| Indirekte Immobilieninvestitionen [Mitglied] | de | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Indirect investment properties [member] | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Immeubles de placement indirect [membre] | fr | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Indirecte vastgoedbeleggingen [member] | nl | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Indirekte Immobilieninvestitionen | de | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Indirect investment properties | en | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Immeubles de placement indirect | fr | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Indirecte vastgoedbeleggingen | nl | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |