Cash and Cash Equivalents - Additional Information (Detail) - Reserve Bank of India RBI ₨ in Millions, $ in Millions	12 Months Ended
Mar. 31, 2015 INR (₨)	Mar. 31, 2015 USD ($)	Mar. 31, 2014 INR (₨)
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents, balance maintained with the RBI to meet the Bank's cash reserve ratio requirement	₨ 221,889.6	$ 3,561.1	₨ 214,951.3
Cash and cash equivalents, description of cash reserve ratio requirement	The cash reserve ratio has to be maintained on an average basis for a two-week period and should not fall below 95% of the required cash reserve ratio on any particular day.

Describe the restrictions with respect to withdrawal or usage and the specific cash or cash equivalent item. Restrictions may include contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 305

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6478312&loc=d3e61473-112792

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.1(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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