Employee Benefits - Remeasurements of Net Defined Benefit Liabilities (Assets) Included in Other Comprehensive Income (Loss) (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]
Group's share of associates regarding remeasurements	₩ 238	₩ 20	₩ 441
Related income tax	(35,235)	(1,169)	9,259
Remeasurements of net defined benefit liabilities (assets) [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Beginning balance	(165,969)	(170,510)	(163,950)
Actuarial profit or loss arising from: Experience adjustment	43,644	56,225	(48,890)
Actuarial profit or loss arising from: Demographic assumptions	(19,952)	(15,379)	(7,702)
Actuarial profit or loss arising from: Financial assumptions	113,772	(12,961)	56,706
Return on plan assets	(8,824)	(22,195)	(16,374)
Group's share of associates regarding remeasurements	238	20	441
Remeasurements	128,878	5,710	(15,819)
Related income tax	(35,235)	(1,169)	9,259
Ending balance	₩ (72,326)	₩ (165,969)	₩ (170,510)

The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions that result in remeasurements of the net defined benefit liability (asset). Demographic assumptions deal with matters such as: (a) mortality; (b) rates of employee turnover, disability and early retirement; (c) the proportion of plan members with dependants who will be eligible for benefits; (d) the proportion of plan members who will select each form of payment option available under the plan terms; and (e) claim rates under medical plans. [Refer: Net defined benefit liability (asset)]

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- Definition

The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)]

+ References

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- Definition

The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from experience adjustments that result in remeasurements of the net defined benefit liability (asset). Experience adjustments deal with the effects of differences between the previous actuarial assumptions and what has actually occurred. [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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 amount of income tax relating to amounts recognised in other comprehensive income in relation to remeasurements of defined benefit plans. [Refer: Other comprehensive income; Reserve of remeasurements of defined benefit plans; Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The amount of other comprehensive income that will not be reclassified to profit or loss, before tax. [Refer: Other comprehensive income]

+ References

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- Definition

A component of equity representing the accumulated remeasurements of defined benefit plans. [Refer: Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

The decrease (increase) in the net defined benefit liability (asset) resulting from the return on plan assets, excluding amounts included in interest income or expense. The return on plans assets is interest, dividends and other revenue derived from the plan assets, together with realised and unrealised gains or losses on the plan assets, less any costs of managing plan assets and less any tax payable by the plan itself, other than tax included in the actuarial assumptions used to measure the present value of the defined benefit obligation. [Refer: Plan assets [member]; Net defined benefit liability (asset); Actuarial assumptions [member]; Interest expense (income), net defined benefit liability (asset)]

+ References

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- Definition

Share of the other comprehensive income of associates and joint ventures accounted for using the equity method that will not be reclassified to profit or loss, before tax.

+ References

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