Net Gratuity Cost (Detail) - Gratuity ₨ in Millions, $ in Millions	12 Months Ended
Mar. 31, 2017 INR (₨)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 INR (₨)	Mar. 31, 2015 INR (₨)
Defined Benefit Plan Disclosure [Line Items]
Service cost	₨ 860.6	$ 13.3	₨ 513.3	₨ 504.7
Interest cost	454.6	7.0	256.1	182.4
Expected return on plan assets	(389.7)	(6.0)	(212.3)	(166.2)
Actuarial (gains)/losses	287.6	4.4	95.2	(9.1)
Net gratuity cost	₨ 1,213.1	$ 18.7	₨ 652.3	₨ 511.8

Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan.

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Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan.

+ References

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Amount of cost recognized for passage of time related to defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)(2)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
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Amount of net periodic benefit cost (credit) for defined benefit plan.

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Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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