Segment Information - Geographic Information (Detail) $ in Millions, $ in Millions	12 Months Ended
Dec. 31, 2024 TWD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 TWD ($)	Dec. 31, 2022 TWD ($)
Disclosure Of Geographical Areas [Line Items]
Revenues	$ 229,968	$ 7,013	$ 223,199	$ 216,739
Taiwan,ROC[Member]
Disclosure Of Geographical Areas [Line Items]
Revenues	220,398		215,265	209,727
Overseas [Member]
Disclosure Of Geographical Areas [Line Items]
Revenues	$ 9,570		$ 7,934	$ 7,012

The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ Details