Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 1,016,275	$ 980,938	$ 2,995,208	$ 3,122,551
Not subject to contracts with customers:
Dividend and interest income, net of broker-dealer related interest expense	22,391	9,668	69,793	31,960
Investment (losses)	(6,694)	(3,861)	(760)	(91,105)
Other revenues	84	239	362	709
Total revenue not from contract with customer	15,781	6,046	69,395	(58,436)
Net revenues	1,032,056	986,984	3,064,603	3,064,115
Base fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	720,969	700,809	2,116,668	2,145,307
Performance-based fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	27,982	13,755	82,868	112,515
Bernstein research services
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	93,875	91,557	285,760	315,806
All-in-management fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	72,240	69,717	211,877	224,337
12b-1 fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	16,388	16,594	47,321	53,547
Other distribution fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	60,421	61,649	175,727	191,547
Shareholder servicing fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	21,539	21,474	62,633	66,282
Other
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 2,861	$ 5,383	$ 12,354	$ 13,210