{"cik":1918102,"taxonomy":"us-gaap","tag":"OperatingLeaseLiabilityNoncurrent","label":"Operating Lease, Liability, Noncurrent","description":"Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.","entityName":"Deep Fission, Inc.","units":{"USD":[{"end":"2026-03-31","val":43386,"accn":"0001104659-26-057835","fy":2026,"fp":"Q1","form":"10-Q","filed":"2026-05-08","frame":"CY2026Q1I"}]}}