Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 20, 2021
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-07434
Entity Registrant Name	Aflac Incorporated
Entity Incorporation, State or Country Code	GA
Entity Tax Identification Number	58-1167100
Entity Address, Address Line One	1932 Wynnton Road
Entity Address, City or Town	Columbus,
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	31999
City Area Code	706.
Local Phone Number	323.3431
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		679,667,234
Amendment Flag	false
Entity Central Index Key	0000004977
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2021
NEW YORK STOCK EXCHANGE, INC.
Title of 12(b) Security	Common Stock, $.10 par value per share
Trading Symbol	AFL
Security Exchange Name	NYSE