Summary of Significant Accounting Policies - Schedule of Repurchase Activity (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Total amount of AB Holding Units Purchased (in units)	5.2	5.6
Total Cash Paid for AB Holding Units Purchased	$ 211.8	$ 262.3
Open-market purchases of AB Holding Units Purchased (in units)	2.3	2.6
Total Cash Paid for Open Market Purchases of AB Holding Units	$ 92.7	$ 117.9