SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Liability For Future Policy Benefit, Expected Net Premium, Activity (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2021		Dec. 31, 2020
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		$ 19,298	$ 25,893
Beginning balance at original discount rate		18,221	22,470
Effect of changes in cash flow assumptions			0	$ (639)
Effect of actual variances from expected experience			(120)	(284)
Adjusted beginning of period balance			18,101	21,547
Issuances		229	947
Interest accrual		111	459
Net premium earned	[1]	(420)	(1,734)
Foreign currency translation		(109)	(2,997)
Other		0	(1)
Ending balance at original discount rate		17,912	18,221	22,470
Effect of change in discount rate assumptions		1,542	1,077
Ending balance		19,454	19,298	25,893
Cancer | Aflac Japan | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			25,893	29,598
Beginning balance at original discount rate			22,470	25,616	[2]
Effect of changes in cash flow assumptions						$ 32
Effect of actual variances from expected experience						(134)
Adjusted beginning of period balance						25,514
Issuances				1,116
Interest accrual				586
Net premium earned	[3]			(2,206)
Foreign currency translation				(2,539)
Other				(1)
Ending balance at original discount rate				22,470
Effect of change in discount rate assumptions				3,423
Ending balance				25,893
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		16,714	21,174
Beginning balance at original discount rate		16,195	18,681
Effect of changes in cash flow assumptions			0	317
Effect of actual variances from expected experience			(25)	61
Adjusted beginning of period balance			16,170	19,059
Issuances		104	639
Interest accrual		92	364
Net premium earned	[1]	(344)	(1,376)
Foreign currency translation		(100)	(2,488)
Other		0	(3)
Ending balance at original discount rate		15,922	16,195	18,681
Effect of change in discount rate assumptions		1,045	519
Ending balance		16,967	16,714	21,174
Medical and other health | Aflac Japan | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			21,174	23,874
Beginning balance at original discount rate			18,681	21,276	[2]
Effect of changes in cash flow assumptions						88
Effect of actual variances from expected experience						(449)
Adjusted beginning of period balance						20,915
Issuances				1,132
Interest accrual				439
Net premium earned	[3]			(1,692)
Foreign currency translation				(2,111)
Other				(2)
Ending balance at original discount rate				18,681
Effect of change in discount rate assumptions				2,493
Ending balance				21,174
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		7,485	10,847
Beginning balance at original discount rate		7,284	10,064
Effect of changes in cash flow assumptions			0	(494)
Effect of actual variances from expected experience			(14)	(81)
Adjusted beginning of period balance			7,270	9,489
Issuances		111	221
Interest accrual		33	146
Net premium earned	[1]	(286)	(1,229)
Foreign currency translation		(44)	(1,343)
Other		0	0
Ending balance at original discount rate		7,084	7,284	10,064
Effect of change in discount rate assumptions		319	201
Ending balance		7,403	7,485	10,847
Life insurance | Aflac Japan | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			10,847	13,384
Beginning balance at original discount rate			10,064	12,476	[2]
Effect of changes in cash flow assumptions						40
Effect of actual variances from expected experience						(135)
Adjusted beginning of period balance						12,381
Issuances				284
Interest accrual				202
Net premium earned	[3]			(1,609)
Foreign currency translation				(1,194)
Other				0
Ending balance at original discount rate				10,064
Effect of change in discount rate assumptions				783
Ending balance				10,847
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		724	834
Beginning balance at original discount rate		799	780
Effect of changes in cash flow assumptions			0	(1)
Effect of actual variances from expected experience			(4)	(16)
Adjusted beginning of period balance			795	763
Issuances		49	146
Interest accrual		7	27
Net premium earned	[1]	(33)	(131)
Foreign currency translation		0	0
Other		4	(6)
Ending balance at original discount rate		822	799	780
Effect of change in discount rate assumptions		(60)	(75)
Ending balance		762	724	834
Life insurance | Aflac U.S. | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			834	783
Beginning balance at original discount rate			780	705	[2]
Effect of changes in cash flow assumptions						31
Effect of actual variances from expected experience						34
Adjusted beginning of period balance						770
Issuances				112
Interest accrual				25
Net premium earned	[3]			(124)
Foreign currency translation				0
Other				(3)
Ending balance at original discount rate				780
Effect of change in discount rate assumptions				54
Ending balance				834
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		2,534	3,283
Beginning balance at original discount rate		2,760	2,999
Effect of changes in cash flow assumptions			0	(52)
Effect of actual variances from expected experience			(48)	(152)
Adjusted beginning of period balance			2,712	2,795
Issuances		117	355
Interest accrual		25	105
Net premium earned	[1]	(118)	(496)
Foreign currency translation		0	0
Other		0	1
Ending balance at original discount rate		2,736	2,760	2,999
Effect of change in discount rate assumptions		(173)	(226)
Ending balance		2,563	2,534	3,283
Accident | Aflac U.S. | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			3,283	3,829
Beginning balance at original discount rate			2,999	3,350	[2]
Effect of changes in cash flow assumptions						(163)
Effect of actual variances from expected experience						(109)
Adjusted beginning of period balance						3,078
Issuances				365
Interest accrual				116
Net premium earned	[3]			(552)
Foreign currency translation				0
Other				(8)
Ending balance at original discount rate				2,999
Effect of change in discount rate assumptions				284
Ending balance				3,283
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		1,635	1,862
Beginning balance at original discount rate		1,775	1,760
Effect of changes in cash flow assumptions			0	5
Effect of actual variances from expected experience			(20)	(43)
Adjusted beginning of period balance			1,755	1,722
Issuances		120	384
Interest accrual		15	57
Net premium earned	[1]	(95)	(382)
Foreign currency translation		0	0
Other		0	(6)
Ending balance at original discount rate		1,795	1,775	1,760
Effect of change in discount rate assumptions		(112)	(140)
Ending balance		1,683	1,635	1,862
Disability | Aflac U.S. | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			1,862	2,118
Beginning balance at original discount rate			1,760	1,921	[2]
Effect of changes in cash flow assumptions						(129)
Effect of actual variances from expected experience						(38)
Adjusted beginning of period balance						1,754
Issuances				345
Interest accrual				61
Net premium earned	[3]			(393)
Foreign currency translation				0
Other				(7)
Ending balance at original discount rate				1,760
Effect of change in discount rate assumptions				102
Ending balance				1,862
Critical Care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		4,486	6,023
Beginning balance at original discount rate		5,050	5,391
Effect of changes in cash flow assumptions			0	(38)
Effect of actual variances from expected experience			(104)	(421)
Adjusted beginning of period balance			4,946	4,932
Issuances		192	537
Interest accrual		46	193
Net premium earned	[1]	(147)	(612)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		5,037	5,050	5,391
Effect of change in discount rate assumptions		(444)	(564)
Ending balance		4,593	4,486	6,023
Critical Care | Aflac U.S. | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			6,023	6,942
Beginning balance at original discount rate			5,391	5,894	[2]
Effect of changes in cash flow assumptions						(302)
Effect of actual variances from expected experience						(290)
Adjusted beginning of period balance						5,302
Issuances				552
Interest accrual				210
Net premium earned	[3]			(665)
Foreign currency translation				0
Other				(8)
Ending balance at original discount rate				5,391
Effect of change in discount rate assumptions				632
Ending balance				6,023
Hospital Indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		1,220	1,467
Beginning balance at original discount rate		1,365	1,380
Effect of changes in cash flow assumptions			0	42
Effect of actual variances from expected experience			(39)	(111)
Adjusted beginning of period balance			1,326	1,311
Issuances		103	273
Interest accrual		11	45
Net premium earned	[1]	(62)	(261)
Foreign currency translation		0	0
Other		0	(3)
Ending balance at original discount rate		1,378	1,365	1,380
Effect of change in discount rate assumptions		(117)	(145)
Ending balance		1,261	1,220	1,467
Hospital Indemnity | Aflac U.S. | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			1,467	1,530
Beginning balance at original discount rate			1,380	1,376	[2]
Effect of changes in cash flow assumptions						0
Effect of actual variances from expected experience						(32)
Adjusted beginning of period balance						1,344
Issuances				263
Interest accrual				45
Net premium earned	[3]			(268)
Foreign currency translation				0
Other				(4)
Ending balance at original discount rate				1,380
Effect of change in discount rate assumptions				87
Ending balance				1,467
Dental/Vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		211	264
Beginning balance at original discount rate		231	241
Effect of changes in cash flow assumptions			0	10
Effect of actual variances from expected experience			(7)	(20)
Adjusted beginning of period balance			224	231
Issuances		10	33
Interest accrual		2	9
Net premium earned	[1]	(10)	(42)
Foreign currency translation		0	0
Other		2	0
Ending balance at original discount rate		228	231	241
Effect of change in discount rate assumptions		(15)	(20)
Ending balance		213	211	264
Dental/Vision | Aflac U.S. | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			264	322
Beginning balance at original discount rate			241	281	[2]
Effect of changes in cash flow assumptions						(26)
Effect of actual variances from expected experience						(14)
Adjusted beginning of period balance						241
Issuances				39
Interest accrual				10
Net premium earned	[3]			(47)
Foreign currency translation				0
Other				(2)
Ending balance at original discount rate				241
Effect of change in discount rate assumptions				23
Ending balance				264
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		1,256	1,586
Beginning balance at original discount rate		1,242	1,461
Effect of changes in cash flow assumptions			0	25
Effect of actual variances from expected experience			(2)	(10)
Adjusted beginning of period balance			1,240	1,476
Issuances		8	62
Interest accrual		5	22
Net premium earned	[1]	(31)	(123)
Foreign currency translation		(8)	(195)
Other		0	0
Ending balance at original discount rate		1,214	1,242	1,461
Effect of change in discount rate assumptions		42	14
Ending balance		1,256	1,256	1,586
Other | Aflac Japan | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			1,586	1,856
Beginning balance at original discount rate			1,461	1,708	[2]
Effect of changes in cash flow assumptions						1
Effect of actual variances from expected experience						(11)
Adjusted beginning of period balance						1,698
Issuances				55
Interest accrual				27
Net premium earned	[3]			(151)
Foreign currency translation				(167)
Other				(1)
Ending balance at original discount rate				1,461
Effect of change in discount rate assumptions				125
Ending balance				1,586
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance		110	153
Beginning balance at original discount rate		118	135
Effect of changes in cash flow assumptions			0	(12)
Effect of actual variances from expected experience			(1)	6
Adjusted beginning of period balance			117	129
Issuances		14	0
Interest accrual		1	5
Net premium earned	[1]	(4)	(17)
Foreign currency translation		0	0
Other		9	1
Ending balance at original discount rate		137	118	135
Effect of change in discount rate assumptions		(6)	(8)
Ending balance		$ 131	110	153
Other | Aflac U.S. | Accounting Standards Update 2018-12
Liability for Future Policy Benefit, Activity [Line Items]
Beginning balance			153	179
Beginning balance at original discount rate			$ 135	152	[2]
Effect of changes in cash flow assumptions						0
Effect of actual variances from expected experience						(3)
Adjusted beginning of period balance						$ 149
Issuances				0
Interest accrual				6
Net premium earned	[3]			(19)
Foreign currency translation				0
Other				(1)
Ending balance at original discount rate				135
Effect of change in discount rate assumptions				18
Ending balance				$ 153

[1] Net premiums earned represent the portion of gross premiums collected from policyholders that is used to fund expected benefit payments.

[2] Includes the adjustment for capping the Transition Date NPR.

[3] Net premiums earned represent the portion of gross premiums collected from policyholders that is used to fund expected benefit payments.