S000073358 [Member] Average Annual Total Returns |
12 Months Ended | 51 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
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| Russell 1000® Index | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | [1] | 17.37% | 11.97% | |
| S&P 500 Index | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | [1] | 17.88% | 12.78% | |
| Northern Trust ESG & Climate US Large Cap Core Index℠ | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | [1] | 14.62% | 11.29% | |
| FlexShares ESG & Climate US Large Cap Core Index Fund | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 14.49% | 11.20% | ||
| Performance Inception Date | Sep. 20, 2021 | |||
| FlexShares ESG & Climate US Large Cap Core Index Fund | After Taxes on Distributions | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 14.16% | 10.84% | ||
| FlexShares ESG & Climate US Large Cap Core Index Fund | After Taxes on Distributions and Sales | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 8.75% | 8.77% | ||
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