POLICY LIABILITIES - Summary of Discounted Expected Future Gross Premiums and Future Benefits and Expenses (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	$ 105,686	$ 121,753
Benefits and Expenses	111,508	132,131
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	40,170	48,363
Benefits and Expenses	40,781	50,161	$ 54,766
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	25,171	30,757
Benefits and Expenses	20,606	25,257	27,419
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	9,367	11,240
Benefits and Expenses	24,265	29,731	31,954
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	2,050	1,914
Benefits and Expenses	1,847	1,764	1,526
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	6,057	6,369
Benefits and Expenses	3,127	3,109	3,098
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	4,404	4,488
Benefits and Expenses	2,330	2,422	2,445
Critical care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	11,900	12,417
Benefits and Expenses	10,701	11,290	11,489
Hospital indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	3,312	3,419
Benefits and Expenses	1,897	1,943	2,074
Dental/vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	761	807
Benefits and Expenses	441	478	488
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	1,204	1,512
Benefits and Expenses	4,225	5,178	5,582
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	1,290	467
Benefits and Expenses	$ 1,288	$ 798	$ 622