Principal Accounting Policies - Advertising and promotional expenses and foreign currency translation (Details) ¥ in Billions, $ in Billions	12 Months Ended
Dec. 31, 2025 CNY (¥) $ / ¥	Dec. 31, 2025 USD ($) $ / ¥	Dec. 31, 2024 CNY (¥)	Dec. 31, 2023 CNY (¥)
Advertising and promotional expenses
Advertising and promotional expenses	¥ 11.4	$ 1.6	¥ 10.9	¥ 10.4
Foreign currency translation
Buying rate per US$	6.9931	6.9931

The total expense recognized in the period for promotion, public relations, and brand or product advertising.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-21

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(4))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Name:	us-gaap_MarketingAndAdvertisingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration