Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Revenues:
Dividend and interest income	$ 35,944	$ 38,940	$ 106,431	$ 127,441
Investment (losses)	(2,721)	(3,512)	(31,084)	(15,398)
Other revenues	34,253	39,673	98,345	104,133
Total revenues	1,152,350	1,106,703	3,355,043	3,284,327
Less: Broker-dealer related interest expense	15,203	21,214	48,382	66,744
Net revenues	1,137,147	1,085,489	3,306,661	3,217,583
Expenses:
Employee compensation and benefits	450,793	424,893	1,310,878	1,300,989
Promotion and servicing:
Amortization of deferred sales commissions	20,872	15,005	62,183	40,152
Trade execution, marketing, T&E and other	36,907	38,312	114,239	134,243
General and administrative	118,203	155,808	414,156	439,450
Contingent payment arrangements	43	(125,947)	149	(120,831)
Interest on borrowings	7,167	8,456	22,768	37,139
Amortization of intangible assets	11,250	11,451	33,733	34,754
Total expenses	853,670	720,208	2,564,721	2,411,016
Operating income	283,477	365,281	741,940	806,567
Gain on divestiture	0	0	0	134,555
Non-operating income	0	0	0	134,555
Pre-tax income	283,477	365,281	741,940	941,122
Income taxes	17,085	14,255	46,566	50,389
Net income	266,392	351,026	695,374	890,733
Net income of consolidated entities attributable to non-controlling interests	7,129	5,054	4,845	17,262
Net income attributable to AB Unitholders	$ 259,263	$ 345,972	$ 690,529	$ 873,471
Earnings Per Unit [Abstract]
Basic net income per AB Unit (in dollars per share)	$ 0.88	$ 1.20	$ 2.34	$ 3.02
Diluted net income per AB Unit (in dollars per share)	$ 0.88	$ 1.20	$ 2.34	$ 3.02
Investment advisory and services fees
Revenues:
Revenue subject to contracts with customers	$ 874,450	$ 842,386	$ 2,573,540	$ 2,444,118
Bernstein research services
Revenues:
Revenue subject to contracts with customers	0	0	0	96,222
Distribution revenues
Revenues:
Revenue subject to contracts with customers	210,424	189,216	607,811	527,811
Promotion and servicing:
Distribution-related payments	$ 208,435	$ 192,230	$ 606,615	$ 545,120