Revenue (Tables)

12 Months Ended

Dec. 31, 2018

Revenue [Abstract]

Disclosure Of Detailed Information On Revenue Explanatory

2018

	Year Ended December 31
	2018
	NT$
	(In Millions)
Revenue from contracts with customers	$	214,461
Other revenues
Rental income		640
Other		382
		1,022
Total	$	215,483

Summary of Disaggregation of Revenue

a. Disaggregation of revenue

For the year ended December 31, 2018

	Domestic Fixed Communi- cations Business		Mobile Communi- cations Business		Internet Business		International Fixed Communi- cations Business		Others		Total
	NT$		NT$		NT$		NT$		NT$		NT$
	(In Millions)
Main Products and Service Revenues
Mobile services revenue	$	—	$	63,906	$	—	$	—	$	—	$	63,906
Sales of products		1,731		35,702		4		251		3,601		41,289
Local telephone and domestic long distance telephone    services revenue		29,996		—		—		—		—		29,996
Broadband access and domestic leased line services    revenue		22,453		—		—		—		—		22,453
Data Communications internet services revenue		—		—		21,137		—		—		21,137
International network and leased telephone services    revenue		—		—		—		8,724		—		8,724
Others		11,923		1,269		8,509		4,449		806		26,956
	$	66,103	$	100,877	$	29,650	$	13,424	$	4,407	$	214,461

Summary of Contract Balances

b. Contract balances

	December 31
	2018
	NT$
	(In Millions)
Trade notes and accounts receivable (Note 11)	$	30,076
Contract assets
Products and service bundling	$	7,123
Other		109
Less : Loss allowance		(19	)
	$	7,213
Current	$	4,869
Noncurrent		2,344
	$	7,213
Contract liabilities
Telecommunications business	$	8,193
Project business		4,508
Products and service bundling		106
Other		476
	$	13,283
Current	$	10,688
Noncurrent		2,595
	$	13,283

Summary of Changes in Contract Assets and Contract Liabilities

Significant changes of contract assets and liabilities recognized resulting from product and service bundling were as follows:

	Year Ended December 31
	2018
	NT$
	(In Millions)
Contract assets
Net increase of customer contracts	$	4,126
Reclassified to trade receivables		(7,532	)
	$	(3,406	)
Contract liabilities
Net increase of customer contracts	$	16
Recognized as revenues		(194	)
	$	(178	)

Summary of Revenue Recognized

Revenue recognized for the period that was included in the contract liability at the beginning of the period was as follows:

	Year Ended December 31
	2018
	NT$
	(In Millions)
Telecommunications business	$	7,157
Project business		627
Others		324
	$	8,108

Summary of Incremental Costs of Obtaining Contracts

c. Incremental costs of obtaining contracts

	December 31
	2018
	NT$
	(In Millions)
Noncurrent
Incremental costs of obtaining contracts	$	1,335