| Document And Entity Information | Dec. 20, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 20, 2023 |
| Entity Registrant Name | First American Financial Corp |
| Entity Central Index Key | 0001472787 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-34580 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 26-1911571 |
| Entity Address, Address Line One | 1 First American Way |
| Entity Address, City or Town | Santa Ana |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92707-5913 |
| City Area Code | (714) |
| Local Phone Number | 250-3000 |
| Entity Information, Former Legal or Registered Name | N/A |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.00001 par value |
| Trading Symbol | FAF |
| Security Exchange Name | NYSE |
