| Document and Entity Information | Aug. 05, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 5, 2020 |
| Entity Registrant Name | PARSONS CORPORATION |
| Entity Central Index Key | 0000275880 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-07782 |
| Entity Incorporation State Country Code | DE |
| Entity Tax Identification Number | 95-3232481 |
| Entity Address Address Line1 | 5875 Trinity Parkway, #300 |
| Entity Address City Or Town | Centreville |
| Entity Address State Or Province | VA |
| Entity Address Postal Zip Code | 20120 |
| 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 each class | Common Stock, $1 par value |
| Trading Symbol(s) | PSN |
| Name of each exchange on which registered | NYSE |
