485BPOS

As Filed with the U.S. Securities and Exchange Commission on February 19, 2013

1933 Act File No. 002-94608

1940 Act File No. 811-04165

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C.  20549
__________________
FORM N-1A
__________________
REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933		T
Pre-Effective Amendment No.		£
Post-Effective Amendment No. 52		T
and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940		T
Amendment No. 54		T
(Check appropriate box or boxes.)
__________________
AMERICAN CENTURY TARGET MATURITIES TRUST (Exact Name of Registrant as Specified in Charter)
__________________
4500 MAIN STREET,  KANSAS CITY, MISSOURI 64111 (Address of Principal Executive Offices)              (Zip Code)
REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (816) 531-5575
CHARLES A. ETHERINGTON 4500 MAIN STREET,  KANSAS CITY, MISSOURI  64111 (Name and Address of Agent for Service)
It is proposed that this filing will become effective (check appropriate box)
þ	immediately upon filing pursuant to paragraph (b)
¨	on (date) pursuant to paragraph (b)
£	60 days after filing pursuant to paragraph (a)(1)
£	on (date) pursuant to paragraph (a)(1)
£	75 days after filing pursuant to paragraph (a)(2)
£	on (date) pursuant to paragraph (a)(2) of rule 485.
If appropriate, check the following box:
£	this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement amendment pursuant to Rule 485(b) promulgated under the Securities Act of 1933, as amended, and has duly caused this amendment to be signed on its behalf by the undersigned, duly authorized, in the City of Kansas City, State of Missouri on the 19th day of February, 2013.

American Century Target Maturities Trust

(Registrant)

By:

*

___________________________________

Jonathan S. Thomas

President

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement amendment has been signed by the following persons in the capacities and on the dates indicated.

SIGNATURES	TITLE	DATE
* _________________________________ Jonathan S. Thomas	President and Trustee	February 19, 2013
* _________________________________ C. Jean Wade	Vice President, Treasurer and Chief Financial Officer	February 19, 2013
* _________________________________ Tanya S. Beder	Trustee	February 19, 2013
* _________________________________ Jeremy I. Bulow	Trustee	February 19, 2013
* _________________________________ Ronald J. Gilson	Chairman of the Board and Trustee	February 19, 2013
* _________________________________ Frederick L.A. Grauer	Trustee	February 19, 2013
* _________________________________ Peter F. Pervere	Trustee	February 19, 2013
* _________________________________ Myron S. Scholes	Trustee	February 19, 2013

* _________________________________ John B. Shoven Trustee February 19, 2013  

*By:        /s/ Kathleen Gunja Nelson

Kathleen Gunja Nelson

Attorney in Fact

Pursuant to Power of Attorney, dated December 18, 2012 (filed electronically as Exhibit q1 to Post-Effective Amendment No. 51 to the Registration Statement of American Century California Tax-Free and Municipal Funds on December 28, 2012, File No. 002-82734, and incorporated herein by reference).

Secretary’s Certificate, dated December 18, 2012 (filed electronically as Exhibit q2 to Post-Effective Amendment No. 51 to the Registration Statement of American Century California Tax-Free and Municipal Funds on December 28, 2012, File No. 002-82734, and incorporated herein by reference).

EXHIBIT INDEX

EXHIBIT NUMBER	DESCRIPTION OF DOCUMENT
Exhibit – 101.INS	XBRL Instance Document
Exhibit – 101.SCH	XBRL Taxonomy Extension Schema Document
Exhibit – 101.DEF	XBRL Taxonomy Extension Definition Linkbase Document
Exhibit – 101.LAB	XBRL Taxonomy Extension Label Linkbase Document
Exhibit – 101.PRE	XBRL Taxonomy Extension Presentation Linkbase Document

XML

Label

Element

Value

[RiskReturnAbstract]

rr_RiskReturnAbstract

Document Type

dei_DocumentType

485BPOS

Document Period End Date

dei_DocumentPeriodEndDate

Sep. 30, 2012

Registrant Name

dei_EntityRegistrantName

AMERICAN CENTURY TARGET MATURITIES TRUST

Central Index Key

dei_EntityCentralIndexKey

0000757928

Amendment Flag

dei_AmendmentFlag

false

Trading Symbol

dei_TradingSymbol

actmt

Document Creation Date

dei_DocumentCreationDate

Jan. 28, 2013

Document Effective Date

dei_DocumentEffectiveDate

Feb. 01, 2013

Prospectus Date

rr_ProspectusDate

Feb. 01, 2013

ZERO COUPON 2015 FUND

[RiskReturnAbstract]

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

RISK/RETURN

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks the highest return consistent with investment in U.S. Treasury securities.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, 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 most recent fiscal year, the fund's portfolio turnover rate was 40% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

40.00%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that you earn a 5% return each year, and that the fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the fund will invest at least 80% of the value of its assets in zero-coupon securities. Typically, other than during the fund’s target maturity year, the fund intends to exceed this 80% requirement and be fully invested in zero-coupon securities.

The fund invests primarily in zero-coupon U.S. Treasury securities and their equivalents, and may invest up to 20% of its assets in AAA-rated zero-coupon U.S. government agency securities. Zero-coupon securities make no periodic interest or principal payments. Instead, they trade at a deep discount to their face value and all of the interest and principal is paid when the securities mature.

The fund is managed to mature in the year 2015 and will be liquidated near the end of its target maturity year. If shares of the fund are held until the fund is liquidated and all distributions are reinvested, the fund’s performance should be similar to an investment in a zero-coupon U.S. Treasury security with the same term to maturity as the fund. The advisor expects that shareholders who hold their shares until the fund is liquidated and reinvest all distributions will realize an investment return and maturity value that do not differ significantly from the anticipated growth rate (AGR) and anticipated value at maturity (AVM) calculated on the day the shares were purchased.

The fund’s anticipated growth rate is an estimate of the annualized rate of growth of the fund that an investor may expect from the purchase date to the fund’s weighted average maturity date.

The anticipated value at maturity is an estimate of the fund’s net asset value as of the fund’s weighted average maturity date. It is based on the maturity values of the zero-coupon securities held by the fund.

As of the fund’s most recent fiscal year end (September 30, 2012), the fund’s Investor Class AGR was -0.05% and its AVM was $114.07. The AGR and AVM for the Advisor Class will differ from that of the Investor Class, depending on the expenses of that class.

When determining whether to sell a security, the portfolio managers consider, among other things, the fund's average maturity, current and anticipated changes in interest rates, current valuation relative to alternatives in the market, general market conditions and any other factors deemed relevant by the portfolio managers.

Securities issued or guaranteed by the U.S. Treasury and certain U.S. government agencies or instrumentalities are supported by the full faith and credit of the U.S. government. Zero-coupon U.S. government agency securities that are ultimately backed by securities or payment obligations of the U.S. Treasury and are considered by the market to be of comparable credit quality, such as Resolution Funding Corporation (REFCORP) bonds, are considered to be zero-coupon U.S. Treasury equivalents by the fund's managers. Securities issued or guaranteed by other U.S. government agencies or instrumentalities, such as the Federal National Mortgage Association (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac), and the Federal Home Loan Bank, are not guaranteed by the U.S. Treasury or supported by the full faith and credit of the U.S. government. However, these agencies or instrumentalities are authorized to borrow from the U.S. Treasury to meet their obligations.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Risk - Generally, when interest rates rise, the fund’s share value will decline. The opposite is true when interest rates decline. Funds with longer weighted average maturities are more sensitive to interest rate changes. Additionally, in extreme low interest rate environments, the fund’s expenses may exceed the yields on the securities in which the fund invests, resulting in a negative anticipated growth rate (AGR). You may lose money as a result of holding fund shares with a negative AGR.

• Unanticipated Capital Gains or Losses - When shareholders redeem their shares before the target maturity date, the fund may need to liquidate holdings to meet these redemptions and unanticipated capital gains or losses may result. The fund will distribute these capital gains or losses to all shareholders.

• Zero-Coupon U.S. Treasury Correlation - Although the fund's investment policies are designed to provide an investment that is similar to investing in a zero-coupon U.S. Treasury security that matures in the year 2015, a precise forecast of the fund's final maturity value and yield to maturity is not possible.

• Market Risk - The value of the securities owned by the fund may go up and down, sometimes rapidly or unpredictably.

• Principal Loss - At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.

An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.

Risk Lose Money [Text]

rr_RiskLoseMoney

Principal Loss - At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Fund Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Investor Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. The table also shows results for a U.S. Treasury zero-coupon security (STRIPS Issue) with a maturity date similar to the fund. The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. For current performance information, including yields, please visit americancentury.com.

Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund's performance from year to year for Investor Class shares. The table shows how the fund's average annual returns for the periods shown compared with those of a broad measure of market performance.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

The table also shows results for a U.S. Treasury zero-coupon security (STRIPS Issue) with a maturity date similar to the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

americancentury.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Calendar Year Total Returns

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Performance Quarter (3Q 2004): 7.63%

Lowest Performance Quarter (2Q 2004): -6.22%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Performance Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2004

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

7.63%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Performance Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2004

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(6.22%)

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns For the calendar year ended December 31, 2012

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown only for Investor Class shares. After-tax returns for other share classes will vary.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

The after-tax returns are shown only for Investor Class shares. After-tax returns for other share classes will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.

ZERO COUPON 2015 FUND | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $10,000)

rr_MaximumAccountFee

25

Management Fee

rr_ManagementFeesOverAssets

0.55%

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

none

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.55%

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

56

3 Years

rr_ExpenseExampleNoRedemptionYear03

177

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

308

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

690

Annual Return 2003

rr_AnnualReturn2003

3.93%

Annual Return 2004

rr_AnnualReturn2004

9.09%

Annual Return 2005

rr_AnnualReturn2005

4.87%

Annual Return 2006

rr_AnnualReturn2006

2.19%

Annual Return 2007

rr_AnnualReturn2007

10.09%

Annual Return 2008

rr_AnnualReturn2008

12.77%

Annual Return 2009

rr_AnnualReturn2009

(0.91%)

Annual Return 2010

rr_AnnualReturn2010

8.85%

Annual Return 2011

rr_AnnualReturn2011

7.52%

Annual Return 2012

rr_AnnualReturn2012

1.45%

1 Year

rr_AverageAnnualReturnYear01

1.45%

5 Years

rr_AverageAnnualReturnYear05

5.81%

10 Years

rr_AverageAnnualReturnYear10

5.90%

ZERO COUPON 2015 FUND | ADVISOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $10,000)

rr_MaximumAccountFee

none

Management Fee

rr_ManagementFeesOverAssets

0.55%

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

none

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.80%

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

82

3 Years

rr_ExpenseExampleNoRedemptionYear03

256

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

445

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

990

1 Year

rr_AverageAnnualReturnYear01

1.20%

5 Years

rr_AverageAnnualReturnYear05

5.55%

10 Years

rr_AverageAnnualReturnYear10

5.63%

ZERO COUPON 2015 FUND | After Taxes on Distributions | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(0.78%)

5 Years

rr_AverageAnnualReturnYear05

3.99%

10 Years

rr_AverageAnnualReturnYear10

4.02%

ZERO COUPON 2015 FUND | After Taxes on Distributions and Sales | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

2.68%

5 Years

rr_AverageAnnualReturnYear05

4.19%

10 Years

rr_AverageAnnualReturnYear10

4.12%

ZERO COUPON 2015 FUND | November 15, 2015 STRIPS Issue

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

1.36%

5 Years

rr_AverageAnnualReturnYear05

6.35%

10 Years

rr_AverageAnnualReturnYear10

6.20%

ZERO COUPON 2015 FUND | BofA Merrill Lynch 10+ Year U.S. Treasury Index

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.67%

5 Years

rr_AverageAnnualReturnYear05

9.61%

10 Years

rr_AverageAnnualReturnYear10

7.61%

ZERO COUPON 2020 FUND

[RiskReturnAbstract]

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

RISK/RETURN

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks the highest return consistent with investment in U.S. Treasury securities.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, 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 most recent fiscal year, the fund's portfolio turnover rate was 47% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

47.00%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that you earn a 5% return each year, and that the fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the fund will invest at least 80% of the value of its assets in zero-coupon securities. Typically, other than during the fund’s target maturity year, the fund intends to exceed this 80% requirement and be fully invested in zero-coupon securities.

The fund invests primarily in zero-coupon U.S. Treasury securities and their equivalents, and may invest up to 20% of its assets in AAA-rated zero-coupon U.S. government agency securities. Zero-coupon securities make no periodic interest or principal payments. Instead, they trade at a deep discount to their face value and all of the interest and principal is paid when the securities mature.

The fund is managed to mature in the year 2020 and will be liquidated near the end of its target maturity year. If shares of the fund are held until the fund is liquidated and all distributions are reinvested, the fund’s performance should be similar to an investment in a zero-coupon U.S. Treasury security with the same term to maturity as the fund. The advisor expects that shareholders who hold their shares until the fund is liquidated and reinvest all distributions will realize an investment return and maturity value that do not differ significantly from the anticipated growth rate (AGR) and anticipated value at maturity (AVM) calculated on the day the shares were purchased.

The fund’s anticipated growth rate is an estimate of the annualized rate of growth of the fund that an investor may expect from the purchase date to the fund’s weighted average maturity date.

The anticipated value at maturity is an estimate of the fund’s net asset value as of the fund’s weighted average maturity date. It is based on the maturity values of the zero-coupon securities held by the fund.

As of the fund’s most recent fiscal year end (September 30, 2012), the fund’s Investor Class AGR was 1.03% and its AVM was $108.09. The AGR and AVM for the Advisor Class will differ from that of the Investor Class, depending on the expenses of that class.

When determining whether to sell a security, the portfolio managers consider, among other things, the fund's average maturity, current and anticipated changes in interest rates, current valuation relative to alternatives in the market, general market conditions and any other factors deemed relevant by the portfolio managers.

Securities issued or guaranteed by the U.S. Treasury and certain U.S. government agencies or instrumentalities are supported by the full faith and credit of the U.S. government. Zero-coupon U.S. government agency securities that are ultimately backed by securities or payment obligations of the U.S. Treasury and are considered by the market to be of comparable credit quality, such as Resolution Funding Corporation (REFCORP) bonds, are considered to be zero-coupon U.S. Treasury equivalents by the fund's managers. Securities issued or guaranteed by other U.S. government agencies or instrumentalities, such as the Federal National Mortgage Association (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac), and the Federal Home Loan Bank, are not guaranteed by the U.S. Treasury or supported by the full faith and credit of the U.S. government. However, these agencies or instrumentalities are authorized to borrow from the U.S. Treasury to meet their obligations.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Risk - Generally, when interest rates rise, the fund’s share value will decline. The opposite is true when interest rates decline. Funds with longer weighted average maturities are more sensitive to interest rate changes. Additionally, in extreme low interest rate environments, the fund’s expenses may exceed the yields on the securities in which the fund invests, resulting in a negative anticipated growth rate (AGR). You may lose money as a result of holding fund shares with a negative AGR.

• Unanticipated Capital Gains or Losses - When shareholders redeem their shares before the target maturity date, the fund may need to liquidate holdings to meet these redemptions and unanticipated capital gains or losses may result. The fund will distribute these capital gains or losses to all shareholders.

• Zero-Coupon U.S. Treasury Correlation - Although the fund's investment policies are designed to provide an investment that is similar to investing in a zero-coupon U.S. Treasury security that matures in the year 2020, a precise forecast of the fund's final maturity value and yield to maturity is not possible.

• Market Risk - The value of the securities owned by the fund may go up and down, sometimes rapidly or unpredictably.

• Principal Loss - At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.

An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.

Risk Lose Money [Text]

rr_RiskLoseMoney

Principal Loss - At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Fund Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Investor Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. The table also shows results for a U.S. Treasury zero-coupon security (STRIPS Issue) with a maturity date similar to the fund. The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. For current performance information, including yields, please visit americancentury.com.

Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund's performance from year to year for Investor Class shares. The table shows how the fund's average annual returns for the periods shown compared with those of a broad measure of market performance.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

The table also shows results for a U.S. Treasury zero-coupon security (STRIPS Issue) with a maturity date similar to the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

americancentury.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Calendar Year Total Returns

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Performance Quarter (3Q 2011): 14.28%

Lowest Performance Quarter (2Q 2004): -7.29%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Performance Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2011

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

14.28%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Performance Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2004

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(7.29%)

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns For the calendar year ended December 31, 2012

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown only for Investor Class shares. After-tax returns for other share classes will vary.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

The after-tax returns are shown only for Investor Class shares. After-tax returns for other share classes will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.

ZERO COUPON 2020 FUND | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $10,000)

rr_MaximumAccountFee

25

Management Fee

rr_ManagementFeesOverAssets

0.55%

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

none

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.55%

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

56

3 Years

rr_ExpenseExampleNoRedemptionYear03

177

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

308

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

690

Annual Return 2003

rr_AnnualReturn2003

3.48%

Annual Return 2004

rr_AnnualReturn2004

12.44%

Annual Return 2005

rr_AnnualReturn2005

10.29%

Annual Return 2006

rr_AnnualReturn2006

0.25%

Annual Return 2007

rr_AnnualReturn2007

9.55%

Annual Return 2008

rr_AnnualReturn2008

16.96%

Annual Return 2009

rr_AnnualReturn2009

(7.42%)

Annual Return 2010

rr_AnnualReturn2010

12.58%

Annual Return 2011

rr_AnnualReturn2011

19.51%

Annual Return 2012

rr_AnnualReturn2012

5.24%

1 Year

rr_AverageAnnualReturnYear01

5.24%

5 Years

rr_AverageAnnualReturnYear05

8.91%

10 Years

rr_AverageAnnualReturnYear10

8.00%

ZERO COUPON 2020 FUND | ADVISOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $10,000)

rr_MaximumAccountFee

none

Management Fee

rr_ManagementFeesOverAssets

0.55%

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

none

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.80%

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

82

3 Years

rr_ExpenseExampleNoRedemptionYear03

256

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

445

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

990

1 Year

rr_AverageAnnualReturnYear01

4.97%

5 Years

rr_AverageAnnualReturnYear05

8.64%

10 Years

rr_AverageAnnualReturnYear10

7.73%

ZERO COUPON 2020 FUND | After Taxes on Distributions | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.84%

5 Years

rr_AverageAnnualReturnYear05

7.11%

10 Years

rr_AverageAnnualReturnYear10

6.06%

ZERO COUPON 2020 FUND | After Taxes on Distributions and Sales | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.53%

5 Years

rr_AverageAnnualReturnYear05

6.73%

10 Years

rr_AverageAnnualReturnYear10

5.86%

ZERO COUPON 2020 FUND | November 15, 2020 STRIPS Issue

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.64%

5 Years

rr_AverageAnnualReturnYear05

10.03%

10 Years

rr_AverageAnnualReturnYear10

8.57%

ZERO COUPON 2020 FUND | BofA Merrill Lynch 10+ Year U.S. Treasury Index

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.67%

5 Years

rr_AverageAnnualReturnYear05

9.61%

10 Years

rr_AverageAnnualReturnYear10

7.61%

ZERO COUPON 2025 FUND

[RiskReturnAbstract]

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

RISK/RETURN

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks the highest return consistent with investment in U.S. Treasury securities.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses you may pay if you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The fund pays transaction costs, such as commissions, 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 most recent fiscal year, the fund's portfolio turnover rate was 73% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

73.00%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods, that you earn a 5% return each year, and that the fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the fund will invest at least 80% of the value of its assets in zero-coupon securities. Typically, other than during the fund’s target maturity year, the fund intends to exceed this 80% requirement and be fully invested in zero-coupon securities.

The fund invests primarily in zero-coupon U.S. Treasury securities and their equivalents, and may invest up to 20% of its assets in AAA-rated zero-coupon U.S. government agency securities. Zero-coupon securities make no periodic interest or principal payments. Instead, they trade at a deep discount to their face value and all of the interest and principal is paid when the securities mature.

The fund is managed to mature in the year 2025 and will be liquidated near the end of its target maturity year. If shares of the fund are held until the fund is liquidated and all distributions are reinvested, the fund’s performance should be similar to an investment in a zero-coupon U.S. Treasury security with the same term to maturity as the fund. The advisor expects that shareholders who hold their shares until the fund is liquidated and reinvest all distributions will realize an investment return and maturity value that do not differ significantly from the anticipated growth rate (AGR) and anticipated value at maturity (AVM) calculated on the day the shares were purchased.

The fund’s anticipated growth rate is an estimate of the annualized rate of growth of the fund that an investor may expect from the purchase date to the fund’s weighted average maturity date.

The anticipated value at maturity is an estimate of the fund’s net asset value as of the fund’s weighted average maturity date. It is based on the maturity values of the zero-coupon securities held by the fund.

As of the fund’s most recent fiscal year end (September 30, 2012), the fund’s Investor Class AGR was 1.98% and its AVM was $115.81. The AGR and AVM for the Advisor Class will differ from that of the Investor Class, depending on the expenses of that class.

When determining whether to sell a security, the portfolio managers consider, among other things, the fund's average maturity, current and anticipated changes in interest rates, current valuation relative to alternatives in the market, general market conditions and any other factors deemed relevant by the portfolio managers.

Securities issued or guaranteed by the U.S. Treasury and certain U.S. government agencies or instrumentalities are supported by the full faith and credit of the U.S. government. Zero-coupon U.S. government agency securities that are ultimately backed by securities or payment obligations of the U.S. Treasury and are considered by the market to be of comparable credit quality, such as Resolution Funding Corporation (REFCORP) bonds, are considered to be zero-coupon U.S. Treasury equivalents by the fund's managers. Securities issued or guaranteed by other U.S. government agencies or instrumentalities, such as the Federal National Mortgage Association (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac), and the Federal Home Loan Bank, are not guaranteed by the U.S. Treasury or supported by the full faith and credit of the U.S. government. However, these agencies or instrumentalities are authorized to borrow from the U.S. Treasury to meet their obligations.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Risk - Generally, when interest rates rise, the fund’s share value will decline. The opposite is true when interest rates decline. Funds with longer weighted average maturities are more sensitive to interest rate changes. Additionally, in extreme low interest rate environments, the fund’s expenses may exceed the yields on the securities in which the fund invests, resulting in a negative anticipated growth rate (AGR). You may lose money as a result of holding fund shares with a negative AGR.

• Unanticipated Capital Gains or Losses - When shareholders redeem their shares before the target maturity date, the fund may need to liquidate holdings to meet these redemptions and unanticipated capital gains or losses may result. The fund will distribute these capital gains or losses to all shareholders.

• Zero-Coupon U.S. Treasury Correlation - Although the fund's investment policies are designed to provide an investment that is similar to investing in a zero-coupon U.S. Treasury security that matures in the year 2025, a precise forecast of the fund's final maturity value and yield to maturity is not possible.

• Market Risk - The value of the securities owned by the fund may go up and down, sometimes rapidly or unpredictably.

• Principal Loss - At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.

An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.

Risk Lose Money [Text]

rr_RiskLoseMoney

Principal Loss - At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Fund Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Investor Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. The table also shows results for a U.S. Treasury zero-coupon security (STRIPS Issue) with a maturity date similar to the fund. The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. For current performance information, including yields, please visit americancentury.com.

Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund's performance from year to year for Investor Class shares. The table shows how the fund's average annual returns for the periods shown compared with those of a broad measure of market performance.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

The table also shows results for a U.S. Treasury zero-coupon security (STRIPS Issue) with a maturity date similar to the fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

americancentury.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Calendar Year Total Returns

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Performance Quarter (3Q 2011): 24.74%

Lowest Performance Quarter (4Q 2010): -10.90%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Performance Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2011

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

24.74%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Performance Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2010

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(10.90%)

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns For the calendar year ended December 31, 2012

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown only for Investor Class shares. After-tax returns for other share classes will vary.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

The after-tax returns are shown only for Investor Class shares. After-tax returns for other share classes will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.

ZERO COUPON 2025 FUND | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $10,000)

rr_MaximumAccountFee

25

Management Fee

rr_ManagementFeesOverAssets

0.55%

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

none

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.55%

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

56

3 Years

rr_ExpenseExampleNoRedemptionYear03

177

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

308

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

690

Annual Return 2003

rr_AnnualReturn2003

2.03%

Annual Return 2004

rr_AnnualReturn2004

16.38%

Annual Return 2005

rr_AnnualReturn2005

14.49%

Annual Return 2006

rr_AnnualReturn2006

(1.21%)

Annual Return 2007

rr_AnnualReturn2007

9.43%

Annual Return 2008

rr_AnnualReturn2008

26.50%

Annual Return 2009

rr_AnnualReturn2009

(20.96%)

Annual Return 2010

rr_AnnualReturn2010

15.05%

Annual Return 2011

rr_AnnualReturn2011

30.35%

Annual Return 2012

rr_AnnualReturn2012

5.71%

1 Year

rr_AverageAnnualReturnYear01

5.71%

5 Years

rr_AverageAnnualReturnYear05

9.64%

10 Years

rr_AverageAnnualReturnYear10

8.82%

ZERO COUPON 2025 FUND | ADVISOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $10,000)

rr_MaximumAccountFee

none

Management Fee

rr_ManagementFeesOverAssets

0.55%

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

none

Total Annual Fund Operating Expenses

rr_NetExpensesOverAssets

0.80%

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

82

3 Years

rr_ExpenseExampleNoRedemptionYear03

256

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

445

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

990

1 Year

rr_AverageAnnualReturnYear01

5.46%

5 Years

rr_AverageAnnualReturnYear05

9.36%

10 Years

rr_AverageAnnualReturnYear10

8.54%

ZERO COUPON 2025 FUND | After Taxes on Distributions | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

4.10%

5 Years

rr_AverageAnnualReturnYear05

7.73%

10 Years

rr_AverageAnnualReturnYear10

6.65%

ZERO COUPON 2025 FUND | After Taxes on Distributions and Sales | INVESTOR CLASS

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

4.54%

5 Years

rr_AverageAnnualReturnYear05

7.34%

10 Years

rr_AverageAnnualReturnYear10

6.50%

ZERO COUPON 2025 FUND | November 15, 2025 STRIPS Issue

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

6.20%

5 Years

rr_AverageAnnualReturnYear05

11.17%

10 Years

rr_AverageAnnualReturnYear10

9.53%

ZERO COUPON 2025 FUND | BofA Merrill Lynch 10+ Year U.S. Treasury Index

[RiskReturnAbstract]

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.67%

5 Years

rr_AverageAnnualReturnYear05

9.61%

10 Years

rr_AverageAnnualReturnYear10

7.61%