Employee Benefits - Changes in Present Value of Defined Benefit Obligations (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure of net defined benefit liability (asset) [Line Items]
Current service cost	₩ 194,469	₩ 204,668	₩ 195,850
Past service cost	(32,006)	(25,749)
Interest cost	534	961	2,391
Defined benefit obligations [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Opening defined benefit obligations	1,595,423	1,562,424
Current service cost	194,469	204,668
Past service cost	(32,006)	(25,749)
Interest cost	42,360	49,145
Remeasurements (before tax)	(137,464)	(27,885)
Benefit payments	(95,675)	(88,562)
Curtailment of plans	(80,470)	(74,459)
Net transfers from (to) related parties	(5,349)	(4,217)
Others	51	58
Closing defined benefit obligations	₩ 1,481,339	₩ 1,595,423	₩ 1,562,424

The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)]

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No definition available.

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The decrease (increase) in a net defined benefit liability (asset) resulting from the remeasurement of that net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)]

+ References

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The decrease (increase) in the net defined benefit liability (asset) resulting from settlements. Settlements are transactions that eliminate all further legal or constructive obligations for part or all of the benefits provided under a defined benefit plan, other than a payment of benefits to, or on behalf of, employees that is set out in the terms of the plan and included in the actuarial assumptions. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]; Actuarial assumptions [member]]

+ References

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The increase (decrease) in the net defined benefit liability (asset) resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Net defined benefit liability (asset)]

+ References

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The increase (decrease) in the net defined benefit liability (asset) resulting from the passage of time. [Refer: Interest expense; Net defined benefit liability (asset)]

+ References

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- Definition

The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

+ References

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The increase (decrease) in the net defined benefit liability (asset) resulting from past service cost. Past service cost is the change in the present value of the defined benefit obligation for employee service in prior periods, resulting from a plan amendment (the introduction or withdrawal of, or changes to, a defined benefit plan) or a curtailment (a significant reduction by the entity in the number of employees covered by a plan). [Refer: Net defined benefit liability (asset); Defined benefit plans [member]]

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The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan. [Refer: Net defined benefit liability (asset)]

+ References

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No definition available.

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