| Document And Entity Information | Oct. 30, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 30, 2024 |
| Entity Registrant Name | Parsons Corporation |
| Entity Central Index Key | 0000275880 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-07782 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 95-3232481 |
| Entity Address, Address Line One | 14291 Park Meadow Drive, Suite 100 |
| Entity Address, City or Town | Chantilly |
| Entity Address, State or Province | VA |
| Entity Address, Postal Zip Code | 20151 |
| City Area Code | (703) |
| Local Phone Number | 988-8500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $1 par value |
| Trading Symbol | PSN |
| Security Exchange Name | NYSE |
