| Document and Entity Information Document | Jul. 28, 2021 |
| Entity Central Index Key | 0000004977 |
| Document Type | 8-K/A |
| Document Period End Date | Jul. 28, 2021 |
| Entity Registrant Name | Aflac Incorporated |
| Entity Incorporation, State or Country Code | GA |
| Entity File Number | 001-07434 |
| Entity Tax Identification Number | 58-1167100 |
| Entity Address, Address Line One | 1932 Wynnton Road |
| Entity Address, City or Town | Columbus |
| Written Communications | false |
| Entity Address, State or Province | GA |
| Entity Address, Postal Zip Code | 31999 |
| City Area Code | 706 |
| Local Phone Number | 323.3431 |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Flag | true |
| Amendment Description | This Amendment No. 1 on Form 8-K/A is being filed solely to furnish a corrected version of Exhibit 99.1. The first page of Exhibit 99.1 included with the original Form 8-K incorrectly referred to “total adjusted revenues” for the first six months of 2021; the corrected reference is “total revenues” for that period. |
| NEW YORK STOCK EXCHANGE, INC. [Member] | |
| Title of 12(b) Security | Common Stock, $.10 Par Value |
| Trading Symbol | AFL |
| Security Exchange Name | NYSE |
