DEFERRED POLICY ACQUISITION COSTS AND INSURANCE EXPENSES - Advertising Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Advertising Costs [Line Items]
Advertising expense	$ 240	$ 254	$ 258
Aflac Japan
Advertising Costs [Line Items]
Advertising expense	112	127	128
Aflac U.S.
Advertising Costs [Line Items]
Advertising expense	$ 128	$ 127	$ 130