Document and Entity Information
| Document and Entity Information | Dec. 04, 2023 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | KEYCORP /NEW/ |
| Amendment Flag | false |
| Entity Central Index Key | 0000091576 |
| Document Type | 8-K |
| Document Period End Date | Dec. 04, 2023 |
| Entity File Number | 001-11302 |
| Entity Incorporation State Country Code | OH |
| Entity Tax Identification Number | 34-6542451 |
| Entity Address, Address Line One | 127 Public Square |
| Entity Address, City or Town | Cleveland |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 44114-1306 |
| City Area Code | (216) |
| Local Phone Number | 689-6300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Shares 1 Par Value [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Shares, $1 par value |
| Trading Symbol | KEY |
| Security Exchange Name | NYSE |
| Depositary Shares Each Representing A 140th Interest In A Share Of Fixed To Floating Rate Perpetual Not Cumulative Preferred Stock Series E 4 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares (each representing a 1/40th interest in a share of Fixed-to-Floating Rate Perpetual Non-Cumulative Preferred Stock, Series E) |
| Trading Symbol | KEY PrI |
| Security Exchange Name | NYSE |
| Depositary Shares Each Representing A 140th Interest In A Share Of Fixed Rate Perpetual Not Cumulative Preferred Stock Series F 1 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares (each representing a 1/40th interest in a share of Fixed Rate Perpetual Non-Cumulative Preferred Stock, Series F) |
| Trading Symbol | KEY PrJ |
| Security Exchange Name | NYSE |
| Depositary Shares Each Representing A 140th Interest In A Share Of Fixed Rate Perpetual Not Cumulative Preferred Stock Series G 2 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares (each representing a 1/40th interest in a share of Fixed Rate Perpetual Non-Cumulative Preferred Stock, Series G) |
| Trading Symbol | KEY PrK |
| Security Exchange Name | NYSE |
| Depositary Shares Each Representing A 140th Interest In A Share Of Fixed Rate Reset Perpetual Not Cumulative Preferred Stock Series H 3 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary Shares (each representing a 1/40th interest in a share of Fixed Rate Reset Perpetual Non-Cumulative Preferred Stock, Series H) |
| Trading Symbol | KEY PrL |
| Security Exchange Name | NYSE |