Long-Term Incentive Compensation Plans - Summary of Changes in Unvested Restricted AB Holding Units (Details) - Restricted Stock Units (RSUs)	12 Months Ended
	Dec. 31, 2021 $ / shares shares
AB Holding Units
Unvested, beginning balance (in units) | shares	18,864,574
Granted (in units) | shares	6,984,456
Vested (in units) | shares	(7,108,465)
Forfeited (in units) | shares	(609,825)
Unvested, ending balance (in units) | shares	18,130,740
Weighted Average Grant Date Fair Value per AB Holding Unit
Unvested, Beginning Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) | $ / shares	$ 28.58
Granted, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) | $ / shares	39.68
Vested, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) | $ / shares	27.99
Forfeited, Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) | $ / shares	28.99
Unvested, Ending Weighted Average Grant Date Fair Value per AB Holding Unit (in dollars per unit) | $ / shares	$ 33.98