S000019579 [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 |
|
| World Selection Index Fund | Class K | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 21.02% | 17.29% | 25.44% | (19.37%) | 24.71% | 15.50% | 28.28% | (7.62%) | 21.20% | 7.52% |