S000005544 [Member] Investment Risks - Nuveen Credit Income Fund	Aug. 31, 2025
Call Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Call Risk—If, during periods of falling interest rates, an issuer exercises its right to prepay principal on its higher-yielding debt securities held by the Fund, the Fund may have to reinvest in securities with lower yields or higher risk of default, which may adversely impact the Fund’s performance.
Collateralized Loan Obligations Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Collateralized Loan Obligations Risk—A CLO is an asset-backed security whose underlying collateral is a pool of loans, which may include, among others, domestic and foreign floating rate and fixed rate senior secured loans, senior unsecured loans, and subordinate corporate loans, including loans that may be rated below investment grade. In addition to the risks associated with loans and high yield securities, CLOs are subject to the risk that distributions from the collateral may not be adequate to make interest or other payments; the quality of the collateral may decline in value or default; the Fund may invest in tranches of CLOs that are subordinate to other tranches; and the CLO’s manager may perform poorly. CLOs may charge management and other administrative fees, which are in addition to those of the Fund.
Contingent Capital Security Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Contingent Capital Security Risk—CoCos have loss absorption mechanisms benefitting the issuer built into their terms. Upon the occurrence of a specified trigger or event, CoCos may be subject to automatic conversion into the issuer’s common stock, which likely will have declined in value and which will be subordinate to the issuer’s other classes of securities, or to an automatic write-down of the principal amount of the securities, potentially to zero, which could result in the Fund losing a portion or all of its investment in such securities. CoCos are often rated below investment grade and are subject to the risks of high yield securities.
Credit Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Credit Risk—Credit risk is the risk that an issuer or other obligated party of a security may be, or perceived (whether by market participants, rating agencies, pricing services or otherwise) to be, unable or unwilling to make dividend, interest and principal payments when due and the related risk that the value of a security may decline because of concerns about the issuer’s ability or willingness to make such payments. Because the Fund invests at least 65% of the value of its assets in high yield securities, the Fund's credit risks are greater than those of funds that buy only investment grade securities.
Credit Spread Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Credit Spread Risk—Credit spread risk is the risk that credit spreads (i.e., the difference in yield between securities that is due to differences in their credit quality) may increase when the market believes that bonds generally have a greater risk of default. Increasing credit spreads may reduce the market values of the Fund’s debt securities. Credit spreads often increase more for lower rated and unrated securities than for investment grade securities. In addition, when credit spreads increase, reductions in market value will generally be greater for longer-maturity securities.
Currency Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Currency Risk—Changes in currency exchange rates will affect the value of non-U.S. securities, the value of dividends and interest earned from such securities, gains and losses realized on the sale of such securities, and derivative transactions tied to such securities. A strong U.S. dollar relative to these other currencies will adversely affect the value of the Fund’s portfolio.
Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity Risk—Cybersecurity risk is the risk of an unauthorized breach and access to Fund assets, customer data (including private shareholder information), or proprietary information, or the risk of an incident occurring that causes the Fund, its investment adviser or sub-adviser, custodian, transfer agent, distributor or other service provider, a financial intermediary or the issuers of securities held by the Fund to suffer a data breach, data corruption or lose operational functionality. Successful cyber-attacks or other cyber-failures or events affecting the Fund, its service providers or the issuers of securities held by the Fund may adversely impact the Fund or its shareholders. Additionally, a cybersecurity breach could affect the issuers in which the Fund invests, which may cause the Fund’s investments to lose value.
Derivatives Risks [Member]
Prospectus [Line Items]
Risk [Text Block]	Derivatives Risk—The use of derivatives is a highly specialized activity that can involve investment techniques, risks, and tax planning different from those associated with more traditional investment instruments and involves transaction costs which could leave the Fund in a worse position than if it had not used these instruments. Derivative instruments can be used to acquire or to transfer the risk and returns of a security or other asset without buying or selling the security or asset, and the risks associated with investing in such derivatives may be different and greater than the risks associated with directly investing in the underlying securities and other instruments, including leverage risk, market risk, counterparty risk, liquidity risk, operational risk and legal risk. These instruments may entail investment exposures that are greater than their cost would suggest. As a result, a small investment in derivatives can result in losses that greatly exceed the original investment. Derivatives can be highly volatile, illiquid and difficult to value. An over-the-counter derivative transaction between the Fund and a counterparty that is not cleared through a central counterparty also involves the risk that a loss may be sustained as a result of the failure of the counterparty to the contract to make required payments. The payment obligation for a cleared derivative transaction is guaranteed by a central counterparty, which exposes the Fund to the creditworthiness of the central counterparty.
Emerging Markets Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Emerging Markets Risk—The risk of foreign investment often increases in countries with emerging markets or that are otherwise economically tied to emerging market countries. For example, these countries may have more unstable governments than developed countries and their economies may be based on only a few industries. Emerging market countries may also have less stringent regulation of accounting, auditing, financial reporting and recordkeeping requirements, which would affect the Fund’s ability to evaluate potential portfolio companies. As a result, there could be less information about issuers in emerging market countries, which could negatively affect the ability of the Fund’s sub-adviser to evaluate local companies or their potential impact on the Fund’s performance. Because their financial markets may be very small, prices of financial instruments in emerging market countries may be volatile and difficult to determine. Financial instruments of issuers in these countries may have lower overall liquidity than those of issuers in more developed countries. In addition, foreign investors such as the Fund are subject to a variety of special restrictions in many emerging market countries. Shareholder claims and regulatory actions that are available in the U.S. may be difficult or impossible to pursue in emerging market countries.
ETF Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	ETF Risk—An ETF is subject to the risks of the underlying securities that it holds. In addition, for index-based ETFs, the performance of an ETF may diverge from the performance of such index (commonly known as tracking error). ETFs are subject to fees and expenses (like management fees and operating expenses) that do not apply to an index, and the Fund will indirectly bear its proportionate share of any such fees and expenses paid by the ETFs in which it invests. Moreover, ETF shares may trade at a premium or discount to their net asset value. As ETFs trade on an exchange, they are subject to the risks of any exchange-traded instrument, including: (i) an active trading market for its shares may not develop or be maintained, (ii) market makers or authorized participants may decide to reduce their role or step away from these activities in times of market stress, (iii) trading of its shares may be halted by the exchange, and (iv) its shares may be delisted from the exchange.
Foreign Investment Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Foreign Investment Risk—Non-U.S. issuers or U.S. issuers with significant non-U.S. operations may be subject to risks in addition to those of issuers located in or that principally operate in the United States as a result of, among other things, political, social and economic developments abroad, as well as armed conflicts and different legal, regulatory and tax environments. Foreign investments may also have lower liquidity and be more difficult to value than investments in U.S. issuers. To the extent the Fund invests a significant portion of its assets in the securities of companies in a single country or region, it may be more susceptible to adverse economic, market, political or regulatory events or conditions affecting that country or region. Foreign investments may also be subject to risk of loss because of more or less foreign government regulation, less public information, less stringent investor protections and less stringent accounting, corporate governance, financial reporting and disclosure standards.
High Yield Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	High Yield Securities Risk—High yield securities, which are rated below investment grade and commonly referred to as “junk” bonds, and unrated securities of comparable quality are high risk investments that may cause income and principal losses for the Fund. They generally are considered to be speculative with respect to the ability to pay interest and repay principal, have greater credit risk, are less liquid, are more likely to experience a default and have more volatile prices than investment grade securities, especially during periods of uncertainty or market turmoil.
Illiquid Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Illiquid Investments Risk—Certain securities held by the Fund are illiquid investments, which may be difficult to sell for the value at which they are carried, if at all, or at any price within the desired time frame and may reduce the returns of the Fund because it may be unable to sell the illiquid investment at an advantageous time or price, which could prevent the Fund from taking advantage of other investment opportunities.
Income Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Income Risk—The Fund's income could decline during periods of falling interest rates or when the Fund experiences defaults on debt securities or defaults or deferrals on preferred securities it holds.
Interest Rate Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Interest Rate Risk—Interest rate risk is the risk that the value of the Fund’s fixed-rate securities will decline because of rising interest rates. Changing interest rates may have unpredictable effects on markets, result in heightened market volatility and detract from the Fund’s performance to the extent that it is exposed to such interest rates. Fixed-rate securities may be subject to a greater risk of rising interest rates than would normally be the case due to the effect of potential government fiscal policy initiatives and resulting market reaction to those initiatives. Higher periods of inflation could lead to government fiscal policies which raise interest rates. When interest rates change, the values of longer-duration fixed-rate securities usually change more than the values of shorter-duration fixed-rate securities. Conversely, fixed-rate securities with shorter durations or maturities will be less volatile but may provide lower returns than fixed-rate securities with longer durations or maturities. Rising interest rates also may lengthen the duration of securities with call features, since exercise of the call becomes less likely as interest rates rise, which in turn will make the securities more sensitive to changes in interest rates and result in even steeper price declines in the event of further interest rate increases. The Fund is also subject to the risk that the income generated by its investments may not keep pace with inflation. There is a risk that interest rates across the financial system may change, possibly significantly and/or rapidly. In general, changing interest rates, including rates that fall below zero, or a lack of market participants may lead to decreased liquidity and increased volatility in the fixed-rate or debt markets, making it more difficult for the Fund to sell fixed-rate investments. Changes in interest rates may also lead to an increase in Fund redemptions, which may result in higher portfolio turnover costs, thereby adversely affecting the Fund’s performance.
Loan Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Loan Risk—The lack of an active trading market for certain loans (including loan participations and assignments) may impair the ability of the Fund to realize full value in the event of the need to sell a loan and may make it difficult to value such loans. Portfolio transactions in loans may settle in as short as seven days but typically can take up to two or three weeks, and in some cases much longer. As a result of these extended settlement periods, the Fund may incur losses if it is required to sell other investments or temporarily borrow to meet its cash needs, including satisfying redemption requests. The risks associated with unsecured loans, which are not backed by a security interest in any specific collateral, are higher than those for comparable loans that are secured by specific collateral. For secured loans, there is a risk that the value of any collateral securing a loan in which the Fund has an interest may decline and that the collateral may not be sufficient to cover the amount owed on the loan and the Fund’s access to the collateral may be limited by bankruptcy or other insolvency laws. Interests in loans made to finance highly leveraged companies or transactions such as corporate acquisitions may be especially vulnerable to adverse changes in economic or market conditions. Loans may have restrictive covenants limiting the ability of a borrower to further encumber its assets. However, in periods of high demand by lenders like the Fund for loan investments, borrowers may limit these covenants and weaken a lender’s ability to access collateral securing the loan; reprice the credit risk associated with the borrower; and mitigate potential loss. The Fund may experience relatively greater realized or unrealized losses or delays and expenses in enforcing its rights with respect to loans with fewer restrictive covenants. Additionally, loans may not be considered “securities” and, as a result, the Fund may not be entitled to rely on the anti-fraud or other protections of the securities laws. Because junior loans have a lower place in an issuer’s capital structure and may be unsecured, junior loans involve a higher degree of overall risk than senior loans of the issuer. The Fund's investments in floating rate loans that pay interest based on the London Interbank Offered Rate (LIBOR) may experience increased volatility and/or illiquidity during the transition away from LIBOR, which was phased out.
Market Risks [Member]
Prospectus [Line Items]
Risk [Text Block]	Market Risk—The market value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably and for short or extended periods of time, due to the particular circumstances of individual issuers or due to general conditions impacting issuers more broadly. Global economies and financial markets have become highly interconnected, and thus economic, market or political conditions or events in one country or region might adversely impact the value of the Fund’s investments whether or not the Fund invests in such country or region. Events such as war, terrorism, natural and environmental disasters and the spread of infectious illnesses or other public health emergencies may have a severe negative impact on the global economy, could cause financial markets to experience extreme volatility and losses, and could result in the disruption of trading and the reduction of liquidity in many instruments. Additionally, as inflation increases, the value of the Fund’s assets can decline.
Market Liquidity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Market Liquidity Risk—Reductions in trading activity or dealer inventories of securities such as bonds and preferred securities, which provide an indication of the ability of financial intermediaries to “make markets” in those securities, have the potential to decrease liquidity and increase price volatility in the markets in which the Fund invests, particularly during periods of economic or market stress. In addition, federal banking regulations may cause certain dealers to reduce their inventories of securities, which may further decrease the Fund’s ability to buy or sell securities. As a result of this decreased liquidity, the Fund may have to accept a lower price to sell a security, sell other securities to raise cash, or give up an investment opportunity, any of which could have a negative effect on performance. If the Fund needed to sell large blocks of securities to meet shareholder redemption requests or to raise cash, those sales could further reduce the securities’ prices and hurt performance.
Mortgage and Asset Backed Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Mortgage- and Asset-Backed Securities Risk—These securities generally can be prepaid at any time, and prepayments that occur either more quickly or more slowly than expected can adversely impact the value of such securities. They are also subject to extension risk, which is the risk that rising interest rates could cause mortgages or other obligations underlying the securities to be prepaid more slowly than expected, thereby lengthening the duration of such securities, increasing their sensitivity to interest rate changes and causing their prices to decline. Mortgage-backed securities are particularly sensitive to prepayment risk, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities. A mortgage-backed security may be negatively affected by the quality of the mortgages underlying such security, the credit quality of its issuer or guarantor, and the nature and structure of its credit support. Mortgage- and asset-backed securities that are not backed by the full faith and credit of the U.S. government are subject to the risk of default on the underlying mortgage, loan or asset, particularly during periods of economic downturn.
Other Investment Companies Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Other Investment Companies Risk—When the Fund invests in other investment companies, including ETFs, you bear both your proportionate share of Fund expenses and, indirectly, the expenses of the other investment companies. Furthermore, the Fund is exposed to the risks to which the other investment companies may be subject.
Preferred Security Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Preferred Security Risk—Preferred securities generally are subordinated to bonds and other debt instruments in a company’s capital structure and therefore will be subject to greater credit risk than those debt instruments. In addition, preferred securities are subject to other risks, such as having no or limited voting rights, being subject to special redemption rights, having distributions deferred or skipped, having floating interest rates or dividends, which may result in a decline in value in a falling interest rate environment, having fixed interest rates or dividends, which may result in a decline in value in a rising interest rate environment, having limited liquidity, changing or unfavorable tax treatments and possibly being issued by companies in heavily regulated industries.
Restricted Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Restricted Securities Risk—The market for restricted securities, including Rule 144A securities, typically is less active than the market for publicly traded securities. Rule 144A securities and other securities exempt from registration under the Securities Act carry the risk that their liquidity may become impaired and the Fund may be unable to dispose of the securities promptly or at current market value.
Sovereign Debt Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Sovereign Debt Risk—In addition to many of the risks of foreign and emerging market risks, sovereign debt instruments are subject to the risk that a governmental entity may delay or refuse to pay interest or repay principal on its sovereign debt. This may be due to, for example, cash flow problems, insufficient foreign currency reserves, political considerations, the relative size of the governmental entity’s debt position in relation to the economy or the failure to put in place economic reforms required by the International Monetary Fund or other multilateral agencies.
Unrated Security Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Unrated Security Risk—Unrated securities determined by the Fund’s sub-adviser to be of comparable quality to rated securities which the Fund may purchase may pay a higher interest rate than such rated securities and be subject to a greater risk of illiquidity or price changes. Less public information is typically available about unrated securities or issuers than rated securities or issuers.
U S Government Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	U.S. Government Securities Risk—U.S. government securities are guaranteed only as to the timely payment of interest and the payment of principal when held to maturity. Accordingly, the current market values for these securities will fluctuate with changes in interest rates. Securities issued or guaranteed by U.S. government agencies and instrumentalities are supported by varying degrees of credit but generally are not backed by the full faith and credit of the U.S. government or may be subject to certain limitations. No assurance can be given that the U.S. government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so, which may increase the risk of loss to the Fund.
Valuation Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Valuation Risk—The sales price the Fund could receive for any particular debt security may differ from the Fund’s valuation of the investment, particularly for debt securities that trade in thin or volatile markets or that are valued using a fair value methodology. The debt securities in which the Fund invests typically are valued by a pricing service utilizing a range of market-based inputs and assumptions, including price quotations obtained from broker-dealers making markets in such instruments, cash flows and transactions for comparable instruments. There is no assurance that the Fund will be able to buy or sell a portfolio security at the price established by the pricing service, which could result in a gain or loss to the Fund. Pricing services generally price debt securities assuming orderly transactions of an institutional “round lot” size, but some trades may occur in smaller, “odd lot” sizes, often at lower prices than institutional round lot trades. Over certain time periods, such differences could materially impact the performance of the Fund, which may not be sustainable. Alternative pricing services may incorporate different assumptions and inputs into their valuation methodologies, potentially resulting in different values for the same securities. As a result, if the Fund were to change pricing services, or if the Fund’s pricing service were to change its valuation methodology, there could be a material impact, either positive or negative, on the Fund’s net asset value.
Active Management Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Active Management Risk—The Fund’s sub-adviser actively manages the Fund’s investments. Consequently, the Fund is subject to the risk that the investment techniques and risk analyses employed by the Fund’s sub-adviser, including its use of proprietary and third-party technology systems, models, algorithms and data management software, may not produce the desired results. This could cause the Fund to lose value or its investment results to lag relevant benchmarks or other funds with similar objectives.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	The value of your investment in this Fund will change daily. You could lose money by investing in the Fund.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

S000005544 [Member] Investment Risks - Nuveen Credit Income Fund

Aug. 31, 2025

Call Risk—If, during periods of falling interest rates, an issuer exercises its right to prepay principal on its higher-yielding debt securities held by the Fund, the Fund may have to reinvest in securities with lower yields or higher risk of default, which may adversely impact the Fund’s performance.