Consolidated Company-Sponsored Investment Funds - Summary of Balance Sheet Amounts (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024
Condensed Balance Sheet Statements, Captions [Line Items]
Total assets	$ 9,253,086	$ 9,071,927
Liabilities	4,257,577	4,148,795
Redeemable non-controlling interest	261,791	48,489
Partners' capital attributable to AB Unitholders	4,733,718	4,874,643	$ 4,484,697
Total liabilities, redeemable non-controlling interest and partners' capital	9,253,086	9,071,927
Company-Sponsored Investment Funds
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	15,563	1,989
Investments	443,015	140,792
Other assets	26,892	14,801
Total assets	485,470	157,582
Liabilities	36,933	1,716
Redeemable non-controlling interest	261,791	48,489
Partners' capital attributable to AB Unitholders	186,746	107,377
Total liabilities, redeemable non-controlling interest and partners' capital	485,470	157,582
VIEs
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	15,518	1,671
Investments	379,850	82,027
Other assets	25,958	1,317
Total assets	421,326	85,015
Liabilities	35,285	345
Redeemable non-controlling interest	241,556	31,670
Partners' capital attributable to AB Unitholders	144,485	53,000
Total liabilities, redeemable non-controlling interest and partners' capital	421,326	85,015
VOEs
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	45	318
Investments	63,165	58,765
Other assets	934	13,484
Total assets	64,144	72,567
Liabilities	1,648	1,371
Redeemable non-controlling interest	20,235	16,819
Partners' capital attributable to AB Unitholders	42,261	54,377
Total liabilities, redeemable non-controlling interest and partners' capital	$ 64,144	$ 72,567