Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Statement of Comprehensive Income [Abstract]
Net income	$ 272,370	$ 207,288	$ 581,006	$ 428,982
Other comprehensive (loss) income:
Foreign currency translation adjustments, before tax	572	26,278	(5,637)	37,027
Income tax (expense)	(83)	(240)	(131)	(185)
Foreign currency translation adjustments, net of tax	489	26,038	(5,768)	36,842
Changes in employee benefit related items:
Amortization of prior service cost	0	0	0	611
Less: reclassification adjustment for (losses) included in net income upon retirement plan liquidation			0	(22,898)
Changes in employee benefit related items	0	0	0	23,509
Income tax (expense)	0	0	0	(147)
Employee benefit related items, net of tax	0	0	0	23,362
Other comprehensive income (loss)	489	26,038	(5,768)	60,204
Less: Comprehensive income (loss) in consolidated entities attributable to non-controlling interests	17,148	(3,179)	30,299	(2,284)
Comprehensive income attributable to AB Unitholders	$ 255,711	$ 236,505	$ 544,939	$ 491,470