Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 367,010	$ 333,239
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred sales commissions	12,148	6,743
Non-cash long-term incentive compensation expense	15,068	27,307
Depreciation and other amortization	72,034	83,997
Unrealized losses (gains) on investments	13,637	(16,724)
Other, net	154	11,537
Changes in assets and liabilities:
(Increase) decrease in securities, segregated	(787,322)	59,965
(Increase) decrease in receivables	(145,247)	43,325
(Increase) decrease in investments	(42,626)	506,061
(Increase) in deferred sales commissions	(34,435)	(10,309)
Decrease (increase) in right-of-use assets	5,278	(1,150)
Increase in other assets	(9,909)	(4,515)
Increase (decrease) in payables	851,419	(440,029)
(Decrease) in lease liabilities	(49,946)	(59,924)
Increase (decrease) in accounts payable and accrued expenses	(2,295)	(61,705)
Increase in accrued compensation and benefits	202,893	180,701
Net cash provided by operating activities	822,087	546,974
Cash flows from investing activities:
Purchases of furniture, equipment and leasehold improvements	(6,531)	(11,276)
Acquisition of businesses, net of cash acquired	(13,552)	5,255
Net cash used in investing activities	(20,083)	(6,021)
Cash flows from financing activities:
(Repayment) of commercial paper, net	0	(85,888)
Proceeds of EQH Facility	125,000	0
(Repayment) of bank loans	0	(25,000)
Increase (decrease) in overdrafts payable	16,570	(19,144)
Distributions to General Partner and Unitholders	(446,624)	(343,471)
Capital contributions (to) from affiliates	(971)
Capital contributions (to) from affiliates		495
Additional investments by AB Holding with proceeds from exercise of compensatory options to buy AB Holding Units	147	8,951
Purchases of AB Holding Units to fund long-term incentive compensation plan awards, net	(47,415)	(58,358)
Other	(958)	291
Net cash (used in) financing activities	(624,100)	(473,098)
Effect of exchange rate changes on cash and cash equivalents	(11,162)	(179)
Net increase (decrease) in cash and cash equivalents	166,742	67,676
Cash and cash equivalents as of beginning of the period	691,171	653,324
Cash and cash equivalents as of end of the period	857,913	721,000
Non-cash investing activities:
Fair value of assets acquired (excluding cash acquired of $0.6 million and $11.8 million, respectively)	18,389	28,966
Fair value of liabilities assumed	437	16,837
Cash acquired from acquisition	600	11,800
Non-cash financing activities:
Payables recorded under contingent payment arrangements	4,400	17,384
Company-sponsored investment funds
Adjustments to reconcile net income to net cash provided by operating activities:
Unrealized losses (gains) on investments	11,938	(32,173)
Changes in assets and liabilities:
(Increase) decrease in investments	334,970	(86,566)
Increase in other assets	7,318	7,194
Cash flows from financing activities:
(Redemptions) subscriptions of non-controlling interest in consolidated company-sponsored investment funds, net	$ (269,849)	$ 49,026