Consolidated Company-Sponsored Investment Funds - Summary of Balance Sheet Amounts (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Condensed Balance Sheet Statements, Captions [Line Items]
Total assets	$ 9,377,218	$ 9,071,927
Liabilities	4,407,610	4,148,795
Redeemable non-controlling interest	201,656	48,489
Partners' capital attributable to AB Unitholders	4,767,952	4,874,643	$ 4,417,683
Total liabilities, redeemable non-controlling interest and partners' capital	9,377,218	9,071,927
Company-Sponsored Investment Funds
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	14,746	1,989
Investments	341,128	140,792
Other assets	12,341	14,801
Total assets	368,215	157,582
Liabilities	18,898	1,716
Redeemable non-controlling interest	201,656	48,489
Partners' capital attributable to AB Unitholders	147,661	107,377
Total liabilities, redeemable non-controlling interest and partners' capital	368,215	157,582
VIEs
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	14,651	1,671
Investments	284,582	82,027
Other assets	9,358	1,317
Total assets	308,591	85,015
Liabilities	15,674	345
Redeemable non-controlling interest	188,779	31,670
Partners' capital attributable to AB Unitholders	104,138	53,000
Total liabilities, redeemable non-controlling interest and partners' capital	308,591	85,015
VOEs
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	95	318
Investments	56,546	58,765
Other assets	2,983	13,484
Total assets	59,624	72,567
Liabilities	3,224	1,371
Redeemable non-controlling interest	12,877	16,819
Partners' capital attributable to AB Unitholders	43,523	54,377
Total liabilities, redeemable non-controlling interest and partners' capital	$ 59,624	$ 72,567