BUSINESS SEGMENT AND SELECTED FOREIGN CURRENCY TRANSLATION ITEMS - Operations by Segment - Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 126,724	$ 131,738
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	101,541	105,734
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	21,861	21,002
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 3,322	$ 5,002