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Revenue - Summary of Contract Balances (Detail) $ in Millions, $ in Millions | Dec. 31, 2020 TWD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 TWD ($) | Jan. 01, 2019 TWD ($)
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Disclosure Of Contract Balance [Abstract] |  |  |  |
Trade notes and accounts receivable, net | $ 22,622 | $ 806 | $ 26,408 | $ 30,076
Contract assets |  |  |  |
Products and service bundling | 7,232 |  | 6,943 | 7,123
Others | 612 |  | 116 | 109
Less : Loss allowance | (18) |  | (17) | (19)
Contract assets | 7,826 |  | 7,042 | 7,213
Current Contract Assets | 5,331 | 190 | 4,441 | 4,869
Noncurrent Contract Assets | 2,495 | 89 | 2,601 | 2,344
Contract liabilities |  |  |  |
Telecommunications business | 13,602 |  | 12,772 | 8,193
Project business | 6,687 |  | 10,360 | 4,508
Products and service bundling | 16 |  | 39 | 106
Others | 421 |  | 510 | 476
Contract liabilities | 20,726 |  | 23,681 | 13,283
Current Contract Liabilities | 13,437 | 479 | 16,840 | 10,688
Noncurrent Contract Liabilities | 7,289 | $ 260 | 6,841 | 2,595
Contract liabilities | $ 20,726 |  | $ 23,681 | $ 13,283

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- Definition Telecommunications business. + References No definition available. + Details
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- Definition The amount of an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer, when that right is conditioned on something other than the passage of time (for example, the entity’s future performance). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 105 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_105&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 116 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_116_a&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The amount of an entity’s obligation to transfer goods or services to a customer for which the entity has received consideration (or the amount is due) from the customer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 105 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_105&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 116 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_116_a&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The amount of current contract assets. [Refer: Contract assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 105 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_105&doctype=Standard -URIDate 2020-01-01 + Details
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