Gratuity and other post-employment benefit plans - Summary of Defined Benefit Plan Liability Recognized in Statement of Financial Position (Detail) - Defined Benefit Gratuity Plan [Member] ₨ in Millions, $ in Millions |
Mar. 31, 2025
INR (₨)
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Mar. 31, 2025
USD ($)
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Mar. 31, 2024
INR (₨)
|
Mar. 31, 2024
USD ($)
|
Mar. 31, 2023
INR (₨)
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Mar. 31, 2022
INR (₨)
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|---|---|---|---|---|---|---|
| Defined benefit liability | ||||||
| Present value of unfunded obligation | ₨ 315 | $ 4 | ₨ 300 | |||
| Net liability | ₨ 315 | $ 4 | ₨ 300 | $ 4 | ₨ 231 | ₨ 189 |