Notes and Accounts Receivable, Net (Tables)

12 Months Ended

Dec. 31, 2017


	December 31, 2016			December 31, 2017
	NT$			NT$
	(In Millions)			(In Millions)
Notes and accounts receivable	$	128,815.4		$	121,605.0
Allowance for doubtful receivables		(480.1	)		(471.8	)


Notes and accounts receivable, net	$	128,335.3		$	121,133.2

Aging analysis of notes and accounts receivable, net


	December 31, 2016		December 31, 2017
	NT$		NT$
	(In Millions)		(In Millions)
Neither past due nor impaired	$	108,411.4	$	105,295.2
Past due but not impaired
Past due within 30 days		15,017.8		13,984.1
Past due 31-60 days		1,844.8		929.7
Past due 61-120 days		3,061.3		582.8
Past due over 121 days		—		341.4


	$	128,335.3	$	121,133.2

Movements of the allowance for doubtful receivables


	Individually Assessed for Impairment			Collectively Assessed for Impairment			Total
	NT$			NT$			NT$
	(In Millions)			(In Millions)			(In Millions)
Balance at January 1, 2015	$	8.1		$	478.6		$	486.7
Provision		28.6			4.8			33.4
Reversal/Write-off		(29.1	)		(4.7	)		(33.8	)
Effect of acquisition of subsidiary		1.8			—			1.8
Effect of exchange rate changes		0.8			(0.7	)		0.1


Balance at December 31, 2015	$	10.2		$	478.0		$	488.2


	Individually Assessed for Impairment			Collectively Assessed for Impairment			Total
	NT$			NT$			NT$
	(In Millions)			(In Millions)			(In Millions)
Balance at January 1, 2016	$	10.2		$	478.0		$	488.2
Provision		—			0.3			0.3
Reversal/Write-off		(8.4	)		—			(8.4	)


Balance at December 31, 2016	$	1.8		$	478.3		$	480.1


Balance at January 1, 2017	$	1.8		$	478.3		$	480.1
Reversal/Write-off		(1.8	)		(6.3	)		(8.1	)
Effect of exchange rate changes		—			(0.2	)		(0.2	)


Balance at December 31, 2017	$	—		$	471.8		$	471.8

Aging analysis of accounts receivable that is individually determined as impaired