Taxation - Movement of valuation allowance (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2022 CNY (¥)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 CNY (¥)	Dec. 31, 2020 CNY (¥)
Taxation
At beginning of the year	¥ (2,207,498)	$ (320,057)	¥ (1,597,607)	¥ (1,263,732)
Changes of valuation allowance	(232,599)	(33,724)	(609,891)	(333,875)
At end of the year	¥ (2,440,097)	$ (353,781)	¥ (2,207,498)	¥ (1,597,607)

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32537-109319

Name:	us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant