DEFERRED POLICY ACQUISITION COSTS AND INSURANCE EXPENSES - Advertising Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Advertising Costs [Line Items]
Advertising expense	$ 204	$ 229	$ 184
Aflac Japan
Advertising Costs [Line Items]
Advertising expense	77	91	72
Aflac U.S.
Advertising Costs [Line Items]
Advertising expense	$ 127	$ 138	$ 112