Business Description and Organization - Limited Partnership Interests in AB Holdings (Details) - AllianceBernstein Corporation	12 Months Ended
	Dec. 31, 2019
EQH and its subsidiaries
Ownership structure of AB Holding
Limited partners or members ownership interest in Company (percent)	63.30%
AB Holding
Ownership structure of AB Holding
Limited partners or members ownership interest in Company (percent)	36.00%
Unaffiliated holders
Ownership structure of AB Holding
Limited partners or members ownership interest in Company (percent)	0.70%
AllianceBernstein L.P.
Ownership structure of AB Holding
Limited partners or members ownership interest in Company (percent)	100.00%