Business Description and Organization (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
AXA and its subsidiaries ownership interest in holding company (in hundredths)		1.40%
Limited partners or members ownership interest in company (in hundredths)		100.00%
General partnership information [Abstract]
General Partnership number of general partnership units owned in Holding Company (in units)	100,000	100,000
General partnership interest in Company (in hundredths)	1.00%	1.00%
AXA and its subsidiaries economic interest in Company (in hundredths)		64.20%
AXA And Its Subsidiaries [Member]
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in company (in hundredths)		61.00%
Holdings [Member]
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in company (in hundredths)		37.50%
Unaffiliated Holders [Member]
Ownership structure of AllianceBernstein expressed as a percentage of general and limited partnership interests [Abstract]
Limited partners or members ownership interest in company (in hundredths)		1.50%