Name:	hood_AdjustmentsToAdditionalPaidInCapitalStockBasedCompensationAwardsAttributableToServicesInBusinessAcquisition
Namespace Prefix:	hood_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Business Combination, Consideration Transferred, Stock Based Compensation Awards Attributable To Post Combination Services

No definition available.

Name:	hood_BusinessCombinationConsiderationTransferredStockBasedCompensationAwardsAttributableToPostCombinationServices
Namespace Prefix:	hood_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Business Combination, Consideration Transferred, Stock-based Compensation Awards Attributable to Pre-combination Services

No definition available.

Name:	hood_BusinessCombinationConsiderationTransferredStockBasedCompensationAwardsAttributableToPreCombinationServices
Namespace Prefix:	hood_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Business Combination, Milestone Payment, Service Period

No definition available.

Name:	hood_BusinessCombinationMilestonePaymentServicePeriod
Namespace Prefix:	hood_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Business Combination, Pro Forma Information, Post Combination Compensation Expense of Acquiree since Acquisition Date, Actual

No definition available.

Name:	hood_BusinessCombinationProFormaInformationPostCombinationCompensationExpenseOfAcquireeSinceAcquisitionDateActual
Namespace Prefix:	hood_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Holdback Agreements Related to Employees

No definition available.

Name:	hood_HoldbackAgreementsRelatedToEmployees
Namespace Prefix:	hood_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

Name:	us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

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

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6578-128477