BUSINESS SEGMENT INFORMATION - Operations by Segment - Assets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 127,871	$ 121,307
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	109,033	102,973
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	16,979	16,112
Other business segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	154	155
Total Business Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	126,166	119,240
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	22,844	19,909
Intercompany eliminations
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ (21,139)	$ (17,842)