|**Summary of Significant Accounting Policies (Tables)** | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
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|**Accounting Policies [Abstract]**                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Schedule of Useful Lives                                | Property and equipment, net, are stated at cost. Depreciation is calculated using the straight-line method over the following useful lives:Buildings20 to 25 yearsComputer equipment and software2 to 6 yearsEquipment, furniture and fixtures, and other3 to 5 yearsLeasehold improvementsLesser of the lease term or the estimated useful lives of the improvements, ranging from 1 to 15 yearsProperty and equipment, net, as of March 31, 2024 and 2023 consisted of (in millions):As of March 31,20242023Computer, equipment and software$965$892Buildings376369Leasehold improvements190186Equipment, furniture and fixtures, and other9292Land6766Construction in progress47111,7371,616Less: accumulated depreciation(1,159)(1,067)Property and equipment, net$578$549
|                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Buildings                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Computer equipment and software                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Equipment, furniture and fixtures, and other            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Leasehold improvements                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|                                                        | As of March 31,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|                                                        | 2024                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
|Computer, equipment and software                        | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
|Buildings                                               | 376                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Leasehold improvements                                  | 190                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Equipment, furniture and fixtures, and other            | 92                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Land                                                    | 67                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Construction in progress                                | 47                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|                                                        | 1,737                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|Less: accumulated depreciation                          | (1,159)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|Property and equipment, net                             | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             

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