DEFERRED POLICY ACQUISITION COSTS - Schedule Of Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			$ 9,239	$ 9,848	$ 9,848
Capitalization			804		1,052
Amortization expense	$ (201)	$ (194)	(608)	(598)	(792)
Foreign currency translation and other			(664)		(869)
Ending balance	8,771		8,771		9,239
Aflac Japan | Cancer
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			3,035	3,464	3,464
Capitalization			247		291
Amortization expense			(139)		(188)
Foreign currency translation and other			(352)		(532)
Ending balance	2,791		2,791		3,035
Aflac Japan | Medical and other health
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			2,161	2,372	2,372
Capitalization			93		161
Amortization expense			(80)		(112)
Foreign currency translation and other			(244)		(260)
Ending balance	1,930		1,930		2,161
Aflac Japan | Life insurance
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			525	595	595
Capitalization			26		33
Amortization expense			(26)		(35)
Foreign currency translation and other			(58)		(68)
Ending balance	467		467		525
Aflac Japan | Other
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			55	51	51
Capitalization			7		12
Amortization expense			(2)		(3)
Foreign currency translation and other			(7)		(5)
Ending balance	53		53		55
Aflac U.S. | Life insurance
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			135	115	115
Capitalization			43		40
Amortization expense			(18)		(20)
Foreign currency translation and other			0		0
Ending balance	160		160		135
Aflac U.S. | Accident
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			904	887	887
Capitalization			109		147
Amortization expense			(103)		(130)
Foreign currency translation and other			0		0
Ending balance	910		910		904
Aflac U.S. | Disability
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			613	604	604
Capitalization			90		117
Amortization expense			(84)		(108)
Foreign currency translation and other			0		0
Ending balance	619		619		613
Aflac U.S. | Critical Care
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			1,304	1,270	1,270
Capitalization			122		160
Amortization expense			(102)		(126)
Foreign currency translation and other			0		0
Ending balance	1,324		1,324		1,304
Aflac U.S. | Hospital Indemnity
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			418	399	399
Capitalization			60		80
Amortization expense			(48)		(61)
Foreign currency translation and other			0		0
Ending balance	430		430		418
Aflac U.S. | Dental/Vision
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			88	90	90
Capitalization			7		11
Amortization expense			(9)		(13)
Foreign currency translation and other			0		0
Ending balance	86		86		88
Aflac U.S. | Other
Deferred Policy Acquisition Cost [Line Items]
Beginning balance			1	$ 1	1
Capitalization			0		0
Amortization expense			3		4
Foreign currency translation and other			(3)		(4)
Ending balance	$ 1		$ 1		$ 1