Business Description Organization and Basis of Presentation (Details)	9 Months Ended
Sep. 30, 2021 shares
AB Holding \| EQH
General partnership information [Abstract]
General partnership interest in Company (percent)	4.10%
AB Holding \| AB
General partnership information [Abstract]
General partnership interest in Company (percent)	1.00%
General Partnership number of general partnership units owned in Holding Company (in units)	100,000
Limited partners or members ownership interest in company (percent)	36.10%
EQH and its subsidiaries \| AB
General partnership information [Abstract]
Limited partners or members ownership interest in company (percent)	63.20%
Unaffiliated holders \| AB
General partnership information [Abstract]
Limited partners or members ownership interest in company (percent)	0.70%
AB \| AB
General partnership information [Abstract]
Limited partners or members ownership interest in company (percent)	100.00%
AB \| EQH and its subsidiaries
General partnership information [Abstract]
General partnership interest in Company (percent)	64.70%

The number of general partner units outstanding.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187171-122770

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- Definition

Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

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- Definition

Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

+ References

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