| Disposals and retirements, intangible assets other than goodwill | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Total disposals and retirements, intangible assets other than goodwill | en | http://www.xbrl.org/2009/role/negatedTotalLabel | http://www.xbrl.org/2003/role/link |
| The decrease in intangible assets other than goodwill resulting from disposals and retirements. [Refer: Intangible assets other than goodwill] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |