Consolidated Company-Sponsored Investment Funds - Balance Sheet Amounts (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Total assets	$ 9,277,776	$ 9,071,927
Liabilities	4,262,658	4,148,795
Redeemable non-controlling interest	178,967	48,489
Partners' capital attributable to AB Unitholders	4,836,151	4,874,643	$ 4,453,362
Total liabilities, non-controlling interest and capital	9,277,776	9,071,927
Company-sponsored investment funds
Variable Interest Entity [Line Items]
Cash and cash equivalents	17,726	1,989
Investments	330,534	140,792
Other assets	25,120	14,801
Total assets	373,380	157,582
Liabilities	25,281	1,716
Redeemable non-controlling interest	178,967	48,489
Partners' capital attributable to AB Unitholders	169,132	107,377
Total liabilities, non-controlling interest and capital	373,380	157,582
VIEs
Variable Interest Entity [Line Items]
Cash and cash equivalents	17,617	1,671
Investments	304,035	82,027
Other assets	24,778	1,317
Total assets	346,430	85,015
Liabilities	25,132	345
Redeemable non-controlling interest	169,091	31,670
Partners' capital attributable to AB Unitholders	152,207	53,000
Total liabilities, non-controlling interest and capital	346,430	85,015
VOEs
Variable Interest Entity [Line Items]
Cash and cash equivalents	109	318
Investments	26,499	58,765
Other assets	342	13,484
Total assets	26,950	72,567
Liabilities	149	1,371
Redeemable non-controlling interest	9,876	16,819
Partners' capital attributable to AB Unitholders	16,925	54,377
Total liabilities, non-controlling interest and capital	$ 26,950	$ 72,567