BUSINESS SEGMENT AND FOREIGN INFORMATION - Information on Transfers of Funds from Aflac Japan (Detail) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 USD ($)	Dec. 31, 2012 JPY (¥)	Dec. 31, 2011 USD ($)	Dec. 31, 2011 JPY (¥)	Dec. 31, 2010 USD ($)	Dec. 31, 2010 JPY (¥)
Segment Reporting Information [Line Items]
Management fees	$ 30		$ 28		$ 30
Allocated expenses	58		43		37
Profit repatriation	422	33,100	143	11,000	317	28,700
Total transfers from Aflac Japan	$ 510		$ 214		$ 384