DEFERRED POLICY ACQUISITION COSTS - Schedule Of Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	$ 9,239	$ 9,848	$ 9,848
Capitalization	270		1,052
Amortization expense	(205)	(207)	(792)
Foreign currency translation and other	(37)		(869)
Ending balance	9,267		9,239
Aflac Japan | Cancer
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	3,035	3,464	3,464
Capitalization	76		291
Amortization expense	(48)		(188)
Foreign currency translation and other	(19)		(532)
Ending balance	3,044		3,035
Aflac Japan | Medical and other health
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	2,161	2,372	2,372
Capitalization	33		161
Amortization expense	(28)		(112)
Foreign currency translation and other	(13)		(260)
Ending balance	2,153		2,161
Aflac Japan | Life insurance
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	525	595	595
Capitalization	9		33
Amortization expense	(9)		(35)
Foreign currency translation and other	(3)		(68)
Ending balance	522		525
Aflac Japan | Other
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	55	51	51
Capitalization	4		12
Amortization expense	0		(3)
Foreign currency translation and other	(1)		(5)
Ending balance	58		55
Aflac U.S. | Life insurance
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	135	115	115
Capitalization	14		40
Amortization expense	(6)		(20)
Foreign currency translation and other	0		0
Ending balance	143		135
Aflac U.S. | Accident
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	904	887	887
Capitalization	39		147
Amortization expense	(34)		(130)
Foreign currency translation and other	0		0
Ending balance	909		904
Aflac U.S. | Disability
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	613	604	604
Capitalization	31		117
Amortization expense	(28)		(108)
Foreign currency translation and other	0		0
Ending balance	616		613
Aflac U.S. | Critical Care
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	1,304	1,270	1,270
Capitalization	41		160
Amortization expense	(34)		(126)
Foreign currency translation and other	0		0
Ending balance	1,311		1,304
Aflac U.S. | Hospital Indemnity
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	418	399	399
Capitalization	21		80
Amortization expense	(16)		(61)
Foreign currency translation and other	0		0
Ending balance	423		418
Aflac U.S. | Dental/Vision
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	88	90	90
Capitalization	2		11
Amortization expense	(3)		(13)
Foreign currency translation and other	0		0
Ending balance	87		88
Aflac U.S. | Other
Deferred Policy Acquisition Cost [Line Items]
Beginning balance	1	$ 1	1
Capitalization	0		0
Amortization expense	1		4
Foreign currency translation and other	(1)		(4)
Ending balance	$ 1		$ 1