| Document and Entity Information | Sep. 23, 2019 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Sep. 23, 2019 |
| Entity Registrant Name | AMERICAN EXPRESS CO |
| Entity Central Index Key | 0000004962 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | NY |
| Entity File Number | 1-7657 |
| Entity Tax Identification Number | 13-4922250 |
| Entity Address, Address Line One | 200 Vesey Street |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10285 |
| City Area Code | 212 |
| Local Phone Number | 640-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Shares (par value $0.20 per Share) |
| Trading Symbol | AXP |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
