Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended																12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Financial Data [Abstract]
Equity in net (loss) income attributable to AllianceBernstein Unitholders	$ (193,458,000)		$ 34,074,000		$ 42,745,000		$ 51,058,000		$ 50,168,000		$ 18,914,000		$ 38,925,000		$ 54,210,000		$ (65,581,000)	$ 162,217,000	$ 192,513,000
Net (loss) income	(199,463,000)		27,003,000		35,512,000		43,680,000		42,925,000		12,215,000		31,772,000		47,246,000		(93,268,000)	134,158,000	167,189,000
Basic net (loss) income per unit (in dollars per share)	$ (1.97)	[1]	$ 0.26	[1]	$ 0.34	[1]	$ 0.42	[1]	$ 0.43	[1]	$ 0.12	[1]	$ 0.31	[1]	$ 0.47	[1]	$ (0.90)	$ 1.33	$ 1.80
Diluted net (loss) income per unit (in dollars per share)	$ (1.97)	[1]	$ 0.26	[1]	$ 0.34	[1]	$ 0.42	[1]	$ 0.42	[1]	$ 0.12	[1]	$ 0.31	[1]	$ 0.46	[1]	$ (0.90)	$ 1.32	$ 1.80
Cash distributions per unit (in dollars per share)	$ 0.12	[2],[3]	$ 0.26	[1]	$ 0.34	[1]	$ 0.42	[1]	$ 0.42	[2]	$ 0.12	[2]	$ 0.31	[2]	$ 0.46	[2]	$ 1.44	$ 1.51	$ 1.44
One-time, non-cash deferred compensation charge	$ 587,100,000																$ 587,100,000

[1] Basic and diluted net income per unit are computed independently for each of the periods presented. Accordingly, the sum of the quarterly net income per unit amounts may not agree to the total for the year.

[2] Declared and paid during the following quarter.

[3] The 2011 distribution excludes the impact of AllianceBernstein's $587.1 million one-time, non-cash deferred compensation charge.