Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	MONEY MARKET OBLIGATIONS TRUST
Prospectus Date	rr_ProspectusDate	Jun. 02, 2015
Cash II Shares | Federated Trust for U.S. Treasury Obligations
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Federated Trust for U.S. Treasury Obligations (the “Fund”)
Objective [Heading]	rr_ObjectiveHeading	RISK/RETURN SUMMARY: INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund is a money market fund that seeks to maintain a stable net asset value (NAV) of $1.00 per Share. The Fund's investment objective is to provide stability of principal and current income consistent with stability of principal.
Expense [Heading]	rr_ExpenseHeading	RISK/RETURN SUMMARY: 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 Cash II Shares (CII) 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)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	July 1, 2016
Fee Waiver Or Reimbursement Over Assets Later Of Termination Or Next Effective Prospectus	mmot_FeeWaiverOrReimbursementOverAssetsLaterOfTerminationOrNextEffectiveProspectus	up to but not including the later of (the “Termination Date”): (a) July 1, 2016; or (b) the date of the Fund's next effective Prospectus.
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Because the Fund's Cash II Shares are new, “Other Expenses” are based on estimated amounts for the current fiscal year.
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 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 operating expenses are based on the contractual limitation as shown in the table above and remain the same. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	RISK/RETURN SUMMARY: INVESTMENTS, RISKS and PERFORMANCE What are the Fund's Main Investment Strategies?
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests exclusively in a portfolio of U.S. Treasury securities maturing in 397 days or less, as well as repurchase agreements collateralized fully by U.S. Treasury securities. The Fund may also hold cash. In pursuing its investment objective and implementing its investment strategies, the Fund will comply with Rule 2a-7 under the Investment Company Act of 1940 (“Rule 2a-7”). Because the Fund refers to U.S. Treasury investments in its name, the SEC requires the Fund to notify shareholders at least 60 days in advance of any change in its investment policies that would enable the Fund to normally invest less than 80% of its assets (plus any borrowings for investment purposes) in U.S. Treasury investments.
Risk [Heading]	rr_RiskHeading	What are the Main Risks of Investing in the Fund?
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	All mutual funds take investment risks. Therefore, even though the Fund is a money market fund that seeks to maintain a stable NAV, it is possible to lose money by investing in the Fund. The primary factors that may negatively impact the Fund's ability to maintain a stable NAV, delay the payment of redemptions by the Fund, or reduce the Fund's daily dividends include: Interest Rate Risk. Prices of U.S. Treasury securities generally fall when interest rates rise. Interest rate changes have a greater effect on the price of U.S. Treasury securities with longer maturities. Counterparty Credit Risk. A party to a transaction involving the Fund may fail to meet its obligations. This could cause the Fund to lose money or to lose the benefit of the transaction or prevent the Fund from selling or buying other securities to implement its investment strategies. Risk Associated with Investing Share Purchase Proceeds. On days during which there are net purchases of Fund Shares, the Fund must invest the proceeds at prevailing market yields or hold cash. If the Fund holds cash, or if the yield of the securities purchased is less than that of the securities already in the portfolio, the Fund's yield will likely decrease. Conversely, net purchases on days on which short-term yields rise will likely cause the Fund's yield to increase. In the event of significant changes in short-term yields or significant net purchases, the Fund retains the discretion to close to new investments. However, the Fund is not required to close, and no assurance can be given that this will be done in any given circumstance. Risk Associated with use of Amortized Cost. In the unlikely event that the Fund's Board of Trustees (“Board”) were to determine, pursuant to Rule 2a-7, that the extent of the deviation between the Fund's amortized cost per Share and its market-based NAV per Share may result in material dilution or other unfair results to shareholders, the Board will cause the Fund to take such action as it deems appropriate to eliminate or reduce to the extent practicable such dilution or unfair results. Additional Factors Affecting Yield. There is no guarantee that the Fund will provide a certain level of income or that any such income will exceed the rate of inflation. Further, the Fund's yield will vary. Risk Related to the Economy. The value of the Fund's portfolio may decline in tandem with a drop in one or more markets in which the Fund invests. Economic, political and financial conditions may, from time to time, cause the Fund to experience volatility, illiquidity, shareholder redemptions, or other potentially adverse effects. Regulatory Reform Risk. Changes in the laws and regulations applicable to and governing money market funds, such as Rule 2a-7 under the Investment Company Act of 1940 (“1940 Act”), can impact the Fund. On July 23, 2014, the SEC voted to amend Rule 2a-7 and other rules and forms related to money market funds. These amendments may affect the manner in which the Fund is structured and operated, as well as the Fund's expenses and returns. Compliance with many of these amendments will be required on October 14, 2016, two years after the effective date for the amendments. U.S. government money market funds are exempt from a number of the changes required by these amendments. As a result of these amendments, the Fund may be required to take certain steps that impact the Fund and the precise nature of such impact has not yet been determined. Technology Risk. The Adviser uses various technologies in managing the Fund, consistent with its investment objective and strategy described in this Prospectus. For example, proprietary and third-party data and systems are utilized to support decision making for the Fund.  Data imprecision, software or other technology malfunctions, programming inaccuracies and similar circumstances may impair the performance of these systems, which may negatively affect Fund performance. The Shares offered by this Prospectus are not deposits or obligations of any bank, are not endorsed or guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	All mutual funds take investment risks. Therefore, even though the Fund is a money market fund that seeks to maintain a stable NAV, it is possible to lose money by investing in the Fund. The primary factors that may negatively impact the Fund's ability to maintain a stable NAV, delay the payment of redemptions by the Fund, or reduce the Fund's daily dividends include:
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	The Shares offered by this Prospectus are not deposits or obligations of any bank, are not endorsed or guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	PERFORMANCE: BAR CHART AND TABLE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	A performance bar chart and total return information for the Shares of the Fund will be provided after the Shares of the Fund have been in operation for a full calendar year. Updated performance information for the Fund is available under the “Products” section at FederatedInvestors.com or by calling 1-800-341-7400.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	A performance bar chart and total return information for the Shares of the Fund will be provided after the Shares of the Fund have been in operation for a full calendar year.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-341-7400
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	FederatedInvestors.com
Cash II Shares | Federated Trust for U.S. Treasury Obligations | CII
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, as applicable)	rr_MaximumDeferredSalesChargeOverOther	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentageof offering price)	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee (as a percentage of amount redeemed, if applicable)	rr_RedemptionFeeOverRedemption	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fee	rr_ManagementFeesOverAssets	0.20%
Distribution (12b-1) Fee	rr_DistributionAndService12b1FeesOverAssets	0.35%
Other Expenses	rr_OtherExpensesOverAssets	0.61%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.16%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	0.26%	[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.90%
1 Year	rr_ExpenseExampleYear01	118
3 Years	rr_ExpenseExampleYear03	368
5 Years	rr_ExpenseExampleYear05	638
10 Years	rr_ExpenseExampleYear10	1,409

[1] Because the Fund's Cash II Shares are new, "Other Expenses" are based on estimated amounts for the current fiscal year.

[2] The Adviser and certain of its affiliates, on their own initiative, have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (excluding acquired fund fees and expenses, extraordinary expenses, and proxy-related expenses paid by the Fund, if any) paid by the Fund's CII class (after the voluntary waivers and/or reimbursements) will not exceed 0.90% (the "Fee Limit") up to but not including the later of (the "Termination Date"): (a) July 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Fund's Board of Trustees.