POLICY LIABILITIES - Schedule of Changes in Present Value of Expected Net Premiums and Expected Future Policy Benefits (Details) - USD ($) $ in Millions		6 Months Ended	12 Months Ended
		Jun. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Present value of expected future policy benefits:
Beginning balance		$ 132,131
Ending balance		112,297	$ 132,131
Net liability for future policy benefits		70,339	83,718
Aflac Japan | Cancer
Present value of expected premiums:
Beginning balance		17,509	19,298
Beginning balance at original discount rate		16,452	18,221
Effect of changes in cash flow assumptions			0	$ (165)
Effect of actual variances from expected experience			(77)	(315)
Adjusted beginning of period balance			16,375	17,741
Issuances		439	1,034
Interest accrual		189	412
Net premiums collected	[1]	(721)	(1,564)
Foreign currency translation		(1,956)	(1,170)
Other		0	(1)
Ending balance at original discount rate		14,326	16,452
Effect of changes in discount rate assumptions		326	1,057
Ending balance		14,652	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			0	(147)
Effect of actual variances from expected experience			(105)	(385)
Adjusted beginning of period balance			43,521	47,145
Issuances		448	1,059
Interest accrual		672	1,473
Benefit payments		(1,357)	(2,987)
Foreign currency translation		(5,192)	(3,064)
Other		0	0
Ending balance at original discount rate		38,092	43,626
Effect of changes in discount rate assumptions		3,456	6,535
Ending balance		41,548	50,161
Net liability for future policy benefits		26,896	32,652
Less: reinsurance recoverable		3,420	4,135
Net liability for future policy benefits after reinsurance recoverable		23,476	28,517
Aflac Japan | Medical and other health
Present value of expected premiums:
Beginning balance		14,697	16,714
Beginning balance at original discount rate		14,040	16,195
Effect of changes in cash flow assumptions			0	(470)
Effect of actual variances from expected experience			(84)	(137)
Adjusted beginning of period balance			13,956	15,588
Issuances		193	418
Interest accrual		149	334
Net premiums collected	[1]	(565)	(1,261)
Foreign currency translation		(1,661)	(1,038)
Other		0	(1)
Ending balance at original discount rate		12,072	14,040
Effect of changes in discount rate assumptions		47	657
Ending balance		12,119	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			0	(507)
Effect of actual variances from expected experience			(97)	(154)
Adjusted beginning of period balance			24,926	26,905
Issuances		199	432
Interest accrual		280	608
Benefit payments		(497)	(1,153)
Foreign currency translation		(2,983)	(1,769)
Other		0	0
Ending balance at original discount rate		21,925	25,023
Effect of changes in discount rate assumptions		(1,230)	234
Ending balance		20,695	25,257
Net liability for future policy benefits		8,576	10,560
Less: reinsurance recoverable		1,247	1,521
Net liability for future policy benefits after reinsurance recoverable		7,329	9,039
Aflac Japan | Life insurance
Present value of expected premiums:
Beginning balance		6,488	7,485
Beginning balance at original discount rate		6,258	7,284
Effect of changes in cash flow assumptions			0	43
Effect of actual variances from expected experience			(39)	(42)
Adjusted beginning of period balance			6,219	7,285
Issuances		105	335
Interest accrual		55	124
Net premiums collected	[1]	(435)	(1,017)
Foreign currency translation		(730)	(469)
Other		0	0
Ending balance at original discount rate		5,214	6,258
Effect of changes in discount rate assumptions		64	230
Ending balance		5,278	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			0	65
Effect of actual variances from expected experience			(46)	(51)
Adjusted beginning of period balance			30,210	32,814
Issuances		107	341
Interest accrual		287	625
Benefit payments		(827)	(1,415)
Foreign currency translation		(3,585)	(2,109)
Other		0	0
Ending balance at original discount rate		26,192	30,256
Effect of changes in discount rate assumptions		(1,822)	(525)
Ending balance		24,370	29,731
Net liability for future policy benefits		19,092	23,243
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		19,092	23,243
Aflac Japan | Other
Present value of expected premiums:
Beginning balance		1,088	1,256
Beginning balance at original discount rate		1,069	1,242
Effect of changes in cash flow assumptions			0	(12)
Effect of actual variances from expected experience			(8)	(15)
Adjusted beginning of period balance			1,061	1,215
Issuances		10	26
Interest accrual		9	20
Net premiums collected	[1]	(50)	(112)
Foreign currency translation		(127)	(80)
Other		0	0
Ending balance at original discount rate		903	1,069
Effect of changes in discount rate assumptions		(12)	19
Ending balance		891	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			0	(27)
Effect of actual variances from expected experience			(14)	(15)
Adjusted beginning of period balance			5,430	5,898
Issuances		12	32
Interest accrual		46	100
Benefit payments		(97)	(206)
Foreign currency translation		(647)	(380)
Other		0	0
Ending balance at original discount rate		4,744	5,444
Effect of changes in discount rate assumptions		(500)	(266)
Ending balance		4,244	5,178
Net liability for future policy benefits		3,353	4,090
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		3,353	4,090
Aflac U.S. | Life insurance
Present value of expected premiums:
Beginning balance		853	724
Beginning balance at original discount rate		909	799
Effect of changes in cash flow assumptions			0	61
Effect of actual variances from expected experience			(18)	(25)
Adjusted beginning of period balance			891	835
Issuances		117	181
Interest accrual		18	31
Net premiums collected	[1]	(76)	(137)
Foreign currency translation		0	0
Other		(3)	(1)
Ending balance at original discount rate		947	909
Effect of changes in discount rate assumptions		(73)	(56)
Ending balance		874	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			0	72
Effect of actual variances from expected experience			(25)	(32)
Adjusted beginning of period balance			1,946	1,818
Issuances		121	185
Interest accrual		38	68
Benefit payments		(57)	(105)
Foreign currency translation		0	0
Other		0	5
Ending balance at original discount rate		2,048	1,971
Effect of changes in discount rate assumptions		(280)	(207)
Ending balance		1,768	1,764
Net liability for future policy benefits		894	911
Less: reinsurance recoverable		15	15
Net liability for future policy benefits after reinsurance recoverable		879	896
Aflac U.S. | Accident
Present value of expected premiums:
Beginning balance		2,488	2,534
Beginning balance at original discount rate		2,630	2,760
Effect of changes in cash flow assumptions			0	(16)
Effect of actual variances from expected experience			3	(58)
Adjusted beginning of period balance			2,633	2,686
Issuances		174	323
Interest accrual		52	102
Net premiums collected	[1]	(236)	(473)
Foreign currency translation		0	0
Other		(3)	(8)
Ending balance at original discount rate		2,620	2,630
Effect of changes in discount rate assumptions		(197)	(142)
Ending balance		2,423	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			0	(11)
Effect of actual variances from expected experience			0	(75)
Adjusted beginning of period balance			3,302	3,305
Issuances		179	331
Interest accrual		65	127
Benefit payments		(259)	(464)
Foreign currency translation		0	0
Other		(1)	3
Ending balance at original discount rate		3,286	3,302
Effect of changes in discount rate assumptions		(266)	(193)
Ending balance		3,020	3,109
Net liability for future policy benefits		597	621
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		597	621
Aflac U.S. | Disability
Present value of expected premiums:
Beginning balance		1,652	1,635
Beginning balance at original discount rate		1,738	1,775
Effect of changes in cash flow assumptions			0	(51)
Effect of actual variances from expected experience			0	(29)
Adjusted beginning of period balance			1,738	1,695
Issuances		203	376
Interest accrual		33	62
Net premiums collected	[1]	(201)	(390)
Foreign currency translation		0	0
Other		(4)	(5)
Ending balance at original discount rate		1,769	1,738
Effect of changes in discount rate assumptions		(108)	(86)
Ending balance		1,661	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			0	(59)
Effect of actual variances from expected experience			(11)	(59)
Adjusted beginning of period balance			2,530	2,518
Issuances		212	392
Interest accrual		49	96
Benefit payments		(229)	(465)
Foreign currency translation		0	0
Other		0	0
Ending balance at original discount rate		2,562	2,541
Effect of changes in discount rate assumptions		(157)	(119)
Ending balance		2,405	2,422
Net liability for future policy benefits		744	770
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		744	770
Aflac U.S. | Critical Care
Present value of expected premiums:
Beginning balance		4,074	4,486
Beginning balance at original discount rate		4,416	5,050
Effect of changes in cash flow assumptions			0	(494)
Effect of actual variances from expected experience			(60)	(223)
Adjusted beginning of period balance			4,356	4,333
Issuances		323	493
Interest accrual		87	179
Net premiums collected	[1]	(286)	(580)
Foreign currency translation		0	0
Other		(3)	(9)
Ending balance at original discount rate		4,477	4,416
Effect of changes in discount rate assumptions		(472)	(342)
Ending balance		4,005	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			0	(592)
Effect of actual variances from expected experience			(84)	(271)
Adjusted beginning of period balance			12,036	11,983
Issuances		336	505
Interest accrual		258	524
Benefit payments		(460)	(893)
Foreign currency translation		0	0
Other		0	1
Ending balance at original discount rate		12,170	12,120
Effect of changes in discount rate assumptions		(1,323)	(830)
Ending balance		10,847	11,290
Net liability for future policy benefits		6,842	7,216
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		6,842	7,216
Aflac U.S. | Hospital Indemnity
Present value of expected premiums:
Beginning balance		1,107	1,220
Beginning balance at original discount rate		1,193	1,365
Effect of changes in cash flow assumptions			0	(142)
Effect of actual variances from expected experience			(6)	(73)
Adjusted beginning of period balance			1,187	1,150
Issuances		138	249
Interest accrual		22	45
Net premiums collected	[1]	(120)	(247)
Foreign currency translation		0	0
Other		0	(4)
Ending balance at original discount rate		1,227	1,193
Effect of changes in discount rate assumptions		(109)	(86)
Ending balance		1,118	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			0	(194)
Effect of actual variances from expected experience			(13)	(99)
Adjusted beginning of period balance			2,063	2,007
Issuances		144	258
Interest accrual		41	84
Benefit payments		(154)	(274)
Foreign currency translation		0	0
Other		1	1
Ending balance at original discount rate		2,095	2,076
Effect of changes in discount rate assumptions		(188)	(133)
Ending balance		1,907	1,943
Net liability for future policy benefits		789	836
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		789	836
Aflac U.S. | Dental/Vision
Present value of expected premiums:
Beginning balance		206	211
Beginning balance at original discount rate		217	231
Effect of changes in cash flow assumptions			0	(9)
Effect of actual variances from expected experience			(7)	(17)
Adjusted beginning of period balance			210	205
Issuances		29	44
Interest accrual		4	8
Net premiums collected	[1]	(20)	(39)
Foreign currency translation		0	0
Other		1	(1)
Ending balance at original discount rate		224	217
Effect of changes in discount rate assumptions		(16)	(11)
Ending balance		208	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			0	(14)
Effect of actual variances from expected experience			(9)	(22)
Adjusted beginning of period balance			497	496
Issuances		30	46
Interest accrual		10	21
Benefit payments		(29)	(59)
Foreign currency translation		0	0
Other		0	2
Ending balance at original discount rate		508	506
Effect of changes in discount rate assumptions		(40)	(28)
Ending balance		468	478
Net liability for future policy benefits		260	272
Less: reinsurance recoverable		0	0
Net liability for future policy benefits after reinsurance recoverable		260	272
Aflac U.S. | Other
Present value of expected premiums:
Beginning balance		277	110
Beginning balance at original discount rate		272	118
Effect of changes in cash flow assumptions			0	(9)
Effect of actual variances from expected experience			11	(2)
Adjusted beginning of period balance			283	107
Issuances		264	169
Interest accrual		9	6
Net premiums collected	[1]	(20)	(17)
Foreign currency translation		0	0
Other		(4)	7
Ending balance at original discount rate		532	272
Effect of changes in discount rate assumptions		0	5
Ending balance		532	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			0	(13)
Effect of actual variances from expected experience			11	(4)
Adjusted beginning of period balance			780	$ 607
Issuances		265	169
Interest accrual		22	33
Benefit payments		(42)	(48)
Foreign currency translation		0	0
Other		2	8
Ending balance at original discount rate		1,027	769
Effect of changes in discount rate assumptions		(2)	29
Ending balance		1,025	798
Net liability for future policy benefits		493	521
Less: reinsurance recoverable		1	0
Net liability for future policy benefits after reinsurance recoverable		$ 492	$ 521

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