S000093944 [Member] Fees and Expenses - AB California Intermediate Municipal ETF	Mar. 31, 2025
Prospectus [Line Items]
Expense Heading [Optional Text]	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may be required to pay commissions and/or other forms of compensation to a broker for transactions in shares, which are not reflected in the tables or the examples below.
Other Expenses, New Fund, Based on Estimates [Text]	Total “Other Expenses” are based on estimated amounts for the current fiscal year.
Shareholder Fees Caption [Optional Text]	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Optional Text]	Annual Fund 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 Fund with the cost of investing in other funds. The Examples assume that you invest $10,000 in the Fund 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 and that the Fund’s operating expenses stay the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Portfolio Turnover [Heading]	Portfolio Turnover
Portfolio Turnover [Text Block]	The Fund 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 Fund shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund’s performance. During the most recent fiscal year of the Predecessor Fund (as defined below), the Predecessor Fund’s portfolio turnover rate was 39% of the average value of its portfolio.
Portfolio Turnover, Rate	39.00%

S000093944 [Member] Fees and Expenses - AB California Intermediate Municipal ETF

Mar. 31, 2025

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may be required to pay commissions and/or other forms of compensation to a broker for transactions in shares, which are not reflected in the tables or the examples below.

Other Expenses, New Fund, Based on Estimates [Text]

Total “Other Expenses” are based on estimated amounts for the current fiscal year.

Shareholder Fees Caption [Optional Text]

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Optional Text]

Annual Fund 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 Fund with the cost of investing in other funds. The Examples assume that you invest $10,000 in the Fund 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 and that the Fund’s operating expenses stay the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Portfolio Turnover [Heading]

Portfolio Turnover

Portfolio Turnover [Text Block]

The Fund 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 Fund shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund’s performance. During the most recent fiscal year of the Predecessor Fund (as defined below), the Predecessor Fund’s portfolio turnover rate was 39% of the average value of its portfolio.

Portfolio Turnover, Rate

39.00%