Retirement Benefit Plans - Fair Value of Plan Assets by Major Categories (Detail) - TWD ($) $ in Millions |
Dec. 31, 2023 |
Dec. 31, 2022 |
|---|---|---|
| Disclosure of fair value of plan assets [abstract] | ||
| Cash | $ 1,351.8 | $ 1,337.9 |
| Equity instruments | 4,998.9 | 4,696.9 |
| Debt instruments | 2,387.2 | 2,128.1 |
| Fair value of plan assets | $ 8,737.9 | $ 8,162.9 |
| X | ||||||||||
- Definition The amount cash and cash equivalents contribute to the fair value of defined benefit plan assets. [Refer: Cash and cash equivalents; Plan assets, at fair value; Defined benefit plans [member]] Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition The amount instruments representing debt (rather than equity) contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [member]] Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The amount instruments representing equity (rather than debt) contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [member]] Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]] Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|