Summary of Significant Accounting Policies - Additional Information (Details)		1 Months Ended		3 Months Ended		12 Months Ended
	Feb. 11, 2022 $ / shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) reportingUnit segment $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2000 USD ($)
Brokerage Transactions
Repledged securities		$ 23,400,000	$ 0	$ 23,400,000	$ 0	$ 23,400,000	$ 0
Collateral advances, allowance		0	0	0	0	0	0
Cash on deposit with clearing organizations for trade facilitation purposes		114,900,000	130,000,000	114,900,000	130,000,000	114,900,000	130,000,000
U.S. Treasury bills pledged as collateral		0	0	0	0	0	0
Goodwill [Abstract]
Goodwill		3,091,763,000	3,082,778,000	3,091,763,000	3,082,778,000	$ 3,091,763,000	3,082,778,000
Number of reportable segments | segment						1
Number of reporting units | reportingUnit						1
Intangible Assets, Net [Abstract]
Intangible assets, net of accumulated amortization		41,531,000	44,496,000	41,531,000	44,496,000	$ 41,531,000	44,496,000
Finite-lived intangible assets subject to amortization, net		26,300,000	29,200,000	26,300,000	29,200,000	26,300,000	29,200,000
Indefinite-lived intangible assets not subject to amortization		15,200,000	15,300,000	15,200,000	15,300,000	15,200,000	15,300,000
Gross carrying amount of intangible assets		53,800,000	65,100,000	53,800,000	65,100,000	53,800,000	65,100,000
Accumulated amortization of intangible assets		27,500,000	$ 35,900,000	27,500,000	35,900,000	27,500,000	35,900,000
Amortization expense on intangible assets						5,697,000	21,372,000	$ 28,759,000
Future estimated annual amortization expense [Abstract]
2022		5,000,000		5,000,000		5,000,000
2023		5,000,000		5,000,000		5,000,000
2024		5,000,000		5,000,000		5,000,000
2025		4,000,000		4,000,000		4,000,000
2026		$ 2,000,000		2,000,000		2,000,000
Impairment of intangible assets				$ 1,000,000.0	1,500,000
Contingent payment arrangements						$ 2,710,000	1,855,000	(510,000)
Deferred Sales Commissions, Net
Period of time the deferred sales commissions are amortized over for U.S. fund shares						1 year
Period of time the deferred sales commissions are amortized over for non-U.S. fund shares						4 years
Impairment of finite-lived intangible assets						$ 0	$ 0
Mutual Fund Underwriting Activities
Period over which receivables from brokers and dealers for sale of shares of company-sponsored mutual funds generally are realized						3 days
Long-term Incentive Compensation Plans [Abstract]
Employee allocation percentage maximum, percent		50.00%		50.00%		50.00%
Long-term incentive cash maximum per employee		$ 250,000		$ 250,000		$ 250,000
Restricted AB Holding Units awarded to employees (in units) | shares		3,400,000	5,000,000			7,000,000	5,700,000
Units issued upon exercise of options (in units) | shares						143,211	5,182
Proceeds from stock options exercised						$ 3,402,000	$ 147,000	11,511,000
Foreign Currency Translation and Transactions
Net foreign currency transaction gains (losses)						$ 8,500,000	$ (3,300,000)	$ (2,000,000)
Cash Distribution [Line Items]
Cash distributions per unit paid to the General Partner and Unitholders (in dollars per unit) | $ / shares						$ 3.86	$ 3.08	$ 2.60
Director
Long-term Incentive Compensation Plans [Abstract]
Long-term incentive awards vesting periods						4 years
Minimum
Intangible Assets, Net [Abstract]
Intangible assets acquired, estimated useful life						7 years
Minimum | Employee
Long-term Incentive Compensation Plans [Abstract]
Long-term incentive awards vesting periods						3 years
Maximum
Intangible Assets, Net [Abstract]
Intangible assets acquired, estimated useful life						20 years
Maximum | Employee
Long-term Incentive Compensation Plans [Abstract]
Long-term incentive awards vesting periods						4 years
AllianceBernstein Corporation | AB Holding
Cash Distribution [Line Items]
Percentage of General Partnership interest in company						1.00%
Employees based outside of the United States
Long-term Incentive Compensation Plans [Abstract]
Employee allocation percentage maximum, percent		100.00%		100.00%		100.00%
Long-term incentive cash maximum per employee		$ 100,000		$ 100,000		$ 100,000
Subsequent Event
Cash Distribution [Line Items]
Cash distribution, distribution declared (in dollars per unit) | $ / shares	$ 1.38
Furniture
Furniture, Equipment and Leasehold Improvements [Abstract]
Useful life						8 years
Equipment | Minimum
Furniture, Equipment and Leasehold Improvements [Abstract]
Useful life						3 years
Equipment | Maximum
Furniture, Equipment and Leasehold Improvements [Abstract]
Useful life						6 years
Sanford C Bernstein Inc Acquisition
Goodwill [Abstract]
Goodwill acquired during period									$ 3,000,000,000
Goodwill		2,800,000,000		2,800,000,000		$ 2,800,000,000
Various smaller acquisitions
Goodwill [Abstract]
Goodwill		$ 291,000,000		291,000,000		$ 291,000,000
Ramius Alternative Solutions LLC
Future estimated annual amortization expense [Abstract]
Contingent payment arrangements				$ 600,000	$ 1,400,000