v3.26.3
Long-term Incentive Compensation Plans - Summary of Share-based Compensation, Employee Stock Purchase Plan, Activity (Details) - USD ($)
shares in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Share-Based Payment Arrangement [Abstract]        
Total amount of AB Holding Units Purchased/Retained (in shares) 1.1 0.1 1.9 1.3
Total Cash Paid for AB Holding Units Purchased/Retained $ 38.4 $ 4.1 $ 67.1 $ 47.8
Open Market Purchases of AB Holding Units Purchased (in shares) 1.0 0.1 1.6 1.1
Total Cash Paid for Open Market Purchases of AB Holding Units $ 38.3 $ 3.9 $ 59.9 $ 42.3