SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Summary of Signficant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended				12 Months Ended					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2009 Accounting Standards Update 2010-26	Dec. 31, 2013 Aflac Japan	Dec. 31, 2012 Aflac Japan	Dec. 31, 2011 Aflac Japan	Dec. 31, 2009 Retained earnings: Accounting Standards Update 2010-26	Dec. 31, 2009 Accumulated Other Comprehensive Income (Loss) Accounting Standards Update 2010-26	Dec. 31, 2013 Dollar denominated investment portfolio Aflac Japan	Dec. 31, 2012 Dollar denominated investment portfolio Aflac Japan	Dec. 31, 2011 Dollar denominated investment portfolio Aflac Japan
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				$ (458)				$ (391)	$ (67)
Aflac Japan's percentage of the Company's total revenues					74.00%	77.00%	75.00%
Percentage of the Company assets					85.00%	87.00%
Income tax expense (benefit) related to items of other comprehensive income (loss)	$ (581)	$ 1,078	$ 392							$ 614	$ 492	$ (152)
Effective income tax rate excluding income tax expense (benefit) related to Aflac Japan's dollar-denominated portfolio										31.00%	32.00%	34.00%