current fiscal year	35	5
Prior	0	73
Total	35	113
Agricultural mortgage loans
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	118	380
Fiscal year before current fiscal year	376	480
Two years before current fiscal year	475	230
Three years before current fiscal year	214	255
Four years before current fiscal year	235	206
Prior	1,190	1,093
Total	2,608	2,644
Total	2,592	2,628
Non-accruing Loans	16	16
Non-accruing Loans with No Allowance	0	0
Interest Income on Non-accruing Loans	0	0
Agricultural mortgage loans | Past Due
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	46	27
Agricultural mortgage loans | 30-59 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	9	1
Agricultural mortgage loans | 60-89 Days
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	7	1
Agricultural mortgage loans | 90 Days Or Greater
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	30	25
Agricultural mortgage loans | Current
Financing Receivable, before Allowance for Credit Loss [Abstract]
Total	2,546	2,601
Agricultural mortgage loans | Greater than 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	18	49
Fiscal year before current fiscal year	48	64
Two years before current fiscal year	63	25
Three years before current fiscal year	23	22
Four years before current fiscal year	12	24
Prior	226	210
Total	390	394
Agricultural mortgage loans | 1.8x to 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	8	52
Fiscal year before current fiscal year	51	37
Two years before current fiscal year	37	25
Three years before current fiscal year	25	14
Four years before current fiscal year	14	14
Prior	73	70
Total	208	212
Agricultural mortgage loans | 1.5x to 1.8x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	26	43
Fiscal year before current fiscal year	43	113
Two years before current fiscal year	113	28
Three years before current fiscal year	28	22
Four years before current fiscal year	23	41
Prior	217	193
Total	450	440
Agricultural mortgage loans | 1.2x to 1.5x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	23	161
Fiscal year before current fiscal year	157	179
Two years before current fiscal year	178	112
Three years before current fiscal year	101	116
Four years before current fiscal year	108	72
Prior	376	355
Total	943	995
Agricultural mortgage loans | 1.0x to 1.2x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	37	75
Fiscal year before current fiscal year	76	83
Two years before current fiscal year	80	31
Three years before current fiscal year	31	77
Four years before current fiscal year	74	54
Prior	284	226
Total	582	546
Agricultural mortgage loans | Less than 1.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	6	0
Fiscal year before current fiscal year	1	4
Two years before current fiscal year	4	9
Three years before current fiscal year	6	4
Four years before current fiscal year	4	1
Prior	14	39
Total	35	57
Agricultural mortgage loans | 0% - 50%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	47	180
Fiscal year before current fiscal year	180	212
Two years before current fiscal year	214	128
Three years before current fiscal year	122	129
Four years before current fiscal year	139	119
Prior	835	738
Total	1,537	1,506
Agricultural mortgage loans | 50% - 70%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	70	200
Fiscal year before current fiscal year	196	268
Two years before current fiscal year	261	102
Three years before current fiscal year	92	126
Four years before current fiscal year	96	87
Prior	337	338
Total	1,052	1,121
Agricultural mortgage loans | 70% - 90%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	1	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	18	17
Total	19	17
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	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	0
Total	0	0
Mortgages Loan
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	708	2,537
Fiscal year before current fiscal year	2,534	2,050
Two years before current fiscal year	2,072	1,049
Three years before current fiscal year	1,044	1,508
Four years before current fiscal year	1,487	1,271
Prior	6,660	5,680
Total	14,505	14,095
Mortgages Loan | Greater than 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	215	1,192
Fiscal year before current fiscal year	1,191	1,307
Two years before current fiscal year	1,322	235
Three years before current fiscal year	233	794
Four years before current fiscal year	784	509
Prior	2,489	2,445
Total	6,234	6,482
Mortgages Loan | 1.8x to 2.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	102	237
Fiscal year before current fiscal year	237	172
Two years before current fiscal year	172	275
Three years before current fiscal year	347	60
Four years before current fiscal year	60	175
Prior	816	442
Total	1,734	1,361
Mortgages Loan | 1.5x to 1.8x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	287	318
Fiscal year before current fiscal year	317	210
Two years before current fiscal year	222	312
Three years before current fiscal year	251	233
Four years before current fiscal year	238	207
Prior	1,461	1,112
Total	2,776	2,392
Mortgages Loan | 1.2x to 1.5x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	23	425
Fiscal year before current fiscal year	421	274
Two years before current fiscal year	178	187
Three years before current fiscal year	176	217
Four years before current fiscal year	155	325
Prior	1,154	1,056
Total	2,107	2,484
Mortgages Loan | 1.0x to 1.2x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	75	365
Fiscal year before current fiscal year	367	83
Two years before current fiscal year	174	31
Three years before current fiscal year	31	165
Four years before current fiscal year	162	54
Prior	654	513
Total	1,463	1,211
Mortgages Loan | Less than 1.0x
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	6	0
Fiscal year before current fiscal year	1	4
Two years before current fiscal year	4	9
Three years before current fiscal year	6	39
Four years before current fiscal year	88	1
Prior	86	112
Total	191	165
Mortgages Loan | 0% - 50%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	47	180
Fiscal year before current fiscal year	180	212
Two years before current fiscal year	214	128
Three years before current fiscal year	122	313
Four years before current fiscal year	323	412
Prior	2,039	1,747
Total	2,925	2,992
Mortgages Loan | 50% - 70%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	520	2,167
Fiscal year before current fiscal year	2,111	1,602
Two years before current fiscal year	1,622	509
Three years before current fiscal year	510	745
Four years before current fiscal year	715	578
Prior	3,503	2,871
Total	8,981	8,472
Mortgages Loan | 70% - 90%
Financing Receivable, before Allowance for Credit Loss [Abstract]
Current fiscal year	141	190
Fiscal year before current fiscal year	243	236
Two years before current fiscal year	236	412
Three years before current fiscal year	412	415
Four years before current fiscal year	414	276
Prior	1,118	989
Total	2,564	2,518
Mortgages Loan | 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	35
Four years before current fiscal year	35	5
Prior	0	73
Total	$ 35	$ 113