Retirement Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Amounts Recognized in Consolidated Statements of Profit or Loss and Other Comprehensive Income of Defined Benefit Plans

Amounts recognized in respect of these defined benefit plans were as follows:


	Years Ended December 31
	2015			2016		2017
	NT$			NT$		NT$
	(In Millions)			(In Millions)		(In Millions)
Current service cost	$	134.5		$	132.8	$	145.0
Net interest expense		144.4			139.4		126.5


Components of defined benefit costs recognized in profit or loss		278.9			272.2		271.5

Remeasurement on the net defined benefit liability:

Return on plan assets (excluding amounts included in net interest expense)		(13.7	)		45.7		29.3
Actuarial loss arising from experience adjustments		297.1			38.2		483.9
Actuarial loss (gain) arising from changes in financial assumptions		544.3			694.6		(258.5	)
Actuarial loss arising from changes in demographic assumptions		—			278.7		—

Components of defined benefit costs recognized in other comprehensive income		827.7			1,057.2		254.7


Total	$	1,106.6		$	1,329.4	$	526.2

Pension Costs of Defined Benefit Plans Recognized in Profit or Loss by Categories

The pension costs of the aforementioned defined benefit plans were recognized in profit or loss by the following categories:


	Years Ended December 31
	2015		2016		2017
	NT$		NT$		NT$
	(In Millions)		(In Millions)		(In Millions)
Cost of revenue	$	189.5	$	177.0	$	175.3
Research and development expenses		81.3		73.4		75.3
General and administrative expenses		3.1		17.4		16.7
Marketing expenses		5.0		4.4		4.2


	$	278.9	$	272.2	$	271.5

Funded Status of Defined Benefit Plans, Movements in Present Value of Defined Benefit Obligation and Fair Value of Plan Assets

The amounts arising from the defined benefit obligation of the Company were as follows:


	December 31, 2016			December 31, 2017
	NT$			NT$
	(In Millions)			(In Millions)
Present value of defined benefit obligation	$	12,480.5		$	12,774.6
Fair value of plan assets		(3,929.1	)		(3,923.9	)


Net defined benefit liability	$	8,551.4		$	8,850.7

Fair Value of Plan Assets by Major Categories

The fair value of the plan assets by major categories at the end of reporting period was as follows:


	December 31, 2016		December 31, 2017
	NT$		NT$
	(In Millions)		(In Millions)
Cash	$	818.4	$	707.5
Equity instruments		1,853.0		1,993.3
Debt instruments		1,257.7		1,223.1


	$	3,929.1	$	3,923.9

Principal Assumptions for Actuarial Valuation of Present Value of Defined Benefit Obligation

The actuarial valuations of the present value of the defined benefit obligation were carried out by qualified actuaries. The principal assumptions of the actuarial valuation were as follows:


	Measurement Date
	December 31, 2016		December 31, 2017
Discount rate		1.50%		1.65%
Future salary increase rate		3.00%		3.00%

Present value of defined benefit obligation [member]

Funded Status of Defined Benefit Plans, Movements in Present Value of Defined Benefit Obligation and Fair Value of Plan Assets

Movements in the present value of the defined benefit obligation were as follows:


	Years Ended December 31
	2015			2016			2017
	NT$			NT$			NT$
	(In Millions)			(In Millions)			(In Millions)
Balance, beginning of year	$	10,265.3		$	11,318.1		$	12,480.5
Current service cost		134.5			132.8			145.0
Interest expense		228.4			213.0			185.6
Remeasurement losses (gains):
Actuarial loss arising from experience adjustments		297.1			38.2			483.9
Actuarial loss (gain) arising from changes in financial assumptions		544.3			694.6			(258.5	)
Actuarial loss arising from changes in demographic assumptions		—			278.7			—
Benefits paid from plan assets		(146.1	)		(194.9	)		(261.9	)
Benefits paid directly by the Company		(5.4	)		—			—


Balance, end of year	$	11,318.1		$	12,480.5		$	12,774.6

Fair value of plan assets [member]

Funded Status of Defined Benefit Plans, Movements in Present Value of Defined Benefit Obligation and Fair Value of Plan Assets

Movements in the fair value of the plan assets were as follows:


	Years Ended December 31
	2015			2016			2017
	NT$			NT$			NT$
	(In Millions)			(In Millions)			(In Millions)
Balance, beginning of year	$	3,697.5		$	3,870.1		$	3,929.1
Interest income		84.0			73.6			59.1
Remeasurement gains (losses) :
Return on plan assets (excluding amounts included in net interest expense)		13.7			(45.7	)		(29.3	)
Contributions from employer		221.0			226.0			226.9
Benefits paid from plan assets		(146.1	)		(194.9	)		(261.9	)


Balance, end of year	$	3,870.1		$	3,929.1		$	3,923.9