Stockholders' Equity - Common Stock Available for Future Issuance (Details) - shares	Dec. 31, 2025	Dec. 31, 2024	Feb. 02, 2022
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)	78,010,211	76,795,708
Common Stock Warrants
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)			14,213,280
Common Stock Warrants, Public Warrants
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)	9,199,947	9,199,947
Common Stock Warrants, Private Warrants
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)	5,013,333	5,013,333
Employee Stock Option
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)	5,431,725	6,063,110
Restricted Stock Units (RSUs)
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)	13,883,881	13,282,923
Performance Shares
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)	5,963,154	5,973,050
SES AI Corporation 2021 Plan
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock available for future issuance (in shares)	38,518,171	37,263,345	36,862,002