Insurance services - Summary of Information Regarding Movement of Total VOBA Contracts (Detail) - 9 months ended Mar. 31, 2024 ₨ in Millions, $ in Millions	INR (₨)	USD ($)
Separate Accounts Disclosure [Abstract]
Beginning balance	₨ 221,738.5	$ 2,660.6
Amortization	(16,707.7)	(200.5)
Experience Adjustment	(635.1)	(7.6)
Ending balance	₨ 204,395.7	$ 2,452.5

The adjustment that represents the periodic charge against earnings to reduce the value of business acquired (VOBA) over the expected life of the underlying insurance contracts. VOBA reflects the estimated fair value of a life insurance business in force and represents the portion of the cost to acquire the business that is allocated to the value of the right to receive future cash flows from insurance contracts existing at the date of acquisition. Such value is the present value of the actuarially determined projected cash flows for the acquired policies. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Name:	us-gaap_AmortizationOfValueOfBusinessAcquiredVOBA
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration