Net Income Per Unit (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
Earnings Per Unit [Abstract]
Net income - basic	$ (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
Additional allocation of equity in net income attributable to AllianceBernstein resulting from assumed dilutive effect of compensatory options																	0	1,640,000	328,000
Net income - diluted																	(93,268,000)	135,798,000	167,517,000
Weighted average units outstanding - basic (in units)																	103,288,000	101,162,000	92,906,000
Dilutive effect of compensatory options (in units)																	0	1,639,000	244,000
Weighted average units outstanding - diluted (in units)																	103,288,000	102,801,000	93,150,000
Basic net income per unit (in dollars per unit)	$ (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 income per unit (in dollars per unit)	$ (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
Out-of-the-money options from the diluted net income per unit (in units)																	3,813,567	4,783,472	5,752,877
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.