AB Fixed Income Taxable Portfolios [Member] Fees and Expenses - AB Fixed Income Taxable Portfolios - AB Core Bond Portfolio	Sep. 30, 2025
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 pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 shares at the end of those periods. The Examples also assume that your investment has a 5% return each year, that the Portfolio’s operating expenses stay the same and that any fee waiver and/or expense limitation is in effect only for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs as reflected in the Examples would be:
Portfolio Turnover [Heading]	Portfolio Turnover
Portfolio Turnover [Text Block]	The Portfolio pays transaction costs, such as commissions, when it buys or sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Portfolio shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Portfolio Operating Expenses or in the Examples, affect the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s portfolio turnover rate was 193% of the average value of its portfolio.
Portfolio Turnover, Rate	193.00%

AB Fixed Income Taxable Portfolios [Member] Fees and Expenses - AB Fixed Income Taxable Portfolios - AB Core Bond Portfolio

Sep. 30, 2025

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 pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

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)

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 shares at the end of those periods. The Examples also assume that your investment has a 5% return each year, that the Portfolio’s operating expenses stay the same and that any fee waiver and/or expense limitation is in effect only for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs as reflected in the Examples would be:

Portfolio Turnover [Heading]

Portfolio Turnover

Portfolio Turnover [Text Block]

The Portfolio pays transaction costs, such as commissions, when it buys or sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Portfolio shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Portfolio Operating Expenses or in the Examples, affect the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s portfolio turnover rate was 193% of the average value of its portfolio.

Portfolio Turnover, Rate

193.00%