Vanguard Mid-Cap Index Fund Annual Total Returns |
12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Investor Prospectus [Member] | Vanguard Mid-Cap Index Fund | Investor Shares | ||||||||
| Prospectus [Line Items] | ||||||||
| Annual Return [Percent] | 11.53% | 15.09% | 15.84% | (18.80%) | 24.36% | 18.10% | 30.86% | (9.34%) |