Business Description, Organization and Basis of Presentation - Additional Information (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026 USD ($) shares	Sep. 30, 2026 shares
Distributions Reclassified to Compensation and Benefits Expense \| Location, Statement of Income, Balance [Axis]: us-gaap:LaborAndRelatedExpense
Distribution Made to Limited Partner [Line Items]
Distributions to non-controlling interest holders \| $	$ 24.6
AB Holding \| AB
Distribution Made to Limited Partner [Line Items]
General partnership interest in company		1.00%
AB Holding \| General Partnership Interest \| AB
Distribution Made to Limited Partner [Line Items]
General partners' capital account, units outstanding \| shares	100,000	100,000
AB
Distribution Made to Limited Partner [Line Items]
Economic interest, percentage	68.30%	68.30%
AB \| EQH and its subsidiaries
Distribution Made to Limited Partner [Line Items]
General partnership interest in company		1.00%
AB \| General Partnership Interest \| AB
Distribution Made to Limited Partner [Line Items]
General partnership interest in company		1.00%

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-5

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S45
-Paragraph 8
-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Section S99
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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