| Cover | May 14, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Amendment Flag | false |
| Document Period End Date | May 14, 2021 |
| Entity File Number | 001-39356 |
| Entity Registrant Name | IAC/INTERACTIVECORP |
| Entity Central Index Key | 0001800227 |
| Entity Tax Identification Number | 84-3727412 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 555 West 18th Street |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10011 |
| City Area Code | 212 |
| Local Phone Number | 314-7300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.0001 |
| Trading Symbol | IAC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
