Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Data [Abstract]
Net revenues		$ 726,726		$ 738,693		$ 792,737		$ 762,571		$ 787,352		$ 749,748		$ 753,648		$ 714,618		$ 3,020,727	$ 3,005,366	$ 2,915,047
Net income attributable to AB Unitholders		$ 161,063		$ 134,976		$ 149,094		$ 141,469		$ 177,425		$ 139,798		$ 136,435		$ 116,725		$ 586,602	$ 570,383	$ 517,676
Basic net income per AB Unit (in dollars per unit)		$ 0.59	[1]	$ 0.49	[1]	$ 0.54	[1]	$ 0.51	[1]	$ 0.65	[1]	$ 0.51	[1]	$ 0.50	[1]	$ 0.43	[1]	$ 2.14	$ 2.10	$ 1.89
Diluted net income per AB Unit (in dollars per unit)		0.59	[1]	0.49	[1]	0.54	[1]	0.51	[1]	0.65	[1]	0.51	[1]	0.50	[1]	0.43	[1]	$ 2.13	$ 2.09	$ 1.88
Cash distributions per AB Unit (in dollars per share)	[2],[3]	$ 0.56		$ 0.50		$ 0.54		$ 0.51		$ 0.63		$ 0.51		$ 0.50		$ 0.44

[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] Cash distributions reflect the impact of our non-GAAP adjustments.

[3] Declared and paid during the following quarter.