Finance costs and fair value change in derivative instruments - Summary of Detailed Information About Finance Costs and Fair Value Change in Derivative Instruments (Detail) ₨ in Millions, $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
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Mar. 31, 2026
INR (₨)
|
Mar. 31, 2026
USD ($)
|
Mar. 31, 2025
INR (₨)
|
Mar. 31, 2024
INR (₨)
|
|
| Disclosure Of Detailed Information About Finance Cost And Fair Value Change in Derivative Instruments [Abstract] | ||||
| Interest expense | ₨ 57,706 | $ 615 | ₨ 49,601 | ₨ 42,051 |
| Bank charges | 1,475 | 16 | 984 | 745 |
| Option premium amortisation | 1,093 | 12 | 601 | 1,900 |
| Loss on fair value changes on derivative instruments | 347 | 4 | 220 | 1,493 |
| Loss on account of modification of contractual cash flows | 19 | |||
| Unwinding of discount on provisions | 695 | 7 | 773 | 977 |
| Unamortised ancillary borrowing cost written off | 438 | 5 | 173 | 321 |
| Total | ₨ 61,754 | $ 658 | ₨ 52,352 | ₨ 47,506 |