Operations by Segment - Assets (Detail) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 106,232	$ 101,039
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	92,290	87,061
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	13,208	13,095
Other business segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	162	155
Total Business Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	105,660	100,311
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	14,950	14,047
Intercompany eliminations
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ (14,378)	$ (13,319)