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, 2025	Dec. 31, 2024	Dec. 31, 2023
Present value of expected future policy benefits:
Beginning balance		$ 111,508
Ending balance		100,522	$ 111,508
Net liability for future policy benefits		62,320	70,381
Aflac Japan | Cancer
Present value of expected future net premiums:
Beginning balance		14,184	17,509
Beginning balance at original discount rate		14,008	16,452
Effect of changes in cash flow assumptions			(661)	$ (625)
Effect of actual variances from expected experience			(436)	(71)
Adjusted beginning of period balance			12,911	15,756
Issuances		1,114	983
Interest accrual		364	378
Net premiums collected	[1]	(1,379)	(1,453)
Foreign currency translation		193	(1,655)
Other		(2)	(1)
Ending balance at original discount rate		13,201	14,008
Effect of changes in discount rate assumptions		(994)	176
Ending balance		12,207	14,184
Present value of expected future policy benefits:
Beginning balance		40,781	50,161
Beginning balance at original discount rate		37,856	43,626
Effect of changes in cash flow assumptions			(1,130)	(815)
Effect of actual variances from expected experience			(483)	(117)
Adjusted beginning of period balance			36,243	42,694
Issuances		1,138	1,004
Interest accrual		1,299	1,356
Benefit payments		(2,723)	(2,773)
Foreign currency translation		481	(4,425)
Other		0	0
Ending balance at original discount rate		36,438	37,856
Effect of changes in discount rate assumptions		(1,451)	2,925
Ending balance		34,987	40,781
Net liability for future policy benefits		22,780	26,597
Less: reinsurance recoverable		4,406	5,085
Net liability for future policy benefits after reinsurance recoverable		18,374	21,512
Aflac Japan | Medical and other health
Present value of expected future net premiums:
Beginning balance		11,817	14,697
Beginning balance at original discount rate		11,845	14,040
Effect of changes in cash flow assumptions			136	(154)
Effect of actual variances from expected experience			(84)	(164)
Adjusted beginning of period balance			11,897	13,722
Issuances		253	361
Interest accrual		292	302
Net premiums collected	[1]	(1,076)	(1,135)
Foreign currency translation		146	(1,405)
Other		(1)	0
Ending balance at original discount rate		11,511	11,845
Effect of changes in discount rate assumptions		(1,162)	(28)
Ending balance		10,349	11,817
Present value of expected future policy benefits:
Beginning balance		20,606	25,257
Beginning balance at original discount rate		21,957	25,023
Effect of changes in cash flow assumptions			108	(228)
Effect of actual variances from expected experience			(102)	(193)
Adjusted beginning of period balance			21,963	24,602
Issuances		260	373
Interest accrual		564	570
Benefit payments		(1,044)	(1,033)
Foreign currency translation		236	(2,555)
Other		0	0
Ending balance at original discount rate		21,979	21,957
Effect of changes in discount rate assumptions		(4,287)	(1,351)
Ending balance		17,692	20,606
Net liability for future policy benefits		7,343	8,789
Less: reinsurance recoverable		1,062	1,245
Net liability for future policy benefits after reinsurance recoverable		6,281	7,544
Aflac Japan | Life insurance
Present value of expected future net premiums:
Beginning balance		5,156	6,488
Beginning balance at original discount rate		5,084	6,258
Effect of changes in cash flow assumptions			(40)	(190)
Effect of actual variances from expected experience			(62)	(97)
Adjusted beginning of period balance			4,982	5,971
Issuances		405	478
Interest accrual		110	110
Net premiums collected	[1]	(795)	(862)
Foreign currency translation		70	(613)
Other		0	0
Ending balance at original discount rate		4,772	5,084
Effect of changes in discount rate assumptions		(225)	72
Ending balance		4,547	5,156
Present value of expected future policy benefits:
Beginning balance		24,265	29,731
Beginning balance at original discount rate		26,330	30,256
Effect of changes in cash flow assumptions			(101)	(302)
Effect of actual variances from expected experience			(61)	(110)
Adjusted beginning of period balance			26,168	29,844
Issuances		417	488
Interest accrual		569	582
Benefit payments		(1,753)	(1,510)
Foreign currency translation		315	(3,074)
Other		0	0
Ending balance at original discount rate		25,716	26,330
Effect of changes in discount rate assumptions		(4,822)	(2,065)
Ending balance		20,894	24,265
Net liability for future policy benefits		16,347	19,109
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		16,347	19,109
Aflac Japan | Other
Present value of expected future net premiums:
Beginning balance		846	1,088
Beginning balance at original discount rate		864	1,069
Effect of changes in cash flow assumptions			5	(19)
Effect of actual variances from expected experience			(12)	(14)
Adjusted beginning of period balance			857	1,036
Issuances		9	16
Interest accrual		16	17
Net premiums collected	[1]	(95)	(101)
Foreign currency translation		13	(104)
Other		0	0
Ending balance at original discount rate		800	864
Effect of changes in discount rate assumptions		(75)	(18)
Ending balance		725	846
Present value of expected future policy benefits:
Beginning balance		4,225	5,178
Beginning balance at original discount rate		4,765	5,444
Effect of changes in cash flow assumptions			74	(7)
Effect of actual variances from expected experience			(21)	(24)
Adjusted beginning of period balance			4,818	5,413
Issuances		14	22
Interest accrual		91	93
Benefit payments		(218)	(208)
Foreign currency translation		53	(555)
Other		0	0
Ending balance at original discount rate		4,758	4,765
Effect of changes in discount rate assumptions		(1,087)	(540)
Ending balance		3,671	4,225
Net liability for future policy benefits		2,946	3,379
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		2,946	3,379
Aflac U.S. | Life insurance
Present value of expected future net premiums:
Beginning balance		909	853
Beginning balance at original discount rate		976	909
Effect of changes in cash flow assumptions			(5)	(5)
Effect of actual variances from expected experience			(32)	(29)
Adjusted beginning of period balance			939	875
Issuances		246	226
Interest accrual		42	37
Net premiums collected	[1]	(171)	(157)
Foreign currency translation		0	0
Other		(5)	(5)
Ending balance at original discount rate		1,051	976
Effect of changes in discount rate assumptions		(30)	(67)
Ending balance		1,021	909
Present value of expected future policy benefits:
Beginning balance		1,847	1,764
Beginning balance at original discount rate		2,126	1,971
Effect of changes in cash flow assumptions			(17)	(3)
Effect of actual variances from expected experience			(53)	(43)
Adjusted beginning of period balance			2,056	1,925
Issuances		254	231
Interest accrual		87	78
Benefit payments		(109)	(108)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		2,288	2,126
Effect of changes in discount rate assumptions		(212)	(279)
Ending balance		2,076	1,847
Net liability for future policy benefits		1,055	938
Less: reinsurance recoverable		25	18
Net liability for future policy benefits after reinsurance recoverable		1,030	920
Aflac U.S. | Accident
Present value of expected future net premiums:
Beginning balance		2,497	2,488
Beginning balance at original discount rate		2,687	2,630
Effect of changes in cash flow assumptions			18	65
Effect of actual variances from expected experience			21	66
Adjusted beginning of period balance			2,726	2,761
Issuances		295	307
Interest accrual		110	106
Net premiums collected	[1]	(487)	(479)
Foreign currency translation		0	0
Other		(7)	(8)
Ending balance at original discount rate		2,637	2,687
Effect of changes in discount rate assumptions		(112)	(190)
Ending balance		2,525	2,497
Present value of expected future policy benefits:
Beginning balance		3,127	3,109
Beginning balance at original discount rate		3,386	3,302
Effect of changes in cash flow assumptions			47	109
Effect of actual variances from expected experience			9	91
Adjusted beginning of period balance			3,442	3,502
Issuances		300	311
Interest accrual		138	133
Benefit payments		(532)	(560)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		3,348	3,386
Effect of changes in discount rate assumptions		(164)	(259)
Ending balance		3,184	3,127
Net liability for future policy benefits		659	630
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		659	630
Aflac U.S. | Disability
Present value of expected future net premiums:
Beginning balance		1,635	1,652
Beginning balance at original discount rate		1,726	1,738
Effect of changes in cash flow assumptions			(22)	(47)
Effect of actual variances from expected experience			20	12
Adjusted beginning of period balance			1,724	1,703
Issuances		341	364
Interest accrual		69	66
Net premiums collected	[1]	(402)	(401)
Foreign currency translation		0	0
Other		(6)	(6)
Ending balance at original discount rate		1,726	1,726
Effect of changes in discount rate assumptions		(41)	(91)
Ending balance		1,685	1,635
Present value of expected future policy benefits:
Beginning balance		2,330	2,422
Beginning balance at original discount rate		2,466	2,541
Effect of changes in cash flow assumptions			(46)	(73)
Effect of actual variances from expected experience			5	(16)
Adjusted beginning of period balance			2,425	2,452
Issuances		355	381
Interest accrual		99	98
Benefit payments		(478)	(465)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		2,401	2,466
Effect of changes in discount rate assumptions		(65)	(136)
Ending balance		2,336	2,330
Net liability for future policy benefits		651	695
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		651	695
Aflac U.S. | Critical care
Present value of expected future net premiums:
Beginning balance		3,901	4,074
Beginning balance at original discount rate		4,340	4,416
Effect of changes in cash flow assumptions			(163)	(106)
Effect of actual variances from expected experience			(2)	(100)
Adjusted beginning of period balance			4,175	4,210
Issuances		488	543
Interest accrual		177	173
Net premiums collected	[1]	(590)	(578)
Foreign currency translation		0	0
Other		(8)	(8)
Ending balance at original discount rate		4,242	4,340
Effect of changes in discount rate assumptions		(297)	(439)
Ending balance		3,945	3,901
Present value of expected future policy benefits:
Beginning balance		10,701	11,290
Beginning balance at original discount rate		12,013	12,120
Effect of changes in cash flow assumptions			(219)	(112)
Effect of actual variances from expected experience			(15)	(144)
Adjusted beginning of period balance			11,779	11,864
Issuances		503	559
Interest accrual		515	515
Benefit payments		(985)	(925)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		11,812	12,013
Effect of changes in discount rate assumptions		(967)	(1,312)
Ending balance		10,845	10,701
Net liability for future policy benefits		6,900	6,800
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		6,900	6,800
Aflac U.S. | Hospital indemnity
Present value of expected future net premiums:
Beginning balance		1,122	1,107
Beginning balance at original discount rate		1,221	1,193
Effect of changes in cash flow assumptions			(8)	(21)
Effect of actual variances from expected experience			16	21
Adjusted beginning of period balance			1,229	1,193
Issuances		211	231
Interest accrual		50	46
Net premiums collected	[1]	(255)	(244)
Foreign currency translation		0	0
Other		(4)	(5)
Ending balance at original discount rate		1,231	1,221
Effect of changes in discount rate assumptions		(60)	(99)
Ending balance		1,171	1,122
Present value of expected future policy benefits:
Beginning balance		1,897	1,943
Beginning balance at original discount rate		2,073	2,076
Effect of changes in cash flow assumptions			(4)	(31)
Effect of actual variances from expected experience			8	21
Adjusted beginning of period balance			2,077	2,066
Issuances		217	237
Interest accrual		87	84
Benefit payments		(310)	(314)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		2,071	2,073
Effect of changes in discount rate assumptions		(116)	(176)
Ending balance		1,955	1,897
Net liability for future policy benefits		784	775
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		784	775
Aflac U.S. | Dental/vision
Present value of expected future net premiums:
Beginning balance		196	206
Beginning balance at original discount rate		209	217
Effect of changes in cash flow assumptions			(10)	(17)
Effect of actual variances from expected experience			(10)	(12)
Adjusted beginning of period balance			189	188
Issuances		50	52
Interest accrual		9	9
Net premiums collected	[1]	(39)	(39)
Foreign currency translation		0	0
Other		(1)	(1)
Ending balance at original discount rate		208	209
Effect of changes in discount rate assumptions		(6)	(13)
Ending balance		202	196
Present value of expected future policy benefits:
Beginning balance		441	478
Beginning balance at original discount rate		477	506
Effect of changes in cash flow assumptions			(15)	(28)
Effect of actual variances from expected experience			(13)	(16)
Adjusted beginning of period balance			449	462
Issuances		50	55
Interest accrual		20	20
Benefit payments		(61)	(60)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		458	477
Effect of changes in discount rate assumptions		(20)	(36)
Ending balance		438	441
Net liability for future policy benefits		236	245
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		236	245
Aflac U.S. | Other
Present value of expected future net premiums:
Beginning balance		826	277
Beginning balance at original discount rate		824	272
Effect of changes in cash flow assumptions			386	(8)
Effect of actual variances from expected experience			146	13
Adjusted beginning of period balance			1,356	277
Issuances		571	592
Interest accrual		73	25
Net premiums collected	[1]	(138)	(53)
Foreign currency translation		0	0
Other		(27)	(17)
Ending balance at original discount rate		1,835	824
Effect of changes in discount rate assumptions		133	2
Ending balance		1,968	826
Present value of expected future policy benefits:
Beginning balance		1,288	798
Beginning balance at original discount rate		1,293	769
Effect of changes in cash flow assumptions			399	(12)
Effect of actual variances from expected experience			148	(7)
Adjusted beginning of period balance			1,840	$ 750
Issuances		574	597
Interest accrual		97	50
Benefit payments		(207)	(104)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		2,304	1,293
Effect of changes in discount rate assumptions		140	(5)
Ending balance		2,444	1,288
Net liability for future policy benefits		476	462
Less: reinsurance recoverable		11	0
Net liability for future policy benefits after reinsurance recoverable		$ 465	$ 462

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