POLICY LIABILITIES - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Health insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior years claims and claims adjustment expense	$ (155)	$ (198)	$ (365)	$ (518)
Aflac Japan | Health insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior years claims and claims adjustment expense			$ (220)
Percentage of total prior year claims and claims adjustment expense			60.00%
Liability for unpaid claims and claims adjustment expense, foreign currency translation gain (loss), prior year claims adjustment expense			$ (41)
Prior year claims and claims adjustment expense excluding effect of foreign currency			$ (261)
Percentage of total prior year claims and claims adjustment expense excluding effect of foreign currency			72.00%
Aflac U.S.
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior Year Claims And Claims Adjustment Expense From Refinement of Estimates			$ (54)
Aflac U.S. | Health insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior years claims and claims adjustment expense			$ (145)
Percentage of total prior year claims and claims adjustment expense			40.00%