INCOME TAXES - Components of Income Tax Expense (Benefit) Applicable to Pretax Earnings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of Provision of Income Taxes [Line Items]
Current	$ 1,181	$ 1,095	$ 794
Deferred	(778)	(98)	(1,413)
Total income tax expense	403	997	(619)
Aflac Japan
Reconciliation of Provision of Income Taxes [Line Items]
Current	913	884	822
Deferred	200	251	(28)
Total income tax expense	1,113	1,135	794
Aflac U.S.
Reconciliation of Provision of Income Taxes [Line Items]
Current	268	211	(28)
Deferred	(978)	(349)	(1,385)
Total income tax expense	$ (710)	$ (138)	$ (1,413)