Contents of Significant Accounts - Post-Employment Benefits - Additional Information (Detail) - TWD ($) $ in Millions |
8 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Aug. 31, 2024 |
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Disclosure of defined benefit plans and defined contribution plans [Line Items] | ||||
| Actual returns on plan assets | $ 244 | $ 241 | ||
| Expected pension fund contribution in 2026 | $ 83 | |||
| Weighted-average durations of defined benefit obligation | 7 years | 8 years | ||
| Defined benefit plan [member] | ||||
| Disclosure of defined benefit plans and defined contribution plans [Line Items] | ||||
| Percentages of employees' total monthly salaries and wages to pension fund | 2.00% | 2.00% | 2.00% | |
| Pension expenses | $ 29 | $ 35 | $ 45 | |
| Defined contribution plan [member] | ||||
| Disclosure of defined benefit plans and defined contribution plans [Line Items] | ||||
| Percentage of employees' monthly salary or wages as monthly contributions to defined contribution plan | 6.00% | 6.00% | 6.00% | |
| Pension expenses | $ 2,059 | $ 1,978 | $ 1,655 | |