DEFERRED POLICY ACQUISITION COSTS - Schedule Of Deferred Policy Acquisition Costs (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	$ 9,132	$ 9,239
Capitalization	1,056	1,086
Amortization expense	(851)	(816)	$ (792)
Foreign currency translation and other	(579)	(377)
Balance, end of year	8,758	9,132	9,239
Aflac Japan
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	5,559
Amortization expense	(321)	(326)	(338)
Balance, end of year	5,102	5,559
Aflac Japan | Cancer
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	2,971	3,035
Capitalization	300	317
Amortization expense	(184)	(184)
Foreign currency translation and other	(311)	(197)
Balance, end of year	2,776	2,971	3,035
Aflac Japan | Medical and other health
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	2,041	2,161
Capitalization	103	123
Amortization expense	(100)	(105)
Foreign currency translation and other	(211)	(138)
Balance, end of year	1,833	2,041	2,161
Aflac Japan | Life insurance
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	491	525
Capitalization	36	33
Amortization expense	(34)	(34)
Foreign currency translation and other	(52)	(33)
Balance, end of year	441	491	525
Aflac Japan | Other
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	56	55
Capitalization	4	8
Amortization expense	(3)	(3)
Foreign currency translation and other	(5)	(4)
Balance, end of year	52	56	55
Aflac U.S.
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	3,573
Amortization expense	(530)	(490)	(455)
Balance, end of year	3,656	3,573
Aflac U.S. | Life insurance
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	172	135
Capitalization	77	61
Amortization expense	(30)	(24)
Foreign currency translation and other	0	0
Balance, end of year	219	172	135
Aflac U.S. | Accident
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	917	904
Capitalization	141	151
Amortization expense	(143)	(138)
Foreign currency translation and other	0	0
Balance, end of year	915	917	904
Aflac U.S. | Disability
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	625	613
Capitalization	129	125
Amortization expense	(118)	(113)
Foreign currency translation and other	0	0
Balance, end of year	636	625	613
Aflac U.S. | Critical care
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	1,336	1,304
Capitalization	165	173
Amortization expense	(153)	(141)
Foreign currency translation and other	0	0
Balance, end of year	1,348	1,336	1,304
Aflac U.S. | Hospital indemnity
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	436	418
Capitalization	89	84
Amortization expense	(73)	(66)
Foreign currency translation and other	0	0
Balance, end of year	452	436	418
Aflac U.S. | Dental/vision
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	86	88
Capitalization	12	10
Amortization expense	(12)	(12)
Foreign currency translation and other	0	0
Balance, end of year	86	86	88
Aflac U.S. | Other
Deferred Policy Acquisition Cost [Line Items]
Balance, beginning of year	1	1
Capitalization	0	1
Amortization expense	(1)	4
Foreign currency translation and other	0	(5)
Balance, end of year	$ 0	$ 1	$ 1