POLICY LIABILITIES - Summary of Interest Expense Related to Insurance Contracts Recognized (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	$ 641	$ 710
Corporate and other
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	0	0
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	285	329
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	71	80
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	133	149
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	9	8
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	6	5
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	8	9
Critical Care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	87	86
Hospital Indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	10	10
Dental/Vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	3	3
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	22	24
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	$ 7	$ 7