INVESTMENTS - Contractual Maturities of Investments in Fixed Maturities (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Held to maturity:
Total fixed maturities held to maturity, amortized cost	$ 41,134	$ 44,415
Held to maturity:
Total fixed maturities held to maturity, fair value	43,958	45,846
Aflac Japan
Available for sale:
Due in one year or less	510
Due after one year through five years	1,992
Due after five years through 10 years	12,602
Due after 10 years	36,658
Mortgage- and asset-backed securities	503
Total fixed maturities available for sale, amortized cost	52,265
Held to maturity:
Due in one year or less	102
Due after one year through five years	1,561
Due after five years through 10 years	2,360
Due after 10 years	37,054
Mortgage- and asset-backed securities	57
Total fixed maturities held to maturity, amortized cost	41,134
Available for sale:
Due in one year or less	520
Due after one year through five years	2,135
Due after five years through 10 years	12,835
Due after 10 years	38,973
Mortgage- and asset-backed securities	550
Total fixed maturities available for sale, fair value	55,013
Held to maturity:
Due in one year or less	102
Due after one year through five years	1,713
Due after five years through 10 years	2,569
Due after 10 years	39,514
Mortgage- and asset-backed securities	60
Total fixed maturities held to maturity, fair value	43,958
Aflac U.S.
Available for sale:
Due in one year or less	52
Due after one year through five years	626
Due after five years through 10 years	1,497
Due after 10 years	8,706
Mortgage- and asset-backed securities	38
Total fixed maturities available for sale, amortized cost	10,919
Held to maturity:
Due in one year or less	0
Due after one year through five years	0
Due after five years through 10 years	0
Due after 10 years	0
Mortgage- and asset-backed securities	0
Total fixed maturities held to maturity, amortized cost	0
Available for sale:
Due in one year or less	53
Due after one year through five years	740
Due after five years through 10 years	1,604
Due after 10 years	9,990
Mortgage- and asset-backed securities	46
Total fixed maturities available for sale, fair value	12,433
Held to maturity:
Due in one year or less	0
Due after one year through five years	0
Due after five years through 10 years	0
Due after 10 years	0
Mortgage- and asset-backed securities	0
Total fixed maturities held to maturity, fair value	$ 0