POLICY LIABILITIES - Summary of Discounted Expected Future Gross Premiums and Future Benefits and Expenses (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	$ 134,041	$ 132,451
Benefits and Expenses	145,078	141,463
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	53,806	53,278
Benefits and Expenses	55,799	54,766
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	35,030	34,693
Benefits and Expenses	28,439	27,419
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	12,875	12,951
Benefits and Expenses	32,714	31,954
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	1,756	1,663
Benefits and Expenses	1,606	1,526
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	6,625	6,510
Benefits and Expenses	3,149	3,098
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	4,554	4,468
Benefits and Expenses	2,495	2,445
Critical Care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	13,013	12,659
Benefits and Expenses	11,817	11,489
Hospital Indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	3,592	3,483
Benefits and Expenses	2,139	2,074
Dental/Vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	826	821
Benefits and Expenses	494	488
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	1,712	1,697
Benefits and Expenses	5,770	5,582
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	252	228
Benefits and Expenses	$ 656	$ 622