Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 279,380	$ 238,563	$ 242,397
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in net income attributable to AB Unitholders	(308,404)	(266,292)	(270,647)
Cash distributions received from AB	298,919	249,463	308,042
Changes in assets and liabilities:
(Increase) in other assets	(31)	(61)	0
Increase (decrease) in other liabilities	150	1,082	(510)
Net cash provided by operating activities	270,014	222,755	279,282
Cash flows from investing activities:
Investments in AB with proceeds from exercises of compensatory options to buy AB Holding Units	(147)	(11,511)	(16,589)
Net cash used in investing activities	(147)	(11,511)	(16,589)
Cash flows from financing activities:
Cash distributions to Unitholders	(270,881)	(222,485)	(280,722)
Capital contributions from (to) AB	867		1,440
Capital contributions from (to) AB		(270)
Proceeds from exercise of compensatory options to buy AB Holding Units	147	11,511	16,589
Net cash used in financing activities	(269,867)	(211,244)	(262,693)
Change in cash and cash equivalents	0	0	0
Cash and cash equivalents as of beginning of the year	0	0	0
Cash and cash equivalents as of end of the year	0	0	0
Cash paid:
Income taxes	28,906	26,650	28,766
Non-cash investing activities:
Issuance of AB Holding Units to fund long-term incentive compensation plan awards	107,366	146,488	168,955
Retirement of AB Holding Units	$ (78,388)	$ (110,752)	$ (194,544)