BUSINESS SEGMENT INFORMATION - Operations by Segment - Assets (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 120,258	$ 117,566
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	93,430	90,210
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	21,881	21,930
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 4,947	$ 5,426