Share-based Compensation - Description of share option plans (Details) - CNY (¥) ¥ in Millions	12 Months Ended
Dec. 31, 2020	Jul. 31, 2014
Description of stock option plan
Total unrecognized compensation expenses related to unvested awards	¥ 3,787.3
Weighted average remaining vesting period	4 years 6 months
Minimum
Description of stock option plan
Vesting Period	2 years
Expiration period	6 years
Maximum
Description of stock option plan
Vesting Period	6 years
Expiration period	7 years
Class Z Ordinary Shares \| Global Share Plan \| Maximum
Description of stock option plan
Aggregate number of shares issuable under the plan		19,880,315
Class Z Ordinary Shares \| 2018 Plan \| Maximum
Description of stock option plan
Aggregate number of shares issuable under the plan	23,367,875

Amount of cost to be recognized for option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Number of shares authorized for issuance under share-based payment arrangement.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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