| Document and Entity Information | Feb. 08, 2022 |
| Document And Entity Information [Line Items] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Document Period End Date | Feb. 8, 2022 |
| Entity Registrant Name | QUANERGY SYSTEMS, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39222 |
| Entity Tax Identification Number | 88-0535845 |
| Entity Address, Address Line One | 433 Lakeside Drive |
| Entity Address, City or Town | Sunnyvale |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94085 |
| City Area Code | 408 |
| Local Phone Number | 245-9500 |
| 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 | On February 8, 2022, Quanergy Systems, Inc., a Delaware corporation (the “Company”) (f/k/a CITIC Capital Acquisition Corp. (“CCAC”)), filed a Current Report on Form 8-K and Amendment No. 1 on Form 8-K/A (together, the “Original Report”) to report the Closing and related matters under Items 1.01, 2.01, 3.02, 4.01, 5.01, 5.02, 5.06 and 9.01 of Form 8-K. This Amendment No. 2 amends the |
| Entity Central Index Key | 0001794621 |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.0001 par value per share |
| Trading Symbol | QNGY |
| Security Exchange Name | NYSE |
| Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Warrants, each whole warrant exercisable for one share of Common Stock at an exercise price of $11.50 per share |
| Trading Symbol | QNGY WS |
| Security Exchange Name | NYSE |
