DEFERRED POLICY ACQUISITION COSTS AND INSURANCE EXPENSES - Rollforward of Deferred Policy Acquisition Costs by Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred policy acquisition costs:
Balance, beginning of year	$ 9,525
Capitalization	1,100	$ 1,100	$ 1,200
Amortization	(1,152)	(1,170)	(1,214)
Balance, end of year	8,593	9,525
Aflac Japan
Deferred policy acquisition costs:
Balance, beginning of year	6,233	6,991
Capitalization	498	593
Amortization	(547)	(653)	(644)
Foreign currency translation and other	(829)	(698)
Balance, end of year	5,355	6,233	6,991
Aflac U.S.
Deferred policy acquisition costs:
Balance, beginning of year	3,292	3,450
Capitalization	556	470
Amortization	(605)	(517)	(570)
Foreign currency translation and other	(5)	(111)
Balance, end of year	$ 3,238	$ 3,292	$ 3,450