BUSINESS SEGMENT INFORMATION - Operations by Segment - Assets (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 115,581	$ 119,767
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	95,739	98,525
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	17,951	18,383
Other business segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	157	128
Total Business Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	113,847	117,036
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	23,307	24,636
Intercompany eliminations
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ (21,573)	$ (21,905)