Investment in jointly controlled entities and associates - Schedule of Investment in Jointly Controlled Entities and Associates (Detail) ₨ in Millions, $ in Millions	Mar. 31, 2025 INR (₨)	Mar. 31, 2025 USD ($)	Mar. 31, 2024 INR (₨)
Disclosure of joint ventures [abstract]
Investment in jointly controlled entities accounted using equity method (refer Note 51(a))	₨ 380	$ 4	₨ 2,862
Investment in associates accounted using equity method (refer Note 51(b))	1	0
Investments in jointly controlled entities	₨ 381	$ 4	₨ 2,862

The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 24
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_24_a&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2024-01-01
-Paragraph B16
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B16&doctype=Appendix&subtype=B
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 54
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_54_e&doctype=Standard
-URIDate 2024-03-27

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Period Type:	instant