Financial Instruments at Fair Value Through Profit or Loss (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Financial Instruments At Fair Value Through Profit Or Loss [Abstract]

Summary of Financial Instruments at Fair Value through Profit or Loss

	December 31
	2018		2019
	NT$		NT$
	(In Millions)
Financial assets-current
Mandatorily measured at FVTPL
Derivatives (not designated for hedge)
Forward exchange contract	$	—	$	—
Non-derivatives
Listed stocks - domestic		—		1
	$	—	$	1
Financial assets-noncurrent
Mandatorily measured at FVTPL
Non-derivatives
Non-listed stocks - domestic	$	293	$	511
Non-listed stocks - foreign		224		267
Forward exchange contracts	$	517	$	778
Financial liabilities-current
Held for trading
Derivatives (not designated for hedge)
Forward exchange contracts	$	1	$	—

Disclosure of Detailed Information Outstanding Derivative Contracts Not Designated for Hedge Explanatory

Outstanding forward exchange contracts not designated for hedge as of balance sheet dates were as follows:

		Maturity	Contract Amount
	Currency	Period	(In Millions)
December 31, 2018
Forward exchange contracts - buy	EUR/NT$	2019.03-06	EUR5/NT$193
Forward exchange contracts - buy	US$/NT$	2019.01	US$2/NT$62
December 31, 2019
Forward exchange contracts - buy	EUR/NT$	2020.03	EUR2/NT$51
Forward exchange contracts - buy	US$/NT$	2020.01	US$1/NT$26