XML 136 R122.htm IDEA: XBRL DOCUMENT v3.8.0.1
Investment Properties - Summary of Investment Properties (Detail)
$ in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2017
TWD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
TWD ($)
Dec. 31, 2015
TWD ($)
Disclosure of detailed information about investment property [Line Items]        
Beginning balance $ 8,115      
Depreciation expense (21)   $ (19) $ (18)
Reversal of impairment loss 11 $ 0 148 142
Ending balance 8,048 $ 272 8,115  
Gross carrying amount [Member]        
Disclosure of detailed information about investment property [Line Items]        
Beginning balance 9,195   9,058 8,883
Disposal       0
Reclassification (60)   137 175
Ending balance 9,135   9,195 9,058
Accumulated depreciation, amortization and impairment [Member]        
Disclosure of detailed information about investment property [Line Items]        
Beginning balance (1,080)   (1,156) (1,262)
Depreciation expense (21)   (19) (18)
Disposal       0
Reclassification 3   (53) (18)
Reversal of impairment loss 11   148 142
Ending balance $ (1,087)   $ (1,080) $ (1,156)