XML 34 R2.htm IDEA: XBRL DOCUMENT v3.24.3
Shareholder Report
 12 Months Ended
Aug. 31, 2024
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSR
Amendment Flag false
Registrant Name NUVEEN INVESTMENT FUNDS INC
Entity Central Index Key 0000820892
Entity Investment Company Type N-1A
Document Period End Date Aug. 31, 2024
C000015185 [Member]  
Shareholder Report [Line Items]  
Fund Name Nuveen Strategic Income Fund
Class Name Class A Shares
Trading Symbol FCDDX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about the Class A Shares of the Nuveen Strategic Income Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information at https://www.nuveen.com/en‑us/mutual‑funds/prospectuses. You can also request this information by contacting us at (800) 257-8787.
Material Fund Change Notice [Text Block]
This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number (800) 257-8787
Additional Information Website https://www.nuveen.com/en‑us/mutual‑funds/prospectuses
Expenses [Text Block]
What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
   
   
Cost of a 
$10,000 investment 
   Costs paid as a percentage of
$10,000 investment*
     
Class A Shares
   $87    0.82%
* Annualized for period less than one year.
Expenses Paid, Amount $ 87
Expense Ratio, Percent 0.82% [1]
Factors Affecting Performance [Text Block]
How did the Fund perform last year? What affected the Fund’s performance?
 
Performance Highlights
 
•  The Nuveen Strategic Income Fund returned 11.04% for Class A Shares at net asset value (NAV) for the 12 months ended August 31, 2024. The Fund outperformed the Bloomberg US Aggregate Bond Index, which returned 7.3%.
 
•  Top contributors to relative performance
 
»   Out-of-benchmark allocation to mortgage credit, particularly agency credit risk transfers.
 
»   Out-of-benchmark exposure to preferred securities.
 
»   Out-of-benchmark exposure to below-investment-grade securities.
 
•  Top detractors from relative performance
 
»   Shorter-duration positioning.
  
Performance Attribution
 
LOGO  Mortgage credit
 
LOGO  Preferred securities
 
LOGO  Below-investment-grade exposure
 
LOGO  Shorter-duration positioning
Performance Past Does Not Indicate Future [Text] Performance data shown represents past performance and does not predict or guarantee future results.
Line Graph [Table Text Block]
LOGO
Average Annual Return [Table Text Block]
Average Annual Total Returns
     
     1‑Year      5‑Year      10‑Year  
       
Class A Shares at NAV (excluding maximum sales charge)
      11.04 %       2.63 %       2.85 % 
       
Class A Shares at maximum sales charge (Offering Price)
      6.36 %       1.74 %       2.41 % 
       
Bloomberg U.S. Aggregate Bond Index
      7.30 %       (0.04 )%       1.64 % 
       
Lipper Multi-Sector Income Funds Classification Average
      9.66 %       1.94 %       2.80 % 
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund Shares.
Updated Performance Information Location [Text Block] For most recent month-end performance, go to https://www.nuveen.com/en-us/mutual-funds/prospectuses or call (800) 257-8787.
Net Assets $ 916,646,285
Holdings Count | Holding 607
Advisory Fees Paid, Amount $ 3,993,167
Investment Company Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Fund Statistics (as of August 31, 2024)
Fund net assets
    $ 916,646,285  
Total number of portfolio holdings
      607  
Portfolio turnover (%)
      60%  
Total management fees paid for the year
    $ 3,993,167  
Holdings [Text Block]
LOGO
LOGO
(1) The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Credit Ratings Selection [Text Block] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Material Fund Change [Text Block]
How has the Fund changed?
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion.
  
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Material Fund Change Expenses [Text Block]
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion.
  
Summary of Change Legend [Text Block]
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Updated Prospectus Phone Number (800) 257- 8787
Updated Prospectus Web Address https://www.nuveen.com/en-us/mutual-funds/prospectuses
Accountant Change Disagreements [Text Block]
Changes in independent registered public accounting firm
On October 24, 2024, the Fund’s Board of Directors engaged PricewaterhouseCoopers LLP (“PwC”) as the independent registered public accounting firm for the Fund and dismissed KPMG LLP (“KPMG”) as the independent registered public accounting firm for the Fund subject to the completion of the August 31, 2024 fiscal year end audit. During the Fund’s fiscal years ended August 31, 2024 and August 31, 2023, and the subsequent interim period through October 29, 2024, there have been no disagreements with KPMG on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures.
C000015187 [Member]  
Shareholder Report [Line Items]  
Fund Name Nuveen Strategic Income Fund
Class Name Class C Shares
Trading Symbol FCBCX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about the Class C Shares of the Nuveen Strategic Income Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information at https://www.nuveen.com/en‑us/mutual‑funds/prospectuses. You can also request this information by contacting us at (800) 257-8787.
Material Fund Change Notice [Text Block]
This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number (800) 257-8787
Additional Information Website https://www.nuveen.com/en‑us/mutual‑funds/prospectuses
Expenses [Text Block]
What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
   
   
Cost of a 
$10,000 investment 
   Costs paid as a percentage of
$10,000 investment*
     
Class C Shares
   $165   1.57%
* Annualized for period less than one year.
Expenses Paid, Amount $ 165
Expense Ratio, Percent 1.57% [2]
Factors Affecting Performance [Text Block]
How did the Fund perform last year? What affected the Fund’s performance?
 
Performance Highlights
 
•  The Nuveen Strategic Income Fund returned 10.11% for Class C Shares at net asset value (NAV) for the 12 months ended August 31, 2024. The Fund outperformed the Bloomberg US Aggregate Bond Index, which returned 7.3%.
 
•  Top contributors to relative performance
 
»   Out-of-benchmark allocation to mortgage credit, particularly agency credit risk transfers.
 
»   Out-of-benchmark exposure to preferred securities.
 
»   Out-of-benchmark exposure to below-investment-grade securities.
 
•  Top detractors from relative performance
 
»   Shorter-duration positioning.
 
  
Performance Attribution
 
LOGO  Mortgage credit
 
LOGO  Preferred securities
 
LOGO  Below-investment-grade exposure
 
LOGO  Shorter-duration positioning
Performance Past Does Not Indicate Future [Text] Performance data shown represents past performance and does not predict or guarantee future results.
Line Graph [Table Text Block]
LOGO
Average Annual Return [Table Text Block]
Average Annual Total Returns
     
     1‑Year      5‑Year      10‑Year  
       
Class C Shares at NAV (excluding maximum sales charge)
      10.11 %       1.87 %       2.25 % 
       
Bloomberg U.S. Aggregate Bond Index
      7.30 %       (0.04 )%       1.64 % 
       
Lipper Multi-Sector Income Funds Classification Average
      9.66 %       1.94 %       2.80 % 
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund Shares.
Updated Performance Information Location [Text Block] For most recent month-end performance, go to https://www.nuveen.com/en-us/mutual-funds/prospectuses or call (800) 257-8787.
Net Assets $ 916,646,285
Holdings Count | Holding 607
Advisory Fees Paid, Amount $ 3,993,167
Investment Company Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Fund Statistics (as of August 31, 2024)
Fund net assets
    $ 916,646,285  
Total number of portfolio holdings
      607  
Portfolio turnover (%)
      60%  
Total management fees paid for the year
    $ 3,993,167  
Holdings [Text Block]
LOGO
LOGO
(1) The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Credit Ratings Selection [Text Block] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Material Fund Change [Text Block]
How has the Fund changed?
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion.
  
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Material Fund Change Expenses [Text Block]
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion.
  
Summary of Change Legend [Text Block]
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Updated Prospectus Phone Number (800) 257- 8787
Updated Prospectus Web Address https://www.nuveen.com/en-us/mutual-funds/prospectuses
Accountant Change Disagreements [Text Block]
Changes in independent registered public accounting firm
On October 24, 2024, the Fund’s Board of Directors engaged PricewaterhouseCoopers LLP (“PwC”) as the independent registered public accounting firm for the Fund and dismissed KPMG LLP (“KPMG”) as the independent registered public accounting firm for the Fund subject to the completion of the August 31, 2024 fiscal year end audit. During the Fund’s fiscal years ended August 31, 2024 and August 31, 2023, and the subsequent interim period through October 29, 2024, there have been no disagreements with KPMG on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures.
C000151934 [Member]  
Shareholder Report [Line Items]  
Fund Name Nuveen Strategic Income Fund
Class Name Class R6 Shares
Trading Symbol FSFRX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about the Class R6 Shares of the Nuveen Strategic Income Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information at https://www.nuveen.com/en-us/mutual-funds/prospectuses. You can also request this information by contacting us at (800) 257-8787.
Material Fund Change Notice [Text Block]
This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number (800) 257-8787
Additional Information Website https://www.nuveen.com/en-us/mutual-funds/prospectuses
Expenses [Text Block]
What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
   
   
Cost of a 
$10,000 investment 
   Costs paid as a percentage of
$10,000 investment*
     
Class R6 Shares
   $51   0.48%
* Annualized for period less than one year.
Expenses Paid, Amount $ 51
Expense Ratio, Percent 0.48% [3]
Factors Affecting Performance [Text Block]
How did the Fund perform last year? What affected the Fund’s performance?
 
Performance Highlights
 
•  The Nuveen Strategic Income Fund returned 11.28% for Class R6 Shares at net asset value (NAV) for the 12 months ended August 31, 2024. The Fund outperformed the Bloomberg US Aggregate Bond Index, which returned 7.3%.
 
•  Top contributors to relative performance
 
»   Out-of-benchmark allocation to mortgage credit, particularly agency credit risk transfers.
 
»   Out-of-benchmark exposure to preferred securities.
 
»   Out-of-benchmark exposure to below-investment-grade securities.
 
•  Top detractors from relative performance
 
»   Shorter-duration positioning.
  
Performance Attribution
 
LOGO  Mortgage credit
 
LOGO  Preferred securities
 
LOGO  Below-investment-grade exposure
 
LOGO  Shorter-duration positioning
Performance Past Does Not Indicate Future [Text] Performance data shown represents past performance and does not predict or guarantee future results.
Line Graph [Table Text Block]
LOGO
Average Annual Return [Table Text Block]
Average Annual Total Returns
     
     1‑Year      5‑Year      Since Inception
(1/20/15)		  
       
Class R6 Shares at NAV
      11.28 %       2.96 %       3.45 % 
       
Bloomberg U.S. Aggregate Bond Index
      7.30 %       (0.04 )%       1.44 % 
       
Lipper Multi-Sector Income Funds Classification Average
      9.66 %       1.94 %       3.03 % 
Performance Inception Date Jan. 20, 2015
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund Shares.
Updated Performance Information Location [Text Block] For most recent month-end performance, go to https://www.nuveen.com/en-us/mutual-funds/prospectuses or call (800) 257-8787.
Net Assets $ 916,646,285
Holdings Count | Holding 607
Advisory Fees Paid, Amount $ 3,993,167
Investment Company Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Fund Statistics (as of August 31, 2024)
Fund net assets
    $ 916,646,285  
Total number of portfolio holdings
      607  
Portfolio turnover (%)
      60%  
Total management fees paid for the year
    $ 3,993,167  
Holdings [Text Block]
LOGO
LOGO
(1) The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Credit Ratings Selection [Text Block] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Material Fund Change [Text Block]
How has the Fund changed?
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Material Fund Change Expenses [Text Block]
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
Summary of Change Legend [Text Block]
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Updated Prospectus Phone Number (800) 257- 8787
Updated Prospectus Web Address https://www.nuveen.com/en-us/mutual-funds/prospectuses
Accountant Change Disagreements [Text Block]
Changes in independent registered public accounting firm
On October 24, 2024, the Fund’s Board of Directors engaged PricewaterhouseCoopers LLP (“PwC”) as the independent registered public accounting firm for the Fund and dismissed KPMG LLP (“KPMG”) as the independent registered public accounting firm for the Fund subject to the completion of the August 31, 2024 fiscal year end audit. During the Fund’s fiscal years ended August 31, 2024 and August 31, 2023, and the subsequent interim period through October 29, 2024, there have been no disagreements with KPMG on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures.
C000015189 [Member]  
Shareholder Report [Line Items]  
Fund Name Nuveen Strategic Income Fund
Class Name Class I Shares
Trading Symbol FCBYX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about the Class I Shares of the Nuveen Strategic Income Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information at https://www.nuveen.com/en‑us/mutual‑funds/prospectuses. You can also request this information by contacting us at (800) 257-8787.
Material Fund Change Notice [Text Block]
This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number (800) 257-8787
Additional Information Website https://www.nuveen.com/en‑us/mutual‑funds/prospectuses
Expenses [Text Block]
What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
   
   
Cost of a 
$10,000 investment 
   Costs paid as a percentage of
$10,000 investment*
     
Class I Shares
   $60    0.57%
* Annualized for period less than one year.
Expenses Paid, Amount $ 60
Expense Ratio, Percent 0.57% [4]
Factors Affecting Performance [Text Block]
How did the Fund perform last year? What affected the Fund’s performance?
 
Performance Highlights
 
•  The Nuveen Strategic Income Fund returned 11.32% for Class I Shares at net asset value (NAV) for the 12 months ended August 31, 2024. The Fund significantly outperformed the Bloomberg US Aggregate Bond Index, which returned 7.3%.
 
•  Top contributors to relative performance
 
»   Out-of-benchmark allocation to mortgage credit, particularly agency credit risk transfers.
 
»   Out-of-benchmark exposure to preferred securities.
 
»   Out-of-benchmark exposure to below-investment-grade securities.
 
•  Top detractors from relative performance
 
»   Shorter-duration positioning.
  
Performance Attribution
 
LOGO  Mortgage credit
 
LOGO  Preferred securities
 
LOGO  Below-investment-grade exposure
 
LOGO  Shorter-duration positioning
Performance Past Does Not Indicate Future [Text] Performance data shown represents past performance and does not predict or guarantee future results.
Line Graph [Table Text Block]
LOGO
Average Annual Return [Table Text Block]
Average Annual Total Returns
     
     1‑Year      5‑Year      10‑Year  
       
Class I Shares at NAV
      11.32 %       2.88 %       3.11 % 
       
Bloomberg U.S. Aggregate Bond Index
      7.30 %       (0.04 )%       1.64 % 
       
Lipper Multi-Sector Income Funds Classification Average
      9.66 %       1.94 %       2.80 % 
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund Shares.
Updated Performance Information Location [Text Block] For most recent month-end performance, go to https://www.nuveen.com/en-us/mutual-funds/prospectuses or call (800) 257-8787.
Net Assets $ 916,646,285
Holdings Count | Holding 607
Advisory Fees Paid, Amount $ 3,993,167
Investment Company Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Fund Statistics (as of August 31, 2024)
Fund net assets
    $ 916,646,285  
Total number of portfolio holdings
      607  
Portfolio turnover (%)
      60%  
Total management fees paid for the year
    $ 3,993,167  
Holdings [Text Block]
LOGO
LOGO
(1) The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Credit Ratings Selection [Text Block] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Material Fund Change [Text Block]
How has the Fund changed?
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Material Fund Change Expenses [Text Block]
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
Summary of Change Legend [Text Block]
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Updated Prospectus Phone Number (800) 257- 8787
Updated Prospectus Web Address https://www.nuveen.com/en-us/mutual-funds/prospectuses
Accountant Change Disagreements [Text Block]
Changes in independent registered public accounting firm
On October 24, 2024, the Fund’s Board of Directors engaged PricewaterhouseCoopers LLP (“PwC”) as the independent registered public accounting firm for the Fund and dismissed KPMG LLP (“KPMG”) as the independent registered public accounting firm for the Fund subject to the completion of the August 31, 2024 fiscal year end audit. During the Fund’s fiscal years ended August 31, 2024 and August 31, 2023, and the subsequent interim period through October 29, 2024, there have been no disagreements with KPMG on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures.
C000015076 [Member]  
Shareholder Report [Line Items]  
Fund Name Nuveen Credit Income Fund
Class Name Class A Shares
Trading Symbol FJSIX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about the Class A Shares of the Nuveen Credit Income Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information at https://www.nuveen.com/en‑us/mutual‑funds/prospectuses. You can also request this information by contacting us at (800) 257-8787.
Material Fund Change Notice [Text Block]
This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number (800) 257-8787
Additional Information Website https://www.nuveen.com/en‑us/mutual‑funds/prospectuses
Expenses [Text Block]
What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
   
   
Cost of a 
$10,000 investment 
   Costs paid as a percentage of
$10,000 investment*
     
Class A Shares
   $111    1.04%
* Annualized for period less than one year.
Expenses Paid, Amount $ 111
Expense Ratio, Percent 1.04% [5]
Factors Affecting Performance [Text Block]
How did the Fund perform last year? What affected the Fund’s performance?
 
Performance Highlights
 
•  The Nuveen Credit Income Fund returned 14.38% for Class A Shares at net asset value (NAV) for the 12 months ended August 31, 2024. The Fund outperformed the Bloomberg U.S. Corporate High Yield 2% Issuer Capped Bond Index, which returned 12.53%.
 
•  Top contributors to relative performance
 
»   Security selection within the high-yield corporate bond allocation, notably in the communications, consumer non-cyclical, and technology industries.
 
»   Out-of-benchmark allocation to mortgage credit, including agency credit risk transfers.
 
»   Out-of-benchmark allocation to emerging markets debt (EMD), particularly below‑investment‑grade securities.
 
•  Top detractors from relative performance
 
»   Out-of-benchmark allocation to commercial mortgage-backed securities (CMBS), particularly exposure to office properties.
 
»   Shorter-duration positioning.
  
Performance Attribution
 
LOGO  High-yield corporate bonds
 
LOGO  Mortgage credit
 
LOGO  EMD
 
LOGO  CMBS
 
LOGO  Shorter-duration positioning
Performance Past Does Not Indicate Future [Text] Performance data shown represents past performance and does not predict or guarantee future results.
Line Graph [Table Text Block]
LOGO
Average Annual Return [Table Text Block]
Average Annual Total Returns
     
     1‑Year      5‑Year      10‑Year  
       
Class A Shares at NAV (excluding maximum sales charge)
      14.38 %       3.86 %       3.30 % 
       
Class A Shares at maximum sales charge (Offering Price)
      8.90 %       2.86 %       2.80 % 
       
Bloomberg U.S. Aggregate Bond Index
      7.30 %       (0.04 )%       1.64 % 
       
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Bond Index
      12.53 %       4.44 %       4.65 % 
       
Lipper Global High Yield Funds Classification Average
      12.05 %       3.56 %       3.61 % 
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund Shares.
Updated Performance Information Location [Text Block] For most recent month‑end performance, go to https://www.nuveen.com/en‑us/mutual‑funds/prospectuses or call (800) 257‑8787.
Net Assets $ 87,654,718
Holdings Count | Holding 251
Advisory Fees Paid, Amount $ 480,574
Investment Company Portfolio Turnover 133.00%
Additional Fund Statistics [Text Block]
Fund Statistics (as of August 31, 2024)
Fund net assets
    $ 87,654,718  
Total number of portfolio holdings
      251  
Portfolio turnover (%)
      133%  
Total management fees paid for the year
    $ 480,574  
Holdings [Text Block]
LOGO
LOGO
(1) The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Credit Ratings Selection [Text Block] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Material Fund Change [Text Block]
How has the Fund changed?
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Material Fund Change Expenses [Text Block]
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
Summary of Change Legend [Text Block]
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Updated Prospectus Phone Number (800) 257- 8787
Updated Prospectus Web Address https://www.nuveen.com/en-us/mutual-funds/prospectuses
Accountant Change Disagreements [Text Block]
Changes in independent registered public accounting firm
On October 24, 2024, the Fund’s Board of Directors engaged PricewaterhouseCoopers LLP (“PwC”) as the independent registered public accounting firm for the Fund and dismissed KPMG LLP (“KPMG”) as the independent registered public accounting firm for the Fund subject to the completion of the August 31, 2024 fiscal year end audit. During the Fund’s fiscal years ended August 31, 2024 and August 31, 2023, and the subsequent interim period through October 29, 2024, there have been no disagreements with KPMG on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures.
C000015078 [Member]  
Shareholder Report [Line Items]  
Fund Name Nuveen Credit Income Fund
Class Name Class C Shares
Trading Symbol FCSIX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about the Class C Shares of the Nuveen Credit Income Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information at https://www.nuveen.com/en‑us/mutual‑funds/prospectuses. You can also request this information by contacting us at (800) 257-8787.
Material Fund Change Notice [Text Block]
This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number (800) 257-8787
Additional Information Website https://www.nuveen.com/en‑us/mutual‑funds/prospectuses
Expenses [Text Block]
What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
   
   
Cost of a 
$10,000 investment 
   Costs paid as a percentage of
$10,000 investment*
     
Class C Shares
   $191    1.79%
* Annualized for period less than one year.
Expenses Paid, Amount $ 191
Expense Ratio, Percent 1.79% [6]
Factors Affecting Performance [Text Block]
How did the Fund perform last year? What affected the Fund’s performance?
 
Performance Highlights
 
•  The Nuveen Credit Income Fund returned 13.57% for Class C Shares at net asset value (NAV) for the 12 months ended August 31, 2024. The Fund outperformed the Bloomberg U.S. Corporate High Yield 2% Issuer Capped Bond Index, which returned 12.53%.
 
•  Top contributors to relative performance
 
»   Security selection within the high-yield corporate bond allocation, notably in the communications, consumer non-cyclical, and technology industries.
 
»   Out-of-benchmark allocation to mortgage credit, including agency credit risk transfers.
 
»   Out-of-benchmark allocation to emerging markets debt (EMD), particularly below‑investment‑grade securities.
 
•  Top detractors from relative performance
 
»   Out-of-benchmark allocation to commercial mortgage-backed securities (CMBS), particularly exposure to office properties.
 
»   Shorter-duration positioning.
  
Performance Attribution
 
LOGO  High-yield corporate bonds
 
LOGO  Mortgage credit
 
LOGO  EMD
 
LOGO  CMBS
 
LOGO   Shorter-duration positioning
Performance Past Does Not Indicate Future [Text] Performance data shown represents past performance and does not predict or guarantee future results.
Line Graph [Table Text Block]
LOGO
Average Annual Return [Table Text Block]
Average Annual Total Returns
     
     1-Year      5-Year      10-Year  
       
Class C Shares at NAV (excluding maximum sales charge)
      13.57 %       3.09 %       2.68 % 
       
Bloomberg U.S. Aggregate Bond Index
      7.30 %       (0.04 )%       1.64 % 
       
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Bond Index
      12.53 %       4.44 %       4.65 % 
       
Lipper Global High Yield Funds Classification Average
      12.05 %       3.56 %       3.61 % 
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund Shares.
Updated Performance Information Location [Text Block] For most recent month-end performance, go to https://www.nuveen.com/en-us/mutual-funds/prospectuses or call (800) 257-8787.
Net Assets $ 87,654,718
Holdings Count | Holding 251
Advisory Fees Paid, Amount $ 480,574
Investment Company Portfolio Turnover 133.00%
Additional Fund Statistics [Text Block]
Fund Statistics (as of August 31, 2024)
Fund net assets
    $ 87,654,718  
Total number of portfolio holdings
      251  
Portfolio turnover (%)
      133%  
Total management fees paid for the year
    $ 480,574  
Holdings [Text Block]
LOGO
LOGO
(1) The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Credit Ratings Selection [Text Block] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Material Fund Change [Text Block]
How has the Fund changed?
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion.
  
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Material Fund Change Expenses [Text Block]
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion.
  
Summary of Change Legend [Text Block]
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Updated Prospectus Phone Number (800) 257- 8787
Updated Prospectus Web Address https://www.nuveen.com/en-us/mutual-funds/prospectuses
Accountant Change Disagreements [Text Block]
Changes in independent registered public accounting firm
On October 24, 2024, the Fund’s Board of Directors engaged PricewaterhouseCoopers LLP (“PwC”) as the independent registered public accounting firm for the Fund and dismissed KPMG LLP (“KPMG”) as the independent registered public accounting firm for the Fund subject to the completion of the August 31, 2024 fiscal year end audit. During the Fund’s fiscal years ended August 31, 2024 and August 31, 2023, and the subsequent interim period through October 29, 2024, there have been no disagreements with KPMG on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures.
C000015080 [Member]  
Shareholder Report [Line Items]  
Fund Name Nuveen Credit Income Fund
Class Name Class I Shares
Trading Symbol FJSYX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about the Class I Shares of the Nuveen Credit Income Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information at https://www.nuveen.com/en‑us/mutual‑funds/prospectuses. You can also request this information by contacting us at (800) 257-8787.
Material Fund Change Notice [Text Block]
This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number (800) 257-8787
Additional Information Website https://www.nuveen.com/en‑us/mutual‑funds/prospectuses
Expenses [Text Block]
What were the Fund costs for the last year? (based on a hypothetical $10,000 investment)
   
   
Cost of a 
$10,000 investment 
   Costs paid as a percentage of
$10,000 investment*
     
Class I Shares
   $85    0.79%
* Annualized for period less than one year.
Expenses Paid, Amount $ 85
Expense Ratio, Percent 0.79% [7]
Factors Affecting Performance [Text Block]
How did the Fund perform last year? What affected the Fund’s performance?
 
Performance Highlights
 
•  The Nuveen Credit Income Fund returned 14.67% for Class I Shares at net asset value (NAV) for the 12 months ended August 31, 2024. The Fund outperformed the Bloomberg U.S. Corporate High Yield 2% Issuer Capped Bond Index, which returned 12.53%.
 
•  Top contributors to relative performance
 
»   Security selection within the high-yield corporate bond allocation, notably in the communications, consumer non-cyclical, and technology industries.
 
»   Out-of-benchmark allocation to mortgage credit, including agency credit risk transfers.
 
»   Out-of-benchmark allocation to emerging markets debt (EMD), particularly below‑investment‑grade securities.
 
•  Top detractors from relative performance
 
»   Out-of-benchmark allocation to commercial mortgage-backed securities (CMBS), particularly exposure to office properties.
 
»   Shorter-duration positioning.
  
Performance Attribution
 
LOGO  High-yield corporate bonds
 
LOGO  Mortgage credit
 
LOGO  EMD
 
LOGO  CMBS
 
LOGO  Shorter-duration positioning
Performance Past Does Not Indicate Future [Text] Performance data shown represents past performance and does not predict or guarantee future results.
Line Graph [Table Text Block]
LOGO
Average Annual Return [Table Text Block]
Average Annual Total Returns
     
     1‑Year      5‑Year      10‑Year  
       
Class I Shares at NAV
      14.67 %       4.07 %       3.54 % 
       
Bloomberg U.S. Aggregate Bond Index
      7.30 %       (0.04 )%       1.64 % 
       
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Bond Index
      12.53 %       4.44 %       4.65 % 
       
Lipper Global High Yield Funds Classification Average
      12.05 %       3.56 %       3.61 % 
No Deduction of Taxes [Text Block] The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund Shares.
Updated Performance Information Location [Text Block] For most recent month‑end performance, go to https://www.nuveen.com/en‑us/mutual‑funds/prospectuses or call (800) 257‑8787.
Net Assets $ 87,654,718
Holdings Count | Holding 251
Advisory Fees Paid, Amount $ 480,574
Investment Company Portfolio Turnover 133.00%
Additional Fund Statistics [Text Block]
Fund Statistics (as of August 31, 2024)
Fund net assets
    $ 87,654,718  
Total number of portfolio holdings
      251  
Portfolio turnover (%)
      133%  
Total management fees paid for the year
    $ 480,574  
Holdings [Text Block]
LOGO
LOGO
(1) The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Credit Ratings Selection [Text Block] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.
Material Fund Change [Text Block]
How has the Fund changed?
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Material Fund Change Expenses [Text Block]
  •  
Management fees: As of May 1, 2024, the Fund’s overall complex-level fee begins at a maximum rate of 0.1600% of the Fund’s average daily net assets, with breakpoints for eligible complex-level assets above $124.3 billion
  
Summary of Change Legend [Text Block]
For more complete information, you may review the Fund’s next prospectus, which is expected to be available by December 30, 2024 at https://www.nuveen.com/en-us/mutual-funds/prospectuses or upon request at (800) 257- 8787.
Updated Prospectus Phone Number (800) 257- 8787
Updated Prospectus Web Address https://www.nuveen.com/en-us/mutual-funds/prospectuses
Accountant Change Disagreements [Text Block]
Changes in independent registered public accounting firm
On October 24, 2024, the Fund’s Board of Directors engaged PricewaterhouseCoopers LLP (“PwC”) as the independent registered public accounting firm for the Fund and dismissed KPMG LLP (“KPMG”) as the independent registered public accounting firm for the Fund subject to the completion of the August 31, 2024 fiscal year end audit. During the Fund’s fiscal years ended August 31, 2024 and August 31, 2023, and the subsequent interim period through October 29, 2024, there have been no disagreements with KPMG on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures.
[1] Annualized for period less than one year.
[2] Annualized for period less than one year.
[3] Annualized for period less than one year.
[4] Annualized for period less than one year.
[5] Annualized for period less than one year.
[6] Annualized for period less than one year.
[7] Annualized for period less than one year.