Net Income per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 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	$ 166,252	$ 181,665	$ 315,366	$ 365,861
Weighted average limited partnership units outstanding – basic (in units)	268,475,000	270,564,000	267,909,000	269,870,000
Dilutive effect of compensatory options to buy AB Holding Units (in units)	48,000	272,000	60,000	303,000
Weighted average limited partnership units outstanding – diluted (in units)	268,523,000	270,836,000	267,969,000	270,173,000
Basic net income per AB Unit (in dollars per unit)	$ 0.61	$ 0.66	$ 1.17	$ 1.34
Diluted net income per AB Unit (in dollars per unit)	$ 0.61	$ 0.66	$ 1.17	$ 1.34
Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units)	29,056	850,155	29,056	1,211,906