Shareholder Report, Line Graph (Details) |
6 Months Ended |
|---|---|
Jun. 30, 2026 | |
| C000009559 [Member] | |
| Account Value [Line Items] | |
| Line Graph and Table Measure Name | Davis Real Estate Portfolio |
| Standard & Poor's 500 Index [Member] | |
| Account Value [Line Items] | |
| Line Graph and Table Measure Name | S&P 500 Index |
| Wilshire U S Real Estate Securities Index [Member] | |
| Account Value [Line Items] | |
| Line Graph and Table Measure Name | Wilshire U.S. Real Estate Securities Index |