v3.26.1
Financial Instruments - Additional Information (Details) - USD ($)
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Disclosure Of Financial Instruments [Line Items]        
Description of reasons for transfers out of level 2 in to level 1 of fair value hierarchy assets During fiscal 2026, quoted debt securities of $10 million were transferred from Level 2 to Level 1 of fair value hierarchy, since these were valued based on quoted price and quoted debt securities of $51 million were transferred from Level 1 to Level 2 of fair value hierarchy, since these were valued based on market observable inputs. During fiscal 2025, quoted debt securities of $35 million were transferred from Level 2 to Level 1 of fair value hierarchy, since these were valued based on quoted price and quoted debt securities of $65 million were transferred from Level 1 to Level 2 of fair value hierarchy, since these were valued based on market observable inputs.    
Percentage point change in unobservable inputs used in fair valuation of Level 3 assets and liabilities that does not have significant impact 1.00% 1.00%    
Exchange rate differences, percentage effect on incremental operating margins 0.44% 0.43% 0.43%  
Derivative maturity description 12 months 12 months    
Impairment loss under expected credit loss on customer balances $ 9,000,000 $ 13,000,000 $ 11,000,000  
Days Sales Outstanding- DSO 67 days 69 days    
Outstanding bank borrowings $ 0      
Working capital 5,396,000,000 $ 6,347,000,000    
Cash and cash equivalents 2,341,000,000 2,861,000,000 1,773,000,000 $ 1,481,000,000
Current investments 1,365,000,000 1,460,000,000    
Outstanding employee benefit obligations 384,000,000 351,000,000    
Liquidity risk on account of outstanding employee benefit obligations 0 0    
Quoted Debt Securities        
Disclosure Of Financial Instruments [Line Items]        
Debt securities, transferred from Level 1 to Level 2 of fair value hierarchy 51,000,000 65,000,000    
Debt securities, transferred from Level 2 to Level 1 of fair value hierarchy 10,000,000 35,000,000    
Derivatives Not Designated As Cash Flow Hedges        
Disclosure Of Financial Instruments [Line Items]        
Net gain (loss) recognized on derivative financial instruments (258,000,000) (12,000,000) $ 22,000,000  
Trade Receivables        
Disclosure Of Financial Instruments [Line Items]        
Maximum exposure to credit risk 3,715,000,000 3,645,000,000    
Unbilled Revenue        
Disclosure Of Financial Instruments [Line Items]        
Maximum exposure to credit risk $ 1,816,000,000 $ 1,764,000,000