XML 13 R12.htm IDEA: XBRL DOCUMENT v2.4.0.6
Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Document Type dei_DocumentType 485BPOS
Document Period End Date dei_DocumentPeriodEndDate Sep. 30, 2011
Registrant Name dei_EntityRegistrantName PUTNAM MONEY MARKET FUND
Central Index Key dei_EntityCentralIndexKey 0000081248
Amendment Flag dei_AmendmentFlag false
Document Creation Date dei_DocumentCreationDate Jan. 27, 2012
Document Effective Date dei_DocumentEffectiveDate Jan. 30, 2012
Prospectus Date rr_ProspectusDate Jan. 30, 2012
Risk/Return [Heading] rr_RiskReturnHeading Fund summaries
Putnam Money Market Fund
  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading PUTNAM MONEY MARKET FUND
Objective [Heading] rr_ObjectiveHeading Goal
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock Putnam Money Market Fund seeks as high a rate of current income as we believe is consistent with preservation of capital and maintenance of liquidity.
Fees and expenses pmmf81248_FundFeesAndExpensesAbstract  
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 rr_ShareholderFeesAbstract  
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder fees (fees paid directly from your investment)
Annual fund operating expenses rr_OperatingExpensesAbstract  
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual fund operating expenses (expenses you pay each year as a percentage of the value of your investment)
Expense Example rr_ExpenseExampleAbstract  
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. It assumes that you invest $10,000 in the fund for the time periods indicated and then, except as indicated, redeem all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same. Your actual costs may be higher or lower.
Strategy [Heading] rr_StrategyHeading Investments
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock We invest mainly in money market instruments that are high quality and have short-term maturities. We invest significantly in certificates of deposit, commercial paper (including asset-backed commercial paper), U.S. government debt and repurchase agreements, corporate obligations and bankers acceptances. We may also invest in U.S. dollar denominated foreign securities of these types. We may consider, among other factors, credit and interest rate risks, as well as general market conditions, when deciding whether to buy or sell investments.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration We invest mainly in money market instruments that are high quality and have short-term maturities. We invest significantly in certificates of deposit, commercial paper (including asset-backed commercial paper), U.S. government debt and repurchase agreements, corporate obligations and bankers acceptances.
Risk [Heading] rr_RiskHeading Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

The effects of inflation may erode the value of your investment over time. Although the fund seeks to preserve the value of your investment at $1.00 per share, deterioration in the credit quality of issuers whose securities the fund holds or an increase in interest rates may impair the value of your investment, and it is possible to lose money by investing in the fund. The values of money market investments usually rise and fall in response to changes in interest rates. Interest rate risk is generally lowest for investments with short maturities (a significant part of the fund’s investments). Although the fund only buys high quality investments, investments backed by a letter of credit have the risk that the provider of the letter of credit will not be able to fulfill its obligations to the issuer.

The fund may not achieve its goal, and it is not intended to be a complete investment program. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Money Market Fund [Text] rr_RiskMoneyMarketFund The effects of inflation may erode the value of your investment over time. Although the fund seeks to preserve the value of your investment at $1.00 per share, deterioration in the credit quality of issuers whose securities the fund holds or an increase in interest rates may impair the value of your investment, and 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 insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Performance pmmf81248_FundPastPerformanceAbstract  
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time. Please remember that past performance is not necessarily an indication of future results. Monthly performance figures for the fund are available at putnam.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time.
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Please remember that past performance is not necessarily an indication of future results.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock Monthly performance figures for the fund are available at putnam.com.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress putnam.com
Annual Total Returns rr_BarChartTableAbstract  
Bar Chart [Heading] rr_BarChartHeading Annual total returns for class A shares
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Year-to-date performance

through 12/31/11

0.01%

Best calendar quarter

Q3 2007

1.26%

Worst calendar quarter

Q1 2011

0.00%
Year to Date Return, Label rr_YearToDateReturnLabel Year-to-date performance through
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Dec. 31, 2011
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 0.01%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Best calendar quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Sep. 30, 2007
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 1.26%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Worst calendar quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jan. 31, 2011
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn 0.00%
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Caption rr_AverageAnnualReturnCaption Average annual total returns after sales charges (for periods ending 12/31/11)
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock Class B share performance does not reflect conversion to class A shares.
Putnam Money Market Fund | Class A
  
Shareholder fees rr_ShareholderFeesAbstract  
Share class rr_ShareholderFeesColumnName Class A
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, whichever is lower) rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Annual fund operating expenses rr_OperatingExpensesAbstract  
Share class rr_OperatingExpensesColumnName Class A
Management fees rr_ManagementFeesOverAssets 0.29%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.50%
Expense Example rr_ExpenseExampleAbstract  
Share class rr_ExpenseExampleByYearColumnName Class A
1 year rr_ExpenseExampleYear01 51
3 years rr_ExpenseExampleYear03 160
5 years rr_ExpenseExampleYear05 280
10 years rr_ExpenseExampleYear10 628
Annual Total Returns rr_BarChartTableAbstract  
2002 rr_AnnualReturn2002 1.42%
2003 rr_AnnualReturn2003 0.72%
2004 rr_AnnualReturn2004 0.91%
2005 rr_AnnualReturn2005 2.81%
2006 rr_AnnualReturn2006 4.71%
2007 rr_AnnualReturn2007 4.97%
2008 rr_AnnualReturn2008 2.71%
2009 rr_AnnualReturn2009 0.29%
2010 rr_AnnualReturn2010 0.05%
2011 rr_AnnualReturn2011 0.01%
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Share class rr_AverageAnnualReturnColumnName Class A
1 year rr_AverageAnnualReturnYear01 0.01%
5 years rr_AverageAnnualReturnYear05 1.58%
10 years rr_AverageAnnualReturnYear10 1.84%
Putnam Money Market Fund | Class B
  
Shareholder fees rr_ShareholderFeesAbstract  
Share class rr_ShareholderFeesColumnName Class B
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, whichever is lower) rr_MaximumDeferredSalesChargeOverOther 5.00% [1]
Annual fund operating expenses rr_OperatingExpensesAbstract  
Share class rr_OperatingExpensesColumnName Class B
Management fees rr_ManagementFeesOverAssets 0.29%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 1.00%
Expense Example rr_ExpenseExampleAbstract  
Share class rr_ExpenseExampleByYearColumnName Class B
1 year rr_ExpenseExampleYear01 102
3 years rr_ExpenseExampleYear03 318
5 years rr_ExpenseExampleYear05 552
10 years rr_ExpenseExampleYear10 1,083
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Share class rr_AverageAnnualReturnColumnName Class B
1 year rr_AverageAnnualReturnYear01 (4.99%)
5 years rr_AverageAnnualReturnYear05 0.96%
10 years rr_AverageAnnualReturnYear10 1.47%
Putnam Money Market Fund | Class C
  
Shareholder fees rr_ShareholderFeesAbstract  
Share class rr_ShareholderFeesColumnName Class C
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, whichever is lower) rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Annual fund operating expenses rr_OperatingExpensesAbstract  
Share class rr_OperatingExpensesColumnName Class C
Management fees rr_ManagementFeesOverAssets 0.29%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 1.00%
Expense Example rr_ExpenseExampleAbstract  
Share class rr_ExpenseExampleByYearColumnName Class C
1 year rr_ExpenseExampleYear01 102
3 years rr_ExpenseExampleYear03 318
5 years rr_ExpenseExampleYear05 552
10 years rr_ExpenseExampleYear10 1,225
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Share class rr_AverageAnnualReturnColumnName Class C
1 year rr_AverageAnnualReturnYear01 (0.99%)
5 years rr_AverageAnnualReturnYear05 1.34%
10 years rr_AverageAnnualReturnYear10 1.47%
Putnam Money Market Fund | Class M
  
Shareholder fees rr_ShareholderFeesAbstract  
Share class rr_ShareholderFeesColumnName Class M
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, whichever is lower) rr_MaximumDeferredSalesChargeOverOther 0.15% [1]
Annual fund operating expenses rr_OperatingExpensesAbstract  
Share class rr_OperatingExpensesColumnName Class M
Management fees rr_ManagementFeesOverAssets 0.29%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.15%
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.65%
Expense Example rr_ExpenseExampleAbstract  
Share class rr_ExpenseExampleByYearColumnName Class M
1 year rr_ExpenseExampleYear01 66
3 years rr_ExpenseExampleYear03 208
5 years rr_ExpenseExampleYear05 362
10 years rr_ExpenseExampleYear10 810
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Share class rr_AverageAnnualReturnColumnName Class M
1 year rr_AverageAnnualReturnYear01 0.01%
5 years rr_AverageAnnualReturnYear05 1.51%
10 years rr_AverageAnnualReturnYear10 1.73%
Putnam Money Market Fund | Class R
  
Shareholder fees rr_ShareholderFeesAbstract  
Share class rr_ShareholderFeesColumnName Class R
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, whichever is lower) rr_MaximumDeferredSalesChargeOverOther none
Annual fund operating expenses rr_OperatingExpensesAbstract  
Share class rr_OperatingExpensesColumnName Class R
Management fees rr_ManagementFeesOverAssets 0.29%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 1.00%
Expense Example rr_ExpenseExampleAbstract  
Share class rr_ExpenseExampleByYearColumnName Class R
1 year rr_ExpenseExampleYear01 102
3 years rr_ExpenseExampleYear03 318
5 years rr_ExpenseExampleYear05 552
10 years rr_ExpenseExampleYear10 1,225
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Share class rr_AverageAnnualReturnColumnName Class R
1 year rr_AverageAnnualReturnYear01 0.01%
5 years rr_AverageAnnualReturnYear05 1.34%
10 years rr_AverageAnnualReturnYear10 1.49%
Putnam Money Market Fund | Class T
  
Shareholder fees rr_ShareholderFeesAbstract  
Share class rr_ShareholderFeesColumnName Class T
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, whichever is lower) rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Annual fund operating expenses rr_OperatingExpensesAbstract  
Share class rr_OperatingExpensesColumnName Class T
Management fees rr_ManagementFeesOverAssets 0.29%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.21%
Total annual fund operating expenses rr_ExpensesOverAssets 0.75%
Expense Example rr_ExpenseExampleAbstract  
Share class rr_ExpenseExampleByYearColumnName Class T
1 year rr_ExpenseExampleYear01 77
3 years rr_ExpenseExampleYear03 240
5 years rr_ExpenseExampleYear05 417
10 years rr_ExpenseExampleYear10 930
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Share class rr_AverageAnnualReturnColumnName Class T
1 year rr_AverageAnnualReturnYear01 0.01%
5 years rr_AverageAnnualReturnYear05 1.46%
10 years rr_AverageAnnualReturnYear10 1.65%
Putnam Money Market Fund | Lipper Money Market Funds Category Average
  
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Label rr_AverageAnnualReturnLabel Lipper Money Market Funds Category Average
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (no deduction for taxes)
1 year rr_AverageAnnualReturnYear01 0.02%
5 years rr_AverageAnnualReturnYear05 1.36%
10 years rr_AverageAnnualReturnYear10 1.56%
Putnam Tax Exempt Money Market Fund
  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading PUTNAM TAX EXEMPT MONEY MARKET FUND
Objective [Heading] rr_ObjectiveHeading Goal
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock Putnam Tax Exempt Money Market Fund seeks as high a rate of current income exempt from federal income tax as we believe is consistent with preservation of capital and maintenance of liquidity.
Fees and expenses pmmf81248_FundFeesAndExpensesAbstract  
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 rr_ShareholderFeesAbstract  
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder fees (fees paid directly from your investment)
Annual fund operating expenses rr_OperatingExpensesAbstract  
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual fund operating expenses (expenses you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination January 30, 2013
Expense Example rr_ExpenseExampleAbstract  
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. It assumes that you invest $10,000 in the fund for the time periods indicated and then, except as indicated, redeem all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same. Only the first year of each period in the example takes into account the expense reimbursement described above. Your actual costs may be higher or lower.
Strategy [Heading] rr_StrategyHeading Investments
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock We invest mainly in money market instruments that pay interest that is exempt from federal income tax but may be subject to the federal alternative minimum tax (AMT), are high quality and have short-term maturities. We may consider, among other factors, credit and interest rate risks, as well as general market conditions, when deciding whether to buy or sell investments.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration We invest mainly in money market instruments that pay interest that is exempt from federal income tax but may be subject to the federal alternative minimum tax (AMT), are high quality and have short-term maturities.
Risk [Heading] rr_RiskHeading Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

The effects of inflation may erode the value of your investment over time. Although the fund seeks to preserve the value of your investment at $1.00 per share, deterioration in the credit quality of issuers whose securities the fund holds or an increase in interest rates may impair the value of your investment, and it is possible to lose money by investing in the fund. The values of money market investments usually rise and fall in response to changes in interest rates. Interest rate risk is generally lowest for investments with short maturities (a significant part of the fund’s investments). Although the fund only buys high quality investments, investments backed by a letter of credit have the risk that the provider of the letter of credit will not be able to fulfill its obligations to the issuer. The amount of information about issuers of tax exempt debt may not be as extensive as that which is available about companies whose securities are publicly traded. Interest the fund receives might be taxable.

The fund may not achieve its goal, and it is not intended to be a complete investment program. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Money Market Fund [Text] rr_RiskMoneyMarketFund The effects of inflation may erode the value of your investment over time. Although the fund seeks to preserve the value of your investment at $1.00 per share, deterioration in the credit quality of issuers whose securities the fund holds or an increase in interest rates may impair the value of your investment, and 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 insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Performance pmmf81248_FundPastPerformanceAbstract  
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time. Please remember that past performance is not necessarily an indication of future results. Monthly performance figures for the fund are available at putnam.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time.
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Please remember that past performance is not necessarily an indication of future results.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock Monthly performance figures for the fund are available at putnam.com.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress putnam.com
Annual Total Returns rr_BarChartTableAbstract  
Bar Chart [Heading] rr_BarChartHeading Annual total returns for class A shares
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

Best calendar quarter

Q2 2007

0.81%

Worst calendar quarter

Q4 2010

0.00%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Best calendar quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2007
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 0.81%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Worst calendar quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Dec. 31, 2010
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn 0.00%
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Caption rr_AverageAnnualReturnCaption Average annual total returns (for periods ending 12/31/11)
Putnam Tax Exempt Money Market Fund | Class A
  
Shareholder fees rr_ShareholderFeesAbstract  
Share class rr_ShareholderFeesColumnName Class A
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, whichever is lower) rr_MaximumDeferredSalesChargeOverOther 1.00% [2]
Annual fund operating expenses rr_OperatingExpensesAbstract  
Share class rr_OperatingExpensesColumnName Class A
Management fees rr_ManagementFeesOverAssets 0.29%
Distribution and service (12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.28%
Total annual fund operating expenses rr_ExpensesOverAssets 0.57%
Expense reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.02%) [3]
Total annual fund operating expenses after expense reimbursement rr_NetExpensesOverAssets 0.55%
Expense Example rr_ExpenseExampleAbstract  
Share class rr_ExpenseExampleByYearColumnName Class A
1 year rr_ExpenseExampleYear01 56
3 years rr_ExpenseExampleYear03 181
5 years rr_ExpenseExampleYear05 316
10 years rr_ExpenseExampleYear10 712
Annual Total Returns rr_BarChartTableAbstract  
2002 rr_AnnualReturn2002 0.97%
2003 rr_AnnualReturn2003 0.56%
2004 rr_AnnualReturn2004 0.59%
2005 rr_AnnualReturn2005 1.86%
2006 rr_AnnualReturn2006 2.92%
2007 rr_AnnualReturn2007 3.14%
2008 rr_AnnualReturn2008 1.74%
2009 rr_AnnualReturn2009 0.06%
2010 rr_AnnualReturn2010 0.03%
2011 rr_AnnualReturn2011 0.01%
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Share class rr_AverageAnnualReturnColumnName Class A
1 year rr_AverageAnnualReturnYear01 0.01%
5 years rr_AverageAnnualReturnYear05 0.99%
10 years rr_AverageAnnualReturnYear10 1.18%
Putnam Tax Exempt Money Market Fund | Lipper Tax Exempt Money Market Funds Category Average
  
Average Annual Total Returns rr_AverageAnnualReturnAbstract  
Label rr_AverageAnnualReturnLabel Lipper Tax Exempt Money Market Funds Category Average
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (no deduction for taxes)
1 year rr_AverageAnnualReturnYear01 0.02%
5 years rr_AverageAnnualReturnYear05 0.99%
10 years rr_AverageAnnualReturnYear10 1.18%
[1] A deferred sales charge on class A, B, C, and T shares may apply to certain redemptions of shares purchased by exchange from another Putnam fund. A deferred sales charge on class M shares may apply to redemptions of shares from certain rollover accounts.
[2] A deferred sales charge on class A shares may apply to certain redemptions of shares purchased by exchange from another Putnam fund.
[3] Reflects Putnam Investment Management, LLC's contractual obligation to limit certain fund expenses through January 30, 2013. This obligation may be notified or discontinued only with approval of the Board of Trustees.