Business Combination - Pro Forma Financial Information (Detail) ₨ in Millions, $ in Millions	12 Months Ended
Mar. 31, 2024 INR (₨)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 INR (₨)	Mar. 31, 2023 USD ($)
Business Combinations [Abstract]
Revenue	₨ 2,303,956.6	$ 26,968.9	₨ 2,147,961.5	$ 25,142.9
Net Income	₨ 645,526.0	$ 7,556.2	₨ 636,783.4	$ 7,453.9

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration