The amounts of income taxes recoverable in future periods in respect of: (a) deductible temporary differences; (b) the carryforward of unused tax losses; and (c) the carryforward of unused tax credits. [Refer: Temporary differences [member]; Unused tax credits [member]; Unused tax losses [member]]

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Temporary difference unused tax losses and unused tax credits, maximum period.

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Deferred tax assets (DTA) (net) / deferred tax liabilities (DTL) (net) - Additional Information (Detail) ₨ in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2026 INR (₨)	Mar. 31, 2025 INR (₨)	Mar. 31, 2024 INR (₨)	Mar. 31, 2026 USD ($)
Statement [Line Items]
Deferred tax assets	₨ 10,319	₨ 7,073		$ 110
Percentage of performed sensitivities reduced in revenues	5.00%
Disallowances of share-based payment expenses, interest expense and other	₨ 1,675	1,675
Unabsorbed Depreciation
Statement [Line Items]
Unabsorbed depreciation	₨ 76	13	₨ 5,187
Unused tax credits
Statement [Line Items]
Temporary difference unused tax losses and unused tax credits, maximum period	15 years
Unused tax credit	₨ 25	₨ 16	₨ 229
Unused tax credits \| Bottom of range [member]
Statement [Line Items]
Temporary difference, unused tax losses and unused tax credits, Expiry terms	4 years	5 years	8 years
Unused tax credits \| Top of range [member]
Statement [Line Items]
Temporary difference, unused tax losses and unused tax credits, Expiry terms	15 years	15 years	15 years
Unused tax losses
Statement [Line Items]
Temporary difference unused tax losses and unused tax credits, maximum period	8 years
Group Tax Losses
Statement [Line Items]
Unabsorbed depreciation	₨ 22,911	₨ 15,002	₨ 17,538
Group Tax Losses \| Bottom of range [member]
Statement [Line Items]
Temporary difference, unused tax losses and unused tax credits, Expiry terms	1 year	1 year	1 year
Group Tax Losses \| Top of range [member]
Statement [Line Items]
Temporary difference, unused tax losses and unused tax credits, Expiry terms	8 years	8 years	8 years