Inventories - Summary of Inventories (Detail) $ in Millions, $ in Millions	Dec. 31, 2020 TWD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 TWD ($)
Classes of current inventories [abstract]
Finished goods	$ 21,705.6		$ 8,924.5
Work in process	91,672.9		51,969.1
Raw materials	14,716.0		16,552.3
Supplies and spare parts	9,258.9		5,535.3
Inventories, total	$ 137,353.4	$ 4,891.5	$ 82,981.2

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A classification of current inventory representing the amount of goods that have completed the production process and are held for sale in the ordinary course of business. [Refer: Inventories]

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The amount of current inventories. [Refer: Inventories]

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A classification of current inventory representing the amount of assets to be consumed in the production process or in the rendering of services. [Refer: Inventories]

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A classification of current inventory representing the amount of interchangeable parts that are kept in an inventory and are used for the repair or replacement of failed parts. [Refer: Inventories]

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A classification of current inventory representing the amount of assets currently in production, which require further processes to be converted into finished goods or services. [Refer: Current finished goods; Inventories]

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