POLICY LIABILITIES - Reconciliation of Future Policy Benefits (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	$ 71,197	$ 70,381
Deferred reinsurance gain liability	152	146
Intercompany eliminations
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	(5,861)	(5,760)
Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Deferred profit liability	1,990	1,844
Deferred reinsurance gain liability	860	806
Corporate and other
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	5,116	5,072
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	26,942	26,597
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	8,902	8,789
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	19,195	19,109
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	975	938
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	626	630
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	690	695
Critical Care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	6,864	6,800
Hospital Indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	772	775
Dental/Vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	245	245
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	3,414	3,379
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	$ 467	$ 462