Spliced Bloomberg U S Treasury 1 3 Year C000080842 Index [Member] Two to 3 Years [Member] One to 2 Years [Member] Under 1 Year [Member] Spliced Bloomberg U S Treasury 1 3 Year Index [Member] Other Assets and Liabilities Net [Member] Bloomberg U S Aggregate Float Adjusted Index [Member] C000080842 [Member] Institutional Shares C000080841 [Member] Admiral Shares C000080843 [Member] ETF Shares C000080846 [Member] C000080844 [Member] C000080845 [Member] Spliced Bloomberg U S Treasury 3 10 Year Index [Member] Two To 4 Years [Member] Four To 6 Years [Member] Six To 8 Years [Member] Eight To 10 Years [Member] Spliced Bloomberg U S Treasury 3 10 Year C000080845 Index [Member] Spliced Bloomberg U S Long Treasury C000080848 Index [Member] Over 25 Years [Member] Twenty To 25 Years [Member] Fifteen To 20 Years [Member] Ten To 15 Years [Member] Spliced Bloomberg U S Long Treasury Index [Member] C000080848 [Member] C000080847 [Member] C000080849 [Member] US Government Corporations and Agencies Securities [Member] Energy Sector [Member] Financial Services Sector [Member] Healthcare Sector [Member] Real Estate Sector [Member] Technology Sector [Member] C000080852 [Member] C000080850 [Member] C000080851 [Member] Bloomberg U S 1 5 Year Corporate Bond Index [Member] Bloomberg U S Aggregate Float Adjusted C000080851 Index [Member] Bloomberg U S 1 5 Year Corporate Bond C000080851 Index [Member] Bloomberg U S Aggregate Float Adjusted C000080850 Index [Member] Bloomberg U S 1 5 Year Corporate Bond C000080850 Index [Member] Bloomberg U S 5 10 Year Corporate Bond C000080853 Index [Member] Bloomberg U S Aggregate Float Adjusted C000080854 Index [Member] Bloomberg U S 5 10 Year Corporate Bond C000080854 Index [Member] Bloomberg U S 5 10 Year Corporate Bond Index [Member] C000080854 [Member] C000080853 [Member] C000080855 [Member] C000080858 [Member] C000080856 [Member] C000080857 [Member] Bloomberg U S 10 Year Corporate Bond Index [Member] Bloomberg U S 10 Year Corporate Bond C000080857 Index [Member] Bloomberg U S MBS Float Adjusted C000080860 Index [Member] Thirty To 40 Years [Member] Twenty To 30 Years [Member] Ten To 20 Years [Member] Zero To 10 Years [Member] Bloomberg U S MBS Float Adjusted Index [Member] C000080860 [Member] C000080859 [Member] C000080861 [Member] C000195056 [Member] Fund Level Bloomberg U S Corporate Bond Index [Member] Vanguard Total International Bond ETF [Member] Vanguard Total Bond Market ETF [Member] Bloomberg Global Aggregate Float Adjusted Composite Index [Member] Bloomberg Global Aggregate Float Adjusted Index [Member] C000203194 [Member] Investment Type [Axis] Net Assets Investment Company Portfolio Turnover No Trading Symbol Flag