| Contributions to plan by employer, net defined benefit liability (asset) | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Contributions to plan by employer, net defined benefit liability (asset) | en | http://www.xbrl.org/2009/role/negatedLabel | http://www.xbrl.org/2003/role/link |
| The decrease (increase) in net defined benefit liability (asset) resulting from contributions to a defined benefit plan by the employer. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |