INVESTMENTS - Economic Maturities of Investments in Perpetual Securities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Aflac Japan
Investments Classified by Economic Maturity Date [Line Items]
Due in one year or less	$ 142
Due after one year through five years	855
Due after five years through 10 years	209
Due after 10 years	1,677
Total perpetual securities available for sale	2,883
Due in one year or less	128
Due after one year through five years	829
Due after five years through 10 years	209
Due after 10 years	1,673
Total perpetual securities available for sale	2,839
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	99
Total perpetual securities available for sale	104
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	103
Total perpetual securities available for sale	$ 108