v3.26.1
Vanguard Total Bond Market Index Fund Investment Objectives and Goals - Admiral Prospectus [Member] - Vanguard Total Bond Market Index Fund
Dec. 31, 2025
Prospectus [Line Items]  
Risk/Return [Heading] <span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">Vanguard Total Bond Market Index Fund</span>
Objective [Heading] <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block] Vanguard Total Bond Market Index Fund (the “Fund”) seeks to track the performance of a broad, market-weighted bond index.