Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 15, 2017	Jun. 30, 2016
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Trading Symbol	AFL
Entity Registrant Name	AFLAC INC
Entity Central Index Key	0000004977
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		401,426,860
Entity Public Float			$ 29,327,044,586
Maximum
Estimation of Percent of Revenues Within Scope of the Guidance to Total Revenues	1.00%