Document and Entity Information - $ / shares	9 Months Ended
	Sep. 30, 2022	Nov. 04, 2022
Document Information [Line Items]
Entity Central Index Key	0001819142
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	001-39845
Entity Registrant Name	SES AI Corporation
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-1567584
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
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false
Common Class A [Member]
Document Information [Line Items]
Title of 12(b) Security	Class A common stock, par value $0.0001 per share
Entity Listing, Par Value Per Share	$ 0.0001
Trading Symbol	SES
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		305,943,955
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		43,881,251
Warrant [Member]
Document Information [Line Items]
Title of 12(b) Security	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