Loans - Interest on Loans by Facility (Detail) ₨ in Millions, $ in Millions	12 Months Ended
Mar. 31, 2026 INR (₨)	Mar. 31, 2026 USD ($)	Mar. 31, 2025 INR (₨)	Mar. 31, 2024 INR (₨)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest on loans	₨ 2,544,315.4	$ 27,116.2	₨ 2,506,518.7	₨ 2,194,525.5
Wholesale loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest on loans	532,299.0	5,673.0	564,679.4	555,377.8
Retail loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest on loans	2,012,016.4	21,443.2	1,941,839.3	1,617,982.2
Other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest on loans	₨ 0.0	$ 0.0	₨ 0.0	₨ 21,165.5

The aggregate interest and fee income generated by: (1) loans the Entity has positive intent and ability to hold for the foreseeable future, or until maturity or payoff, including commercial and consumer loans, whether domestic or foreign, which may consist of: (a) industrial and agricultural; (b) real estate; and (c) real estate construction loans; (d) trade financing; (e) lease financing; (f) home equity lines-of-credit; (g) automobile and other vehicle loans; and (h) credit card and other revolving-type loans and (2) loans and leases held-for-sale which may include mortgage loans, direct financing, and sales-type leases.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-21

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration