| Document and Entity Information | Apr. 23, 2021 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 23, 2021 |
| Entity Registrant Name | REGIONS FINANCIAL CORPORATION |
| Entity Central Index Key | 0001281761 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-34034 |
| Entity Tax Identification Number | 63-0589368 |
| Entity Address, Address Line One | 1900 Fifth Avenue North |
| Entity Address, City or Town | Birmingham |
| Entity Address, State or Province | AL |
| Entity Address, Postal Zip Code | 35203 |
| City Area Code | 800 |
| Local Phone Number | 734-4667 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $.01 par value |
| Trading Symbol | RF |
| Security Exchange Name | NYSE |
| Series A Preferred Stock | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 6.375% Non-Cumulative Perpetual Preferred Stock, Series A |
| Trading Symbol | RF PRA |
| Security Exchange Name | NYSE |
| Series B Preferred Stock | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 6.375% Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series B |
| Trading Symbol | RF PRB |
| Security Exchange Name | NYSE |
| Series C Preferred Stock | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 5.700% Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series C |
| Trading Symbol | RF PRC |
| Security Exchange Name | NYSE |
