Business Description Organization and Basis of Presentation (Policies)	3 Months Ended
Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The interim condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). In the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of the interim results, have been made. The preparation of the condensed consolidated financial statements requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the dates of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the interim reporting periods. Actual results could differ from those estimates. The condensed consolidated statement of financial condition as of December 31, 2019 was derived from audited financial statements, but it does not include all disclosures required by accounting principles generally accepted in the United States of America (“GAAP”).
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include AB and its majority-owned and/or controlled subsidiaries, and the consolidated entities that are considered to be variable interest entities (“VIEs”) and voting interest entities (“VOEs”) in which AB has a controlling financial interest. Non-controlling interests on the condensed consolidated statements of financial condition include the portion of consolidated company-sponsored investment funds in which we do not have direct equity ownership. All significant inter-company transactions and balances among the consolidated entities have been eliminated.
Reclassifications	Reclassifications During 2020, prior period amounts for the changes in right-of-use assets and lease liabilities previously presented with amounts related to the adoption of ASC 842 in our Condensed Consolidated Statement of Cash Flows, are now presented net of the adoption impact of ASU 842 to conform to the current period's presentation.
Recently Adopted Accounting Pronouncements / Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326). This new guidance relates to the accounting for credit losses on financial instruments and introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. It also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment. The guidance removes Step 2 of the goodwill impairment test, which had required a hypothetical purchase price allocation. As a result of the revised guidance, a goodwill impairment will be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. The amendment modifies the disclosure requirements for fair value measurements by removing, modifying or adding certain disclosures. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations. In August 2018, the FASB issued ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract. The amendment aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements that currently exist in GAAP for capitalizing implementation costs incurred to develop or obtain internal-use software. Implementation costs would either be capitalized or expensed as incurred depending on the project stage. All costs in the preliminary and post-implementation project stages are expensed as incurred, while certain costs within the application development stage are capitalized. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations. Accounting Pronouncements Not Yet Adopted in 2020 In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Topic 715-20). The amendment modifies the disclosure requirements for employers that sponsor defined benefit pension or other post-retirement plans. The revised guidance is effective for financial statements issued for fiscal years beginning after December 15, 2020, with early adoption permitted. The revised guidance will not have a material impact on our financial condition or results of operations. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify US GAAP for other areas of Topic 740 by clarifying and amending the existing guidance. The revised guidance is effective for financial statements issued for fiscal years beginning after December 15, 2020, with early adoption permitted. The revised guidance will not have a material impact on our financial condition or results of operations.
Goodwill	Goodwill Goodwill is tested annually, as of September 30, for impairment. Throughout the year, the carrying value of goodwill is also reviewed for impairment if certain events or changes in circumstances occur, and trigger whether an interim impairment test may be required. Such changes in circumstances may be, but not limited to, sustained decrease in AB Holding Unit price or declines in market capitalization that would suggest that the fair value of the reporting unit is less than the carrying amount; significant and unanticipated declines in assets under management, revenues, or lower than expected earnings in the current quarter, next quarter or year. Any of these changes in circumstances could suggest the possibility that goodwill is impaired, however, none of these events or circumstances by itself would indicate that it is more likely than not that goodwill is impaired, they are merely recognized as triggering events for the consideration of impairment and must be viewed in combination with any mitigating or positive factors. A holistic evaluation of all events since the most recent quantitative impairment test must be done to determine whether it is more likely than not that the reporting unit is impaired. As of January 1, 2020, we adopted ASU 2017-04, Simplifying the Test for Goodwill Impairment. The guidance removes Step 2 of the goodwill impairment test, which had required a hypothetical purchase price allocation. As a result of the revised guidance, a goodwill impairment will be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. Under this guidance, the goodwill impairment test no longer includes a determination by management of whether a decline in fair value is temporary; however, it is important to consider how the severity and anticipated duration of the current market conditions is reflected in management's determination of fair value. We have determined that AB has only one reporting segment and reporting unit. As of March 31, 2020, there was $3.1 billion of goodwill recorded on the consolidated statement of financial condition. During the first quarter of 2020, the unit price per AB Holding Unit declined significantly in response to the precipitous decline in the financial markets. As such, we performed an interim impairment evaluation of goodwill utilizing the Market Approach where the fair value of the reporting unit is based on its unadjusted market valuation (AB Holding Units outstanding multiplied by AB Holding’s Unit price). We have considered the results of the market approach analysis performed along with a number of other factors (including current market conditions) and determined that the fair value of the reporting unit exceeded its carrying value as of March 31, 2020. As such, no goodwill impairment existed. We will continue to monitor and evaluate any events that may trigger an impairment of goodwill.

Business Description Organization and Basis of Presentation (Policies)

3 Months Ended

Mar. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The interim condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). In the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of the interim results, have been made. The preparation of the condensed consolidated financial statements requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the dates of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the interim reporting periods. Actual results could differ from those estimates. The condensed consolidated statement of financial condition as of December 31, 2019 was derived from audited financial statements, but it does not include all disclosures required by accounting principles generally accepted in the United States of America (“GAAP”).

Principles of Consolidation

The condensed consolidated financial statements include AB and its majority-owned and/or controlled subsidiaries, and the consolidated entities that are considered to be variable interest entities (“VIEs”) and voting interest entities (“VOEs”) in which AB has a controlling financial interest. Non-controlling interests on the condensed consolidated statements of financial condition include the portion of consolidated company-sponsored investment funds in which we do not have direct equity ownership. All significant inter-company transactions and balances among the consolidated entities have been eliminated.

Reclassifications

During 2020, prior period amounts for the changes in right-of-use assets and lease liabilities previously presented with amounts related to the adoption of ASC 842 in our Condensed Consolidated Statement of Cash Flows, are now presented net of the adoption impact of ASU 842 to conform to the current period's presentation.

Recently Adopted Accounting Pronouncements / Accounting Pronouncements Not Yet Adopted

Recently Adopted Accounting Pronouncements

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326). This new guidance relates to the accounting for credit losses on financial instruments and introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. It also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations.

In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment. The guidance removes Step 2 of the goodwill impairment test, which had required a hypothetical purchase price allocation. As a result of the revised guidance, a goodwill impairment will be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. The amendment modifies the disclosure requirements for fair value measurements by removing, modifying or adding certain disclosures. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations.

In August 2018, the FASB issued ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract. The amendment aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements that currently exist in GAAP for capitalizing implementation costs incurred to develop or obtain internal-use software. Implementation costs would either be capitalized or expensed as incurred depending on the project stage. All costs in the preliminary and post-implementation project stages are expensed as incurred, while certain costs within the application development stage are capitalized. We adopted this standard prospectively on January 1, 2020. The adoption of this standard did not have a material impact on our financial condition or results of operations.

Accounting Pronouncements Not Yet Adopted in 2020

In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Topic 715-20). The amendment modifies the disclosure requirements for employers that sponsor defined benefit pension or other post-retirement plans. The revised guidance is effective for financial statements issued for fiscal years beginning after December 15, 2020, with early adoption permitted. The revised guidance will not have a material impact on our financial condition or results of operations.

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify US GAAP for other areas of Topic 740 by clarifying and amending the existing guidance. The revised guidance is effective for financial statements issued for fiscal years beginning after December 15, 2020, with early adoption permitted. The revised guidance will not have a material impact on our financial condition or results of operations.

Goodwill

Goodwill is tested annually, as of September 30, for impairment. Throughout the year, the carrying value of goodwill is also reviewed for impairment if certain events or changes in circumstances occur, and trigger whether an interim impairment test may be required. Such changes in circumstances may be, but not limited to, sustained decrease in AB Holding Unit price or declines in market capitalization that would suggest that the fair value of the reporting unit is less than the carrying amount; significant and unanticipated declines in assets under management, revenues, or lower than expected earnings in the current quarter, next quarter or year. Any of these changes in circumstances could suggest the possibility that goodwill is impaired, however, none of these events or circumstances by itself would indicate that it is more likely than not that goodwill is impaired, they are merely recognized as triggering events for the consideration of impairment and must be viewed in combination with any mitigating or positive factors. A holistic evaluation of all events since the most recent quantitative impairment test must be done to determine whether it is more likely than not that the reporting unit is impaired.

As of January 1, 2020, we adopted ASU 2017-04, Simplifying the Test for Goodwill Impairment. The guidance removes Step 2 of the goodwill impairment test, which had required a hypothetical purchase price allocation. As a result of the revised guidance, a goodwill impairment will be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. Under this guidance, the goodwill impairment test no longer includes a determination by management of whether a decline in fair value is temporary; however, it is important to consider how the severity and anticipated duration of the current market conditions is reflected in management's determination of fair value. We have determined that AB has only one reporting segment and reporting unit.

As of March 31, 2020, there was $3.1 billion of goodwill recorded on the consolidated statement of financial condition. During the first quarter of 2020, the unit price per AB Holding Unit declined significantly in response to the precipitous decline in the financial markets. As such, we performed an interim impairment evaluation of goodwill utilizing the Market Approach where the fair value of the reporting unit is based on its unadjusted market valuation (AB Holding Units outstanding multiplied by AB Holding’s Unit price). We have considered the results of the market approach analysis performed along with a number of other factors (including current market conditions) and determined that the fair value of the reporting unit exceeded its carrying value as of March 31, 2020. As such, no goodwill impairment existed. We will continue to monitor and evaluate any events that may trigger an impairment of goodwill.