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Risk/Return: rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName T. Rowe Price U.S. Treasury Funds, Inc.
Prospectus Date rr_ProspectusDate Oct. 01, 2012
U.S. Treasury Intermediate Fund
  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading U.S. Treasury Intermediate Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks a high level of income consistent with maximum credit protection and moderate fluctuation in principal.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock This table describes the fees and expenses that you may pay if you buy and hold shares of the fund.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Fees and Expenses of the Fund
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 56.9% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 56.90%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock This example is intended to help you compare the cost of investing in 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 of 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 remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] rr_StrategyHeading Investments, Risks, and Performance

Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock The fund invests at least 80% of its net assets (including any borrowings for investment purposes) in U.S. Treasury securities, which are backed by the full faith and credit of the federal government. The remainder is invested in other securities backed by the full faith and credit of the U.S. government. The fund’s weighted average maturity is expected to normally range between three and ten years.

U.S. Treasury securities in which the fund may invest include Treasury bills, notes, and bonds, and repurchase agreements thereon, as well as Treasury inflation protected securities and Treasury STRIPS, which are zero-coupon securities created by separating the principal and interest payments on U.S. Treasury securities.

The fund’s other investments include the following:
  • Securities backed by the full faith and credit of the U.S. government (including, but not limited to securities issued by Government National Mortgage Association and other government agencies, and certain corporate debt securities guaranteed by the Federal Deposit Insurance Corporation) and repurchase agreements thereon;
  • Futures agreements collateralized by such investments; and
  • Shares of a T. Rowe Price internal money fund or short-term bond fund that invests exclusively in securities backed by the full faith and credit of the U.S. government.
The fund may sell holdings for a variety of reasons, such as to adjust the portfolio’s average maturity or to shift assets into and out of higher-yielding securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. While U.S. government-backed securities generally are considered to be among the highest credit quality, they are subject to market risk. The U.S. government guarantees the timely payment of interest and principal on Treasury securities but does not guarantee their price. The principal risks of investing in this fund are summarized as follows:

Active management risk The fund is subject to the risk that the investment adviser’s judgments about the attractiveness, value, or potential appreciation of the fund’s investments may prove to be incorrect. If the securities selected and strategies employed by the fund fail to produce the intended results, the fund could underperform other funds with similar objectives and investment strategies.

Interest rate risk This is the risk that a rise in interest rates will cause the price of a fixed rate debt security to fall. Prices fall because the bonds and notes in the fund’s portfolio become less attractive to other investors when securities with higher yields become available. Generally, securities with longer maturities and funds with longer weighted average maturities carry greater interest rate risk.

Credit risk This is the risk that an issuer of a debt security could suffer an adverse change in financial condition that results in a payment default, security downgrade, or inability to meet a financial obligation. The fund should have relatively low credit risk because it invests only in securities backed by the U.S. government and other investments involving such securities.

Liquidity risk This is the risk that the fund may not be able to sell a holding in a timely manner at a desired price.

Repurchase agreement risk This is the risk that a counterparty to a repurchase agreement becomes insolvent or fails to repurchase securities from the fund as required, which could increase the fund’s costs or prevent the fund from immediately accessing its collateral.

Derivatives risk To the extent the fund uses futures, it is exposed to additional volatility in comparison to investing directly in bonds and other debt securities. Futures can be illiquid and difficult to value and involve the risk that anticipated interest rate movements will not be accurately predicted. Treasury STRIPS are less liquid, potentially more volatile, and have a higher sensitivity to changes in interest rates than Treasury bonds with the same maturity.
Risk Lose Money [Text] rr_RiskLoseMoney The fund’s share price fluctuates, which means you could lose money by investing in the fund.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index. The fund’s past performance (before and after taxes) is not necessarily an indication of future performance.

The fund can also experience short-term performance swings, as shown by the best and worst calendar quarter returns during the years depicted.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart showing calendar year returns and the average annual total returns table indicate risk by illustrating how much returns can differ from one year to the next and how fund performance compares with that of a comparable market index.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-225-5132
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress troweprice.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 future performance.
Bar Chart [Heading] rr_BarChartHeading
U.S. Treasury Intermediate Fund
Calendar Year Returns
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
  Quarter Total
  Ended  Return
Best Quarter12/31/088.51%
Worst Quarter             12/31/10        -3.09%

 The fund's return for the six months ended 6/30/12 was 2.14%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns
Periods ended
December 31, 2011
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 shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock In addition, the average annual total returns table shows hypothetical after-tax returns to suggest how taxes paid by a shareholder may influence returns. 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 shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or individual retirement account.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock Updated performance information is available through troweprice.com or may be obtained by calling 1-800-225-5132.
U.S. Treasury Intermediate Fund | U.S. Treasury Intermediate Fund
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) rr_MaximumDeferredSalesChargeOverOfferingPrice none
Redemption fee rr_RedemptionFeeOverRedemption none
Maximum account fee rr_MaximumAccountFee 20 [1]
Management fees rr_ManagementFeesOverAssets 0.30%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.19%
Total annual fund operating expenses rr_ExpensesOverAssets 0.49%
1 year rr_ExpenseExampleYear01 50
3 years rr_ExpenseExampleYear03 157
5 years rr_ExpenseExampleYear05 274
10 years rr_ExpenseExampleYear10 616
2002 rr_AnnualReturn2002 12.02%
2003 rr_AnnualReturn2003 1.83%
2004 rr_AnnualReturn2004 1.17%
2005 rr_AnnualReturn2005 1.50%
2006 rr_AnnualReturn2006 2.51%
2007 rr_AnnualReturn2007 9.91%
2008 rr_AnnualReturn2008 14.10%
2009 rr_AnnualReturn2009 (1.37%)
2010 rr_AnnualReturn2010 7.04%
2011 rr_AnnualReturn2011 10.43%
Year to Date Return, Label rr_YearToDateReturnLabel The fund's return for the six months ended 6/30/12
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Jun. 30, 2012
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 2.14%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Best Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2008
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 8.51%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Worst Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Dec. 31, 2010
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (3.09%)
1 Year rr_AverageAnnualReturnYear01 none
5 Years rr_AverageAnnualReturnYear05 7.90%
10 Years rr_AverageAnnualReturnYear10 5.79%
U.S. Treasury Intermediate Fund | Returns after taxes on distributions | U.S. Treasury Intermediate Fund
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 9.24%
5 Years rr_AverageAnnualReturnYear05 6.47%
10 Years rr_AverageAnnualReturnYear10 4.49%
U.S. Treasury Intermediate Fund | Returns after taxes on distributions and sale of fund shares | U.S. Treasury Intermediate Fund
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 6.88%
5 Years rr_AverageAnnualReturnYear05 5.99%
10 Years rr_AverageAnnualReturnYear10 4.29%
U.S. Treasury Intermediate Fund | Barclays U.S. 4-10 Year Treasury Bond Index (reflects no deduction for fees, expenses, or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 11.68%
5 Years rr_AverageAnnualReturnYear05 8.16%
10 Years rr_AverageAnnualReturnYear10 6.40%
U.S. Treasury Intermediate Fund | Lipper General U.S. Treasury Funds Average
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 15.83%
5 Years rr_AverageAnnualReturnYear05 6.99%
10 Years rr_AverageAnnualReturnYear10 6.97%
[1] Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.