| Document and Entity Information | Apr. 27, 2021 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | REGIONS FINANCIAL CORP |
| Entity Address, State or Province | AL |
| Amendment Flag | false |
| Entity Central Index Key | 0001281761 |
| Current Fiscal Year End Date | --12-31 |
| Document Type | 8-K |
| Document Period End Date | Apr. 27, 2021 |
| Entity Incorporation State 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, 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 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $.01 par value |
| Trading Symbol | RF |
| Security Exchange Name | NYSE |
| Series A Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares, each representing a 1/40th Interest in a Share of 6.375% Non-Cumulative Perpetual Preferred Stock, Series A |
| Trading Symbol | RF PRA |
| Security Exchange Name | NYSE |
| Series B Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares, each representing a 1/40th Interest in a Share of 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 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares, each representing a 1/40th Interest in a Share of 5.700% Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series C |
| Trading Symbol | RF PRC |
| Security Exchange Name | NYSE |
| Series E Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares, each representing a 1/40th Interest in a Share of 4.45% Non-Cumulative Perpetual Preferred Stock, Series E |
| Trading Symbol | RF PRE |
| Security Exchange Name | NYSE |
