Net Income per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Unit [Abstract]
General partnership interest in Company (percent)			1.00%
Limited Partners interest in Company (as a percent)			99.00%
Net income per unit, basic and diluted [Abstract]
Net income attributable to AB Unitholders	$ 187,811	$ 203,674	$ 503,177	$ 569,535
Weighted average limited partnership units outstanding – basic (in units)	268,567,000	269,603,000	268,131,000	269,783,000
Dilutive effect of compensatory options to buy AB Holding Units (in units)	36,000	245,000	52,000	282,000
Weighted average limited partnership units outstanding – diluted (in units)	268,603,000	269,848,000	268,183,000	270,065,000
Basic net income per AB Unit (in dollars per unit)	$ 0.69	$ 0.75	$ 1.86	$ 2.09
Diluted net income per AB Unit (in dollars per unit)	$ 0.69	$ 0.75	$ 1.86	$ 2.09
Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units)	29,056	824,245	29,056	844,973