| Document and Entity Information | Jan. 27, 2022 |
| Document And Entity Information [Line Items] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Document Period End Date | Jan. 27, 2022 |
| Entity Registrant Name | System1, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39331 |
| Entity Tax Identification Number | 98-1531250 |
| Entity Address, Address Line One | 4235 Redwood Avenue |
| Entity Address, City or Town | Marina Del Rey |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90066 |
| City Area Code | 310 |
| Local Phone Number | 924-6037 |
| Entity Information, Former Legal or Registered Name | Trebia Acquisition Corp. |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Amendment Description | Unless the context otherwise requires, “we,” “us,” “our,” “System1” and the “Company” refer to System1, Inc., a Delaware corporation (f/k/a Trebia Acquisition Corp., a Cayman Islands exempted company), and its consolidated subsidiaries following the closing of the Business Combination. Unless the context otherwise requires, references to “Trebia” refer to Trebia Acquisition Corp., prior to the closing of the Business Combination (“Trebia”). All references herein to the “Board” refer to the board of directors of the Company.The Company is filing this Form 8-K/A (this “Amendment”) to amend its Current Report on Form 8-K, originally filed with the Securities and Exchange Commission (the “SEC”) on February 2, 2022 (the “Original Form 8-K”) by amending and restating the “Security Ownership of Certain Beneficial Owners and Management” table previously set forth in Item 2.01 of the Original Form 8-K. Except as expressly set forth herein, this Amendment does not amend, modify or update the disclosures contained in the Original Form 8-K. Terms used in this Amendment but not defined herein, or for which definitions are not otherwise incorporated by reference herein, shall have the meaning given to such terms in the Original Form 8-K. |
| Entity Central Index Key | 0001805833 |
| Former Address [Member] | |
| Document And Entity Information [Line Items] | |
| Entity Address, Address Line One | 41 Madison Avenue |
| Entity Address, Address Line Two | Suite 2020 |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10010 |
| Class A ordinary shares [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Class A Common stock, $0.0001 par value per share |
| Trading Symbol | SST |
| Security Exchange Name | NYSE |
| Warrants [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Redeemable warrants, each whole warrant exercisable for one Class A common stock share at an exercise price of $11.50 per share |
| Trading Symbol | SST.WS |
| Security Exchange Name | NYSE |
