Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 207,288	$ 313,752	$ 428,982	$ 539,707
Other comprehensive income (loss):
Foreign currency translation adjustment, before reclassification and tax	26,278	(1,579)	37,027	(11,888)
Less: reclassification adjustment for (losses) included in net income upon liquidation	0	(10,197)	0	(10,197)
Foreign currency translation adjustments, before tax	26,278	8,618	37,027	(1,691)
Income tax (expense) benefit	(240)	(54)	(185)	55
Foreign currency translation adjustments, net of tax	26,038	8,564	36,842	(1,636)
Changes in employee benefit related items:
Amortization of prior service cost	0	6	611	12
Recognized actuarial (loss) gain	0	(110)	0	559
Less: reclassification adjustment for (losses) included in net income upon retirement plan liquidation	0	0	(22,898)	0
Changes in employee benefit related items	0	(104)	23,509	571
Income tax (expense)	0	(2)	(147)	(7)
Employee benefit related items, net of tax	0	(106)	23,362	564
Other comprehensive income (loss)	26,038	8,458	60,204	(1,072)
Less: Comprehensive (loss) income in consolidated entities attributable to non-controlling interests	(3,179)	4,180	(2,284)	12,208
Comprehensive income attributable to AB Unitholders	$ 236,505	$ 318,030	$ 491,470	$ 526,427