Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
New York City unincorporated business tax (percent)	4.00%
Federal tax rate on partnership gross income (percent)	3.50%
Income Tax Contingency [Line Items]
Multiplied by: weighted average equity ownership interest (percent)	39.60%	39.30%
Equity in net income attributable to AB Unitholders	$ 86,281	$ 76,382
Computation of income tax [Abstract]
AB qualifying revenues	$ 695,980	$ 700,215
Multiplied by: weighted average equity ownership interest for calculating tax (percent)	36.30%	35.70%
Multiplied by: federal tax (percent)	3.50%	3.50%
Federal income taxes	$ 8,836	$ 8,749
State income taxes	223	196
Total income taxes	$ 9,059	$ 8,945
Effective tax rate (percent)	10.50%	11.70%
Changes in components for calculation of income tax [Abstract]
Change in net income attributable to AB Unitholders (percent)	12.20%
Change in equity in net income attributable to AB Unitholders (percent)	13.00%
Change in AB qualifying revenues (percent)	(0.60%)
Change in income taxes (percent)	1.30%
Variable Interest Entity, Primary Beneficiary
Income Tax Contingency [Line Items]
Net income attributable to AB Unitholders	$ 217,927	$ 194,151