Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

GEORGE PUTNAM BALANCED FUND

Prospectus Date

rr_ProspectusDate

Nov. 30, 2014

GEORGE PUTNAM FUND OF BOSTON

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund summary

Objective [Heading]

rr_ObjectiveHeading

Goal

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

George Putnam Balanced Fund seeks to provide a balanced investment composed of a well-diversified portfolio of stocks and bonds which produce both capital growth and current income.

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. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Putnam funds. More information about these and other discounts is available from your financial advisor and in How do I buy fund shares? beginning on page 16 of the fund’s prospectus and in How to buy shares beginning on page II-1 of the fund’s statement of additional information (SAI).

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 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-related costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or the above example, affect fund performance. The fund’s turnover rate in the most recent fiscal year was 98%.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

98.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Putnam funds. More information about these and other discounts is available from your financial advisor and in How do I buy fund shares? beginning on page 16 of the fund’s prospectus and in How to buy shares beginning on page II-1 of the fund’s statement of additional information (SAI).

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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 a combination of bonds and common stocks (growth or value stocks or both) of large U.S. companies, with a greater focus on common stocks. For example, we may purchase stocks of companies with stock prices that reflect a value lower than that which we place on the company. We may also consider other factors that we believe will cause the stock price to rise. We buy bonds of governments and private companies that are mostly investment-grade in quality with intermediate- to long-term maturities (three years or longer). We may consider, among other factors, a company’s valuation, financial strength, growth potential, competitive position in its industry, projected future earnings, cash flows and dividends when deciding whether to buy or sell equity investments, and, among other factors, credit, interest rate and prepayment risks, as well as general market conditions, when deciding whether to buy or sell fixed income investments. We may also use derivatives, such as futures, options, warrants and swap contracts, for both hedging and non-hedging purposes.

Risk [Heading]

rr_RiskHeading

Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

It is important to understand that you can lose money by investing in the fund.

The value of stocks and bonds in the fund’s portfolio may fall or fail to rise over extended periods of time for a variety of reasons, including general financial market conditions, changing market perceptions of the risk of default, changes in government intervention in the financial markets, and factors related to a specific issuer or industry. These factors may also lead to periods of high volatility and reduced liquidity in the bond markets. Growth stocks may be more susceptible to earnings disappointments, and value stocks may fail to rebound. Bond investments are subject to interest rate risk, which means the value of the fund’s bond investments is likely to fall if interest rates rise. Bond investments also are subject to credit risk, which is the risk that the issuer of the bond may default on payment of interest or principal. Interest rate risk is generally greater for longer-term bonds, and credit risk is generally greater for below-investment-grade bonds (sometimes referred to as “junk bonds”), which may be considered speculative. Our use of derivatives may increase these risks by increasing investment exposure or, in the case of many over-the-counter instruments, because of the potential inability to terminate or sell derivatives positions and the potential failure of the other party to the instrument to meet its obligations.

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 Lose Money [Text]

rr_RiskLoseMoney

It is important to understand that you can 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.

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. The bar chart does not reflect the impact of sales charges. If it did, performance would be lower. 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 Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

The fund’s performance is compared to the Barclays U.S. Aggregate Bond Index, an unmanaged index of U.S. investment-grade fixed income securities. The fund’s performance is also compared to the S&P 500 Index, an unmanaged index of large U.S. company stocks. In addition, the fund’s performance is compared to the George Putnam Blended Index, an unmanaged index administered by Putnam Management, 60% of which is the S&P 500 Index and 40% of which is the Barclays U.S. Aggregate Bond Index.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

putnam.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Please remember that past performance is not necessarily an indication of future results.

Bar Chart [Heading]

rr_BarChartHeading

Annual total returns for class A shares before sales charges

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

The bar chart does not reflect the impact of sales charges. If it did, performance would be lower.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Year-to-date performance through 9/30/14	6.79%
Best calendar quarter Q2 2009	12.57%
Worst calendar quarter Q4 2008	-26.96%

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-date performance through

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2014

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

6.79%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best calendar quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

12.57%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst calendar quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(26.96%)

Performance Table Heading

rr_PerformanceTableHeading

Average annual total returns after sales charges
(for periods ending 12/31/13)

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

As of May 30, 2014, the S&P 500 Index replaced the Russell 1000 Value Index as the primary benchmark for the equity portion of the fund’s portfolio because, in Putnam Management’s opinion, it is more representative than the Russell 1000 Value Index of the large company stocks in which the fund invests.

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns reflect the historical highest individual federal marginal income tax rates and do not reflect 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.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax returns are shown for class A shares only and will vary for other classes.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The fund’s performance is compared to the Barclays U.S. Aggregate Bond Index, an unmanaged index of U.S. investment-grade fixed income securities. The fund’s performance is also compared to the S&P 500 Index, an unmanaged index of large U.S. company stocks. In addition, the fund’s performance is compared to the George Putnam Blended Index, an unmanaged index administered by Putnam Management, 60% of which is the S&P 500 Index and 40% of which is the Barclays U.S. Aggregate Bond Index.

As of May 30, 2014, the S&P 500 Index replaced the Russell 1000 Value Index as the primary benchmark for the equity portion of the fund’s portfolio because, in Putnam Management’s opinion, it is more representative than the Russell 1000 Value Index of the large company stocks in which the fund invests. The average annual total returns of the Russell 1000 Value Index for the one-year, five-year and ten-year periods ending on December 31, 2013 were 32.53%, 16.67% and 7.58%.

After-tax returns reflect the historical highest individual federal marginal income tax rates and do not reflect 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 shown for class A shares only and will vary for other classes. These after-tax returns do not apply if you hold your fund shares through a 401(k) plan, an IRA, or another tax-advantaged arrangement.

Class B share performance reflects conversion to class A shares after eight years.

GEORGE PUTNAM FUND OF BOSTON | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.99%

1 year

rr_ExpenseExampleYear01

670

3 years

rr_ExpenseExampleYear03

872

5 years

rr_ExpenseExampleYear05

1,091

10 years

rr_ExpenseExampleYear10

1,718

2004

rr_AnnualReturn2004

8.32%

2005

rr_AnnualReturn2005

4.04%

2006

rr_AnnualReturn2006

12.25%

2007

rr_AnnualReturn2007

0.92%

2008

rr_AnnualReturn2008

(40.30%)

2009

rr_AnnualReturn2009

25.80%

2010

rr_AnnualReturn2010

11.15%

2011

rr_AnnualReturn2011

2.71%

2012

rr_AnnualReturn2012

12.36%

2013

rr_AnnualReturn2013

17.76%

1 year

rr_AverageAnnualReturnYear01

10.99%

5 years

rr_AverageAnnualReturnYear05

12.36%

10 years

rr_AverageAnnualReturnYear10

3.16%

GEORGE PUTNAM FUND OF BOSTON | Class B

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, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

5.00%

^[2]

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.74%

1 year

rr_ExpenseExampleYear01

677

3 years

rr_ExpenseExampleYear03

848

5 years

rr_ExpenseExampleYear05

1,144

10 years

rr_ExpenseExampleYear10

1,853

1 year

rr_ExpenseExampleNoRedemptionYear01

177

3 years

rr_ExpenseExampleNoRedemptionYear03

548

5 years

rr_ExpenseExampleNoRedemptionYear05

944

10 years

rr_ExpenseExampleNoRedemptionYear10

1,853

1 year

rr_AverageAnnualReturnYear01

11.92%

5 years

rr_AverageAnnualReturnYear05

12.57%

10 years

rr_AverageAnnualReturnYear10

3.13%

GEORGE PUTNAM FUND OF BOSTON | Class C

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, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[3]

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.74%

1 year

rr_ExpenseExampleYear01

277

3 years

rr_ExpenseExampleYear03

548

5 years

rr_ExpenseExampleYear05

944

10 years

rr_ExpenseExampleYear10

2,052

1 year

rr_ExpenseExampleNoRedemptionYear01

177

3 years

rr_ExpenseExampleNoRedemptionYear03

548

5 years

rr_ExpenseExampleNoRedemptionYear05

944

10 years

rr_ExpenseExampleNoRedemptionYear10

2,052

1 year

rr_AverageAnnualReturnYear01

15.85%

5 years

rr_AverageAnnualReturnYear05

12.85%

10 years

rr_AverageAnnualReturnYear10

3.00%

GEORGE PUTNAM FUND OF BOSTON | Class M

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

3.50%

Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

0.65%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.75%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.49%

1 year

rr_ExpenseExampleYear01

496

3 years

rr_ExpenseExampleYear03

805

5 years

rr_ExpenseExampleYear05

1,135

10 years

rr_ExpenseExampleYear10

2,067

1 year

rr_AverageAnnualReturnYear01

13.08%

5 years

rr_AverageAnnualReturnYear05

12.31%

10 years

rr_AverageAnnualReturnYear10

2.89%

GEORGE PUTNAM FUND OF BOSTON | Class R

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, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.50%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.24%

1 year

rr_ExpenseExampleYear01

126

3 years

rr_ExpenseExampleYear03

393

5 years

rr_ExpenseExampleYear05

681

10 years

rr_ExpenseExampleYear10

1,500

1 year

rr_AverageAnnualReturnYear01

17.44%

5 years

rr_AverageAnnualReturnYear05

13.41%

10 years

rr_AverageAnnualReturnYear10

3.53%

GEORGE PUTNAM FUND OF BOSTON | Class R5

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, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

Other expenses

rr_OtherExpensesOverAssets

0.21%

^[4]

Total annual fund operating expenses

rr_ExpensesOverAssets

0.73%

1 year

rr_ExpenseExampleYear01

75

3 years

rr_ExpenseExampleYear03

233

5 years

rr_ExpenseExampleYear05

406

10 years

rr_ExpenseExampleYear10

906

1 year

rr_AverageAnnualReturnYear01

18.08%

^[5]

5 years

rr_AverageAnnualReturnYear05

13.98%

^[5]

10 years

rr_AverageAnnualReturnYear10

4.04%

^[5]

GEORGE PUTNAM FUND OF BOSTON | Class R6

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, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

Other expenses

rr_OtherExpensesOverAssets

0.11%

^[4]

Total annual fund operating expenses

rr_ExpensesOverAssets

0.63%

1 year

rr_ExpenseExampleYear01

64

3 years

rr_ExpenseExampleYear03

202

5 years

rr_ExpenseExampleYear05

351

10 years

rr_ExpenseExampleYear10

786

1 year

rr_AverageAnnualReturnYear01

18.08%

^[5]

5 years

rr_AverageAnnualReturnYear05

13.98%

^[5]

10 years

rr_AverageAnnualReturnYear10

4.04%

^[5]

GEORGE PUTNAM FUND OF BOSTON | Class Y

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, whichever is lower)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.52%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.74%

1 year

rr_ExpenseExampleYear01

76

3 years

rr_ExpenseExampleYear03

237

5 years

rr_ExpenseExampleYear05

411

10 years

rr_ExpenseExampleYear10

918

1 year

rr_AverageAnnualReturnYear01

18.08%

5 years

rr_AverageAnnualReturnYear05

13.98%

10 years

rr_AverageAnnualReturnYear10

4.04%

GEORGE PUTNAM FUND OF BOSTON | after taxes on distributions | Class A

Risk/Return:

rr_RiskReturnAbstract

1 year

rr_AverageAnnualReturnYear01

10.62%

5 years

rr_AverageAnnualReturnYear05

12.03%

10 years

rr_AverageAnnualReturnYear10

2.20%

GEORGE PUTNAM FUND OF BOSTON | after taxes on distributions and sale of fund shares | Class A

Risk/Return:

rr_RiskReturnAbstract

1 year

rr_AverageAnnualReturnYear01

6.49%

5 years

rr_AverageAnnualReturnYear05

9.93%

10 years

rr_AverageAnnualReturnYear10

2.42%

GEORGE PUTNAM FUND OF BOSTON | S&P 500 Index (no deduction for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 year

rr_AverageAnnualReturnYear01

32.39%

5 years

rr_AverageAnnualReturnYear05

17.94%

10 years

rr_AverageAnnualReturnYear10

7.41%

GEORGE PUTNAM FUND OF BOSTON | Barclays U.S. Aggregate Bond Index (no deduction for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 year

rr_AverageAnnualReturnYear01

(2.02%)

5 years

rr_AverageAnnualReturnYear05

4.44%

10 years

rr_AverageAnnualReturnYear10

4.55%

GEORGE PUTNAM FUND OF BOSTON | George Putnam Blended Index (no deduction for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 year

rr_AverageAnnualReturnYear01

17.57%

5 years

rr_AverageAnnualReturnYear05

12.94%

10 years

rr_AverageAnnualReturnYear10

6.86%

[1] Applies only to certain redemptions of shares bought with no initial sales charge.

[2] This charge is phased out over six years.

[3] This charge is eliminated after one year.

[4] Other expenses for class R5 and class R6 shares have been annualized.

[5] Performance for class R5 and class R6 shares prior to their inception (12/2/13) is derived from the historical performance of class Y shares and has not been adjusted for the lower investor servicing fees applicable to class R5 and class R6 shares; had it, returns would have been higher.