Income Taxes - Additional Information (Detail) - INR (₨) ₨ / shares in Units, ₨ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Disclosure of income tax expense [line items] | |||
| Deferred tax asset of unused tax losses not recognized | ₨ 13,613 | ₨ 10,816 | |
| Tax loss carry-forwards | 56,119 | 44,274 | |
| Tax loss carry-forwards not currently subject to expiration dates | 51,505 | 40,292 | |
| Tax loss carry-forwards expires in various years | ₨ 4,614 | 3,982 | |
| Tax loss carry-forwards expiration period | 2046 | ||
| Cumulative earnings of subsidiaries on which deferred taxes has not been created | ₨ 69,693 | 86,937 | |
| Decrease of current tax expense due to tax holidays | ₨ 13,092 | ₨ 11,798 | ₨ 14,308 |
| Tax incentives per share | ₨ 1.25 | ₨ 1.13 | ₨ 1.35 |
| Branch profit tax percentage | 15.00% | ||
| Expiry of tax holiday period | 2034-35 | ||
| Unused tax losses [member] | |||
| Disclosure of income tax expense [line items] | |||
| Recognized deferred tax assets of loss carry forward | ₨ 784 | ₨ 898 | |