XML 161 R143.htm IDEA: XBRL DOCUMENT v3.8.0.1
Finance Costs - Summary of Finance Costs (Detail)
$ in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2017
TWD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
TWD ($)
Dec. 31, 2015
TWD ($)
Material income and expense [abstract]        
Interest expense, Corporate bonds $ 2,563.6   $ 3,014.7 $ 3,103.7
Interest expense, Bank loans 766.6   291.2 74.6
Interest expense, Finance leases       11.7
Interest expense, Others 0.1   0.2 0.3
Finance costs $ 3,330.3 $ 112.4 $ 3,306.1 $ 3,190.3