Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
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)	36.10%	36.40%	36.10%	36.40%
Equity in net income attributable to AB Unitholders	$ 75,358	$ 97,407	$ 169,711	$ 186,314
Computation of income tax [Abstract]
AB qualifying revenues	$ 665,807	$ 580,471	$ 1,410,524	$ 1,286,863
Multiplied by: weighted average equity ownership interest for calculating tax (percent)	30.60%	31.20%	31.00%	30.90%
Multiplied by: federal tax (percent)	3.50%	3.50%	3.50%	3.50%
Federal income taxes	$ 7,120	$ 6,332	$ 15,306	$ 13,904
State income taxes	97	158	336	406
Total income taxes	$ 7,217	$ 6,490	$ 15,642	$ 14,310
Effective tax rate (percent)	9.60%	6.70%	9.20%	7.70%
Changes in components for calculation of income tax [Abstract]
Change in net income attributable to AB Unitholders (percent)	(22.00%)		(8.20%)
Change in equity in net income attributable to AB Unitholders (percent)	(22.60%)		(8.90%)
Change in AB qualifying revenues (percent)	14.70%		9.60%
Change in income taxes (percent)	11.20%		9.30%
Variable Interest Entity, Primary Beneficiary
Income Tax Contingency [Line Items]
Net income attributable to AB Unitholders	$ 208,769	$ 267,570	$ 469,496	$ 511,701