| Property, plant and equipment under operating leases [member] | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Concept not required as it has an expiry date of 01-01-2019 | en | http://www.xbrl.org/2009/role/deprecatedLabel | http://www.xbrl.org/2003/role/link |
| 2019-01-01 | en | http://www.xbrl.org/2009/role/deprecatedDateLabel | http://www.xbrl.org/2003/role/link |
| This member stands for a class of property, plant and equipment representing assets that are leased out under operating leases. [Refer: Property, plant and equipment] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |