Subsequent Events	6 Months Ended
	Jun. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated events that have occurred through the filing date of this Quarterly Report on Form 10-Q. Based on its evaluation, other than any items recorded or disclosed within the condensed consolidated financial statements and related notes, including as discussed below, the Company has determined no subsequent events were required to be recognized or disclosed.On July 6, 2023, the Company completed a securitization transaction, for which it was the retaining sponsor and the sole collateral contributor. The transaction included $204.7 million of Upstart-powered core personal loans and generated approximately $162.6 million in net cash proceeds. The weighted-average yield of the senior securitization notes issued was approximately 9.4%. The Company has retained 100% of the residual certificates issued as part of the securitization and is the primary beneficiary of the securitization trust. The Company has consolidated the securitization trust into its consolidated financial statements effective as of the closing date.