v3.22.1
Summary of Significant Accounting Policies - Additional Information (Detail)
¥ / shares in Units, $ / shares in Units, ¥ in Millions, $ in Millions
12 Months Ended
Dec. 31, 2021
CNY (¥)
Customer
Segment
¥ / shares
Dec. 31, 2021
USD ($)
Segment
Customer
$ / shares
Dec. 31, 2020
CNY (¥)
Unit
Segment
¥ / shares
Dec. 31, 2019
CNY (¥)
¥ / shares
Jan. 01, 2022
CNY (¥)
Jan. 01, 2022
USD ($)
Dec. 31, 2021
USD ($)
Customer
Dec. 30, 2021
Accounting Policies [Abstract]                
Exchange rate used for conversion of financial statements from RMB to US dollar               6.3726
Number of reportable segments | Segment 2 2 2          
Number of reporting units | Unit     2          
Allowance for contract asset ¥ 85   ¥ 27       $ 13  
Advertising and promotional expenses 12,200 $ 1,900 8,400 ¥ 10,500        
Cash and cash equivalents, restricted cash and short-term investments ¥ 198,800           $ 31,200  
Number of customers with receivable balance exceeding 10% 0           0  
Number of customer or any Baidu Union partner with revenue greater than 10% 0 0            
Depreciation of US$ against RMB, as a percentage 2.34% 2.34%            
Net (loss) income ¥ 7,591 $ 1,191 19,026 ¥ (2,288)        
Decrease in opening balance of additional paid in capital         ¥ 738 $ 116    
Decrease in opening balance of non-controlling interests         309 48    
Increase in opening balance of accumulated retained earnings         398 62    
Increase in opening balance of convertible senior notes         ¥ 636 $ 100    
Debt Securities, Held-to-maturity, Allowance for Credit Loss ¥ 338   ¥ 285       $ 53  
Common Class A and Class B [Member]                
Accounting Policies [Abstract]                
Earnings per share - diluted | (per share) [1] ¥ 3.51 $ 0.55 ¥ 8.12 ¥ 0.70        
Earnings per share - basic | (per share) [1] ¥ 3.58 $ 0.56 ¥ 8.19 ¥ 0.71        
Licensed Copyrights And Produced Content                
Accounting Policies [Abstract]                
Supplement cash flow disclosure of operating activities ¥ 19,300 $ 3,000            
Online Payment Agencies                
Accounting Policies [Abstract]                
Allowance for doubtful accounts of online payment agencies | ¥ ¥ 0   ¥ 0          
Short-term Investments | Maximum                
Accounting Policies [Abstract]                
Maturity period used to classify short-term investments 12 months 12 months            
Cash and cash equivalents | Maximum                
Accounting Policies [Abstract]                
Maturity period used to classify cash and cash equivalents 3 months 3 months            
Other Current Assets, net                
Accounting Policies [Abstract]                
Contract assets ¥ 2,900   1,800       462  
Allowance for contract asset 85   27       13  
Deferred revenue                
Accounting Policies [Abstract]                
Contract with Customer, Liability, Revenue Recognized 4,700 $ 735            
Customer deposits and deferred​ revenue​                
Accounting Policies [Abstract]                
Contract liabilities ¥ 6,300   ¥ 6,700       $ 1,000  
Credit Concentration Risk | Onshore China | Financial Instruments                
Accounting Policies [Abstract]                
Concentration risk by percentage 91.00% 91.00%            
Credit Concentration Risk | Onshore China | Financial Institution One [Member]                
Accounting Policies [Abstract]                
Concentration risk by percentage 23.00% 23.00%            
Credit Concentration Risk | Onshore China | Financial Institution Two [Member]                
Accounting Policies [Abstract]                
Concentration risk by percentage 20.00% 20.00%            
Credit Concentration Risk | Offshore China | Financial Instruments                
Accounting Policies [Abstract]                
Concentration risk by percentage 9.00% 9.00%            
Customer Concentration Risk | Sales Revenue, Net | Maximum                
Accounting Policies [Abstract]                
Concentration risk by percentage 10.00% 10.00%            
Office building and its related facility                
Accounting Policies [Abstract]                
Property, plant and equipment, salvage value, percentage 4.00%           4.00%  
Change In Accounting Estimate [Member]                
Accounting Policies [Abstract]                
Depreciation expense ¥ 982 $ 154            
Net (loss) income ¥ 814 $ 128            
Change In Accounting Estimate [Member] | Common Class A and Class B [Member]                
Accounting Policies [Abstract]                
Earnings per share - diluted | (per share) ¥ 0.28 $ 0.04            
Earnings per share - basic | (per share) ¥ 0.28 $ 0.04            
[1] Basic and diluted earnings per share and the number of shares for the years ended December 31, 2019 and 2020 have been retrospectively adjusted for the Share Subdivision that took effect on March 1, 2021 as detailed in Notes 1 and 21.