Summary of significant accounting policies- Long-lived assets (Details)
¥ in Millions, $ in Millions
 12 Months Ended
Mar. 31, 2023
CNY (¥)
Mar. 31, 2023
USD ($)
Mar. 31, 2022
CNY (¥)
Mar. 31, 2021
CNY (¥)
Summary of significant accounting policies        
Amortization expenses ¥ 19,139 $ 2,787 ¥ 20,257 ¥ 21,520
Impairment of long-lived assets other than goodwill and licensed copyrights ¥ 1,922   ¥ 973 ¥ 0
User base and customer relationships | Minimum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 3 years 3 years    
User base and customer relationships | Maximum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 16 years 16 years    
Trade names, trademarks and domain names | Minimum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 5 years 5 years    
Trade names, trademarks and domain names | Maximum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 20 years 20 years    
Developed technology and patents | Minimum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 2 years 2 years    
Developed technology and patents | Maximum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 7 years 7 years    
Non-compete agreements | Maximum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 10 years 10 years    
Licensed copyrights | Digital media and entertainment        
Summary of significant accounting policies        
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration] Finite-Lived Intangible Assets, Net Finite-Lived Intangible Assets, Net Finite-Lived Intangible Assets, Net Finite-Lived Intangible Assets, Net
Impairment charges ¥ 1,133   ¥ 745 ¥ 1,688
Licensed copyrights | Cost of revenue | Digital media and entertainment        
Summary of significant accounting policies        
Amortization expenses ¥ 8,446   ¥ 8,610 ¥ 9,093
Licensed copyrights | Minimum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 6 months 6 months    
Licensed copyrights | Maximum        
Summary of significant accounting policies        
Estimated useful lives of intangible assets (in months/years) 10 years 10 years    
Computer equipment and software | Minimum        
Summary of significant accounting policies        
Estimated useful lives of property and equipment (in years) 3 years 3 years    
Computer equipment and software | Maximum        
Summary of significant accounting policies        
Estimated useful lives of property and equipment (in years) 5 years 5 years    
Furniture, office and transportation equipment and others | Minimum        
Summary of significant accounting policies        
Estimated useful lives of property and equipment (in years) 3 years 3 years    
Furniture, office and transportation equipment and others | Maximum        
Summary of significant accounting policies        
Estimated useful lives of property and equipment (in years) 10 years 10 years    
Building and other property | Minimum        
Summary of significant accounting policies        
Estimated useful lives of property and equipment (in years) 10 years 10 years    
Building and other property | Maximum        
Summary of significant accounting policies        
Estimated useful lives of property and equipment (in years) 50 years 50 years