v3.26.1
Financial Instruments - Schedule of Movement of Assets and Liabilities Valued Using Level 3 Inputs (Details) - USD ($)
$ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]      
Balance at the beginning $ 11,333    
Balance at the end 10,357 $ 11,333  
Balance at the beginning 3,468    
Balance at the end 3,570 3,468  
Financial Liability Under Option Arrangements      
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]      
Balance at the beginning 77    
Balance at the end 93 77  
Unquoted Equity and Preference Securities      
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]      
Balance at the beginning 23    
Balance at the end 72 23  
Level 3 | Financial Liability Under Option Arrangements      
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]      
Balance at the beginning 77 72 $ 73
Addition 1    
Change in fair value 10 6  
Translation difference 5 (1) (1)
Balance at the end 93 77 72
Level 3 | Liability Towards Contingent Consideration      
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]      
Balance at the beginning 3   12
Addition due to business combination 8 4  
Payments (1)   (12)
Translation difference 1 (1)  
Balance at the end 11 3  
Level 3 | Unquoted Equity and Preference Securities      
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]      
Balance at the beginning 23 11 24
Purchase of investments   3  
Fair value gain/(loss) recognised through profit and loss 3    
Fair value gain/(loss) recognised through other comprehensive income 47 9 5
Transferred from Level 3 to Level 1 based on quotes prices     (14)
Translation difference (1)   (4)
Balance at the end 72 23 11
Level 3 | Others      
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]      
Balance at the beginning 23 24 21
Purchase of investments 4 4 2
Fair value gain/(loss) recognised through profit and loss 2 (3) 4
Sale of investments   (1) (3)
Translation difference (1) (1)  
Balance at the end $ 28 $ 23 $ 24