BUSINESS SEGMENT AND FOREIGN INFORMATION - Additional Information (Detail) In Millions, unless otherwise specified							12 Months Ended
	Dec. 31, 2012 USD ($) segment	Dec. 31, 2012 JPY (¥)	Dec. 31, 2011 USD ($)	Dec. 31, 2011 JPY (¥)	Dec. 31, 2012 Aflac Japan USD ($)	Dec. 31, 2011 Aflac Japan USD ($)	Dec. 31, 2012 Upper Limit Building	Dec. 31, 2012 Upper Limit Machinery and Equipment	Dec. 31, 2012 Upper Limit Furniture and Fixtures
Segment Reporting Information [Line Items]
Reportable insurance business segments	2	2
Liability accrued for obligations to the Japanese life insurance policyholder protection corporation (LIPPC)	$ 23	¥ 2,000	$ 71	¥ 5,500
Property and Equipment, maximum estimated useful life (in years)							50 years	20 years	20 years
Total receivables related to Aflac Japan's operations	$ 976		$ 680		$ 566	$ 309
Percentage of total receivables related to Aflac Japan's operations					58.20%	45.40%