POLICY LIABILITIES - Summary of Interest Expense Related to Insurance Contracts Recognized (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	$ 2,310	$ 2,436	$ 2,546
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	978	1,061	1,140
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	268	274	278
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	472	501	524
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	41	37	35
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	27	25	23
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	32	34	37
Critical care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	342	345	346
Hospital indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	38	39	40
Dental/vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	11	13	12
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	76	80	84
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	$ 25	$ 27	$ 27