POLICY LIABILITIES - Summary of Undiscounted Expected Future Gross Premiums and Future Benefits and Expenses (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	$ 188,305	$ 191,005
Benefits and Expenses	233,786	235,775
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	74,340	75,529
Benefits and Expenses	83,000	84,246
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	49,626	50,720
Benefits and Expenses	50,445	50,778
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	16,406	16,946
Benefits and Expenses	52,836	53,271
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	2,502	2,375
Benefits and Expenses	2,926	2,787
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	9,408	9,481
Benefits and Expenses	4,602	4,636
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	5,886	5,858
Benefits and Expenses	3,288	3,267
Critical Care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	21,050	21,069
Benefits and Expenses	22,022	22,113
Hospital Indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	5,199	5,164
Benefits and Expenses	3,359	3,338
Dental/Vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	1,180	1,208
Benefits and Expenses	749	759
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	2,279	2,322
Benefits and Expenses	9,337	9,433
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums	429	333
Benefits and Expenses	$ 1,222	$ 1,147