| Cover Page | Oct. 12, 2021 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 12, 2021 |
| Entity Registrant Name | Synovus Financial Corp. |
| Entity Incorporation, State or Country Code | GA |
| Entity File Number | 1-10312 |
| Entity Tax Identification Number | 58-1134883 |
| Entity Address, Address Line One | 1111 Bay Avenue |
| Entity Address, Address Line Two | Suite 500 |
| Entity Address, City or Town | Columbus |
| Entity Address, State or Province | GA |
| Entity Address, Postal Zip Code | 31901 |
| City Area Code | 706 |
| Local Phone Number | 641-6500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000018349 |
| Amendment Flag | false |
| Common Stock, $1.00 Par Value | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $1.00 Par Value |
| Trading Symbol | SNV |
| Security Exchange Name | NYSE |
| Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series D | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series D |
| Trading Symbol | SNV-PrD |
| Security Exchange Name | NYSE |
| Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series E | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series E |
| Trading Symbol | SNV-PrE |
| Security Exchange Name | NYSE |
