v3.26.1
Shareholder Report
6 Months Ended
Mar. 31, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name BERNSTEIN SANFORD C FUND INC
Entity Central Index Key 0000832808
Entity Investment Company Type N-1A
Document Period End Date Mar. 31, 2026
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
C000213294  
Shareholder Report [Line Items]  
Fund Name AB Core Bond Portfolio
Class Name Class Z
Trading Symbol IDPZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the AB Core Bond Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Material Fund Change Notice [Text Block] This report describes changes to the Portfolio that occurred during the reporting period.
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/IDPZX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class Z
$14
0.27%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 14
Expense Ratio, Percent 0.27% [1]
AssetsNet $ 4,467,945,686
Holdings Count | Holding 712
Advisory Fees Paid, Amount $ 4,278,917
InvestmentCompanyPortfolioTurnover 110.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$4,467,945,686
# of Portfolio Holdings
712
Portfolio Turnover Rate
110%
Total Advisory Fees Paid (Net)
$4,278,917
Holdings [Text Block]

Portfolio Breakdown (% of Net Assets)

Table Summary
Governments - Treasuries
29.1%
Corporates - Investment Grade
26.6%
Mortgage Pass-Throughs
19.6%
Collateralized Mortgage Obligations
6.0%
Asset-Backed Securities
4.9%
Commercial Mortgage-Backed Securities
1.3%
Corporates - Non-Investment Grade
0.9%
Agencies
0.8%
Others
2.2%
Short-Term Investments
18.1%
Other assets less liabilities
-9.5%
Total
100.0%
Material Fund Change [Text Block]

Material Portfolio Changes 

This is a summary of certain changes to the Portfolio during the reporting period.

At meetings held on May 6-8, 2025, the Board of Directors of the Portfolio approved the following:

(i) a contractual waiver of a portion of the advisory fee paid by the Portfolio; (ii) contractual limits on Portfolio operating expenses; (iii) a name change from Intermediate Duration Portfolio to AB Core Bond Portfolio;and (iv) the adoption of non-fundamental investment policy to invest, under normal circumstances, at least 80% of its net assets, including any borrowings for investment purposes, in fixed-income securities. For more information on these policies, please see the Portfolio's statutory prospectus dated January 31, 2026.

Material Fund Change Name [Text Block] (iii) a name change from Intermediate Duration Portfolio to AB Core Bond Portfolio;
Material Fund Change Expenses [Text Block] (i) a contractual waiver of a portion of the advisory fee paid by the Portfolio; (ii) contractual limits on Portfolio operating expenses;
Material Fund Change Strategies [Text Block] and (iv) the adoption of non-fundamental investment policy to invest, under normal circumstances, at least 80% of its net assets, including any borrowings for investment purposes, in fixed-income securities. For more information on these policies, please see the Portfolio's statutory prospectus dated January 31, 2026.
Summary of Change Legend [Text Block]

This is a summary of certain changes to the Portfolio during the reporting period.

At meetings held on May 6-8, 2025, the Board of Directors of the Portfolio approved the following:

C000030494  
Shareholder Report [Line Items]  
Fund Name AB Core Bond Portfolio
Class Name Core Bond Class
Trading Symbol SNIDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the AB Core Bond Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Material Fund Change Notice [Text Block] This report describes changes to the Portfolio that occurred during the reporting period.
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SNIDX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Core Bond Class
$16
0.31%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.31% [2]
AssetsNet $ 4,467,945,686
Holdings Count | Holding 712
Advisory Fees Paid, Amount $ 4,278,917
InvestmentCompanyPortfolioTurnover 110.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$4,467,945,686
# of Portfolio Holdings
712
Portfolio Turnover Rate
110%
Total Advisory Fees Paid (Net)
$4,278,917
Holdings [Text Block]

Portfolio Breakdown (% of Net Assets)

Table Summary
Governments - Treasuries
29.1%
Corporates - Investment Grade
26.6%
Mortgage Pass-Throughs
19.6%
Collateralized Mortgage Obligations
6.0%
Asset-Backed Securities
4.9%
Commercial Mortgage-Backed Securities
1.3%
Corporates - Non-Investment Grade
0.9%
Agencies
0.8%
Others
2.2%
Short-Term Investments
18.1%
Other assets less liabilities
-9.5%
Total
100.0%
Material Fund Change [Text Block]

Material Portfolio Changes 

This is a summary of certain changes to the Portfolio during the reporting period.

At meetings held on May 6-8, 2025, the Board of Directors of the Portfolio approved the following:

(i) a contractual waiver of a portion of the advisory fee paid by the Portfolio; (ii) contractual limits on Portfolio operating expenses; (iii) a name change from Intermediate Duration Portfolio to AB Core Bond Portfolio;and (iv) the adoption of non-fundamental investment policy to invest, under normal circumstances, at least 80% of its net assets, including any borrowings for investment purposes, in fixed-income securities. For more information on these policies, please see the Portfolio's statutory prospectus dated January 31, 2026.

Material Fund Change Name [Text Block] (iii) a name change from Intermediate Duration Portfolio to AB Core Bond Portfolio;
Material Fund Change Expenses [Text Block] (i) a contractual waiver of a portion of the advisory fee paid by the Portfolio; (ii) contractual limits on Portfolio operating expenses;
Material Fund Change Strategies [Text Block] and (iv) the adoption of non-fundamental investment policy to invest, under normal circumstances, at least 80% of its net assets, including any borrowings for investment purposes, in fixed-income securities. For more information on these policies, please see the Portfolio's statutory prospectus dated January 31, 2026.
Summary of Change Legend [Text Block]

This is a summary of certain changes to the Portfolio during the reporting period.

At meetings held on May 6-8, 2025, the Board of Directors of the Portfolio approved the following:

C000157746  
Shareholder Report [Line Items]  
Fund Name Diversified Municipal Portfolio
Class Name Advisor Class
Trading Symbol AIDYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Diversified Municipal Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/AIDYX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Advisor Class
$21
0.41%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 21
Expense Ratio, Percent 0.41% [3]
AssetsNet $ 5,291,469,789
Holdings Count | Holding 1,113
Advisory Fees Paid, Amount $ 9,514,965
InvestmentCompanyPortfolioTurnover 14.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$5,291,469,789
# of Portfolio Holdings
1,113
Portfolio Turnover Rate
14%
Total Advisory Fees Paid (Net)
$9,514,965
Holdings [Text Block]

State Breakdown (% of Net Assets)

Table Summary
California
10.3%
New York
10.1%
Texas
6.7%
Florida
5.9%
New Jersey
5.0%
Pennsylvania
4.7%
Illinois
4.0%
Alabama
3.8%
South Carolina
3.7%
Colorado
3.6%
Georgia
3.4%
Washington
2.7%
Wisconsin
2.6%
Other
32.7%
Other assets less liabilities
0.8%
Total
100.0%

Credit Rating BreakdownFootnote Reference* 

Table Summary
AAA
8.5%
AA
43.2%
A
25.2%
BBB
9.5%
BB
2.8%
B
0.2%
A-1+
6.6%
Not Rated
4.0%
Total
100.0%
Footnote Description
Footnote*
The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
Credit Ratings Selection [Text Block] The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
C000030490  
Shareholder Report [Line Items]  
Fund Name Diversified Municipal Portfolio
Class Name Class A
Trading Symbol AIDAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Diversified Municipal Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/AIDAX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class A
$33
0.66%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 33
Expense Ratio, Percent 0.66% [4]
AssetsNet $ 5,291,469,789
Holdings Count | Holding 1,113
Advisory Fees Paid, Amount $ 9,514,965
InvestmentCompanyPortfolioTurnover 14.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$5,291,469,789
# of Portfolio Holdings
1,113
Portfolio Turnover Rate
14%
Total Advisory Fees Paid (Net)
$9,514,965
Holdings [Text Block]

State Breakdown (% of Net Assets)

Table Summary
California
10.3%
New York
10.1%
Texas
6.7%
Florida
5.9%
New Jersey
5.0%
Pennsylvania
4.7%
Illinois
4.0%
Alabama
3.8%
South Carolina
3.7%
Colorado
3.6%
Georgia
3.4%
Washington
2.7%
Wisconsin
2.6%
Other
32.7%
Other assets less liabilities
0.8%
Total
100.0%

Credit Rating BreakdownFootnote Reference* 

Table Summary
AAA
8.5%
AA
43.2%
A
25.2%
BBB
9.5%
BB
2.8%
B
0.2%
A-1+
6.6%
Not Rated
4.0%
Total
100.0%
Footnote Description
Footnote*
The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
Credit Ratings Selection [Text Block] The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
C000030492  
Shareholder Report [Line Items]  
Fund Name Diversified Municipal Portfolio
Class Name Class C
Trading Symbol AIMCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Diversified Municipal Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/AIMCX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class C
$71
1.41%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 71
Expense Ratio, Percent 1.41% [5]
AssetsNet $ 5,291,469,789
Holdings Count | Holding 1,113
Advisory Fees Paid, Amount $ 9,514,965
InvestmentCompanyPortfolioTurnover 14.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$5,291,469,789
# of Portfolio Holdings
1,113
Portfolio Turnover Rate
14%
Total Advisory Fees Paid (Net)
$9,514,965
Holdings [Text Block]

State Breakdown (% of Net Assets)

Table Summary
California
10.3%
New York
10.1%
Texas
6.7%
Florida
5.9%
New Jersey
5.0%
Pennsylvania
4.7%
Illinois
4.0%
Alabama
3.8%
South Carolina
3.7%
Colorado
3.6%
Georgia
3.4%
Washington
2.7%
Wisconsin
2.6%
Other
32.7%
Other assets less liabilities
0.8%
Total
100.0%

Credit Rating BreakdownFootnote Reference* 

Table Summary
AAA
8.5%
AA
43.2%
A
25.2%
BBB
9.5%
BB
2.8%
B
0.2%
A-1+
6.6%
Not Rated
4.0%
Total
100.0%
Footnote Description
Footnote*
The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
Credit Ratings Selection [Text Block] The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
C000202546  
Shareholder Report [Line Items]  
Fund Name Diversified Municipal Portfolio
Class Name Class Z
Trading Symbol AIDZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Diversified Municipal Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/AIDZX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class Z
$20
0.39%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 20
Expense Ratio, Percent 0.39% [6]
AssetsNet $ 5,291,469,789
Holdings Count | Holding 1,113
Advisory Fees Paid, Amount $ 9,514,965
InvestmentCompanyPortfolioTurnover 14.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$5,291,469,789
# of Portfolio Holdings
1,113
Portfolio Turnover Rate
14%
Total Advisory Fees Paid (Net)
$9,514,965
Holdings [Text Block]

State Breakdown (% of Net Assets)

Table Summary
California
10.3%
New York
10.1%
Texas
6.7%
Florida
5.9%
New Jersey
5.0%
Pennsylvania
4.7%
Illinois
4.0%
Alabama
3.8%
South Carolina
3.7%
Colorado
3.6%
Georgia
3.4%
Washington
2.7%
Wisconsin
2.6%
Other
32.7%
Other assets less liabilities
0.8%
Total
100.0%

Credit Rating BreakdownFootnote Reference* 

Table Summary
AAA
8.5%
AA
43.2%
A
25.2%
BBB
9.5%
BB
2.8%
B
0.2%
A-1+
6.6%
Not Rated
4.0%
Total
100.0%
Footnote Description
Footnote*
The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
Credit Ratings Selection [Text Block] The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
C000084883  
Shareholder Report [Line Items]  
Fund Name Diversified Municipal Portfolio
Class Name Municipal Class
Trading Symbol SNDPX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Diversified Municipal Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SNDPX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Municipal Class
$24
0.48%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.48% [7]
AssetsNet $ 5,291,469,789
Holdings Count | Holding 1,113
Advisory Fees Paid, Amount $ 9,514,965
InvestmentCompanyPortfolioTurnover 14.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$5,291,469,789
# of Portfolio Holdings
1,113
Portfolio Turnover Rate
14%
Total Advisory Fees Paid (Net)
$9,514,965
Holdings [Text Block]

State Breakdown (% of Net Assets)

Table Summary
California
10.3%
New York
10.1%
Texas
6.7%
Florida
5.9%
New Jersey
5.0%
Pennsylvania
4.7%
Illinois
4.0%
Alabama
3.8%
South Carolina
3.7%
Colorado
3.6%
Georgia
3.4%
Washington
2.7%
Wisconsin
2.6%
Other
32.7%
Other assets less liabilities
0.8%
Total
100.0%

Credit Rating BreakdownFootnote Reference* 

Table Summary
AAA
8.5%
AA
43.2%
A
25.2%
BBB
9.5%
BB
2.8%
B
0.2%
A-1+
6.6%
Not Rated
4.0%
Total
100.0%
Footnote Description
Footnote*
The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
Credit Ratings Selection [Text Block] The Portfolio’s quality rating breakdown is expressed as a percentage of the Portfolio’s total investments in municipal securities and may vary over time. The quality ratings are determined by using the S&P Global Ratings (“S&P”), Moody’s Investors Services, Inc. (“Moody’s”) and Fitch Ratings, Ltd. (“Fitch”). The Portfolio considers the credit ratings issued by S&P, Moody’s and Fitch and uses the highest rating issued by the agencies. These ratings are a measure of the quality and safety of a bond or portfolio, based on the issuer’s financial condition. AAA is the highest (best) and D is the lowest (worst). If applicable, the pre-refunded category includes bonds which are secured by U.S. Government securities and therefore are deemed high-quality investment grade by AllianceBernstein L.P. (the "Adviser"). If applicable, Not Applicable (N/A) includes non-credit worthy investments, such as equities, currency contracts, futures and options. If applicable, the Not Rated category includes bonds that are not rated by a nationally recognized statistical rating organization. The Adviser evaluates the creditworthiness of non-rated securities based on a number of factors including, but not limited to, cash flows, enterprise value and economic environment.
C000083494  
Shareholder Report [Line Items]  
Fund Name Overlay A Portfolio
Class Name Class 1
Trading Symbol SAOOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Overlay A Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SAOOX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 1
$36
0.72%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 36
Expense Ratio, Percent 0.72% [8]
AssetsNet $ 396,939,143
Holdings Count | Holding 705
Advisory Fees Paid, Amount $ 698,224
InvestmentCompanyPortfolioTurnover 32.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$396,939,143
# of Portfolio Holdings
705
Portfolio Turnover Rate
32%
Total Advisory Fees Paid (Net)
$698,224
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
55.4%
Developed International
12.6%
Emerging Markets
7.1%
Real Assets
6.7%
Global Bond
x
US
19.3%
Developed International
0.7%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 1: SAOOX

1

C000083495  
Shareholder Report [Line Items]  
Fund Name Overlay A Portfolio
Class Name Class 2
Trading Symbol SAOTX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Overlay A Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SAOTX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 2
$31
0.62%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 31
Expense Ratio, Percent 0.62% [9]
AssetsNet $ 396,939,143
Holdings Count | Holding 705
Advisory Fees Paid, Amount $ 698,224
InvestmentCompanyPortfolioTurnover 32.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$396,939,143
# of Portfolio Holdings
705
Portfolio Turnover Rate
32%
Total Advisory Fees Paid (Net)
$698,224
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
55.4%
Developed International
12.6%
Emerging Markets
7.1%
Real Assets
6.7%
Global Bond
x
US
19.3%
Developed International
0.7%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 2: SAOTX

1

C000083498  
Shareholder Report [Line Items]  
Fund Name Overlay B Portfolio
Class Name Class 1
Trading Symbol SBOOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Overlay B Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SBOOX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 1
$39
0.78%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.78% [10]
AssetsNet $ 288,696,290
Holdings Count | Holding 1,107
Advisory Fees Paid, Amount $ 678,089
InvestmentCompanyPortfolioTurnover 75.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$288,696,290
# of Portfolio Holdings
1,107
Portfolio Turnover Rate
75%
Total Advisory Fees Paid (Net)
$678,089
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
20.2%
Developed International
4.5%
Emerging Markets
2.6%
Global Credit
x
Investment Grade
9.3%
Real Assets
3.4%
Global Bond
x
US
38.6%
Developed International
10.5%
Linkers
21.1%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 1: SBOOX

1

C000083499  
Shareholder Report [Line Items]  
Fund Name Overlay B Portfolio
Class Name Class 2
Trading Symbol SBOTX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Overlay B Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SBOTX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 2
$34
0.67%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 34
Expense Ratio, Percent 0.67% [11]
AssetsNet $ 288,696,290
Holdings Count | Holding 1,107
Advisory Fees Paid, Amount $ 678,089
InvestmentCompanyPortfolioTurnover 75.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$288,696,290
# of Portfolio Holdings
1,107
Portfolio Turnover Rate
75%
Total Advisory Fees Paid (Net)
$678,089
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
20.2%
Developed International
4.5%
Emerging Markets
2.6%
Global Credit
x
Investment Grade
9.3%
Real Assets
3.4%
Global Bond
x
US
38.6%
Developed International
10.5%
Linkers
21.1%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 2: SBOTX

1

C000083496  
Shareholder Report [Line Items]  
Fund Name Tax-Aware Overlay A Portfolio
Class Name Class 1
Trading Symbol SATOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Tax-Aware Overlay A Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SATOX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 1
$30
0.60%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.60% [12]
AssetsNet $ 780,170,898
Holdings Count | Holding 710
Advisory Fees Paid, Amount $ 1,527,332
InvestmentCompanyPortfolioTurnover 24.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$780,170,898
# of Portfolio Holdings
710
Portfolio Turnover Rate
24%
Total Advisory Fees Paid (Net)
$1,527,332
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
53.3%
Developed International
12.0%
Emerging Markets
6.9%
Real Assets
7.7%
Global Bond
x
US
19.7%
Developed International
-%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 1: SATOX

1

C000083497  
Shareholder Report [Line Items]  
Fund Name Tax-Aware Overlay A Portfolio
Class Name Class 2
Trading Symbol SATTX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Tax-Aware Overlay A Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SATTX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 2
$25
0.50%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.50% [13]
AssetsNet $ 780,170,898
Holdings Count | Holding 710
Advisory Fees Paid, Amount $ 1,527,332
InvestmentCompanyPortfolioTurnover 24.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$780,170,898
# of Portfolio Holdings
710
Portfolio Turnover Rate
24%
Total Advisory Fees Paid (Net)
$1,527,332
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
53.3%
Developed International
12.0%
Emerging Markets
6.9%
Real Assets
7.7%
Global Bond
x
US
19.7%
Developed International
-%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 2: SATTX

1

C000083500  
Shareholder Report [Line Items]  
Fund Name Tax-Aware Overlay B Portfolio
Class Name Class 1
Trading Symbol SBTOX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Tax-Aware Overlay B Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SBTOX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 1
$40
0.79%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 40
Expense Ratio, Percent 0.79% [14]
AssetsNet $ 441,760,009
Holdings Count | Holding 736
Advisory Fees Paid, Amount $ 1,289,607
InvestmentCompanyPortfolioTurnover 11.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$441,760,009
# of Portfolio Holdings
736
Portfolio Turnover Rate
11%
Total Advisory Fees Paid (Net)
$1,289,607
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
21.8%
Developed International
5.0%
Emerging Markets
2.8%
Real Assets
-%
Global Bond
x
US
71.7%
Developed International
-%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 1: SBTOX

1

C000083501  
Shareholder Report [Line Items]  
Fund Name Tax-Aware Overlay B Portfolio
Class Name Class 2
Trading Symbol SBTTX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Tax-Aware Overlay B Portfolio (the “Portfolio”) for the period of October 1, 2025 to March 31, 2026.
Additional Information [Text Block] Portfolio
Additional Information Phone Number (800) 227 4618
Additional Information Website https://www.abfunds.com/link/BWM/SBTTX-S
Expenses [Text Block]

What were the Portfolio costs for the last six months?

(Based on a hypothetical $10,000 investment)

Table Summary
Class Name
Cost of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Class 2
$35
0.69%Footnote Reference*
Footnote Description
Footnote*
Annualized
Expenses Paid, Amount $ 35
Expense Ratio, Percent 0.69% [15]
AssetsNet $ 441,760,009
Holdings Count | Holding 736
Advisory Fees Paid, Amount $ 1,289,607
InvestmentCompanyPortfolioTurnover 11.00%
Additional Fund Statistics [Text Block]

Key Portfolio Statistics

Table Summary
Net Assets
$441,760,009
# of Portfolio Holdings
736
Portfolio Turnover Rate
11%
Total Advisory Fees Paid (Net)
$1,289,607
Holdings [Text Block]

Portfolio BreakdownFootnote Reference1 

Table Summary
Global Equity
x
US
21.8%
Developed International
5.0%
Emerging Markets
2.8%
Real Assets
-%
Global Bond
x
US
71.7%
Developed International
-%
Footnote Description
Footnote1
The Portfolio's portfolio breakdown includes derivative exposure and is expressed as approximate percentages of the Portfolio's total net assets, based on the Adviser's internal classification. The percentages will vary over time, and the total of the percentages may be less than or greater than 100% in light of the leveraging effect of the derivative transactions.

Class 2: SBTTX

1

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