|**Balance Sheet Details (Tables)**               | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                       
|------------------------------------------------ | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Balance Sheet Related Disclosures [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                      
|Inventories Schedule                             | Inventories as ofDecember 31, 2015andMarch 31, 2015consisted of (in millions):As of December 31, 2015As of March 31, 2015Finished goods$41$35Raw materials and work in process11Inventories$42$36                                                                                                                                                                                                    
|                                                
|                                                 |                                                                                                                                                                                                                                                                                                                                                                                                      
|                                                 | As of December 31, 2015                                                                                                                                                                                                                                                                                                                                                                              
|Finished goods                                   | $                                                                                                                                                                                                                                                                                                                                                                                                    
|Raw materials and work in process                | 1                                                                                                                                                                                                                                                                                                                                                                                                    
|Inventories                                      | $                                                                                                                                                                                                                                                                                                                                                                                                    
|Property And Equipment, Net Schedule             | Property and equipment, net, as ofDecember 31, 2015andMarch 31, 2015consisted of (in millions):As of December 31, 2015As of March 31, 2015Computer, equipment and software$663$655Buildings303315Leasehold improvements125126Equipment, furniture and fixtures, and other7373Land6162Construction in progress1271,2371,238Less: accumulated depreciation(822)(779)Property and equipment, net$415$459
|                                                
|                                                 |                                                                                                                                                                                                                                                                                                                                                                                                      
|                                                 | As of December 31, 2015                                                                                                                                                                                                                                                                                                                                                                              
|Computer, equipment and software                 | $                                                                                                                                                                                                                                                                                                                                                                                                    
|Buildings                                        | 303                                                                                                                                                                                                                                                                                                                                                                                                  
|Leasehold improvements                           | 125                                                                                                                                                                                                                                                                                                                                                                                                  
|Equipment, furniture and fixtures, and other     | 73                                                                                                                                                                                                                                                                                                                                                                                                   
|Land                                             | 61                                                                                                                                                                                                                                                                                                                                                                                                   
|Construction in progress                         | 12                                                                                                                                                                                                                                                                                                                                                                                                   
|                                                 | 1,237                                                                                                                                                                                                                                                                                                                                                                                                
|Less: accumulated depreciation                   | (822                                                                                                                                                                                                                                                                                                                                                                                                 
|Property and equipment, net                      | $                                                                                                                                                                                                                                                                                                                                                                                                    
|Accrued And Other Current Liabilities Schedule   | Accrued and other current liabilities as ofDecember 31, 2015andMarch 31, 2015consisted of (in millions):As of December 31, 2015As of March 31, 2015Other accrued expenses$308$298Accrued compensation and benefits218263Accrued royalties216119Deferred net revenue (other)98114Accrued and other current liabilities$840$794                                                                        
|                                                
|                                                 |                                                                                                                                                                                                                                                                                                                                                                                                      
|                                                 | As of December 31, 2015                                                                                                                                                                                                                                                                                                                                                                              
|Other accrued expenses                           | $                                                                                                                                                                                                                                                                                                                                                                                                    
|Accrued compensation and benefits                | 218                                                                                                                                                                                                                                                                                                                                                                                                  
|Accrued royalties                                | 216                                                                                                                                                                                                                                                                                                                                                                                                  
|Deferred net revenue (other)                     | 98                                                                                                                                                                                                                                                                                                                                                                                                   
|Accrued and other current liabilities            | $                                                                                                                                                                                                                                                                                                                                                                                                    

X- ReferencesNo definition available.
+ Details**Name:**
us-gaap_BalanceSheetRelatedDisclosuresAbstract**Namespace Prefix:**
us-gaap_**Data Type:**
xbrli:stringItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation.
+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.13) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 13 -Subparagraph b -Article 5
+ Details**Name:**
us-gaap_PropertyPlantAndEquipmentTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure of the (a) carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business (accounts payable); (b) other payables; and (c) accrued liabilities. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). An alternative caption includes accrued expenses.
+ ReferencesNo definition available.
+ Details**Name:**
us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionTabular disclosure of the carrying amount as of the balance sheet date of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process.
+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6361739&loc=d3e7789-107766Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 2 -Paragraph 6 -Subparagraph a,b,c -Article 5
+ Details**Name:**
us-gaap_ScheduleOfInventoryCurrentTableTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration