S000012717 [Member] 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 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| GLOBAL REAL ESTATE INDEX FUND | GLOBAL REAL ESTATE INDEX FUND | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 10.42% | 2.68% | 10.02% | (24.32%) | 22.71% | (8.38%) | 23.15% | (6.68%) | 14.36% | 4.35% |