| Erträge aus Direktinvestitionen [Mitglied] | de | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Direct investment properties [member] | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Immeubles de placement en direct [membre] | fr | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Directe vastgoedbeleggingen [member] | nl | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Direktinvestitionen in Immobilien | de | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Direct investment properties | en | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Immeubles de placement en direct | fr | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Directe vastgoedbeleggingen | nl | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |