POLICY LIABILITIES - Schedule of Changes in Present Value of Expected Net Premiums and Expected Future Policy Benefits (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Present value of expected future policy benefits:
Beginning balance		$ 132,131
Ending balance		111,508	$ 132,131
Net liability for future policy benefits		70,381	83,718
Aflac Japan | Cancer
Present value of expected future net premiums:
Beginning balance		17,509	19,298
Beginning balance at original discount rate		16,452	18,221
Effect of changes in cash flow assumptions			(625)	$ (165)
Effect of actual variances from expected experience			(71)	(315)
Adjusted beginning of period balance			15,756	17,741
Issuances		983	1,034
Interest accrual		378	412
Net premiums collected	[1]	(1,453)	(1,564)
Foreign currency translation		(1,655)	(1,170)
Other		(1)	(1)
Ending balance at original discount rate		14,008	16,452
Effect of changes in discount rate assumptions		176	1,057
Ending balance		14,184	17,509
Present value of expected future policy benefits:
Beginning balance		50,161	54,766
Beginning balance at original discount rate		43,626	47,677
Effect of changes in cash flow assumptions			(815)	(147)
Effect of actual variances from expected experience			(117)	(385)
Adjusted beginning of period balance			42,694	47,145
Issuances		1,004	1,059
Interest accrual		1,356	1,473
Benefit payments		(2,773)	(2,987)
Foreign currency translation		(4,425)	(3,064)
Other		0	0
Ending balance at original discount rate		37,856	43,626
Effect of changes in discount rate assumptions		2,925	6,535
Ending balance		40,781	50,161
Net liability for future policy benefits		26,597	32,652
Less: reinsurance recoverable		5,085	4,135
Net liability for future policy benefits after reinsurance recoverable		21,512	28,517
Aflac Japan | Medical and other health
Present value of expected future net premiums:
Beginning balance		14,697	16,714
Beginning balance at original discount rate		14,040	16,195
Effect of changes in cash flow assumptions			(154)	(470)
Effect of actual variances from expected experience			(164)	(137)
Adjusted beginning of period balance			13,722	15,588
Issuances		361	418
Interest accrual		302	334
Net premiums collected	[1]	(1,135)	(1,261)
Foreign currency translation		(1,405)	(1,038)
Other		0	(1)
Ending balance at original discount rate		11,845	14,040
Effect of changes in discount rate assumptions		(28)	657
Ending balance		11,817	14,697
Present value of expected future policy benefits:
Beginning balance		25,257	27,419
Beginning balance at original discount rate		25,023	27,566
Effect of changes in cash flow assumptions			(228)	(507)
Effect of actual variances from expected experience			(193)	(154)
Adjusted beginning of period balance			24,602	26,905
Issuances		373	432
Interest accrual		570	608
Benefit payments		(1,033)	(1,153)
Foreign currency translation		(2,555)	(1,769)
Other		0	0
Ending balance at original discount rate		21,957	25,023
Effect of changes in discount rate assumptions		(1,351)	234
Ending balance		20,606	25,257
Net liability for future policy benefits		8,789	10,560
Less: reinsurance recoverable		1,245	1,521
Net liability for future policy benefits after reinsurance recoverable		7,544	9,039
Aflac Japan | Life insurance
Present value of expected future net premiums:
Beginning balance		6,488	7,485
Beginning balance at original discount rate		6,258	7,284
Effect of changes in cash flow assumptions			(190)	43
Effect of actual variances from expected experience			(97)	(42)
Adjusted beginning of period balance			5,971	7,285
Issuances		478	335
Interest accrual		110	124
Net premiums collected	[1]	(862)	(1,017)
Foreign currency translation		(613)	(469)
Other		0	0
Ending balance at original discount rate		5,084	6,258
Effect of changes in discount rate assumptions		72	230
Ending balance		5,156	6,488
Present value of expected future policy benefits:
Beginning balance		29,731	31,954
Beginning balance at original discount rate		30,256	32,800
Effect of changes in cash flow assumptions			(302)	65
Effect of actual variances from expected experience			(110)	(51)
Adjusted beginning of period balance			29,844	32,814
Issuances		488	341
Interest accrual		582	625
Benefit payments		(1,510)	(1,415)
Foreign currency translation		(3,074)	(2,109)
Other		0	0
Ending balance at original discount rate		26,330	30,256
Effect of changes in discount rate assumptions		(2,065)	(525)
Ending balance		24,265	29,731
Net liability for future policy benefits		19,109	23,243
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		19,109	23,243
Aflac Japan | Other
Present value of expected future net premiums:
Beginning balance		1,088	1,256
Beginning balance at original discount rate		1,069	1,242
Effect of changes in cash flow assumptions			(19)	(12)
Effect of actual variances from expected experience			(14)	(15)
Adjusted beginning of period balance			1,036	1,215
Issuances		16	26
Interest accrual		17	20
Net premiums collected	[1]	(101)	(112)
Foreign currency translation		(104)	(80)
Other		0	0
Ending balance at original discount rate		864	1,069
Effect of changes in discount rate assumptions		(18)	19
Ending balance		846	1,088
Present value of expected future policy benefits:
Beginning balance		5,178	5,582
Beginning balance at original discount rate		5,444	5,940
Effect of changes in cash flow assumptions			(7)	(27)
Effect of actual variances from expected experience			(24)	(15)
Adjusted beginning of period balance			5,413	5,898
Issuances		22	32
Interest accrual		93	100
Benefit payments		(208)	(206)
Foreign currency translation		(555)	(380)
Other		0	0
Ending balance at original discount rate		4,765	5,444
Effect of changes in discount rate assumptions		(540)	(266)
Ending balance		4,225	5,178
Net liability for future policy benefits		3,379	4,090
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		3,379	4,090
Aflac U.S. | Life insurance
Present value of expected future net premiums:
Beginning balance		853	724
Beginning balance at original discount rate		909	799
Effect of changes in cash flow assumptions			(5)	61
Effect of actual variances from expected experience			(29)	(25)
Adjusted beginning of period balance			875	835
Issuances		226	181
Interest accrual		37	31
Net premiums collected	[1]	(157)	(137)
Foreign currency translation		0	0
Other		(5)	(1)
Ending balance at original discount rate		976	909
Effect of changes in discount rate assumptions		(67)	(56)
Ending balance		909	853
Present value of expected future policy benefits:
Beginning balance		1,764	1,526
Beginning balance at original discount rate		1,971	1,778
Effect of changes in cash flow assumptions			(3)	72
Effect of actual variances from expected experience			(43)	(32)
Adjusted beginning of period balance			1,925	1,818
Issuances		231	185
Interest accrual		78	68
Benefit payments		(108)	(105)
Foreign currency translation		0	0
Other		0	5
Ending balance at original discount rate		2,126	1,971
Effect of changes in discount rate assumptions		(279)	(207)
Ending balance		1,847	1,764
Net liability for future policy benefits		938	911
Less: reinsurance recoverable		18	15
Net liability for future policy benefits after reinsurance recoverable		920	896
Aflac U.S. | Accident
Present value of expected future net premiums:
Beginning balance		2,488	2,534
Beginning balance at original discount rate		2,630	2,760
Effect of changes in cash flow assumptions			65	(16)
Effect of actual variances from expected experience			66	(58)
Adjusted beginning of period balance			2,761	2,686
Issuances		307	323
Interest accrual		106	102
Net premiums collected	[1]	(479)	(473)
Foreign currency translation		0	0
Other		(8)	(8)
Ending balance at original discount rate		2,687	2,630
Effect of changes in discount rate assumptions		(190)	(142)
Ending balance		2,497	2,488
Present value of expected future policy benefits:
Beginning balance		3,109	3,098
Beginning balance at original discount rate		3,302	3,391
Effect of changes in cash flow assumptions			109	(11)
Effect of actual variances from expected experience			91	(75)
Adjusted beginning of period balance			3,502	3,305
Issuances		311	331
Interest accrual		133	127
Benefit payments		(560)	(464)
Foreign currency translation		0	0
Other		0	3
Ending balance at original discount rate		3,386	3,302
Effect of changes in discount rate assumptions		(259)	(193)
Ending balance		3,127	3,109
Net liability for future policy benefits		630	621
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		630	621
Aflac U.S. | Disability
Present value of expected future net premiums:
Beginning balance		1,652	1,635
Beginning balance at original discount rate		1,738	1,775
Effect of changes in cash flow assumptions			(47)	(51)
Effect of actual variances from expected experience			12	(29)
Adjusted beginning of period balance			1,703	1,695
Issuances		364	376
Interest accrual		66	62
Net premiums collected	[1]	(401)	(390)
Foreign currency translation		0	0
Other		(6)	(5)
Ending balance at original discount rate		1,726	1,738
Effect of changes in discount rate assumptions		(91)	(86)
Ending balance		1,635	1,652
Present value of expected future policy benefits:
Beginning balance		2,422	2,445
Beginning balance at original discount rate		2,541	2,636
Effect of changes in cash flow assumptions			(73)	(59)
Effect of actual variances from expected experience			(16)	(59)
Adjusted beginning of period balance			2,452	2,518
Issuances		381	392
Interest accrual		98	96
Benefit payments		(465)	(465)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		2,466	2,541
Effect of changes in discount rate assumptions		(136)	(119)
Ending balance		2,330	2,422
Net liability for future policy benefits		695	770
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		695	770
Aflac U.S. | Critical care
Present value of expected future net premiums:
Beginning balance		4,074	4,486
Beginning balance at original discount rate		4,416	5,050
Effect of changes in cash flow assumptions			(106)	(494)
Effect of actual variances from expected experience			(100)	(223)
Adjusted beginning of period balance			4,210	4,333
Issuances		543	493
Interest accrual		173	179
Net premiums collected	[1]	(578)	(580)
Foreign currency translation		0	0
Other		(8)	(9)
Ending balance at original discount rate		4,340	4,416
Effect of changes in discount rate assumptions		(439)	(342)
Ending balance		3,901	4,074
Present value of expected future policy benefits:
Beginning balance		11,290	11,489
Beginning balance at original discount rate		12,120	12,846
Effect of changes in cash flow assumptions			(112)	(592)
Effect of actual variances from expected experience			(144)	(271)
Adjusted beginning of period balance			11,864	11,983
Issuances		559	505
Interest accrual		515	524
Benefit payments		(925)	(893)
Foreign currency translation		0	0
Other		0	1
Ending balance at original discount rate		12,013	12,120
Effect of changes in discount rate assumptions		(1,312)	(830)
Ending balance		10,701	11,290
Net liability for future policy benefits		6,800	7,216
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		6,800	7,216
Aflac U.S. | Hospital indemnity
Present value of expected future net premiums:
Beginning balance		1,107	1,220
Beginning balance at original discount rate		1,193	1,365
Effect of changes in cash flow assumptions			(21)	(142)
Effect of actual variances from expected experience			21	(73)
Adjusted beginning of period balance			1,193	1,150
Issuances		231	249
Interest accrual		46	45
Net premiums collected	[1]	(244)	(247)
Foreign currency translation		0	0
Other		(5)	(4)
Ending balance at original discount rate		1,221	1,193
Effect of changes in discount rate assumptions		(99)	(86)
Ending balance		1,122	1,107
Present value of expected future policy benefits:
Beginning balance		1,943	2,074
Beginning balance at original discount rate		2,076	2,300
Effect of changes in cash flow assumptions			(31)	(194)
Effect of actual variances from expected experience			21	(99)
Adjusted beginning of period balance			2,066	2,007
Issuances		237	258
Interest accrual		84	84
Benefit payments		(314)	(274)
Foreign currency translation		0	0
Other		0	1
Ending balance at original discount rate		2,073	2,076
Effect of changes in discount rate assumptions		(176)	(133)
Ending balance		1,897	1,943
Net liability for future policy benefits		775	836
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		775	836
Aflac U.S. | Dental/vision
Present value of expected future net premiums:
Beginning balance		206	211
Beginning balance at original discount rate		217	231
Effect of changes in cash flow assumptions			(17)	(9)
Effect of actual variances from expected experience			(12)	(17)
Adjusted beginning of period balance			188	205
Issuances		52	44
Interest accrual		9	8
Net premiums collected	[1]	(39)	(39)
Foreign currency translation		0	0
Other		(1)	(1)
Ending balance at original discount rate		209	217
Effect of changes in discount rate assumptions		(13)	(11)
Ending balance		196	206
Present value of expected future policy benefits:
Beginning balance		478	488
Beginning balance at original discount rate		506	532
Effect of changes in cash flow assumptions			(28)	(14)
Effect of actual variances from expected experience			(16)	(22)
Adjusted beginning of period balance			462	496
Issuances		55	46
Interest accrual		20	21
Benefit payments		(60)	(59)
Foreign currency translation		0	0
Other		0	2
Ending balance at original discount rate		477	506
Effect of changes in discount rate assumptions		(36)	(28)
Ending balance		441	478
Net liability for future policy benefits		245	272
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		245	272
Aflac U.S. | Other
Present value of expected future net premiums:
Beginning balance		277	110
Beginning balance at original discount rate		272	118
Effect of changes in cash flow assumptions			(8)	(9)
Effect of actual variances from expected experience			13	(2)
Adjusted beginning of period balance			277	107
Issuances		592	169
Interest accrual		25	6
Net premiums collected	[1]	(53)	(17)
Foreign currency translation		0	0
Other		(17)	7
Ending balance at original discount rate		824	272
Effect of changes in discount rate assumptions		2	5
Ending balance		826	277
Present value of expected future policy benefits:
Beginning balance		798	622
Beginning balance at original discount rate		769	624
Effect of changes in cash flow assumptions			(12)	(13)
Effect of actual variances from expected experience			(7)	(4)
Adjusted beginning of period balance			750	$ 607
Issuances		597	169
Interest accrual		50	33
Benefit payments		(104)	(48)
Foreign currency translation		0	0
Other		0	8
Ending balance at original discount rate		1,293	769
Effect of changes in discount rate assumptions		(5)	29
Ending balance		1,288	798
Net liability for future policy benefits		462	521
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		$ 462	$ 521

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