Significant Related Party Transactions - Additional Information (Detail) - TWD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Disclosure of transactions between related parties [line items] | ||
| Cash dividends receivable | $ 619 | $ 0 |
| Domestic [member] | Bottom of range [member] | ||
| Disclosure of transactions between related parties [line items] | ||
| Collection periods for accounts receivables | month-end 30 days | |
| Domestic [member] | Top of range [member] | ||
| Disclosure of transactions between related parties [line items] | ||
| Collection periods for accounts receivables | month-end 60 days | |
| Overseas [member] | Bottom of range [member] | ||
| Disclosure of transactions between related parties [line items] | ||
| Collection periods for accounts receivables | month-end 30 days or net 30 days | |
| Overseas [member] | Top of range [member] | ||
| Disclosure of transactions between related parties [line items] | ||
| Collection periods for accounts receivables | month-end 60 days or net 60 days |