BUSINESS SEGMENT INFORMATION - Operations by Segment - Assets (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 135,629	$ 157,542
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	107,698	128,536
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	20,828	23,106
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 7,103	$ 5,900