Label | Element | Value | ||||||||
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Nuveen Bond Index Fund | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk/Return [Heading] | oef_RiskReturnHeading | Nuveen Bond Index Fund | ||||||||
Objective [Heading] | oef_ObjectiveHeading | Investment objective | ||||||||
Objective, Primary [Text Block] | oef_ObjectivePrimaryTextBlock | The Fund seeks total return that corresponds with the total return of a broad U.S. investment-grade bond market index. |
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Expense Heading [Optional Text] | oef_ExpenseHeading | Fees and expenses | ||||||||
Expense Narrative [Text Block] | oef_ExpenseNarrativeTextBlock | The following tables describe the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the Fund or other Nuveen mutual funds. More information about these and other discounts, as well as eligibility requirements for each share class, is available from your financial advisor and in “How You Can Buy and Sell Shares” on page 172 of the Fund’s Prospectus and “Purchase and Redemption of Fund Shares” on page 103 of the Fund’s Statement of Additional Information. In addition, more information about sales charge discounts and waivers for purchases of shares through specific financial intermediaries is set forth in the appendix to the Fund’s Prospectus entitled “Variations in Sales Charge Reductions and Waivers Available Through Certain Intermediaries. The tables and examples below do not reflect any commissions that shareholders may be required to pay directly to their financial intermediaries when buying or selling Class I shares. |
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Shareholder Fees Caption [Optional Text] | oef_ShareholderFeesCaption | SHAREHOLDER FEES (fees paid directly from your investment) | ||||||||
Operating Expenses Caption [Optional Text] | oef_OperatingExpensesCaption | ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment) | ||||||||
Portfolio Turnover [Heading] | oef_PortfolioTurnoverHeading | Portfolio turnover | ||||||||
Portfolio Turnover [Text Block] | oef_PortfolioTurnoverTextBlock | The Fund pays transaction costs, such as commissions, as applicable, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended March 31, 2025, the Fund’s portfolio turnover rate was 16% of the average value of its portfolio. |
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Portfolio Turnover, Rate | oef_PortfolioTurnoverRate | 16.00% | ||||||||
Expense Example [Heading] | oef_ExpenseExampleHeading | Example | ||||||||
Expense Example Narrative [Text Block] | oef_ExpenseExampleNarrativeTextBlock | This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before fee waivers and/or expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement arrangements will each remain in place for the durations noted in the table above. Although your actual costs may be higher or lower, based on these assumptions your costs would be: |
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Strategy [Heading] | oef_StrategyHeading | Principal investment strategies | ||||||||
Strategy Narrative [Text Block] | oef_StrategyNarrativeTextBlock | Under normal circumstances, the Fund invests at least 80% of its assets in bonds within its benchmark and portfolio tracking index, the Bloomberg U.S. Aggregate Bond Index (the “Index”). The Fund uses a sampling technique to create a portfolio that closely matches the overall investment characteristics of the Index (for example, duration, sector diversification and credit quality) without investing in all of the securities in its index. At times the Fund may purchase securities not held in the Index, but which Teachers Advisors, LLC (“Advisors”) believes have similar investment characteristics to securities held in its index. Generally, the Fund intends to invest in a wide spectrum of public, investment-grade, taxable debt securities denominated in U.S. dollars including government securities, as well as mortgage-backed, commercial mortgage-backed and asset-backed securities. The Fund’s investments in mortgage-backed securities may include pass-through securities sold by private, governmental and government-related organizations and U.S. Government-sponsored enterprises (“GSEs”), to the extent that such instruments are held by the Index. The Fund may also invest in securities having a variable or floating interest rate. The Fund generally will invest in foreign securities denominated in U.S. dollars only to the extent they are included or eligible to be included in the Index. For purposes of the 80% investment policy, the term “assets” means net assets, plus the amount of any borrowings for investment purposes. The securities purchased by the Fund will mainly be high-quality instruments rated in the top four credit categories by a nationally recognized statistical rating organization (“NRSRO”) or deemed to be of the same quality by Advisors using its own credit quality analysis. The Fund may continue to hold instruments that were rated as high-quality when purchased, but which subsequently are downgraded to below-investment-grade status or have their ratings withdrawn by one or more rating agencies. Because the return of the Index is not reduced by investment and other operating expenses, the Fund’s ability to match the Index is negatively affected by the costs of buying and selling securities, as well as other fees and expenses. The use of the Index by the Fund is not a fundamental policy of the Fund and may be changed without shareholder approval. The Fund is classified as a diversified investment company, as defined under the Investment Company Act of 1940, as amended (the “1940 Act”). However, the Fund may become non-diversified under the 1940 Act without the approval of Fund shareholders solely as a result of a change in relative market capitalization or index weighting of one or more constituents of its benchmark index, the Bloomberg U.S. Aggregate Bond Index, which the Fund seeks to track. |
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Bar Chart and Performance Table [Heading] | oef_BarChartAndPerformanceTableHeading | Past performance | ||||||||
Performance Narrative [Text Block] | oef_PerformanceNarrativeTextBlock | The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of Class R6 of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of Class R6 may vary from the other share classes. Below the bar chart are the best and worst returns of Class R6 for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for Class A, Class I, Premier Class, Class R6, Retirement Class and Class W over the applicable one-year, five-year, ten-year and since-inception periods ended December 31, 2024, and how those returns compare to those of the Fund’s benchmark and broad-based securities market index. After-tax performance is shown only for Class R6 shares, and after-tax returns for the other classes of shares will vary from the after-tax returns presented for Class R6 shares. The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The benchmark and broad-based securities market index listed below is unmanaged, and you cannot invest directly in an index. The returns for the benchmark index reflect no deduction for fees, expenses or taxes. For current performance information of each share class, including performance to the most recent month-end, please visit www.nuveen.com/performance or call 800-257-8787. |
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Performance Information Illustrates Variability of Returns [Text] | oef_PerformanceInformationIllustratesVariabilityOfReturns | The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. | ||||||||
Performance Availability Website Address [Text] | oef_PerformanceAvailabilityWebSiteAddress | www.nuveen.com/performance | ||||||||
Performance Past Does Not Indicate Future [Text] | oef_PerformancePastDoesNotIndicateFuture | Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. | ||||||||
Bar Chart [Heading] | oef_BarChartHeading | ANNUAL TOTAL RETURNS FOR CLASS R6 SHARES (%)† Nuveen Bond Index Fund | ||||||||
Bar Chart Footnotes [Text Block] | oef_BarChartFootnotesTextBlock | † The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2025, was 4.00%. |
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Bar Chart Closing [Text Block] | oef_BarChartClosingTextBlock | Best quarter: 6.64%, for the quarter ended December 31, 2023. Worst quarter: -5.89%, for the quarter ended March 31, 2022. |
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Performance Table Heading | oef_PerformanceTableHeading | AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2024 | ||||||||
Index No Deduction for Fees, Expenses, or Taxes [Text] | oef_IndexNoDeductionForFeesExpensesTaxes | (reflects no deductions for fees, expenses or taxes) | ||||||||
Performance Table Uses Highest Federal Rate | oef_PerformanceTableUsesHighestFederalRate | After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. | ||||||||
Performance Table Not Relevant to Tax Deferred | oef_PerformanceTableNotRelevantToTaxDeferred | The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). | ||||||||
Performance Table One Class of after Tax Shown [Text] | oef_PerformanceTableOneClassOfAfterTaxShown | After-tax returns are shown for only one class, and after-tax returns for other classes will vary. | ||||||||
Performance Table Closing [Text Block] | oef_PerformanceTableClosingTextBlock | Current performance of
the Fund’s shares may be higher or lower than that shown above. After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary. |
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Thirty Day Yield Phone | oef_ThirtyDayYieldPhone | 800-842-2252 | ||||||||
Nuveen Bond Index Fund | Principal investment risks | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks: |
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Nuveen Bond Index Fund | Risk Lose Money [Member] | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | You could lose money over short or long periods by investing in this Fund. | ||||||||
Nuveen Bond Index Fund | Interest Rate Risk (a type of Market Risk) | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Interest Rate Risk (a type of Market Risk)—The risk that changes in interest rates can adversely affect the value or liquidity of, and income generated by, fixed-income investments. This risk is heightened to the extent the Fund invests in longer duration fixed-income investments and during periods when prevailing interest rates are changing. 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-income or debt markets, making it more difficult for the Fund to sell fixed-income investments. When interest rates change, the values of longer duration fixed-income securities usually change more than the values of shorter duration fixed-income securities. Conversely, fixed-income securities with shorter durations or maturities will be less volatile but may provide lower returns than fixed-income securities with longer durations or maturities. Other factors that may affect the value of debt securities include, but are not limited to, economic, political, public health, and other crises and responses by governments and companies to such crises. |
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Nuveen Bond Index Fund | Prepayment Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Prepayment Risk—The risk that, during periods of falling interest rates, borrowers may pay off their mortgage loans sooner than expected, forcing the Fund to reinvest the unanticipated proceeds at lower interest rates and resulting in a decline in income. |
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Nuveen Bond Index Fund | Extension Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Extension Risk—The risk that, during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing the Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available. |
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Nuveen Bond Index Fund | Issuer Risk (often called Financial Risk) | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Issuer Risk (often called Financial Risk)—The risk that an issuer’s earnings prospects, credit rating and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time. |
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Nuveen Bond Index Fund | Credit Risk (a type of Issuer Risk) | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Credit Risk (a type of Issuer Risk)—The risk that the issuer of fixed-income investments may not be able or willing, or may be perceived (whether by market participants, rating agencies, pricing services or otherwise) as not able or willing, to meet interest or principal payments when the payments become due. Actual or perceived changes in economic, social, public health, financial or political conditions in general or that affect a particular type of investment, issuer, guarantor or counterparty can reduce the ability of the party to meet its obligations, which can affect the credit quality, liquidity and/or value of an investment. |
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Nuveen Bond Index Fund | Credit Spread Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Credit Spread Risk—The risk that credit spreads (i.e., the difference in yield between securities that is due to differences in each security’s respective credit quality) may increase when market participants believe that bonds generally have a greater risk of default, which could result in a decline in the market values of the Fund’s debt securities. |
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Nuveen Bond Index Fund | Income Volatility Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Income Volatility Risk—The risk that the level of current income from a portfolio of fixed-income investments may decline in certain interest rate environments. |
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Nuveen Bond Index Fund | Market Volatility, Liquidity and Valuation Risk (types of Market Risk) | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Market Volatility, Liquidity and Valuation Risk (types of Market Risk)—The risk that volatile or dramatic reductions in trading activity make it difficult for the Fund to properly value its investments and that the Fund may not be able to purchase or sell an investment at an attractive price, if at all. |
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Nuveen Bond Index Fund | Index Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index. |
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Nuveen Bond Index Fund | Fixed-Income Foreign Investment Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Fixed-Income Foreign Investment Risk—Investment in fixed-income securities or financial instruments of foreign issuers involves increased risks due to adverse issuer, political, regulatory, currency, market or economic developments as well as armed conflicts. These developments may impact the ability of a foreign debt issuer to make timely and ultimate payments on its debt obligations to the Fund or impair the Fund’s ability to enforce its rights against the foreign debt issuer. These risks are heightened in emerging or developing markets. Foreign investments may also have lower overall liquidity and be more difficult to value than investments in U.S. issuers. 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. Changes in the value of foreign currencies may make the return on an investment increase or decrease, unrelated to the quality or performance of the investment itself. The imposition of sanctions, exchange controls (including repatriation restrictions), confiscations, trade restrictions (including tariffs) and other restrictions by the United States or other governments may also negatively impact the Fund’s investments. Economic sanctions and other similar governmental actions or developments could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell certain foreign securities or groups of foreign securities, and/or thus may make the Fund’s investments in such securities less liquid (or illiquid) or more difficult to value. The type and severity of sanctions and other measures that may be imposed could vary broadly in scope, and their impact is impossible to predict. |
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Nuveen Bond Index Fund | U.S. Government Securities Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · U.S. Government Securities Risk—Securities issued by the U.S. Government or one of its agencies or instrumentalities may receive varying levels of support from the U.S. Government, which could affect the Fund’s ability to recover should they default. To the extent the Fund invests significantly in securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities, any market movements, regulatory changes or changes in political or economic conditions that affect the securities of the U.S. Government or its agencies or instrumentalities in which the Fund invests may have a significant impact on the Fund’s performance. |
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Nuveen Bond Index Fund | Illiquid Investments Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Illiquid Investments Risk—The risk that illiquid investments 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. |
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Nuveen Bond Index Fund | Downgrade Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Downgrade Risk—The risk that securities are subsequently downgraded should Advisors and/or rating agencies believe the issuer’s business outlook or creditworthiness has deteriorated. |
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Nuveen Bond Index Fund | Call Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Call Risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in the Fund’s income. |
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Nuveen Bond Index Fund | Floating and Variable Rate Securities Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Floating and Variable Rate Securities Risk—Floating and variable rate securities provide for a periodic adjustment in the interest rate paid on the securities. The rate adjustment intervals may be regular and range from daily up to annually, or may be based on an event, such as a change in the prime rate. Floating and variable rate securities may be subject to greater liquidity risk than other debt securities, meaning that there may be limitations on the Fund’s ability to sell the securities at any given time. Such securities also may lose value. |
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Nuveen Bond Index Fund | Non-Diversification Risk | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Risk [Text Block] | oef_RiskTextBlock | · Non-Diversification Risk—While the Fund is considered to be a diversified investment company under the 1940 Act, the Fund may become non-diversified under the 1940 Act without Fund shareholder approval when necessary to continue to track its benchmark index. Non-diversified status means that the Fund can invest a greater percentage of its assets in the securities of a single issuer than a diversified fund. Investing in a non-diversified fund involves greater risk than investing in a diversified fund because a loss in value of a particular investment may have a greater effect on the fund’s return since that investment may represent a larger portion of the fund’s total portfolio assets. |
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Nuveen Bond Index Fund | Bloomberg U.S. Aggregate Bond Index | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Average Annual Return, Label [Optional Text] | oef_AverageAnnualReturnLabel | Bloomberg U.S. Aggregate Bond Index | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.25% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (0.33%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.35% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.41% | ||||||||
Performance Inception Date | oef_PerfInceptionDate | Dec. 04, 2015 | ||||||||
Nuveen Bond Index Fund | Bloomberg U.S. Aggregate Bond Index | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.34% | ||||||||
Performance Inception Date | oef_PerfInceptionDate | Sep. 28, 2018 | ||||||||
Nuveen Bond Index Fund | Class A | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 3.75% | ||||||||
Maximum Deferred Sales Charge (as a percentage of Offering Price) | oef_MaximumDeferredSalesChargeOverOfferingPrice | 0.00% | ||||||||
Maximum Sales Charge on Reinvested Dividends and Distributions (as a percentage) | oef_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther | 0.00% | ||||||||
Redemption Fee (as a percentage of Amount Redeemed) | oef_RedemptionFeeOverRedemption | 0.00% | ||||||||
Shareholder Fee, Other | oef_ShareholderFeeOther | $ 15.00 | ||||||||
Management Fees (as a percentage of Assets) | oef_ManagementFeesOverAssets | 0.06% | ||||||||
Distribution and Service (12b-1) Fees | oef_DistributionAndService12b1FeesOverAssets | 0.25% | ||||||||
Other Expenses (as a percentage of Assets): | oef_OtherExpensesOverAssets | 0.14% | [1] | |||||||
Expenses (as a percentage of Assets) | oef_ExpensesOverAssets | 0.45% | ||||||||
Fee Waiver or Reimbursement | oef_FeeWaiverOrReimbursementOverAssets | (0.01%) | [2] | |||||||
Net Expenses (as a percentage of Assets) | oef_NetExpensesOverAssets | 0.44% | ||||||||
Fee Waiver or Reimbursement over Assets, Date of Termination | oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination | July 31, 2026 | ||||||||
Expenses Restated to Reflect Current [Text] | oef_ExpensesRestatedToReflectCurrent | Restated to reflect estimate for the current fiscal year. | ||||||||
Expense Example, with Redemption, 1 Year | oef_ExpenseExampleYear01 | $ 418 | ||||||||
Expense Example, with Redemption, 3 Years | oef_ExpenseExampleYear03 | 513 | ||||||||
Expense Example, with Redemption, 5 Years | oef_ExpenseExampleYear05 | 617 | ||||||||
Expense Example, with Redemption, 10 Years | oef_ExpenseExampleYear10 | $ 920 | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (2.82%) | [3] | |||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (1.44%) | [3] | |||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 0.52% | [3] | |||||||
Nuveen Bond Index Fund | Class I | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 0.00% | ||||||||
Maximum Deferred Sales Charge (as a percentage of Offering Price) | oef_MaximumDeferredSalesChargeOverOfferingPrice | 0.00% | ||||||||
Maximum Sales Charge on Reinvested Dividends and Distributions (as a percentage) | oef_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther | 0.00% | ||||||||
Redemption Fee (as a percentage of Amount Redeemed) | oef_RedemptionFeeOverRedemption | 0.00% | ||||||||
Shareholder Fee, Other | oef_ShareholderFeeOther | $ 0 | ||||||||
Management Fees (as a percentage of Assets) | oef_ManagementFeesOverAssets | 0.06% | ||||||||
Distribution and Service (12b-1) Fees | oef_DistributionAndService12b1FeesOverAssets | 0.00% | ||||||||
Other Expenses (as a percentage of Assets): | oef_OtherExpensesOverAssets | 0.11% | ||||||||
Expenses (as a percentage of Assets) | oef_ExpensesOverAssets | 0.17% | ||||||||
Fee Waiver or Reimbursement | oef_FeeWaiverOrReimbursementOverAssets | 0.00% | [2] | |||||||
Net Expenses (as a percentage of Assets) | oef_NetExpensesOverAssets | 0.17% | ||||||||
Fee Waiver or Reimbursement over Assets, Date of Termination | oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination | July 31, 2026 | ||||||||
Expense Example, with Redemption, 1 Year | oef_ExpenseExampleYear01 | $ 17 | ||||||||
Expense Example, with Redemption, 3 Years | oef_ExpenseExampleYear03 | 55 | ||||||||
Expense Example, with Redemption, 5 Years | oef_ExpenseExampleYear05 | 96 | ||||||||
Expense Example, with Redemption, 10 Years | oef_ExpenseExampleYear10 | $ 217 | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.32% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (0.48%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.19% | ||||||||
Performance Inception Date | oef_PerfInceptionDate | Dec. 04, 2015 | ||||||||
Nuveen Bond Index Fund | Premier Class | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 0.00% | ||||||||
Maximum Deferred Sales Charge (as a percentage of Offering Price) | oef_MaximumDeferredSalesChargeOverOfferingPrice | 0.00% | ||||||||
Maximum Sales Charge on Reinvested Dividends and Distributions (as a percentage) | oef_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther | 0.00% | ||||||||
Redemption Fee (as a percentage of Amount Redeemed) | oef_RedemptionFeeOverRedemption | 0.00% | ||||||||
Shareholder Fee, Other | oef_ShareholderFeeOther | $ 0 | ||||||||
Management Fees (as a percentage of Assets) | oef_ManagementFeesOverAssets | 0.06% | ||||||||
Distribution and Service (12b-1) Fees | oef_DistributionAndService12b1FeesOverAssets | 0.15% | ||||||||
Other Expenses (as a percentage of Assets): | oef_OtherExpensesOverAssets | 0.01% | ||||||||
Expenses (as a percentage of Assets) | oef_ExpensesOverAssets | 0.22% | ||||||||
Fee Waiver or Reimbursement | oef_FeeWaiverOrReimbursementOverAssets | 0.00% | [2] | |||||||
Net Expenses (as a percentage of Assets) | oef_NetExpensesOverAssets | 0.22% | ||||||||
Fee Waiver or Reimbursement over Assets, Date of Termination | oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination | July 31, 2026 | ||||||||
Expense Example, with Redemption, 1 Year | oef_ExpenseExampleYear01 | $ 23 | ||||||||
Expense Example, with Redemption, 3 Years | oef_ExpenseExampleYear03 | 71 | ||||||||
Expense Example, with Redemption, 5 Years | oef_ExpenseExampleYear05 | 124 | ||||||||
Expense Example, with Redemption, 10 Years | oef_ExpenseExampleYear10 | $ 280 | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.27% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (0.53%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.09% | ||||||||
Nuveen Bond Index Fund | Class R6 | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 0.00% | ||||||||
Maximum Deferred Sales Charge (as a percentage of Offering Price) | oef_MaximumDeferredSalesChargeOverOfferingPrice | 0.00% | ||||||||
Maximum Sales Charge on Reinvested Dividends and Distributions (as a percentage) | oef_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther | 0.00% | ||||||||
Redemption Fee (as a percentage of Amount Redeemed) | oef_RedemptionFeeOverRedemption | 0.00% | ||||||||
Shareholder Fee, Other | oef_ShareholderFeeOther | $ 0 | ||||||||
Management Fees (as a percentage of Assets) | oef_ManagementFeesOverAssets | 0.06% | ||||||||
Distribution and Service (12b-1) Fees | oef_DistributionAndService12b1FeesOverAssets | 0.00% | ||||||||
Other Expenses (as a percentage of Assets): | oef_OtherExpensesOverAssets | 0.01% | ||||||||
Expenses (as a percentage of Assets) | oef_ExpensesOverAssets | 0.07% | ||||||||
Fee Waiver or Reimbursement | oef_FeeWaiverOrReimbursementOverAssets | 0.00% | [2] | |||||||
Net Expenses (as a percentage of Assets) | oef_NetExpensesOverAssets | 0.07% | ||||||||
Fee Waiver or Reimbursement over Assets, Date of Termination | oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination | July 31, 2026 | ||||||||
Expense Example, with Redemption, 1 Year | oef_ExpenseExampleYear01 | $ 7 | ||||||||
Expense Example, with Redemption, 3 Years | oef_ExpenseExampleYear03 | 23 | ||||||||
Expense Example, with Redemption, 5 Years | oef_ExpenseExampleYear05 | 40 | ||||||||
Expense Example, with Redemption, 10 Years | oef_ExpenseExampleYear10 | $ 90 | ||||||||
Year to Date Return, Label [Optional Text] | oef_YearToDateReturnLabel | The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2025, was | ||||||||
Bar Chart, Year to Date Return, Date | oef_BarChartYearToDateReturnDate | Jun. 30, 2025 | ||||||||
Bar Chart, Year to Date Return | oef_BarChartYearToDateReturn | 4.00% | ||||||||
Highest Quarterly Return, Label [Optional Text] | oef_HighestQuarterlyReturnLabel | Best quarter | ||||||||
Highest Quarterly Return, Date | oef_BarChartHighestQuarterlyReturnDate | Dec. 31, 2023 | ||||||||
Highest Quarterly Return | oef_BarChartHighestQuarterlyReturn | 6.64% | ||||||||
Lowest Quarterly Return, Label [Optional Text] | oef_LowestQuarterlyReturnLabel | Worst quarter | ||||||||
Lowest Quarterly Return, Date | oef_BarChartLowestQuarterlyReturnDate | Mar. 31, 2022 | ||||||||
Lowest Quarterly Return | oef_BarChartLowestQuarterlyReturn | (5.89%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.43% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (0.38%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.24% | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | 0.53% | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | 2.38% | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | 3.42% | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | (0.02%) | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | 8.38% | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | 7.49% | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | (1.81%) | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | (13.24%) | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | 5.64% | ||||||||
Annual Return [Percent] | oef_AnnlRtrPct | 1.43% | ||||||||
Nuveen Bond Index Fund | Class R6 | After Taxes on Distributions | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 0.03% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (1.47%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 0.16% | ||||||||
Nuveen Bond Index Fund | Class R6 | After Taxes on Distributions and Sales | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 0.84% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (0.72%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 0.50% | ||||||||
Nuveen Bond Index Fund | Retirement Class | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 0.00% | ||||||||
Maximum Deferred Sales Charge (as a percentage of Offering Price) | oef_MaximumDeferredSalesChargeOverOfferingPrice | 0.00% | ||||||||
Maximum Sales Charge on Reinvested Dividends and Distributions (as a percentage) | oef_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther | 0.00% | ||||||||
Redemption Fee (as a percentage of Amount Redeemed) | oef_RedemptionFeeOverRedemption | 0.00% | ||||||||
Shareholder Fee, Other | oef_ShareholderFeeOther | $ 0 | ||||||||
Management Fees (as a percentage of Assets) | oef_ManagementFeesOverAssets | 0.06% | ||||||||
Distribution and Service (12b-1) Fees | oef_DistributionAndService12b1FeesOverAssets | 0.00% | ||||||||
Other Expenses (as a percentage of Assets): | oef_OtherExpensesOverAssets | 0.26% | ||||||||
Expenses (as a percentage of Assets) | oef_ExpensesOverAssets | 0.32% | ||||||||
Fee Waiver or Reimbursement | oef_FeeWaiverOrReimbursementOverAssets | 0.00% | [2] | |||||||
Net Expenses (as a percentage of Assets) | oef_NetExpensesOverAssets | 0.32% | ||||||||
Fee Waiver or Reimbursement over Assets, Date of Termination | oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination | July 31, 2026 | ||||||||
Expense Example, with Redemption, 1 Year | oef_ExpenseExampleYear01 | $ 33 | ||||||||
Expense Example, with Redemption, 3 Years | oef_ExpenseExampleYear03 | 103 | ||||||||
Expense Example, with Redemption, 5 Years | oef_ExpenseExampleYear05 | 180 | ||||||||
Expense Example, with Redemption, 10 Years | oef_ExpenseExampleYear10 | $ 406 | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.07% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (0.63%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 0.98% | ||||||||
Nuveen Bond Index Fund | Class W | ||||||||||
Risk/Return: | oef_RiskReturnAbstract | |||||||||
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) | oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice | 0.00% | ||||||||
Maximum Deferred Sales Charge (as a percentage of Offering Price) | oef_MaximumDeferredSalesChargeOverOfferingPrice | 0.00% | ||||||||
Maximum Sales Charge on Reinvested Dividends and Distributions (as a percentage) | oef_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther | 0.00% | ||||||||
Redemption Fee (as a percentage of Amount Redeemed) | oef_RedemptionFeeOverRedemption | 0.00% | ||||||||
Shareholder Fee, Other | oef_ShareholderFeeOther | $ 0 | ||||||||
Management Fees (as a percentage of Assets) | oef_ManagementFeesOverAssets | 0.06% | ||||||||
Distribution and Service (12b-1) Fees | oef_DistributionAndService12b1FeesOverAssets | 0.00% | ||||||||
Other Expenses (as a percentage of Assets): | oef_OtherExpensesOverAssets | 0.01% | ||||||||
Expenses (as a percentage of Assets) | oef_ExpensesOverAssets | 0.07% | ||||||||
Fee Waiver or Reimbursement | oef_FeeWaiverOrReimbursementOverAssets | (0.07%) | [2],[4] | |||||||
Net Expenses (as a percentage of Assets) | oef_NetExpensesOverAssets | 0.00% | ||||||||
Fee Waiver or Reimbursement over Assets, Date of Termination | oef_FeeWaiverOrReimbursementOverAssetsDateOfTermination | July 31, 2026 | ||||||||
Expense Example, with Redemption, 1 Year | oef_ExpenseExampleYear01 | $ 0 | ||||||||
Expense Example, with Redemption, 3 Years | oef_ExpenseExampleYear03 | 0 | ||||||||
Expense Example, with Redemption, 5 Years | oef_ExpenseExampleYear05 | 0 | ||||||||
Expense Example, with Redemption, 10 Years | oef_ExpenseExampleYear10 | $ 0 | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.50% | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | (0.30%) | ||||||||
Average Annual Return, Percent | oef_AvgAnnlRtrPct | 1.35% | ||||||||
Performance Inception Date | oef_PerfInceptionDate | Sep. 28, 2018 | ||||||||
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