Fees and Expenses - AB Government Money Market Portfolio	Apr. 30, 2025 USD ($)
Prospectus [Line Items]
Expense Heading [Optional Text]	FEES AND EXPENSES OF THE PORTFOLIO:
Expense Narrative [Text Block]	This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Portfolio. You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Advisor Class shares, which are not reflected in the tables or examples below. You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in the family of AB Mutual Funds sponsored by AllianceBernstein L.P., the Portfolio’s investment adviser (the “Adviser”). More information about these and other discounts is available from your financial intermediary and in Investing in the Portfolio—Sales Charge Reduction Programs for Class A shares on page 12 of this Prospectus, in Appendix B—Financial Intermediary Waivers to this Prospectus and in Purchase of Shares—Sales Charge Reduction Programs for Class A shares on page 40 of the Portfolio’s Statement of Additional Information (“SAI”).
Expense Breakpoint Discounts [Text]	You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in the family of AB Mutual Funds sponsored by AllianceBernstein L.P., the Portfolio’s investment adviser (the “Adviser”).
Expense Breakpoint, Minimum Investment Required [Amount]	$ 1,000,000
Shareholder Fees Caption [Optional Text]	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Optional Text]	Annual Portfolio Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Expenses Deferred Charges [Text Block]	Purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, may be subject to a 1%, 1‑year contingent deferred sales charge, or CDSC, which may be subject to waiver in certain circumstances.For Class C shares, the CDSC is 0% after the first year. Class C shares automatically convert to Class A shares after eight years.
Expense Example [Heading]	Examples
Expense Example Narrative [Text Block]	The Examples are intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Examples assume that you invest $10,000 in the Portfolio for the time periods indicated and then redeem all of your Portfolio shares at the end of those periods. The Examples also assume that your investment has a 5% return each year and that the Portfolio’s operating expenses stay the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Fees and Expenses - AB Government Money Market Portfolio

Apr. 30, 2025

USD ($)

FEES AND EXPENSES OF THE PORTFOLIO:

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Portfolio. You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Advisor Class shares, which are not reflected in the tables or examples below. You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in the family of AB Mutual Funds sponsored by AllianceBernstein L.P., the Portfolio’s investment adviser (the “Adviser”). More information about these and other discounts is available from your financial intermediary and in Investing in the Portfolio—Sales Charge Reduction Programs for Class A shares on page 12 of this Prospectus, in Appendix B—Financial Intermediary Waivers to this Prospectus and in Purchase of Shares—Sales Charge Reduction Programs for Class A shares on page 40 of the Portfolio’s Statement of Additional Information (“SAI”).

Expense Breakpoint Discounts [Text]

You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in the family of AB Mutual Funds sponsored by AllianceBernstein L.P., the Portfolio’s investment adviser (the “Adviser”).

Expense Breakpoint, Minimum Investment Required [Amount]

$ 1,000,000

Shareholder Fees Caption [Optional Text]

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Optional Text]

Annual Portfolio Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Expenses Deferred Charges [Text Block]

Purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, may be subject to a 1%, 1‑year contingent deferred sales charge, or CDSC, which may be subject to waiver in certain circumstances.For Class C shares, the CDSC is 0% after the first year. Class C shares automatically convert to Class A shares after eight years.

Expense Example [Heading]

Examples

Expense Example Narrative [Text Block]

The Examples are intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Examples assume that you invest $10,000 in the Portfolio for the time periods indicated and then redeem all of your Portfolio shares at the end of those periods. The Examples also assume that your investment has a 5% return each year and that the Portfolio’s operating expenses stay the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be: