Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 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)	36.20%	36.40%
Equity in net income attributable to AB Unitholders	$ 94,353	$ 88,907
Computation of income tax [Abstract]
AB qualifying revenues	$ 744,717	$ 706,392
Multiplied by: weighted average equity ownership interest for calculating tax (percent)	31.40%	30.60%
Multiplied by: federal tax (percent)	3.50%	3.50%
Federal income taxes	$ 8,186	$ 7,572
State income taxes	239	248
Total income taxes	$ 8,425	$ 7,820
Effective tax rate (percent)	8.90%	8.80%
Changes in components for calculation of income tax [Abstract]
Change in net income attributable to AllianceBernstein Unitholders (percent)	6.80%
Change in equity in net income attributable to AllianceBernstein Unitholders (percent)	6.10%
Change in AllianceBernstein qualifying revenues (percent)	5.40%
Change in income taxes (percent)	7.70%
Variable Interest Entity, Primary Beneficiary
Income Tax Contingency [Line Items]
Net income attributable to AB Unitholders	$ 260,727	$ 244,131