DEFERRED POLICY ACQUISITION COSTS AND INSURANCE EXPENSES - Lease and Rental Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Lease and Rental Expense [Line Items]
Lease and rental expense	$ 68	$ 66	$ 81
Aflac Japan
Lease and Rental Expense [Line Items]
Lease and rental expense	52	55	71
Aflac U.S.
Lease and Rental Expense [Line Items]
Lease and rental expense	15	10	9
All other
Lease and Rental Expense [Line Items]
Lease and rental expense	$ 1	$ 1	$ 1