dei_DocumentType

Other

dei_EntityRegistrantName

Vanguard Valley Forge Funds

Amendment Flag

dei_AmendmentFlag

false

Document Effective Date

dei_DocumentEffectiveDate

Jan. 15, 2013

Risk/Return:

rr_RiskReturnAbstract

StrategyNarrative

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The Fund employs an indexing investment approach designed to track the performance of two benchmark indexes. The Fund invests by sampling its target indexes, meaning that it holds a range of securities that, in the aggregate, approximates the full indexes in terms of key characteristics.

With approximately 60% of its assets, the Fund seeks to track the investment performance of the CRSP US Total Market Index, which represents approximately 100% of the investable U.S. stock market and includes large-, mid-, small-, and micro-cap stocks regularly traded on the New York Stock Exchange and Nasdaq. The Fund typically holds 1,200-1,300 of the stocks in the Index and a representative sample of the remaining stocks.

With approximately 40% of its assets, the Fund seeks to track the investment performance of the Barclays U.S. Aggregate Float Adjusted Index, which represents a wide spectrum of public, investment-grade, taxable, fixed income securities in the United States-including government, corporate, and international dollar-denominated bonds, as well as mortgage-backed and asset-backed securities, all with maturities of more than 1 year. At least 80% of the bond portion of the Fund is invested in bonds held in the Barclays U.S. Aggregate Float Adjusted Index, and all of the Fund's bond holdings are selected through the sampling process. The bond portion of the Fund maintains a dollar-weighted average maturity consistent with that of the Index, which ranges between 5 and 10 years.

Prospectus Date

rr_ProspectusDate

Apr. 26, 2012

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

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 Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the share classes presented compare with those of relevant market indexes and other comparative indexes, which have investment characteristics similar to those of the Fund. Keep in mind that the Fund's past performance (before and after taxes) 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.

Risk/Return:

rr_RiskReturnAbstract

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of two benchmark indexes. The Fund invests by sampling its target indexes, meaning that it holds a range of securities that, in the aggregate, approximates the full indexes in terms of key characteristics.

With approximately 60% of its assets, the Fund seeks to track the investment performance of the CRSP US Total Market Index, which represents approximately 100% of the investable U.S. stock market and includes large-, mid-, small-, and micro-cap stocks regularly traded on the New York Stock Exchange and Nasdaq. The Fund typically holds 1,200-1,300 of the stocks in the Index and a representative sample of the remaining stocks.

With approximately 40% of its assets, the Fund seeks to track the investment performance of the Barclays U.S. Aggregate Float Adjusted Index, which represents a wide spectrum of public, investment-grade, taxable, fixed income securities in the United States-including government, corporate, and international dollar-denominated bonds, as well as mortgage-backed and asset-backed securities, all with maturities of more than 1 year. At least 80% of the bond portion of the Fund is invested in bonds held in the Barclays U.S. Aggregate Float Adjusted Index, and all of the Fund's bond holdings are selected through the sampling process. The bond portion of the Fund maintains a dollar-weighted average maturity consistent with that of the Index, which ranges between 5 and 10 years.

Prospectus Date

rr_ProspectusDate

Apr. 26, 2012

Bar Chart Narrative

rr_BarChartNarrativeTextBlock

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 Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the share classes presented compare with those of relevant market indexes and other comparative indexes, which have investment characteristics similar to those of the Fund. Keep in mind that the Fund's past performance (before and after taxes) 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.

Risk/Return:

rr_RiskReturnAbstract

StrategyNarrative

rr_StrategyNarrativeTextBlock

The Fund employs an indexing investment approach designed to track the performance of two benchmark indexes. The Fund invests by sampling its target indexes, meaning that it holds a range of securities that, in the aggregate, approximates the full indexes in terms of key characteristics.

With approximately 60% of its assets, the Fund seeks to track the investment performance of the CRSP US Total Market Index, which represents approximately 100% of the investable U.S. stock market and includes large-, mid-, small-, and micro-cap stocks regularly traded on the New York Stock Exchange and Nasdaq. The Fund typically holds 1,200-1,300 of the stocks in the Index and a representative sample of the remaining stocks.

With approximately 40% of its assets, the Fund seeks to track the investment performance of the Barclays U.S. Aggregate Float Adjusted Index, which represents a wide spectrum of public, investment-grade, taxable, fixed income securities in the United States-including government, corporate, and international dollar-denominated bonds, as well as mortgage-backed and asset-backed securities, all with maturities of more than 1 year. At least 80% of the bond portion of the Fund is invested in bonds held in the Barclays U.S. Aggregate Float Adjusted Index, and all of the Fund's bond holdings are selected through the sampling process. The bond portion of the Fund maintains a dollar-weighted average maturity consistent with that of the Index, which ranges between 5 and 10 years.