BUSINESS SEGMENT INFORMATION - Operations by Segment - Assets (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 128,442	$ 126,724
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	101,132	101,541
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	22,501	21,861
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 4,809	$ 3,322