Gross Unrealized Losses and Fair Value of Available for Sale Debt Securities (Detail) ₨ in Millions, $ in Millions	Mar. 31, 2020 INR (₨)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 INR (₨)
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	₨ 122,669.6	$ 1,627.1	₨ 32,187.5
Less Than 12 Months Unrealized Losses	1,105.3	14.7	137.0
12 Months or Greater Fair Value	178,262.5	2,364.5	767,531.0
12 Months or Greater Unrealized Losses	1,623.2	21.5	11,866.3
Fair Value	300,932.1	3,991.6	799,718.5
Unrealized Losses	2,728.5	$ 36.2	12,003.3
Debt securities, other than asset and mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	81,158.9		17,996.3
Less Than 12 Months Unrealized Losses	960.6		88.1
12 Months or Greater Fair Value	177,416.2		763,992.6
12 Months or Greater Unrealized Losses	1,617.9		11,792.6
Fair Value	258,575.1		781,988.9
Unrealized Losses	2,578.5		11,880.7
Debt securities, other than asset and mortgage-backed securities \| Government of India securities
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	24,492.8		0.0
Less Than 12 Months Unrealized Losses	69.8		0.0
12 Months or Greater Fair Value	158,735.8		568,759.0
12 Months or Greater Unrealized Losses	1,421.8		9,834.9
Fair Value	183,228.6		568,759.0
Unrealized Losses	1,491.6		9,834.9
Debt securities, other than asset and mortgage-backed securities \| Credit Substitutes
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	38,039.9		17,996.3
Less Than 12 Months Unrealized Losses	481.2		88.1
12 Months or Greater Fair Value	18,680.4		165,700.5
12 Months or Greater Unrealized Losses	196.1		1,475.7
Fair Value	56,720.3		183,696.8
Unrealized Losses	677.3		1,563.8
Debt securities, other than asset and mortgage-backed securities \| Other corporate/financial institution bonds
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	18,626.2		0.0
Less Than 12 Months Unrealized Losses	409.6		0.0
12 Months or Greater Fair Value	0.0		2,117.6
12 Months or Greater Unrealized Losses	0.0		6.3
Fair Value	18,626.2		2,117.6
Unrealized Losses	409.6		6.3
Debt securities, other than asset and mortgage-backed securities \| State government securities
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	0.0		0.0
Less Than 12 Months Unrealized Losses	0.0		0.0
12 Months or Greater Fair Value	0.0		27,415.5
12 Months or Greater Unrealized Losses	0.0		475.7
Fair Value	0.0		27,415.5
Unrealized Losses	0.0		475.7
Debt securities, other than asset and mortgage-backed securities \| Government securities outside India
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	0.0		0.0
Less Than 12 Months Unrealized Losses	0.0		0.0
12 Months or Greater Fair Value	0.0		0.0
12 Months or Greater Unrealized Losses	0.0		0.0
Fair Value	0.0		0.0
Unrealized Losses	0.0		0.0
Mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	0.0		0.0
Less Than 12 Months Unrealized Losses	0.0		0.0
12 Months or Greater Fair Value	0.0		45.7
12 Months or Greater Unrealized Losses	0.0		0.4
Fair Value	0.0		45.7
Unrealized Losses	0.0		0.4
Asset-backed securities
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	41,510.7		14,191.2
Less Than 12 Months Unrealized Losses	144.7		48.9
12 Months or Greater Fair Value	846.3		3,492.7
12 Months or Greater Unrealized Losses	5.3		73.3
Fair Value	42,357.0		17,683.9
Unrealized Losses	150.0		122.2
Other securities (including mutual fund units)
Gain (Loss) on Securities [Line Items]
Less Than 12 Months Fair Value	0.0		0.0
Less Than 12 Months Unrealized Losses	0.0		0.0
12 Months or Greater Fair Value	0.0		0.0
12 Months or Greater Unrealized Losses	0.0		0.0
Fair Value	0.0		0.0
Unrealized Losses	₨ 0.0		₨ 0.0

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922890-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922890-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922888-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=hdb_DebtSecuritiesOtherThanAssetAndMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=hdb_GovernmentOfIndiaSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=hdb_CreditSubstitutesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=hdb_OtherCorporateFinancialInstitutionBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=hdb_SecuritiesIssuedByStateGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=hdb_GovernmentSecuritiesOutsideIndiaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=hdb_OtherSecuritiesIncludingMutualFundUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: