INVESTMENTS - Economic Maturities of Investments in Perpetual Securities (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014
Aflac Japan
Investments Classified by Economic Maturity Date [Line Items]
Due in one year or less	$ 364
Due after one year through five years	673
Due after five years through 10 years	217
Due after 10 years	1,744
Total perpetual securities available for sale, amortized cost	2,998
Due in one year or less	354
Due after one year through five years	664
Due after five years through 10 years	257
Due after 10 years	1,831
Total perpetual securities available for sale, fair value	3,106
Aflac U.S.
Investments Classified by Economic Maturity Date [Line Items]
Due in one year or less	0
Due after one year through five years	5
Due after five years through 10 years	0
Due after 10 years	38
Total perpetual securities available for sale, amortized cost	43
Due in one year or less	0
Due after one year through five years	5
Due after five years through 10 years	0
Due after 10 years	57
Total perpetual securities available for sale, fair value	$ 62