DEFERRED POLICY ACQUISITION COSTS AND INSURANCE EXPENSES - Lease and Rental Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Lease and Rental Expense [Line Items]
Lease and rental expense	$ 65	$ 68	$ 66
Aflac Japan
Lease and Rental Expense [Line Items]
Lease and rental expense	46	52	55
Aflac U.S.
Lease and Rental Expense [Line Items]
Lease and rental expense	18	15	10
All other
Lease and Rental Expense [Line Items]
Lease and rental expense	$ 1	$ 1	$ 1