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, 2023	Dec. 31, 2022	Dec. 31, 2021
Present value of expected future policy benefits:
Beginning balance		$ 141,463
Ending balance		132,131	$ 141,463
Liability amounts		83,718	88,241
Aflac Japan | Cancer
Present value of expected premiums:
Beginning balance		19,298	25,893
Beginning balance at original discount rate		18,221	22,470
Effect of changes in cash flow assumptions			(165)	$ (639)
Effect of actual variances from expected experience			(315)	(284)
Adjusted beginning of period balance			17,741	21,547
Issuances		1,034	947
Interest accrual		412	459
Net premiums collected	[1]	(1,564)	(1,734)
Foreign currency translation		(1,170)	(2,997)
Other		(1)	(1)
Ending balance at original discount rate		16,452	18,221	22,470
Effect of changes in discount rate assumptions		1,057	1,077
Ending balance		17,509	19,298	25,893
Present value of expected future policy benefits:
Beginning balance		54,766	72,747
Beginning balance at original discount rate		47,677	56,807
Effect of changes in cash flow assumptions			(147)	(721)
Effect of actual variances from expected experience			(385)	(333)
Adjusted beginning of period balance			47,145	55,753
Issuances		1,059	960
Interest accrual		1,473	1,599
Benefit payments		(2,987)	(3,050)
Foreign currency translation		(3,064)	(7,585)
Other		0	0
Ending balance at original discount rate		43,626	47,677	56,807
Effect of changes in discount rate assumptions		6,535	7,089
Ending balance		50,161	54,766	72,747
Liability amounts		32,652	35,468
Less: reinsurance recoverable		4,135	0
Net liability for future policy benefits after reinsurance recoverable		28,517	35,468
Aflac Japan | Medical and other health
Present value of expected premiums:
Beginning balance		16,714	21,174
Beginning balance at original discount rate		16,195	18,681
Effect of changes in cash flow assumptions			(470)	317
Effect of actual variances from expected experience			(137)	61
Adjusted beginning of period balance			15,588	19,059
Issuances		418	639
Interest accrual		334	364
Net premiums collected	[1]	(1,261)	(1,376)
Foreign currency translation		(1,038)	(2,488)
Other		(1)	(3)
Ending balance at original discount rate		14,040	16,195	18,681
Effect of changes in discount rate assumptions		657	519
Ending balance		14,697	16,714	21,174
Present value of expected future policy benefits:
Beginning balance		27,419	36,021
Beginning balance at original discount rate		27,566	31,398
Effect of changes in cash flow assumptions			(507)	352
Effect of actual variances from expected experience			(154)	83
Adjusted beginning of period balance			26,905	31,833
Issuances		432	646
Interest accrual		608	642
Benefit payments		(1,153)	(1,375)
Foreign currency translation		(1,769)	(4,180)
Other		0	0
Ending balance at original discount rate		25,023	27,566	31,398
Effect of changes in discount rate assumptions		234	(147)
Ending balance		25,257	27,419	36,021
Liability amounts		10,560	10,705
Less: reinsurance recoverable		1,521	1,579
Net liability for future policy benefits after reinsurance recoverable		9,039	9,126
Aflac Japan | Life insurance
Present value of expected premiums:
Beginning balance		7,485	10,847
Beginning balance at original discount rate		7,284	10,064
Effect of changes in cash flow assumptions			43	(494)
Effect of actual variances from expected experience			(42)	(81)
Adjusted beginning of period balance			7,285	9,489
Issuances		335	221
Interest accrual		124	146
Net premiums collected	[1]	(1,017)	(1,229)
Foreign currency translation		(469)	(1,343)
Other		0	0
Ending balance at original discount rate		6,258	7,284	10,064
Effect of changes in discount rate assumptions		230	201
Ending balance		6,488	7,485	10,847
Present value of expected future policy benefits:
Beginning balance		31,954	42,720
Beginning balance at original discount rate		32,800	39,002
Effect of changes in cash flow assumptions			65	(550)
Effect of actual variances from expected experience			(51)	(91)
Adjusted beginning of period balance			32,814	38,361
Issuances		341	222
Interest accrual		625	670
Benefit payments		(1,415)	(1,248)
Foreign currency translation		(2,109)	(5,205)
Other		0	0
Ending balance at original discount rate		30,256	32,800	39,002
Effect of changes in discount rate assumptions		(525)	(846)
Ending balance		29,731	31,954	42,720
Liability amounts		23,243	24,469
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		23,243	24,469
Aflac Japan | Other
Present value of expected premiums:
Beginning balance		1,256	1,586
Beginning balance at original discount rate		1,242	1,461
Effect of changes in cash flow assumptions			(12)	25
Effect of actual variances from expected experience			(15)	(10)
Adjusted beginning of period balance			1,215	1,476
Issuances		26	62
Interest accrual		20	22
Net premiums collected	[1]	(112)	(123)
Foreign currency translation		(80)	(195)
Other		0	0
Ending balance at original discount rate		1,069	1,242	1,461
Effect of changes in discount rate assumptions		19	14
Ending balance		1,088	1,256	1,586
Present value of expected future policy benefits:
Beginning balance		5,582	7,322
Beginning balance at original discount rate		5,940	6,787
Effect of changes in cash flow assumptions			(27)	96
Effect of actual variances from expected experience			(15)	(10)
Adjusted beginning of period balance			5,898	6,873
Issuances		32	68
Interest accrual		100	106
Benefit payments		(206)	(202)
Foreign currency translation		(380)	(905)
Other		0	0
Ending balance at original discount rate		5,444	5,940	6,787
Effect of changes in discount rate assumptions		(266)	(358)
Ending balance		5,178	5,582	7,322
Liability amounts		4,090	4,326
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		4,090	4,326
Aflac U.S. | Life insurance
Present value of expected premiums:
Beginning balance		724	834
Beginning balance at original discount rate		799	780
Effect of changes in cash flow assumptions			61	(1)
Effect of actual variances from expected experience			(25)	(16)
Adjusted beginning of period balance			835	763
Issuances		181	146
Interest accrual		31	27
Net premiums collected	[1]	(137)	(131)
Foreign currency translation		0	0
Other		(1)	(6)
Ending balance at original discount rate		909	799	780
Effect of changes in discount rate assumptions		(56)	(75)
Ending balance		853	724	834
Present value of expected future policy benefits:
Beginning balance		1,526	1,843
Beginning balance at original discount rate		1,778	1,694
Effect of changes in cash flow assumptions			72	(1)
Effect of actual variances from expected experience			(32)	(21)
Adjusted beginning of period balance			1,818	1,672
Issuances		185	149
Interest accrual		68	62
Benefit payments		(105)	(103)
Foreign currency translation		0	0
Other		5	(2)
Ending balance at original discount rate		1,971	1,778	1,694
Effect of changes in discount rate assumptions		(207)	(252)
Ending balance		1,764	1,526	1,843
Liability amounts		911	802
Less: reinsurance recoverable		15	9
Net liability for future policy benefits after reinsurance recoverable		896	793
Aflac U.S. | Accident
Present value of expected premiums:
Beginning balance		2,534	3,283
Beginning balance at original discount rate		2,760	2,999
Effect of changes in cash flow assumptions			(16)	(52)
Effect of actual variances from expected experience			(58)	(152)
Adjusted beginning of period balance			2,686	2,795
Issuances		323	355
Interest accrual		102	105
Net premiums collected	[1]	(473)	(496)
Foreign currency translation		0	0
Other		(8)	1
Ending balance at original discount rate		2,630	2,760	2,999
Effect of changes in discount rate assumptions		(142)	(226)
Ending balance		2,488	2,534	3,283
Present value of expected future policy benefits:
Beginning balance		3,098	3,949
Beginning balance at original discount rate		3,391	3,594
Effect of changes in cash flow assumptions			(11)	(70)
Effect of actual variances from expected experience			(75)	(177)
Adjusted beginning of period balance			3,305	3,347
Issuances		331	364
Interest accrual		127	128
Benefit payments		(464)	(456)
Foreign currency translation		0	0
Other		3	8
Ending balance at original discount rate		3,302	3,391	3,594
Effect of changes in discount rate assumptions		(193)	(293)
Ending balance		3,109	3,098	3,949
Liability amounts		621	564
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		621	564
Aflac U.S. | Disability
Present value of expected premiums:
Beginning balance		1,635	1,862
Beginning balance at original discount rate		1,775	1,760
Effect of changes in cash flow assumptions			(51)	5
Effect of actual variances from expected experience			(29)	(43)
Adjusted beginning of period balance			1,695	1,722
Issuances		376	384
Interest accrual		62	57
Net premiums collected	[1]	(390)	(382)
Foreign currency translation		0	0
Other		(5)	(6)
Ending balance at original discount rate		1,738	1,775	1,760
Effect of changes in discount rate assumptions		(86)	(140)
Ending balance		1,652	1,635	1,862
Present value of expected future policy benefits:
Beginning balance		2,445	2,871
Beginning balance at original discount rate		2,636	2,670
Effect of changes in cash flow assumptions			(59)	5
Effect of actual variances from expected experience			(59)	(48)
Adjusted beginning of period balance			2,518	2,627
Issuances		392	397
Interest accrual		96	94
Benefit payments		(465)	(483)
Foreign currency translation		0	0
Other		0	1
Ending balance at original discount rate		2,541	2,636	2,670
Effect of changes in discount rate assumptions		(119)	(191)
Ending balance		2,422	2,445	2,871
Liability amounts		770	810
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		770	810
Aflac U.S. | Critical care
Present value of expected premiums:
Beginning balance		4,486	6,023
Beginning balance at original discount rate		5,050	5,391
Effect of changes in cash flow assumptions			(494)	(38)
Effect of actual variances from expected experience			(223)	(421)
Adjusted beginning of period balance			4,333	4,932
Issuances		493	537
Interest accrual		179	193
Net premiums collected	[1]	(580)	(612)
Foreign currency translation		0	0
Other		(9)	0
Ending balance at original discount rate		4,416	5,050	5,391
Effect of changes in discount rate assumptions		(342)	(564)
Ending balance		4,074	4,486	6,023
Present value of expected future policy benefits:
Beginning balance		11,489	15,388
Beginning balance at original discount rate		12,846	13,079
Effect of changes in cash flow assumptions			(592)	(43)
Effect of actual variances from expected experience			(271)	(465)
Adjusted beginning of period balance			11,983	12,571
Issuances		505	550
Interest accrual		524	539
Benefit payments		(893)	(823)
Foreign currency translation		0	0
Other		1	9
Ending balance at original discount rate		12,120	12,846	13,079
Effect of changes in discount rate assumptions		(830)	(1,357)
Ending balance		11,290	11,489	15,388
Liability amounts		7,216	7,003
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		7,216	7,003
Aflac U.S. | Hospital indemnity
Present value of expected premiums:
Beginning balance		1,220	1,467
Beginning balance at original discount rate		1,365	1,380
Effect of changes in cash flow assumptions			(142)	42
Effect of actual variances from expected experience			(73)	(111)
Adjusted beginning of period balance			1,150	1,311
Issuances		249	273
Interest accrual		45	45
Net premiums collected	[1]	(247)	(261)
Foreign currency translation		0	0
Other		(4)	(3)
Ending balance at original discount rate		1,193	1,365	1,380
Effect of changes in discount rate assumptions		(86)	(145)
Ending balance		1,107	1,220	1,467
Present value of expected future policy benefits:
Beginning balance		2,074	2,552
Beginning balance at original discount rate		2,300	2,300
Effect of changes in cash flow assumptions			(194)	40
Effect of actual variances from expected experience			(99)	(130)
Adjusted beginning of period balance			2,007	2,210
Issuances		258	282
Interest accrual		84	85
Benefit payments		(274)	(277)
Foreign currency translation		0	0
Other		1	0
Ending balance at original discount rate		2,076	2,300	2,300
Effect of changes in discount rate assumptions		(133)	(226)
Ending balance		1,943	2,074	2,552
Liability amounts		836	854
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		836	854
Aflac U.S. | Dental/vision
Present value of expected premiums:
Beginning balance		211	264
Beginning balance at original discount rate		231	241
Effect of changes in cash flow assumptions			(9)	10
Effect of actual variances from expected experience			(17)	(20)
Adjusted beginning of period balance			205	231
Issuances		44	33
Interest accrual		8	9
Net premiums collected	[1]	(39)	(42)
Foreign currency translation		0	0
Other		(1)	0
Ending balance at original discount rate		217	231	241
Effect of changes in discount rate assumptions		(11)	(20)
Ending balance		206	211	264
Present value of expected future policy benefits:
Beginning balance		488	616
Beginning balance at original discount rate		532	549
Effect of changes in cash flow assumptions			(14)	13
Effect of actual variances from expected experience			(22)	(23)
Adjusted beginning of period balance			496	539
Issuances		46	34
Interest accrual		21	21
Benefit payments		(59)	(62)
Foreign currency translation		0	0
Other		2	0
Ending balance at original discount rate		506	532	549
Effect of changes in discount rate assumptions		(28)	(44)
Ending balance		478	488	616
Liability amounts		272	277
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		272	277
Aflac U.S. | Other
Present value of expected premiums:
Beginning balance		110	153
Beginning balance at original discount rate		118	135
Effect of changes in cash flow assumptions			(9)	(12)
Effect of actual variances from expected experience			(2)	6
Adjusted beginning of period balance			107	129
Issuances		169	0
Interest accrual		6	5
Net premiums collected	[1]	(17)	(17)
Foreign currency translation		0	0
Other		7	1
Ending balance at original discount rate		272	118	135
Effect of changes in discount rate assumptions		5	(8)
Ending balance		277	110	153
Present value of expected future policy benefits:
Beginning balance		622	837
Beginning balance at original discount rate		624	645
Effect of changes in cash flow assumptions			(13)	(15)
Effect of actual variances from expected experience			(4)	7
Adjusted beginning of period balance			607	637
Issuances		169	0
Interest accrual		33	32
Benefit payments		(48)	(45)
Foreign currency translation		0	0
Other		8	0
Ending balance at original discount rate		769	624	645
Effect of changes in discount rate assumptions		29	(2)
Ending balance		798	622	$ 837
Liability amounts		521	512
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		$ 521	$ 512

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