Business Description and Organization - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Ownership structure of AB expressed as percentage of general and limited partnership interests
General partnership units (in units)	100,000	100,000
EQH | AXA
Ownership structure of AB expressed as percentage of general and limited partnership interests
General partnership interest (percent)	10.00%
AB Holding | EQH
Ownership structure of AB expressed as percentage of general and limited partnership interests
General partnership interest (percent)	4.10%
AB Holding | AllianceBernstein Corporation
Ownership structure of AB expressed as percentage of general and limited partnership interests
General partnership interest (percent)	1.00%
General partnership units (in units)	100,000
AllianceBernstein L.P. | EQH and its subsidiaries
Ownership structure of AB expressed as percentage of general and limited partnership interests
General partnership interest (percent)	64.80%