Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	VANGUARD WELLESLEY INCOME FUND
Prospectus Date	rr_ProspectusDate	Jan. 26, 2016
Admiral Shares for Participants | VANGUARD WELLESLEY INCOME FUND
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summary
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide long-term growth of income and a high and sustainable level of current income, along with moderate long-term capital appreciation.
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 Admiral 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 more taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the previous expense example, reduce the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 59% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	59.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following example is intended to help you compare the cost of investing in the Fund’s Admiral Shares with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invested $10,000 in the Fund’s shares. This example assumes that the Shares provide a return of 5% each year and that total annual fund operating expenses remain as stated in the preceding table. You would incur these hypothetical expenses whether or not you redeem your investment at the end of the given period. 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	The Fund invests approximately 60% to 65% of its assets in investment-grade fixed income securities that the advisor believes will generate a reasonable level of current income, including corporate, U.S. Treasury, and government agency bonds, as well as mortgage-backed securities. The remaining 35% to 40% of Fund assets are invested in common stocks of companies that have a history of above-average dividends or expectations of increasing dividends.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Fund is subject to the risks associated with the stock and bond markets, any of which could cause an investor to lose money. However, because fixed income securities such as bonds usually are less volatile than stocks and because the Fund invests more than half of its assets in fixed income securities, the Fund’s overall level of risk should be low to moderate. • With approximately 60% to 65% of its assets allocated to bonds, the Fund is proportionately subject to the following bond risks: interest rate risk, which is the chance that bond prices will decline because of rising interest rates; income risk, which is the chance that the Fund’s income will decline because of falling interest rates; credit risk, which is the chance that a bond issuer will fail to pay interest or principal in a timely manner or that negative perceptions of the issuer’s ability to make such payments will cause the price of that bond to decline; liquidity risk, which is the chance that the Fund may not be able to sell a security in a timely manner at a desired price; and call risk, which is the chance that during periods of falling interest rates, issuers of callable bonds may call (redeem) securities with higher coupon rates or interest rates before their maturity dates. The Fund would then lose any price appreciation above the bond’s call price and would be forced to reinvest the unanticipated proceeds at lower interest rates, resulting in a decline in the Fund’s income. Such redemptions and subsequent reinvestments would also increase the Fund’s portfolio turnover rate. For mortgage-backed securities, this risk is known as prepayment risk. • With approximately 35% to 40% of its assets allocated to stocks, the Fund is proportionately subject to the following stock risks: stock market risk, which is the chance that stock prices overall will decline; and investment style risk, which is the chance that returns from mid- and large-capitalization dividend-paying value stocks will trail returns from the overall stock market. Mid- and large-cap stocks each tend to go through cycles of doing better—or worse—than other segments of the stock market or the stock market in general. These periods have, in the past, lasted for as long as several years. Historically, mid-cap stocks have been more volatile in price than large-cap stocks because, among other things, mid-size companies are more sensitive to changing economic conditions. • The Fund is also subject to manager risk, which is the chance that poor security selection will cause the Fund to underperform relevant benchmarks or other funds with a similar investment objective. In addition, significant investments in the financial and industrial sectors subject the Fund to proportionately higher exposure to the risks of these sectors. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Lose Money [Text]	rr_RiskLoseMoney	The Fund is subject to the risks associated with the stock and bond markets, any of which could cause an investor to lose money.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Annual Total Returns
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Admiral Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Admiral Shares compare with those of a relevant market index and a composite bond/stock index, which have investment characteristics similar to those of the Fund. Keep in mind that the Fund’s past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Admiral Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Admiral Shares compare with those of a relevant market index and a composite bond/stock index, which have investment characteristics similar to those of the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-662-7447
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	vanguard.com/performance
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Keep in mind that the Fund’s past performance does not indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns — Vanguard Wellesley Income Fund Admiral Shares
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the bar chart, the highest return for a calendar quarter was 10.17% (quarter ended September 30, 2009), and the lowest return for a quarter was –6.62% (quarter ended March 31, 2009).
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for Periods Ended December 31, 2015
Admiral Shares for Participants | VANGUARD WELLESLEY INCOME FUND | Admiral Shares
Risk/Return:	rr_RiskReturnAbstract
Purchase Fee	rr_MaximumCumulativeSalesChargeOverOther	none
Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.15%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.16%
1 Year	rr_ExpenseExampleYear01	$ 16
3 Years	rr_ExpenseExampleYear03	52
5 Years	rr_ExpenseExampleYear05	90
10 Years	rr_ExpenseExampleYear10	205
1 Year	rr_ExpenseExampleNoRedemptionYear01	16
3 Years	rr_ExpenseExampleNoRedemptionYear03	52
5 Years	rr_ExpenseExampleNoRedemptionYear05	90
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 205
2006	rr_AnnualReturn2006	11.39%
2007	rr_AnnualReturn2007	5.76%
2008	rr_AnnualReturn2008	(9.79%)
2009	rr_AnnualReturn2009	16.14%
2010	rr_AnnualReturn2010	10.71%
2011	rr_AnnualReturn2011	9.74%
2012	rr_AnnualReturn2012	10.10%
2013	rr_AnnualReturn2013	9.27%
2014	rr_AnnualReturn2014	8.15%
2015	rr_AnnualReturn2015	1.35%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	10.17%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2009
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(6.62%)
1 Year	rr_AverageAnnualReturnYear01	1.35%
5 Years	rr_AverageAnnualReturnYear05	7.67%
10 Years	rr_AverageAnnualReturnYear10	7.05%
Admiral Shares for Participants | VANGUARD WELLESLEY INCOME FUND | Barclays U.S. Credit A or Better Bond Index
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.69%	[1]
5 Years	rr_AverageAnnualReturnYear05	4.25%	[1]
10 Years	rr_AverageAnnualReturnYear10	4.85%	[1]
Admiral Shares for Participants | VANGUARD WELLESLEY INCOME FUND | Wellesley Income Composite Index
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.79%	[1]
5 Years	rr_AverageAnnualReturnYear05	7.42%	[1]
10 Years	rr_AverageAnnualReturnYear10	6.24%	[1]

[1] Comparative Indexes (reflect no deduction for fees or expenses)