Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Cash flows from operating activities:
Net income	$ 428,982	$ 539,707
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred sales commissions	41,311	25,147
Non-cash long-term incentive compensation expense	10,809	20,885
Depreciation and other amortization	43,003	46,319
(Gain) on divestiture	0	(134,555)
Non-cash lease expense	35,085	57,705
Retirement plan loss	20,756	0
Retirement plan funding	(1,700)	0
Other, net	3,828	15,017
Changes in assets and liabilities:
Decrease in securities, segregated	16,808	276,098
Decrease in receivables	69,369	33,358
(Increase) in deferred sales commissions	(35,214)	(62,552)
(Decrease) in payables	(36,650)	(269,927)
(Decrease) increase in accounts payable and accrued expenses	(11,975)	64,332
Increase in accrued compensation and benefits	187,325	212,993
Cash payments to relieve operating lease liabilities	(32,682)	(34,911)
Net cash provided by operating activities	489,815	945,908
Cash flows from investing activities:
Purchases of furniture, equipment and leasehold improvements	(18,157)	(56,565)
Divestiture of business (includes $304.0 million in cash proceeds)	0	(40,196)
Capital contribution to equity method investments	0	(39,401)
Debt repayment from equity method investments	0	86,200
Net cash contribution (to) affiliates	0	(752)
Net cash (used in) investing activities	(18,157)	(50,714)
Cash flows from financing activities:
Repayment of debt, net	(60,000)	(534,316)
Decrease in overdrafts payable	0	(2)
Distributions to General Partner and Unitholders	(599,035)	(481,109)
Capital contributions (to) AB Holding	(1,307)	0
Purchases of AB Holding Units to fund long-term incentive compensation plan awards, net	(43,646)	(33,789)
Other, net	(3,318)	(5,603)
Net cash (used in) financing activities	(491,720)	(1,168,192)
Effect of exchange rate changes on cash and cash equivalents	40,776	(12,665)
Net increase (decrease) in cash and cash equivalents	20,714	(285,663)
Cash and cash equivalents as of beginning of the period	834,033	1,160,889
Cash and cash equivalents as of end of the period	854,747	875,226
Excluding Company-Sponsored Investment Funds
Adjustments to reconcile net income to net cash provided by operating activities:
Unrealized (gains) on investments	(3,823)	(5,944)
Equity in losses of equity method investments	16,652	27,893
Changes in assets and liabilities:
Decrease in investments	2,156	27,092
Decrease (increase) in other assets	14,872	(47,392)
(Increase) decrease in investments of consolidated company-sponsored investment funds	2,156	27,092
Company-Sponsored Investment Funds
Adjustments to reconcile net income to net cash provided by operating activities:
Unrealized (gains) on investments	(165)	(11,527)
Changes in assets and liabilities:
Decrease in investments	(302,058)	155,631
(Increase) decrease in investments of consolidated company-sponsored investment funds	(302,058)	155,631
(Increase) decrease in other assets of consolidated company-sponsored investment funds	(12,091)	21,623
Increase (decrease) in other liabilities of consolidated company-sponsored investment funds	35,217	(11,084)
Cash flows from financing activities:
Terminations of non-controlling interest in consolidated company-sponsored investment funds, net	$ 215,586
Redemptions of non-controlling interest in consolidated company-sponsored investment funds, net		$ (113,373)