| Document and Entity Information | Mar. 15, 2023 |
| Document Information [Line Items] | |
| Entity Registrant Name | SES AI CORPORATION |
| Amendment Flag | false |
| Entity Central Index Key | 0001819142 |
| Document Type | 8-K |
| Document Period End Date | Mar. 15, 2023 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-39845 |
| Entity Tax Identification Number | 88-0641865 |
| Entity Address, Address Line One | 35 Cabot Road |
| Entity Address, City or Town | Woburn |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 01801 |
| City Area Code | 339 |
| Local Phone Number | 298-8750 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document Information [Line Items] | |
| Security 12b Title | Class A common stock, $0.0001 par value per share |
| Trading Symbol | SES |
| Security Exchange Name | NYSE |
| Warrant [Member] | |
| Document Information [Line Items] | |
| Security 12b Title | Warrants, each exercisable for one share of Class A common stock at an exercise price of $11.50 per share |
| Trading Symbol | SES WS |
| Security Exchange Name | NYSE |
