POLICY LIABILITIES - Reconciliation of Future Policy Benefits (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Deferred profit liability - limited-payment contracts	$ 1,669	$ 1,740
Deferred profit liability - reinsurance	590	692
Future policy benefits	78,448	88,241
Intercompany eliminations
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	(2,334)	(667)
Corporate and other
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	2,375	686
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	30,716	35,468
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	9,699	10,705
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	21,678	24,469
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	802	802
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	575	564
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	754	810
Critical Care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	6,599	7,003
Hospital Indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	775	854
Dental/Vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	256	277
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	3,814	4,326
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	$ 480	$ 512