Business Description, Organization and Basis of Presentation (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in Company (percent)	100.00%
Threshold amount for including institutions in private clients (less than $25 million)	$ 25
AXA and its subsidiaries ownership interest in Holding company (percent)	1.50%
Units outstanding (in shares)	100,000	100,000
General partnership interest (percent)	1.00%
AXA and its subsidiaries economic interest in Company (percent)	63.40%
AXA and its subsidiaries
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in Company (percent)	62.80%
AB Holding
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in Company (percent)	35.80%
Unaffiliated holders
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in Company (percent)	1.40%