Summary of significant accounting policies - Guarantee liabilities and Financial guarantee derivative (Details)	12 Months Ended
Dec. 31, 2022
ZhongAn
Summary of significant accounting policies
Period for compensation in case of default by borrowers	2 days

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration