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Net Defined Benefit Liabilities - Summary of Sensitivity of the Defined Benefit Obligations (Detail) ₩ in Millions	Dec. 31, 2017 KRW (₩)
Discount rate [Member]
Disclosure of sensitivity analysis for actuarial assumptions [Line items]
Percentage changes in assumption	0.50%
Effect on defined benefit obligation, increase in assumption	₩ (62,000)
Effect on defined benefit obligation, decrease in assumption	₩ 76,560
Salary growth rate [Member]
Disclosure of sensitivity analysis for actuarial assumptions [Line items]
Percentage changes in assumption	0.50%
Effect on defined benefit obligation, increase in assumption	₩ 71,273
Effect on defined benefit obligation, decrease in assumption	₩ (57,848)

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

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- Definition

The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

+ References

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- Definition

The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

+ References

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- Definition

Percentage of reasonably possible increase decrease in actuarial assumption.

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