BUSINESS SEGMENT AND FOREIGN INFORMATION - Operations by Segment - Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 131,017	$ 157,542
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	105,173	128,536
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	20,779	23,106
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 5,065	$ 5,900