Trade receivables - Additional Information (Detail) - INR (₨) ₨ in Millions |
12 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Trade receivables [Line Items] | ||
| Reversal / write back for credit losses | ₨ 938 | ₨ 209 |
| Provisions for credit losses | 269 | 281 |
| Unbilled Revenue | ₨ 6,882 | ₨ 6,983 |
| Bottom of Range | ||
| Trade receivables [Line Items] | ||
| Trade receivables, collection period | 7 days | |
| Top of Range | ||
| Trade receivables [Line Items] | ||
| Trade receivables, collection period | 90 days | |