INVESTMENTS - Contractual Maturities of Investments in Fixed Maturities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Held to maturity:
Total fixed maturities held to maturity, amortized cost	$ 44,415	$ 54,426
Held to maturity:
Total fixed maturities held to maturity, fair value	45,846	54,841
Aflac Japan
Available for sale:
Due in one year or less	646
Due after one year through five years	1,820
Due after five years through 10 years	9,713
Due after 10 years	32,752
Mortgage- and asset-backed securities	622
Total fixed maturities available for sale, amortized cost	45,553
Held to maturity:
Due in one year or less	4,547
Due after one year through five years	1,473
Due after five years through 10 years	1,967
Due after 10 years	36,370
Mortgage- and asset-backed securities	58
Total fixed maturities held to maturity, amortized cost	44,415
Available for sale:
Due in one year or less	653
Due after one year through five years	1,960
Due after five years through 10 years	9,657
Due after 10 years	33,514
Mortgage- and asset-backed securities	664
Total fixed maturities available for sale, fair value	46,448
Held to maturity:
Due in one year or less	4,547
Due after one year through five years	1,598
Due after five years through 10 years	2,062
Due after 10 years	37,578
Mortgage- and asset-backed securities	61
Total fixed maturities held to maturity, fair value	45,846
Aflac U.S.
Available for sale:
Due in one year or less	50
Due after one year through five years	474
Due after five years through 10 years	1,557
Due after 10 years	8,517
Mortgage- and asset-backed securities	38
Total fixed maturities available for sale, amortized cost	10,636
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	52
Due after one year through five years	552
Due after five years through 10 years	1,624
Due after 10 years	9,016
Mortgage- and asset-backed securities	46
Total fixed maturities available for sale, fair value	11,290
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