v3.26.1
Financial Instruments - Schedule of Carrying Value of Financial Instruments by Categories (Detail) - INR (₨)
₨ in Millions
Mar. 31, 2026
Mar. 31, 2025
Disclosure of detailed information about financial instruments [line items]    
Financial assets amortised cost ₨ 121,366 ₨ 76,169
Financial assets 809,186 757,162
Financial liabilities 331,306 292,926
Trade payables and accrued expenses [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Liabilities at FVTPL 0 0
Financial liabilities measured at fair value through other comprehensive income - mandatory 0 0
Financial liabilities designated upon initial recognition 0 0
Financial liabilities amortised cost 99,318 88,252
Financial liabilities 99,318 88,252
Other financial liabilities [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Liabilities at FVTPL 1,634 1,864
Financial liabilities measured at fair value through other comprehensive income - mandatory 0 0
Financial liabilities designated upon initial recognition 0 0
Financial liabilities amortised cost 16,466 9,807
Financial liabilities 18,100 11,671
Loans, borrowings and bank overdrafts [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Liabilities at FVTPL 0 0
Financial liabilities measured at fair value through other comprehensive income - mandatory 0 0
Financial liabilities designated upon initial recognition 0 0
Financial liabilities amortised cost 167,874 161,817
Financial liabilities 167,874 161,817
Lease liabilities [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Liabilities at FVTPL 0 0
Financial liabilities measured at fair value through other comprehensive income - mandatory 0 0
Financial liabilities designated upon initial recognition 0 0
Financial liabilities amortised cost 35,036 30,218
Financial liabilities 35,036 30,218
Derivative liabilities [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Liabilities at FVTPL 1,453 75
Financial liabilities measured at fair value through other comprehensive income - mandatory 0 0
Financial liabilities designated upon initial recognition 9,525 893
Financial liabilities amortised cost 0 0
Financial liabilities 10,978 968
Fair value through profit or loss [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Liabilities at FVTPL 3,087 1,939
Mandatory [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities measured at fair value through other comprehensive income - mandatory 0 0
Designated upon initial recognition [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets designated upon initial recognition 12,736 13,208
Financial liabilities designated upon initial recognition 9,525 893
Financial liabilities at amortised cost [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities amortised cost 318,694 290,094
Financial Assets Cash And Cash Equivalents [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 105,555 121,974
Financial assets 105,555 121,974
Equity instruments [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 7,336 4,955
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 12,143 12,493
Financial assets amortised cost 0 0
Financial assets 19,479 17,448
Fixed maturity plan mutual funds [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 1,281 1,503
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 0 0
Financial assets 1,281 1,503
Short-term mutual funds [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 79,719 88,776
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 0 0
Financial assets 79,719 88,776
Non-convertible debentures [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 210,328 219,389
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 0 0
Financial assets 210,328 219,389
Government securities [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 8,948 10,651
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 0 0
Financial assets 8,948 10,651
Commercial papers [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 14,227 2,858
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 0 0
Financial assets 14,227 2,858
Bonds [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 10,385 21,138
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 0 0
Financial assets 10,385 21,138
Inter corporate and term deposits [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 121,366 76,169
Financial assets 121,366 76,169
Trade receivables [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 136,250 118,044
Financial assets 136,250 118,044
Unbilled receivables [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 84,256 64,280
Financial assets 84,256 64,280
Other financial assets [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 0 0
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 0 0
Financial assets amortised cost 16,504 13,112
Financial assets 16,504 13,112
Derivative assets [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 295 1,105
Financial assets measured at fair value through other comprehensive income - mandatory 0 0
Financial assets designated upon initial recognition 593 715
Financial assets amortised cost 0 0
Financial assets 888 1,820
Fair value through profit or loss [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial Assets at FVTPL 88,631 96,339
Mandatory [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets measured at fair value through other comprehensive income - mandatory 243,888 254,036
Financial assets at amortised cost [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets amortised cost ₨ 463,931 ₨ 393,579