Assumptions Used to Estimate Fair Values of Share Options Granted - Baidu, Inc. (Detail) - Parent Company	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate		2.57%
Risk-free interest rate, minimum	1.58%		1.81%
Risk-free interest rate, maximum	2.49%		2.08%
Dividend yield	0.00%	0.00%	0.00%
Expected volatility range, minimum	34.62%	34.47%	35.99%
Expected volatility range, maximum	35.14%	35.36%	38.41%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected life	5 years 9 months 29 days	4 years 10 months 20 days	4 years 11 months 26 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected life	6 years 10 days	6 years 3 months	6 years 3 days

No definition available.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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No definition available.

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The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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No definition available.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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No definition available.

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- Definition

The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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No definition available.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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