Net Income per Unit - Summary of Earnings Per Unit, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Earnings Per Unit [Abstract]
Net income attributable to AB Unitholders	$ 255,222	$ 210,467	$ 550,707	$ 431,266
Weighted average limited partnership Units outstanding – basic (in shares)	294,526	292,064	294,130	292,125
Weighted average limited partnership Units outstanding – diluted (in shares)	294,526	292,064	294,130	292,125
Net income per AB Unit - basic (in dollars per share)	$ 0.86	$ 0.71	$ 1.85	$ 1.46
Net income per AB Unit - diluted (in dollars per share)	$ 0.86	$ 0.71	$ 1.85	$ 1.46