v3.25.4
Performance Management - AB Global Real Estate Investment Fund II
Oct. 31, 2025
Prospectus [Line Items]  
Bar Chart and Performance Table [Heading] BAR CHART AND PERFORMANCE INFORMATION
Performance Narrative [Text Block]
The bar chart and performance information provide an indication of the historical risk of an investment in the Fund by showing:
•  
how the Fund’s performance changed from year to year over ten years; and
•  
how the Fund’s average annual returns for one, five and ten years compare to those of a broad-based securities market index.
You can obtain updated performance information for the Fund at www.bernstein.com (click on “Investments,” then “Mutual Fund Performance at a Glance”).
The Fund’s past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Performance Past Does Not Indicate Future [Text] The Fund’s past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.
Performance Information Illustrates Variability of Returns [Text] how the Fund’s performance changed from year to year over ten years; andhow the Fund’s average annual returns for one, five and ten years compare to those of a broad-based securities market index.
Performance Additional Market Index [Text] The FTSE EPRA/NAREIT Developed Real Estate Index provides information about the performance of REITs in global markets. Performance returns for the FTSE EPRA/NAREIT Developed Real Estate Index (net) are calculated applying dividend withholding tax rates applicable to non‑resident persons who do not benefit from double taxation treaties. The FTSE NAREIT Equity REIT Index provides information about the performance of REITs in the U.S.
Bar Chart Narrative [Text Block]
The annual returns in the bar chart are for the Fund’s Class I shares.
Bar Chart [Heading] Bar Chart
Bar Chart Closing [Text Block] Calendar Year End (%) During the period shown in the bar chart, the Fund’s: Best Quarter was up 16.85%, 3rd quarter, 2024; and Worst Quarter was down -26.82%, 1st quarter, 2020.
Performance Table Heading Performance Table Average Annual Total Returns (For the periods ended December 31, 2025)
Performance Table Uses Highest Federal Rate After‑tax Returns:–Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes;
Performance Table Not Relevant to Tax Deferred actual after-tax returns depend on an individual investor’s tax situation and are likely to differ from those shown; and–Are not relevant to investors who hold Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.
Performance Availability Website Address [Text] www.bernstein.com
Class I  
Prospectus [Line Items]  
Highest Quarterly Return, Label [Optional Text] Best Quarter
Highest Quarterly Return 16.85%
Highest Quarterly Return, Date Sep. 30, 2024
Lowest Quarterly Return, Label [Optional Text] Worst Quarter
Lowest Quarterly Return (26.82%)
Lowest Quarterly Return, Date Mar. 31, 2020