| 鉄道・運輸機構長期未払金 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 鉄道・運輸機構長期未払金、固定負債、鉄道事業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Long-term accounts payable to Japan railway construction, transport and technology agency | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Long-term accounts payable to Japan railway construction, transport and technology agency-NCL-RWY | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |