v3.26.1
Financial instruments (Details 3) - INR (₨)
₨ in Millions
Mar. 31, 2026
Mar. 31, 2025
Forward Contract| CAD - INR| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract One [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount ₨ 11 ₨ 1
Forward contract| US$ - INR| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Two [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 914 842
Forward contract| US$ - INR| Sell [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Seventeen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   30
Forward contract| US$ - INR| Sell [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Twenty Two [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 228  
Forward contract| ZAR - INR| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Three [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 231 216
Forward contract| GBP - INR| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Four [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 11 10
Forward contract| AUD - INR| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Five [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 4 8
Forward Contract| EUR - INR| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Six [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 26 12
Forward contract| US$ - MXN| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Seven [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 13  
Forward contract| US$ - BRL| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Seven [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   10
Forward contract| US$ - BRL| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Eight [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 17  
Forward contract| US$ - BRL| Buy [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Nineteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   18
Forward contract| US$ - CLP| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Eight [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   4
Forward contract| US$ - CLP| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Nine [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 4  
Forward contract| US$ - COP| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Nine [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   9
Forward contract| US$ - COP| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Ten [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 3  
Forward contract| US$ - KZT| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Ten [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   8
Forward contract| US$ - KZT| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Eleven [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 12  
Forward contract| RUB - US$| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Eleven [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   3,700
Forward contract| RUB - US$| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Twelve [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 1,000  
Forward contract| RUB - US$| Sell [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Eighteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   2,500
Forward contract| RUB - US$| Sell [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Twenty Three [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 1,610  
Forward contract| AUD - GBP| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Thirteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 8  
Forward contract| EUR - DKK| sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Fourteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 3  
Forward contract| EUR - US$| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Twelve [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   78
Forward contract| EUR - US$| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Fifteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 65  
Forward contract| US$ - DKK| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Sixteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 28  
Forward contract| GBP - US$| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Thirteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   31
Forward contract| GBP - US$| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Seventeen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 19  
Forward contract| AUD - US$| Sell [Member] | Hedges of recognised assets and liabilities [Member] | Contract Eighteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 27  
Forward contract| US$ - RON| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Fifteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   15
Forward contract| US$ - RON| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Nineteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 23  
Forward Contract| US$ - CAD| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Twenty [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 15  
Principal only swap| US$ - INR| Swap [Member] | Hedges of recognised assets and liabilities [Member] | Contract Sixteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   100
Principal only swap| US$ - INR| Swap [Member] | Hedges of recognised assets and liabilities [Member] | Contract Twenty One [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 100  
Forward contract| BRL - US$| Sell [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Twenty Four [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount 5  
Forward contract| US$ - AUD| Buy [Member] | Hedges of recognised assets and liabilities [Member] | Contract Fourteen [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   4
Option contract| US$ - INR| Sell [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Twenty [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount   ₨ 771
Option contract| US$ - INR| Sell [Member] | Hedges of highly probable forecasted transactions [Member] | Contract Twenty Five [Member]    
Disclosure notional amount of outstanding foreign exchange derivative contracts [Line Items]    
Notional amount ₨ 255