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 BlackRock Bond Fund, Inc.
Entity Central Index Key 0000276463
Entity Investment Company Type N-1A
Document Period End Date Mar. 31, 2026
C000011391 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Total Return Fund
Class Name Class R Shares
Trading Symbol MRCBX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Total Return Fund (the “Fund”) for the period of October 1, 2025 to March 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class R Shares $52 1.03%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 52
Expense Ratio, Percent 1.03% [1]
Net Assets $ 17,809,513,268
Holdings Count | Holding 8,506
Investment Company Portfolio Turnover 373.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,809,513,268
Number of Portfolio Holdings 8,506
Portfolio Turnover Rate 373%
Holdings [Text Block]
What did the Fund invest in?
(as of March 31, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 49.0 %
Corporate Bonds 17.3 %
Non-Agency Mortgage-Backed Securities 10.7 %
Asset-Backed Securities 9.1 %
U.S. Treasury Obligations 7.9 %
Foreign Government Obligations 1.6 %
Floating Rate Loan Interests 1.2 %
Investment Companies 1.1 %
Preferred Securities 1.0 %
Common Stocks 0.5 %
Municipal Bonds 0.4 %
Fixed Rate Loan Interests 0.1 %
Foreign Agency Obligations 0.1 %
Warrants — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 63.3 %
AA/Aa 1.8 %
A 5.1 %
BBB/Baa 9.0 %
BB/Ba 1.9 %
B 0.5 %
CCC/Caa 0.6 %
CC/Ca 0.1 %
N/R 17.7 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000052631 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Total Return Fund
Class Name Class K Shares
Trading Symbol MPHQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Total Return Fund (the “Fund”) for the period of October 1, 2025 to March 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Class K Shares $18 0.36%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 18
Expense Ratio, Percent 0.36% [2]
Net Assets $ 17,809,513,268
Holdings Count | Holding 8,506
Investment Company Portfolio Turnover 373.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,809,513,268
Number of Portfolio Holdings 8,506
Portfolio Turnover Rate 373%
Holdings [Text Block]
What did the Fund invest in?
(as of March 31, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 49.0 %
Corporate Bonds 17.3 %
Non-Agency Mortgage-Backed Securities 10.7 %
Asset-Backed Securities 9.1 %
U.S. Treasury Obligations 7.9 %
Foreign Government Obligations 1.6 %
Floating Rate Loan Interests 1.2 %
Investment Companies 1.1 %
Preferred Securities 1.0 %
Common Stocks 0.5 %
Municipal Bonds 0.4 %
Fixed Rate Loan Interests 0.1 %
Foreign Agency Obligations 0.1 %
Warrants — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 63.3 %
AA/Aa 1.8 %
A 5.1 %
BBB/Baa 9.0 %
BB/Ba 1.9 %
B 0.5 %
CCC/Caa 0.6 %
CC/Ca 0.1 %
N/R 17.7 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000037620 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Total Return Fund
Class Name Investor C Shares
Trading Symbol MFHQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Total Return Fund (the “Fund”) for the period of October 1, 2025 to March 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor C Shares $72 1.44%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 72
Expense Ratio, Percent 1.44% [3]
Net Assets $ 17,809,513,268
Holdings Count | Holding 8,506
Investment Company Portfolio Turnover 373.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,809,513,268
Number of Portfolio Holdings 8,506
Portfolio Turnover Rate 373%
Holdings [Text Block]
What did the Fund invest in?
(as of March 31, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 49.0 %
Corporate Bonds 17.3 %
Non-Agency Mortgage-Backed Securities 10.7 %
Asset-Backed Securities 9.1 %
U.S. Treasury Obligations 7.9 %
Foreign Government Obligations 1.6 %
Floating Rate Loan Interests 1.2 %
Investment Companies 1.1 %
Preferred Securities 1.0 %
Common Stocks 0.5 %
Municipal Bonds 0.4 %
Fixed Rate Loan Interests 0.1 %
Foreign Agency Obligations 0.1 %
Warrants — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 63.3 %
AA/Aa 1.8 %
A 5.1 %
BBB/Baa 9.0 %
BB/Ba 1.9 %
B 0.5 %
CCC/Caa 0.6 %
CC/Ca 0.1 %
N/R 17.7 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000037618 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Total Return Fund
Class Name Investor A1 Shares
Trading Symbol MEHQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Total Return Fund (the “Fund”) for the period of October 1, 2025 to March 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A1 Shares $30 0.59%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 30
Expense Ratio, Percent 0.59% [4]
Net Assets $ 17,809,513,268
Holdings Count | Holding 8,506
Investment Company Portfolio Turnover 373.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,809,513,268
Number of Portfolio Holdings 8,506
Portfolio Turnover Rate 373%
Holdings [Text Block]
What did the Fund invest in?
(as of March 31, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 49.0 %
Corporate Bonds 17.3 %
Non-Agency Mortgage-Backed Securities 10.7 %
Asset-Backed Securities 9.1 %
U.S. Treasury Obligations 7.9 %
Foreign Government Obligations 1.6 %
Floating Rate Loan Interests 1.2 %
Investment Companies 1.1 %
Preferred Securities 1.0 %
Common Stocks 0.5 %
Municipal Bonds 0.4 %
Fixed Rate Loan Interests 0.1 %
Foreign Agency Obligations 0.1 %
Warrants — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 63.3 %
AA/Aa 1.8 %
A 5.1 %
BBB/Baa 9.0 %
BB/Ba 1.9 %
B 0.5 %
CCC/Caa 0.6 %
CC/Ca 0.1 %
N/R 17.7 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000011387 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Total Return Fund
Class Name Investor A Shares
Trading Symbol MDHQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Total Return Fund (the “Fund”) for the period of October 1, 2025 to March 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Investor A Shares $39 0.77%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.77% [5]
Net Assets $ 17,809,513,268
Holdings Count | Holding 8,506
Investment Company Portfolio Turnover 373.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,809,513,268
Number of Portfolio Holdings 8,506
Portfolio Turnover Rate 373%
Holdings [Text Block]
What did the Fund invest in?
(as of March 31, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 49.0 %
Corporate Bonds 17.3 %
Non-Agency Mortgage-Backed Securities 10.7 %
Asset-Backed Securities 9.1 %
U.S. Treasury Obligations 7.9 %
Foreign Government Obligations 1.6 %
Floating Rate Loan Interests 1.2 %
Investment Companies 1.1 %
Preferred Securities 1.0 %
Common Stocks 0.5 %
Municipal Bonds 0.4 %
Fixed Rate Loan Interests 0.1 %
Foreign Agency Obligations 0.1 %
Warrants — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 63.3 %
AA/Aa 1.8 %
A 5.1 %
BBB/Baa 9.0 %
BB/Ba 1.9 %
B 0.5 %
CCC/Caa 0.6 %
CC/Ca 0.1 %
N/R 17.7 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000052630 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Total Return Fund
Class Name Service Shares
Trading Symbol MSHQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Total Return Fund (the “Fund”) for the period of October 1, 2025 to March 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Service Shares $38 0.75%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.75% [6]
Net Assets $ 17,809,513,268
Holdings Count | Holding 8,506
Investment Company Portfolio Turnover 373.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,809,513,268
Number of Portfolio Holdings 8,506
Portfolio Turnover Rate 373%
Holdings [Text Block]
What did the Fund invest in?
(as of March 31, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 49.0 %
Corporate Bonds 17.3 %
Non-Agency Mortgage-Backed Securities 10.7 %
Asset-Backed Securities 9.1 %
U.S. Treasury Obligations 7.9 %
Foreign Government Obligations 1.6 %
Floating Rate Loan Interests 1.2 %
Investment Companies 1.1 %
Preferred Securities 1.0 %
Common Stocks 0.5 %
Municipal Bonds 0.4 %
Fixed Rate Loan Interests 0.1 %
Foreign Agency Obligations 0.1 %
Warrants — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 63.3 %
AA/Aa 1.8 %
A 5.1 %
BBB/Baa 9.0 %
BB/Ba 1.9 %
B 0.5 %
CCC/Caa 0.6 %
CC/Ca 0.1 %
N/R 17.7 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
C000011390 [Member]  
Shareholder Report [Line Items]  
Fund Name BlackRock Total Return Fund
Class Name Institutional Shares
Trading Symbol MAHQX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about BlackRock Total Return Fund (the “Fund”) for the period of October 1, 2025 to March 31, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441‑7762.
Additional Information Phone Number (800) 441‑7762
Additional Information Website blackrock.com/fundreports
Expenses [Text Block]
What were the Fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Class name Costs of a $10,000
investment		 Costs paid as a percentage of a
$10,000 investment
Institutional Shares $22 0.44%(a)
​(a)
Annualized.
Expenses Paid, Amount $ 22
Expense Ratio, Percent 0.44% [7]
Net Assets $ 17,809,513,268
Holdings Count | Holding 8,506
Investment Company Portfolio Turnover 373.00%
Additional Fund Statistics [Text Block]
Key Fund statistics
Net Assets $17,809,513,268
Number of Portfolio Holdings 8,506
Portfolio Turnover Rate 373%
Holdings [Text Block]
What did the Fund invest in?
(as of March 31, 2026)
Portfolio composition
Investment Type Percent of Total
Investments(a)
U.S. Government Sponsored Agency Securities 49.0 %
Corporate Bonds 17.3 %
Non-Agency Mortgage-Backed Securities 10.7 %
Asset-Backed Securities 9.1 %
U.S. Treasury Obligations 7.9 %
Foreign Government Obligations 1.6 %
Floating Rate Loan Interests 1.2 %
Investment Companies 1.1 %
Preferred Securities 1.0 %
Common Stocks 0.5 %
Municipal Bonds 0.4 %
Fixed Rate Loan Interests 0.1 %
Foreign Agency Obligations 0.1 %
Warrants — %(b)
Credit quality allocation
Credit Rating(c) Percent of Total
Investments(a)
AAA/Aaa(d) 63.3 %
AA/Aa 1.8 %
A 5.1 %
BBB/Baa 9.0 %
BB/Ba 1.9 %
B 0.5 %
CCC/Caa 0.6 %
CC/Ca 0.1 %
N/R 17.7 %
​(a)
Excludes short-term securities, short investments and options, if any.
​(b)
Rounds to less than 0.1%.
​(c)
For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
​(d)
The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Quality Explanation [Text Block] The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and/or U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Credit Ratings Selection [Text Block] For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
[1] Annualized.
[2]
Annualized.
[3] Annualized.
[4]
Annualized.
[5] Annualized.
[6] Annualized.
[7]
Annualized.